1. Introduction · Web view1.1. The bycatch problem Bycatch can be defined as the incidental...

Sustainable Management of Bycatch in Latin America and Caribbean Trawl Fisheries

REBYC-II LAC - SURINAME

Bycatch and discards in Suriname trawl fisheries (2012 – 2017)

a baseline study

- December 2017 -

Pieter Meeremans1, Yolanda Babb-Echteld2 and Tomas Willems3

1Technical Project Assistant REBYC-II LAC2Senior Fisheries Officer and National Focal Point REBYC-II LAC3National Project Coordinator REBYC-II LAC

Ministry of Agriculture, Animal Husbandry and Fisheries (LVV), Fisheries Department

Cornelis Jongbawstraat 50, Paramaribo, Suriname

Contact: [email protected]

mailto:[email protected]

Table of Contents

1. Introduction................................................................................................................................2

1.1. The bycatch problem..........................................................................................................2

1.2. Bottom trawl fisheries in Suriname.....................................................................................3

1.3. Aim......................................................................................................................................4

2. Methods.....................................................................................................................................5

1.2. The seabob trawl fishery.....................................................................................................5

2.2. The shrimp trawl fishery......................................................................................................8

2.3. The finfish trawl fishery.......................................................................................................9

3. Results.....................................................................................................................................12

3.1. The seabob trawl fishery...................................................................................................12

3.1.1. General catch and bycatch characteristics.................................................................12

3.1.2. Target catch and bycatch composition and sizes.......................................................14

3.2. The shrimp trawl fishery....................................................................................................22


3.2.2. Catch and bycatch composition and sizes.................................................................24

3.3. The finfish trawl fishery.....................................................................................................29


3.3.2. Catch and bycatch composition and sizes.................................................................31

4. Discussion...............................................................................................................................43

4.1. Seabob trawl fishery.........................................................................................................43

4.2. Shrimp trawl fishery..........................................................................................................44

4.2. Finfish trawl fishery...........................................................................................................47

4.4. Comparison of the three Suriname trawl fisheries............................................................49

4.5. Some aspects concerning bycatch management and discard reduction..........................52

5. References..............................................................................................................................54

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1. Introduction1.1. The bycatch problem

Bycatch can be defined as the incidental capture of non-target species (OECD, 2001). Part

of the bycatch, represented by specimens of economic importance and sufficient

commercial size, will be retained (Branco et al., 2015). The rest of the bycatch, often dying

or dead, is returned to the sea or ‘discarded’. Discards consist mainly of small and low value

‘trash’ fish and invertebrates, but it may also include seabirds and species of conservation

concern, such as elasmobranchs and sea turtles (Davies et al., 2009; LVV & FAO, 2016).

Bycatch is considered a serious problem, as it raises ecological, economic and social

issues. Discarded bycatch does not only impact the populations of the captured species, but

of entire marine ecosystems. Especially when key stone species are involved, ecosystems

can become unbalanced and degraded (Zimmerhackel et al., 2015). In addition, a lot of

bycatch species, like marine mammals, elasmobranchs, seabirds and sea turtles have

become threatened or endangered, and this partly due to the activity of trawling. As some of

these species belong to the highest trophic levels, their removal can seriously impact the

marine environment (Hall et al., 2000; Earys, 2007).

Bycatch also contributes to the decline of fish stocks, since juveniles of the target species

are discarded, often dead, and as such are not able to reproduce. Throwing overboard

undersized individuals of commercial valuable species equals discarding future income

(Zimmerhackel et al., 2015). More bycatch can also reduce tow duration and cause longer

sorting time, cause damage to the codend, and decrease the quality of the target species,

factors that increase the costs (Earys, 2007).

Many coastal communities depend on fish and seafood as source of proteins and essential

micronutrients. Fish represents about 17 % of the world population’s intake of animal protein

(FAO, 2016) and even more than 50 % in several developing states (FAO, 2009).

Discarding fish is generally considered as a waste of natural resources (Hall et al., 2000;

Kelleher, 2005; Earys, 2007) and returning fish to the sea implicates also removing fish from

people’s diets. As such, since often poor countries are being affected, serious health

problems can arise (Love et al., 2015; Pilling et al., 2015).

Food loss could be reduced by retaining juveniles and trash fish and bringing it to market.

However, it’s possible this will increase the amount of bycatch, as fishermen will deliberately

3

catch these ‘discards’ when target catches are poor. Therefore, measures should be taken

first to reduce the amount of bycatch. Juveniles are then given the opportunity to become

adults and thus play a more important role in assuring food security (Eayrs, 2007).

1.2. Bottom trawl fisheries in SurinameBycatch is especially known to occur in bottom trawl fisheries (Davies et al., 2009; Suuronen

et al., 2012). Bottom trawling is one of the most widespread fishing techniques in the world,

but it is also considered as the most wasteful one (Gillett, 2008), with bycatch rates up to 95

% of the total catch (Davies et al., 2009). In Suriname, bottom trawlers represent a major

component of the country’s marine fisheries, and target both shrimp and finfish. According to

the target species, three bottom trawling fleets are discerned: seabob trawling, shrimp

trawling and finfish trawling.

The seabob trawl fishery targets Xiphopenaeus kroyeri (seabob). The smaller

Nematopalaemon schmitti (whitebelly shrimp) might also be present in the catches and is

processed together with X. kroyeri. The fleet exists out of 22 licensed vessels. The fishery

lands between 6,000 and 10,000 tons annually, most of which is exported (LVV Fisheries

Department, 2013).

The shrimp trawl fishery targets large sea shrimp like Penaeus subtilis (brown shrimp),

Penaeus brasiliensis (pink spotted shrimp or ‘hopper’), Penaeus notialis (pink shrimp) and

Penaeus schmitti (white shrimp). The fishery contains 22 licensed vessels and lands

between 400 and 600 tons annually. The shrimp are mainly exported to Europe and the

USA (LVV Fisheries Department, 2013).

The finfish or multi-species bottom trawl fishery targets different demersal fishes like

Cynoscion virescens (green weakfish/trout), Micropogonias furnieri (whitemouth croaker),

Sphyraena guachancho (barracuda), Lutjanus purpureus (red snapper), Lutjanus synagris

(lane snapper), Orthopristis ruber (corocoro grunt/black snapper), Trichiurus lepturus

(largehead hairtail), Cynoscion jamaicensis/similis (Jamaican and tonkin weakfish/witwitie)

and Notarius grandicassis (poes/Thomas sea catfish). Between 6,000 and 8,000 tons of fish

are landed annually, most of which is exported to Europe, the USA and the Caribbean. At

present, 23 licenses have been issued for this fishery (LVV Fisheries Department, 2013).

4

1.3. AimDespite efforts to reduce bycatch and discards in the Suriname trawl fisheries, bycatch is

still a major concern in all three trawling sub-sectors. The Suriname fisheries management

(2014-2018) therefore states that all trawl fisheries should adopt the most suitable TED and

BRD to minimize bycatch and discards (LVV Fisheries Department, 2013). These efforts are

now being supported by the regional FAO/GEF project REBYC-II LAC: “Sustainable

management of bycatch in Latin America and Caribbean trawl fisheries”. The project started

its activities in 2015 and addresses the bycatch and discard problem by improving the

management of bycatch and reducing the discards. In the framework of this project,

Suriname, together with Brazil, Colombia, Costa Rica, Mexico and Trinidad and Tobago aim

to

i) insure that enabling institutional and regulatory frameworks are in place

ii) encourage effective management of bycatch through improved information,

participatory approaches and appropriate incentives

iii) support enhanced and equitable livelihoods (FAO/GEF, 2015).

The aim of this report is to provide a knowledge baseline of bycatch and discard in the

different trawl fisheries subsectors in Suriname. To this end, the best and most recent

available information on bycatch and discards in all three trawl subsectors, collected by

onboard observers, was reviewed and summarized. From this baseline, future changes in

bycatch ratios due to the implementation of new fishing gear and best practices can be

monitored. As such, the decision-making process for fisheries management can be better

informed.

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2. Methods1.2. The seabob trawl fishery

The seabob trawling fleet uses ‘Florida-type’ outrigger trawlers, with an overall length of 20-

23 m and engine power around 400 hp. The vessels are equipped for quad-rig bottom-

trawling, and the use of Turtle Excluder Devices (TEDs) and square-mesh panel Bycatch

Reduction Devices (BRDs) is obligatory (LVV Fisheries Department, 2010). The minimum

mesh size of the net’s codend is 45 mm.The fishery acquired Marine Stewardship Council

(MSC) certification. Fishing trips typically last six to eight days and fishing takes place day

and night (Southall et al., 2011).

Sampling

Bycatch data were collected during six commercial fishing trips on board FV Neptune-6 in

the period April – November 2014 (Table 1). During each trip, catch samples were obtained

from every haul during two to three consecutive days of fishing. In total, 68 hauls were

sampled.

Table 1. Overview and details on the sampled hauls from the trips with the seabob trawler.

Start date End date Hauls (nr.) Average trawling

time (hours)

Average depth

(meters)

2 April 2014 4 April 2014 10 3:25 ± 0:30 27.1 ± 2.0

22 May 2014 23 May 2014 7 3:46 ± 0:40 23.0 ± 0.6

13 July 2014 15 July 2014 11 3:40 ± 0:23 19.6 ± 0.9

23 August 2014 25 August 2014 16 3:35 ± 0.35 21.4 ± 0.7

6 October 2014 8 October 2014 15 3:38 ± 0:15 N/A

17 November 2014 18 November 2014 9 3:41 ± 0:31 24.3 ± 0.2

Study area

The study was carried out on commercial seabob fishing grounds which are delimited by the

10 and 15 fathoms depth contours and up to 18 fathoms in the eastern part of the shelf (LVV

Fisheries Department, 2010). The sampled hauls were mainly performed in the eastern part

of the study area (Fig. 1).

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Figure 1. Study area with the location of the sampled hauls. Start locations of sampled hauls of the seabob fishery (blue diamonds ), the shrimp fishery (green squares ) and the finfish fishery (red circles ).

Protocol on board

Upon retrieval of the trawls, the catch from all four codends was dumped simultaneously on

deck. Large organisms that were unlikely to end up in the catch subsample (e.g. large

stingrays) were first sorted from the total catch, identified and measured to the nearest

centimeter. Next, the catch was homogenized with shovels and a subsample of a full or half

basket (40 resp. 20 L) was taken, depending on the available manpower to process the

subsample. The subsample was broken down into four components including the target

catch (seabob and whitebelly shrimp) and three bycatch components: fish, jellyfish and

invertebrates (crabs, starfish, molluscs, Penaeus sp. shrimp etc.). The volume (0.1 L

precision) and weight (0.1 kg precision) of the shrimp fraction was determined. Before

returning the shrimp to the crew for further processing, approximately 20 randomly selected

seabob shrimp were taken to be measured (carapace length) upon return in the lab. The

three bycatch components were processed as follows. After weighing (0.1 kg precision) the

7

fish fraction, all fishes were sorted per species and measured to the nearest centimeter

(total length for finfish, disc width for rays). For the jellyfish fraction, only the weight (0.1 kg

precision) was determined, as jellyfishes were often broken and could not be counted.

Although different species of jellyfish were observed, they were not identified to species

level and further analyzed as ‘jellyfish’. The benthos (benthic invertebrates) fraction was not

processed on board but stored on ice in plastic bags and identified and weighted per

species (0.1 g precision) upon return in the lab. After the total catch was processed by the

crew, the total catch volume of shrimp was estimated by counting the number of processed

baskets of shrimp for each haul.

Data analysis

For each haul, the total weight of the different catch fractions (target seabob catch, fish,

jellyfish and invertebrates) was estimated based on the total seabob catch (as sorted by the

crew) and the ratios between the catch fractions as obtained in the subsample. Next,

bycatch-to-shrimp ratios, catch rates or catch-per-unit-effort (CPUE; in kg/h) and relative

contribution by weight (RC; in %) of the different catch fractions were calculated, after which

the average and standard deviation were taken over the different hauls. Additionally, CPUE

(kg/h) and RC (%) were also calculated for each species of fish and invertebrates. Next, the

proportion of retained bycatch was estimated. Based on own experience during sampling,

and information from captains (J. Jagroop and S. Hall, pers. comm.), retained bycatch was

defined as the combined weight of the fish species Macrodon ancylodon (king weakfish), C.

virescens and Nebris microps (smalleye croaker) measuring >25 cm, and the weight of

bycaught P. subtilis. Weights of the fish species were obtained by length-weight conversions

(LVV and FAO, 2017). For each of these species and for every haul, the RC (%) of the

retained portion was calculated, after which the average was taken over all hauls. The sum

of the relative contributions of the retained portions of these species makes up the total

retained bycatch. Total discarded bycatch and total bycatch were calculated similarly.

Further, for the commercial fish species M. ancylodon, C. virescens and N. microps, the

ratio retained to discarded was assessed. Finally, for every target and bycatch species (if

length of more than 20 individuals measured) length frequency distributions were

constructed.

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2.2. The shrimp trawl fisheryThe vessels and trawling gear used of the shrimp trawling fleet are similar to seabob

trawling. The nets, however, are used in their original position (upside down in seabob

trawling). The minimum mesh size of the codend is 45 mm. The use of TEDs is obligated in

this fishery since 1998, and the fishery is required to use square-mesh panel BRDs similar

to the seabob fishery (LVV Fisheries Department, 2013). Fishing trips typically last 30-50

days and operation takes place mainly at night (Mr. Acton and Director of Carib Fisheries,

pers. comm.).

Sampling

Bycatch data were collected during two commercial fishing trips, one on board FV Ranmar

61 in the period October – December 2014 and one on board FV Starshrimper in December

2015 (Table 2). In total, catch samples were obtained from 142 hauls.

Table 2. Overview and details on the sampled hauls from both shrimp trawler trips.


time (hours)

Average depth

(meters)

29 October 2014 14 December 2014 105 5:02 ± 1:02 74.6 ± 7.4

6 December 2015 21 December 2015 37 3:42 ± 0:57 72.4 ± 5.3

Study area

The study was carried out on shrimp fishing grounds which stretch out from the line nominal

to a depth of 15 fathoms (LVV Fisheries Department, 2013). The sampled hauls were mainly

performed in the eastern part of the study area (Fig. 1).

Protocol on board

When the trawl nets were retrieved only the codends were taken on board and the catch

was dumped on the back deck. First the weight of the total catch was estimated. Species

like sharks and rays are normally discarded immediately and in that case the estimated

weight of each individual was recorded. Subsequently the crew sorted the catch by species

(or higher taxonomic level, further referred to as “taxon”). Each taxon was sorted in a

9

different basket or tray. Two baskets per taxon were used for taxa which were partly

retained, partly discarded, according to their size. Shrimp species were only sorted during

the second trip. After sorting, the observer recorded the weight of all baskets, obtaining the

weight of all taxa in the total catch, specifying whether the taxon was retained or (partly)

discarded. As there was only one observer on board, length measurements were not taken.

Data analysis

All weight data recorded on board were converted in catch-per-unit-effort (CPUE; in kg/h)

and relative contribution by weight (RC; in %). CPUE and RC were calculated per taxon,

with a distinction between retained and discarded. Target catch CPUE was calculated as the

sum of the target shrimp species. CPUEs and RCs of the different bycatch fractions (fish,

jellyfish and invertebrates) were obtained in a similar way. CPUEs and RCs of total retained

and discarded bycatch were calculated, and for taxa which were partly retained, partly

discarded, the retained fraction was calculated. Finally, CPUEs of the target and bycatch

fractions were used to obtain bycatch-to-shrimp ratios. Al these indices were first calculated

per haul, to allow calculating the average and standard deviation over all sampled hauls.

2.3. The finfish trawl fisheryThe Suriname finfish trawl fleet consists predominantly of two types of vessels: converted

shrimp trawlers and former ‘kotters’ from the Netherlands. Vessels are typically around 20 m

long with an 500 hp engine. Most vessels are rigged for stern trawling, in which a single

otter trawl is towed along the sea floor, held open by one pair of steel otter boards. The

minimum mesh size of the net’s codend is 80 mm. Fishing trips typically last four to eight

days and fishing takes mostly place during daytime alone (LVV Fisheries Department,

2013).

Sampling

Catch composition data were collected during three commercial fishing trips in the period

March – June 2017 (Table 3). Each trip was made on board a different vessel: FV Vier

Gebroeders, FV Minerva and FV Berendina-Hermina. In total, 60 hauls were sampled.

Table 3. Overview and details on the sampled hauls from the finfish trawler trips.


time (hours)

Average depth

(meters)

10

22 March 2017 24 March 2017 10 3.55 ± 0.39 27.1 ± 0.6

1 May 2017 5 May 2017 24 2.56 ± 0.26 36.7 ± 1.8

16 June 2017 22 June 2017 26 3.44 ± 0.29 29.4 ± 2.8

Study area

Finfish trawling is allowed from the line nominal to a depth of 15 fathoms (LVV Fisheries

Department, 2010). The sampled hauls were taken across the area (Fig. 1).

Protocol on board

After the codend was brought on board, it was emptied in a specially designed container on

the back deck, from where a conveyer belt brings the catch to a sorting belt. Before the

sorting process starts, the total catch volume was estimated by measuring the height of the

catch in the container. This measure was later multiplied by the length and width of the

container to obtain the total catch volume. While the catch was processed by the crew, a

discard sample of 20L was taken from the end of the catch sorting belt, after retained fish

had been picked out from the catch. The 20L sample was taken by filling a 10L bucket at the

start of the sorting process, and one at the end, to account for variation in the discard

composition during processing of the catch. Usually, larger organisms including

elasmobranchs and marine turtles are too big to be taken up by the conveyor belt and would

not end up in the discard sample. They were therefore set aside by the crew while sorting

the catch, and identified and measured before and during the catch sorting process. When

the catch was sorted, the weight of all retained species was recorded by estimating the

number cases of sorted catch per species. At several points during the data collection, the

average weight of a case of fish was estimated by weighting cases of fish of different

species. Length-frequency data on the retained species was collected by measuring (total

length, to the nearest cm) at least 20 randomly selected individuals per species. Rather than

measuring each species in each haul, length data was collected of about half of the species

in each haul, alternating the species. After the catch was processed, the discard sample

was weighted and sorted to species level. All fish species in the sample were measured

(total length to the nearest cm). In case of high abundances, a minimum of 30 randomly

selected fishes was measured and the remainder was counted. Invertebrates, jellyfish, etc.

were counted and their weight was estimated.

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Data analysis

While the weight of the retained species was noted on board, weights of the discarded

species were calculated by raising the weight from the discard sample to the total catch

level, after extrapolating length-frequency distributions to the discard sample and length-

weight conversions (LVV and FAO, 2017). The weight of the elasmobranch species, that

were set aside before and during the sorting process, was calculated through length-weight

conversions and added to the raised weight of the elasmobranch species from the discard

sample. For each haul, CPUE (in kg/h) and RC (in % by weight) were calculated per

species, after which the average per species was taken over the different hauls. Because

the fishery targets many species, but some only at certain sizes, the terms ‘target catch’ and

‘bycatch’ need some attention. Instead of ‘target catch’, we used ‘retained fish’. The

‘bycatch’ in this fishery refers mainly to discarded fish, but may also include jellyfish,

invertebrates, etc. For each haul, the total CPUE and RC of the different catch fractions

(fish, jellyfish, invertebrates and marine turtles) were calculated, specifying between retained

and discarded when applicable. Subsequently, bycatch-to-retained fish ratios were

calculated and their average and standard deviation was taken over the different hauls.

Finally, for every target and bycatch species (if length of more than 20 individuals measured)

length frequency distributions were constructed.

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3. Results3.1. The seabob trawl fishery

3.1.1. General catch and bycatch characteristicsIn the period April – November 2014, 68 hauls were sampled during six

commercial fishing trips. Tow duration varied between 2:10 h and 4:55 h (3:37 ±

0:28 h; Mean ± SD). Average water depth during fishing was 22.8 ± 2.8 m. Catch

rate (CPUE) averaged 204.9 ± 180.1 kg of total catch per hour of trawling.

Catches were dominated by seabob shrimp, the target catch, accounting for 59 ±

13 % of the total catch by weight. The bycatch was dominated by fish,

representing 31 ± 14 % of the catch, followed by jellyfish (8 ± 10 %) and other

invertebrates (2 ± 3 %) (Fig. 2a). Accordingly, total bycatch – to – seabob and

the different bycatch fraction-to-seabob ratios were all < 1 (Table 4). Retained

bycatch represented ca. 4% of the total catch by weight. The majority of the

bycatch consisted of small and non-commercial fish, jellyfish and other

invertebrates, which was discarded (Fig. 2b).

Table 4. Catch composition in the seabob trawl fishery off Suriname based on 68 catch samples. For each catch fraction, including

seabob and different bycatch fractions, the average (±SD) catch-per-unit-effort (CPUE) and relative catch portion (by weight) are

given. Further, average bycatch-to-seabob ratios are presented.

Seabob Bycatch

Total Bycatch Fish Jellyfish Invertebrates

CPUE (kg/h) 113.4 ± 74.

6 91.5 ± 119.9 72.1 ± 114.4 16.7 ± 23.5 2.7 ± 6.0

Fraction (%) 59.1 ± 13.3 40.9 ± 13.3 31.2 ± 13.5 8.0 ± 9.8 1.7 ± 3.4

Bycatch ratios

bycatch:seabob fish:seabob jellyfish:seabob invertebrates:seabob

0.81 ± 0.58 0.61 ± 0.45 0.17 ± 0.28 0.03 ± 0.07

13

Target catch59%

Fish31%

Jellyfish8%

Invertebrates2%

GENERAL cATCH COMPOSITION IN THE SEABOB TRAWL FISHERya

Target catch59%

Discards37%

C. virescens1%

M. ancylodon2%

N. microps1%

P. subtilis0%retained bycatch in the seabob trawl fisheryb

Figure 2. Average relative portions (by weight) of target catch and the different bycatch fractions (fish, jellyfish

and invertebrates) in the seabob trawl fishery off Suriname. a) Average proportions of target catch and bycatch

fractions. b) Average proportions of target catch, retained and discarded bycatch, and species proportions of

the retained bycatch.

A total of 80 species were observed in the catch samples from the seabob trawl

fishery. Most of these (54) were fish species, while 24 invertebrate species were

14

observed. The five most common species (by weight) were: X. kroyeri (target

catch; 59 %), Stellifer microps (smalleye stardrum; 11 %), Scyphozoa spp.

(jellyfish; 8 %), C. jamaicensis/similis (4 %) and M. ancylodon (2 %) (Fig. 3).

X. kroyeri59%

S. microps 11%

Scyphozoa spp.8%

C. jamaicensis/similis4%

M. ancylodon2%

D. guttata2%

S. rastrifer1%

N. microps1%

T. lepturus 1%

P. elegans1% Others

9%

catch composition - contribution by species

Figure 3. Average relative portions (by weight) of the species captured in the seabob trawl fishery off Suriname.

‘Others’ includes 70 species with low relative contributions.

3.1.2. Target catch and bycatch composition and sizes

3.1.2.1. Target catch composition

X. kroyeri is the single target species in the seabob trawl fishery. Although

small amounts of N. schmitti are known to occur occasionally among the

X. kroyeri, their relative abundance was not assessed (Table 5). The

average carapace length of the target species X. kroyeri (n = 2011) was

16.1 ± 4.9 mm and the most common length 20 mm (Fig. 4).

Table 5. Target species identified in the seabob trawl fishery off Suriname. The frequency of occurrence (%FO) and catch-per-unit-

effort (CPUE; kg/h) is given for both species together, as the relative abundance of N. schmitti was not assessed.

Class Order Family Species %FO CPUE (kg/h)

Malacostrac

a

Decapoda

Penaeidae Xiphopenaeus kroyeri 100 113.4 ± 74.6

15

Palaemonidae Nematopalaemon schmitti

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1718 19 20 21 22 23 24 25 26 2728 29 30 31 32 33 34 35 36 3738 39 400

20

40

60

80

100

120

140

160

180

200

Figure 4. Length (carapace) frequency distribution of the target species X. kroyeri, n = 2011.

3.1.2.2. Fish bycatch

Fifty-four species of fish were identified in the bycatch. Twenty-two of these were

rather rare, occurring in less than 5% of the samples (Table 6). Fish bycatch was

largely dominated by two Sciaenid fishes (drums/croakers), S. microps and C.

jamaicensis/similis, accounting for nearly 50% of fish bycatch (by weight) and both

species occurred in 100% of the samples. While the remaining 50% included a

diverse array of species, Sciaenidae was the major fish family here as well (Fig. 5

and 6).

Table 6. Fish bycatch species identified from 68 catch samples in the seabob trawl fishery off Suriname. For each species the

frequency of occurrence (%FO) and catch-per-unit-effort (CPUE) is given, both in terms of weight (kg/h) and numbers (#/h).

Class Order Family Species %FOCPUE (kg/h)

CPUE (#/h)

Actinopterygii Anguiloformes

Muraenesocida

e

Cynoponticus savanna 7.4 0.6 ± 3.1 1.0 ± 4.1

Muraenidae Gymnothorax ocellatus 1.5 <0.1 ± 0.2 0.2 ± 1.3

Aulopiformes

16

Length (mm)

Number of individuals

Synodontidae Saurida caribbaea 2.9 <0.1 ± 0.0 0.2 ± 1.1

Batrachoidiformes

BatrachoididaeBatrachoides

surinamensis 4.4 <0.1 ± 0.1 0.4 ± 2.1

Clupeiformes

Clupeidae Harengula jaguana 20.6 0.3 ± 1.1 6.6 ± 24.5

Harengula sp. 1.5 <0.1 ± 0.0 0.1 ± 0.7

Engraulidae Anchoa spinifer85.3 1.1 ± 1.5

374.5 ±

732.8

Anchoviella

lepidentostole 29.4 <0.1 ± 0.1 24.7 ± 85.1

PristigasteridaeOdontognathus

mucronatus 36.8 0.1 ± 0.1 12.5 ± 27.4

Lophiiformes

Ogcocephalidae Ogcocephalus sp. 1.5 <0.1 ± 0.0 0.3 ± 2.5

Perciformes

Carangidae Caranx hippos 2.9 0.9 ± 7.0 0.3 ± 2.0

Selene brownii 4.4 <0.1 ± 0.1 0.9 ± 5.7

Selene vomer 7.4 0.2 ± 0.8 2.1 ± 10.5

Centropomidae Centropomus ensiferus 1.5 0.1 ± 1.1 0.2 ± 1.8

Ephippidae Chaetodipterus faber 5.9 <0.1 ± 0.0 0.6 ± 3.1

Haemulida Haemulon boschmae 8.8 0.1 ± 0.5 1.5 ± 5.3

Orthopristis ruber 8.8 0.2 ± 0.9 1.9 ± 7.4

Polynemidae Polydactylus oligodon 32.4 0.6 ± 1.6 7.0 ± 17.7

SciaenidaeCtenosciaena

gracilicirrhus 22.1 0.4 ± 1.3 20.5 ± 59.9

Cynoscion

jamaicensis/similis 100.0

11.6 ±

31.6

822.8 ±

1477.0

Cynoscion virescens 51.5 2.5 ± 7.0 28.7 ± 45.9

Larimus breviceps 22.1 2.2 ± 12.4 20.1 ± 117.2

Lonchurus elegans 30.9 1.4 ± 2.9 11.6 ± 21.9

Lonchurus lanceolatus 4.4 0.1 ± 0.8 2.3 ± 12.2

Macrodon ancylodon 66.2 5.1 ± 9.3 47.6 ± 74.3

Menticirrhus americanus 5.9 0.3 ± 1.1 0.9 ± 4.0

Micropogonias furnieri 1.5 <0.1 ± 0.3 0.1 ± 1.2

Nebris microps 51.5 2.0 ± 4.1 13.2 ± 18.5

Paralonchurus

brasiliensis 66.2 1.2 ± 4.6 43.1 ± 60.4

Plagioscion auratus 30.9 0.3 ± 0.6 9.4 ± 19.7

Stellifer microps100.0 24.3 ± 33.5

1598.1 ±

1710.3

17

Stellifer rastrifer79.4 2.6 ± 4.4

229.7 ±

361.3

Serranidae Diplectrum sp. 1.5 <0.1 ± 0.0 0.1 ± 0.8

Stromateidae Peprilus paru 4.4 <0.1 ± 0.0 1.1 ± 5.6

Trichiuridae Trichiurus lepturus 58.8 3.0 ± 7.9 34.8 ± 75.9

Pleuronectiformes

Achiridae Achirus achirus 33.8 0.3 ± 1.2 7.2 ± 18.4

Cynoglossidae Symphurus plagiusa 73.5 0.9 ± 1.5 70.7 ± 109.9

Scorpaeniformes

Dactylopteridae Dactylopterus volitans 1.5 <0.1 ± 0.0 0.2 ± 1.8

Triglidae Prionotus punctatus 7.4 <0.1 ± 0.1 0.6 ± 2.4

Siluriformes

Ariidae Amphiarius phrygiatus 2.9 0.2 ± 1.4 0.4 ± 3.0

Amphiarius rugispinis 22.1 0.4 ± 1.5 8.7 ± 34.5

Aspistor quadriscutis 4.4 0.2 ± 1.1 0.5 ± 2.5

Bagre bagre 20.6 1.6 ± 6.7 4.1 ± 13.0

Notarius grandicassis 2.9 0.2 ± 1.7 1.2 ± 8.5

Tetraodontiformes

Diodontidae Chilomycterus antillarum 1.5 <0.1 ± 0.3 0.5 ± 4.0

Tetraodontidae Colomesus psittacus 4.4 0.1 ± 0.7 0.8 ± 4.1

Sphoeroides testudineus 1.5 <0.1 ± 0.1 0.2 ± 1.7

Elasmobranchii Carcharhiniformes

Triakidae Mustelus higmani 2.9 0.1 ± 0.4 0.2 ± 1.4

Myliobatiformes

Dasyatidae Dasyatis geijskesi 2.9 1.2 ± 8.9 0.6 ± 3.4

Dasyatis guttata 20.6 3.5 ± 11.8 4.3 ± 11.5

Gymnuridae Gymnura micrura 20.6 1.2 ± 9.4 5.4 ± 18.3

UrotrygonidaeUrotrygon

microphthalmum 22.1 <0.1 ± 0.1 5.4 ± 14.4

Rhinopristiformes

Rhinobatidae Rhinobatos percellens 4.4 0.5 ± 2.8 0.8 ± 4.0

Torpediniformes

Narcinidae Narcine brasiliensis 13.2 0.2 ± 1.0 4.7 ± 25.2

18

S. microps35%

C. jamaicensis14%M. ancylodon

8%D. guttata

6%

S. rastrifer4%

N. microps4%

T. lepturus4%

P. elegans3%

C. virescens3%

B. bagre2%

Others17%

Fish bycatch composition - contribution by species

Figure 5. Average relative portions (by weight) of fish bycatch species in the seabob trawl fishery off Suriname.

‘Others’ includes 44 species with low relative contributions.

Sciaenidae75%

Dasyatidae7%

Trichiuridae4%

Ariidae3%

Cynoglossidae2%

Engraulidae2%

Others7%

fish bycatch composition - contribution by family

Figure 6. Average relative portions (by weight) of fish bycatch families in the seabob trawl fishery off Suriname.

‘Others’ includes 24 families with low relative contributions.

Most fishes were small, measuring under 20 cm total length. The five most common

bycatch species (based on %FO; Table 6), C. jamaicensis/similis, S. microps, Anchoa

spinifer (spicule anchovy), Stellifer rastrifer (rake stardrum) and Symphurus plagiusa

(blackcheek tonguefish) mostly measured around 10 cm total length (Fig. 7a). Further,

19

the commercially valuable species M. ancylodon, C. virescens and N. microps had peak

length-distributions below 25 cm, the average size at which they are retained (Fig. 7b, 7c

and 7d). Retained fish bycatch, calculated as the combined weight of fishes of these

three species measuring >25 cm, accounted for 10.1 ± 11.1 % of the fish fraction (by

weight). M. ancylodon was the most important retained species (5.3 ± 7.5 % of the fish

fraction, by weight), followed by C. virescens (1.9 ± 5.8 %) and N. microps (2.9 ± 5.3 %).

More than half of the caught M. ancylodon (60 %, by weight) and N. microps (53 %) was

retained. Most of C. virescens (71 %) was thrown back overboard (Fig. 8).

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 300

200

400

600

800

1000

1200

A. spinifer

C. jamaicensis

S. microps

S. rastrifer

S. plagusia

1 2 3 4 5 6 7 8 9 1011 12 13 14 15 160

5

10

15

20

25

30

35

40

45

M. ancylodon discarded M. ancylodon retained

20

Length (cm)


Length (cm)


a

b

1 4 7 10 13 160

5

10

15

20

25

30C. virescens discarded C. virescens retained

Length (cm)

1 2 3 4 5 6 7 8 9 1011 12 130

2

4

6

8

10

12

14N. microps discarded N. microps retained

Length (cm)

d

Figure 7. Length frequency distributions of the most common fish bycatch species (a) and of the commercial fish species

M. ancylodon (b), C. virescens (c) and N. microps (d).

C . v i r e sc e n s M . a n c y l o d o n N . m i c r o p s

29

6053

71

4047

% retained % discarded

Figure 8 Average proportions (by weight) of retained and discarded catch for three main commercial fish bycatch

species in the seabob trawl fishery off Suriname.

21



c

3.1.2.3. Invertebrate bycatch

Nine of the 24 identified benthic invertebrate taxa (Table 7) occurred in less than 5 %

of all samples. The only commercially valuable and retained invertebrate species

was P. subtilis, representing 25 % of the invertebrate bycatch by weight. The rest of

the invertebrate fraction was mainly made up of the crab species Callinectes ornatus

(blue swimming crab), Persephona lichtensteinii (clock crab) and Calappa sulcata

(yellow box crab), the gastropod Marsupina bufo (chestnut frog shell), the soft coral

Renilla muelleri (Mueller’s sea pansy) and the shrimp Exhippolysmata oplophoroides

(cock shrimp) (Fig. 9).

Table 6. Epibenthic invertebrate species identified from 68 catch samples in the seabob trawl fishery off Suriname. For each

species the frequency of occurrence (%FO) and catch-per-unit-effort (CPUE; kg/h) is given, both in terms of weight (kg/h) and

numbers (#/h).

Higher rank Species %FO CPUE (kg/h) CPUE (#/h)CRUSTACEA

Decapoda - PenaeoideaPenaeus subtilis 67.6 0.69 ± 1.26 49.8 ± 89.3

Decapoda - AnomuraClibanarius foresti 8.8 0.02 ± 0.10 5.4 ± 25.4Dardanus fucosus 2.9 0.01 ± 0.03 0.5 ± 2.7Anomura sp. 5.9 <0.01 ± 0.01 0.8 ± 4.0

Decapoda - BrachyuraAcanthilia intermedia 1.5 <0.01 ± 0.01 0.4 ± 3.0Brachyura sp. 1.5 <0.01 ± 0.00 0.1 ± 1.2Calappa sulcata 33.8 0.19 ± 0.65 6.0 ± 9.8Callinectes ornatus 80.9 0.37 ± 1.09 243.8 ± 1193.2Hepatus gronovii 33.8 0.09 ± 0.18 9.0 ± 29.4Hepatus pudibundus 4.4 <0.01 ± 0.01 0.5 ± 2.3Paradasygyius tuberculatus 14.7 <0.01 ± 0.01 4.4 ± 19.7Persephona lichtensteinii 67.6 0.28 ± 1.08 222.5 ± 1194.3Portunus gibbesii 2.9 <0.01 ± 0.01 0.5 ± 2.9Raninidae sp. 7.4 <0.01 ± 0.00 0.7 ± 2.5

Decapoda - CarideaExhippolysmata oplophoroides 42.6 0.21 ± 1.20 223.4 ± 1207.6

StomatopodaSquilla sp. 48.5 0.04 ± 0.09 36.2 ± 98.1

MOLLUSCABivalvia

Bivalvia sp. 2.9 <0.01 ± 0.00 0.3 ± 1.8Cephalopoda

Loligo sp. 8.8 <0.01 ± 0.01 1.3 ± 5.4Gastropoda

Distorsio clathrata 1.5 <0.01 ± 0.01 0.1 ± 1.2Marsupina bufo 45.6 0.48 ± 1.12 47.8 ± 114.0Tonna galea 2.9 0.01 ± 0.06 0.1 ± 1.2Naticarius canrena 5.9 0.01 ± 0.02 0.7 ± 3.3

22

CNIDARIAAnthozoa

Renilla muelleri 32.4 0.33 ± 2.51 159.3 ± 1195.6

ANNELIDAPolychaeta sp. 1.5 <0.01 ± 0.00 0.2 ± 1.8

M. bufo23%

F. subtilis22%

C. ornatus13%

R. muelleri10%

P. lichtensteinii10%

E. oplophoroides7%

C. sulcata6%

H. gronovii3%

Squilla sp.2%

C. foresti1% Others

1%

invertebrate bycatch composition - contribution by species

Figure 9. Average relative portions (by weight) of epibenthic invertebrate species in the bycatch of the seabob fishery off Suriname. ‘Others’ includes 14 species with low relative contributions.

3.2. The shrimp trawl fishery

3.2.1. General catch and bycatch characteristicsIn the period October – December 2014 and December 2015, 142 hauls were

sampled during two commercial fishing trips. Tow duration varied between 0:40 h

and 6:40 h (4:41 ± 1:10 h; Mean ± SD). Average water depth during fishing was

74.0 ± 7.0 m. Catch rate (CPUE) averaged 36.6 ± 16.4 kg of total catch per hour

of trawling. Catches were dominated by fish, accounting for 49 ± 21 % of the total

catch by weight, followed by shrimp (the target catch; 25 ± 15 %), invertebrates

(23 ± 22 %) and jellyfish (3 ± 14 %) (Fig. 10a). Total bycatch – to – shrimp ratio

was 5:1 and the bycatch fraction – to – shrimp ratios varied between 1:2 and 3:1

(Table 7). Retained bycatch represented 16 % of the total catch by weight. The

majority of the bycatch included small and non-commercial fish, jellyfish and

other invertebrates, which was discarded (Fig. 10b).

Table 7. Catch composition in shrimp trawl fishery off Suriname based on 142 catch samples. For each catch fraction, including

shrimp and different bycatch fractions, the average (±SD) catch-per-unit-effort (CPUE) and relative catch portion (by weight) are

given. Further, average bycatch-to-shrimp ratios are presented.

23

Shrimp Bycatch

Total Bycatch Fish Jellyfish Invertebrates

CPUE (kg/h) 8.1 ± 3.9 28.6 ± 15.9 16.6 ± 7.9 2.2 ± 12.0 9.7 ± 11.1

Fraction (%) 25.4 ± 15.

5 74.6 ± 15.5 48.7 ± 20.6 2.8 ± 13.8 23.1 ± 22.3

Bycatch ratios

bycatch:shrimp fish:shrimp jellyfish:shrimp benthos:shrimp

4.8 ± 5.9 2.9 ± 5.2 0.5 ± 2.8 1.4 ± 1.8

Target catch25%

Fish49%

Invertebrates23%

Jellyfish3%

general catch composition in the shrimp trawl fishery

24

a

Target catch25%

Discards59%

C. jamaicensis/ similis

7%

L. purpureus2%R. aurorubens

2%Haemulidae spp.

2%Cephalopoda1%

Others2%

RETAINED BYCATCH IN THE SHRIMP TRAWL FISHERYb

Figure 10. Average relative portions (by weight) of target catch and the different bycatch fractions (fish, jellyfish and other

invertebrates) (a) and of target catch, retained and discarded bycatch (b) in the shrimp fishery off Suriname. Target catch

includes the shrimp species P. brasiliensis, P. notalis and P. subtilis.

Twenty-four different taxa were observed in the catches of the Suriname

shrimp trawl fishery. In addition to the target catch (Table 8) and the

jellyfish (not further identified), the fish fraction consisted of 16 taxa and

the invertebrate fraction of eight taxa. The five most common taxa (by

weight; fig. 11) were: Penaeus spp. (target catch; 26%), Mugilidae spp.

(mullets; 24%), Brachyura spp. (crabs; 12%), Ostreidae spp. (oysters;

9%) and C. jamaicensis/similis (7%).

Penaeus spp.25%

Mugilidae spp.24%

Brachyura spp. 12%Ostreidae spp. 9%


Bothidae & Soleidae spp.3%

Haemulon vittatum3%

Scyphozoa3%

L. purpureus3%

Haemulidae spp.2%

Others (cephalopods, mollusca and fish)8%

catch composition - contribution by taxon

25

Figure 11. Average relative portions (by weight) of the caught organisms of the shrimp fishery off

Suriname. ‘Others’ includes at least 12 taxa with low relative contributions

3.2.2. Catch and bycatch composition and sizes

3.2.2.1. Target catch composition

Based on the data from the second trip, it was calculated that the majority

of the target catch was P. notialis (71%), followed by P. brasiliensis

(25%) and P. subtilis (4%) (Fig. 12).

Table 8. Target species identified in the shrimp fishery off Suriname. The frequency of occurrence

(%FO) and catch-per-unit-effort (CPUE; kg/h) is given. The different shrimp species were sorted

during the second trip, but not during the first trip (MIX). In MIX also P. schmitti could be included.

Higher rank Species %FO CPUE (kg/h)CRUSTACEA Decapoda - Penaeidae P. brasiliensis 18.3 0.7 ± 2.0

P. notialis 25.4 1.8 ± 3.5P. subtilis 3.5 0.1 ± 0.3MIX 73.2 5.5 ± 4.4

P. subtilis4%

P. brasiliensis25%

P. notialis71%

Figure 12. Average relative portions (by weight) of the target species in the shrimp fishery off

Suriname, based on data of the second trip.

26

3.2.2.2. Fish bycatch

Eight fish species were identified to the species level, the others to the

family level. In total 12 different families could be distinguished. Three

families, Carangidae, Scombridae and Stromateidae, were rather rare,

occurring in less than 5% of the samples (Table 9). Fish bycatch was

largely dominated by fishes belonging to the Mugilidae family, accounting

for nearly 50% of the fish bycatch (by weight). The biggest families in the

remaining 50% included Sciaenidae (15%), Lutjanidae (12%) and

Haemulidae (10%) (Fig. 13).

Table 9. Fish bycatch taxa identified from 142 catch samples in the shrimp fishery off Suriname. For each taxon, the frequency of

occurrence (%FO) and catch-per-unit-effort (CPUE) is given, both in terms of weight (kg/h) and numbers (#/h).

Class Order Family %FO Species %FO CPUE (kg/h)

Actinopterygii

Perciformes

Bramidae 57.7 0.6 ± 0.6Carangidae 2.1 Selene setapinnis 2.1 <0.1 ± 0.4Haemulidae 76.1 Haemulidae spp. 4.2 0.6 ± 4.0

Haemulon vittatum 73.2 1.1 ± 0.8Lutjanidae 90.8 Lutjanus purpureus 77.5 1.0 ± 1.0

Lutjanus synagris 3.5 0.1 ± 1.0Rhomboplites aurorubens 30.3 0.8 ± 3.0Lutjanidae spp. 4.2 0.2 ± 1.2

Mugilidae 78.9 8.6 ± 6.5Sciaenidae 90.1 Cynoscion jamaicensis/similis 90.1 2.2 ± 2.3Scombridae 0.7 Scomboromurus cavalla 0.7 <0.1 ± 0.1Stromateidae 0.7 Peprilus paru 0.7 <0.1 ± 0.1

PleuronectiformesBothidae 75.4 1.0 ± 1.0Soleidae

ScorpaeniformesScorpaenidae 12.0 0.1 ± 0.3Triglidae 16.9 0.2 ± 0.6

27

Bothidae & soleidae7%

Haemulidae10%

Lutjanidae11%

Mugilidae50%

Bramidae3%

Sciaenidae15%

Scorpaenidae1%

Triglidae2% Others

0%

Fish bycatch composition - contributiion by family

Figure 13. Average relative portions (by weight) of fish bycatch families in the shrimp fishery off

Suriname. ‘Others’ includes 3 families with low relative contributions.

Retained fish bycatch accounted for 28.4 ± 23.5 % of the fish fraction (by

weight). C. jamaicensis/similis was the most important retained species

(14.3 ± 15.4 % of the fish fraction, by weight), followed by L. purpureus

(6.9 ± 8.8 %), R. aurorubens (3.1 ± 9.9 %) and Haemulidae spp. (2.0 ±

13.2 %). Other retained fish species accounted each for less than 1% of

the fish fraction. Several species were retained completely: L. synagris,

P. paru, S. cavalla and Scombridae spp. Others were retained almost

completely: C. jamaicensis/similis (95%), L. purpureus (97%), R.

aurorubens and Haemulidae spp. (97%). Bramidae, Bothidae & Soleidae

and Mugilidae spp. were almost completely discarded (>95%), and five

species were fully discarded: Haemulon vittatum, Selene setapinnis,

Lutjanidae spp. (L. purpureus and L. synagris excluded), Triglidae spp.

and Scorpaenidae spp. (Figure 14).

28

L . sy n a g r i s

S c o m b r i da e s p p .

P . pa r u

S . ca v a l l a

R . au r o r u b e n s

L . pu r p u r eu s

H a em u l i da e s p p .

C . ja m a i c

en s i s / s i mi l i

s

B o t h i da e &

S o l ei d

a e s p p .

Mu g i l id a e s p p .

B r a m i da e sp p .

H . vi tt

a t u m

S . se t a p i n

n i s

L u t j an i d

a e sp p .

S c o r p a e n i da e s p p .

T r i gl i d

a e sp p .

100 100 100 100 97 97 97 95

3 1 1 0 0 0 0 0

0 0 0 0 3 3 3 5

97 99 99 100 100 100 100 100


Figure 14. Average portions (by weight) of retained and discarded catch for the different taxa of the fish bycatch in the shrimp

fishery off Suriname.


Four invertebrate taxa were identified (Table 10). Brachyura species were

the most common invertebrates, occurring in 56 % of all samples (Fig.

15). Most invertebrates were discarded. The main retained invertebrate

species were Cephalopoda representing 8 % of the invertebrate bycatch

by weight (Fig. 16). The rest of the retained invertebrate fraction was

made up of crab species and oysters, each representing less than 1 % of

the invertebrate bycatch (Fig. 15 and 16).

29

Table 10. Invertebrate taxa identified in the shrimp fishery off Suriname. The frequency of occurrence

(%FO) and catch-per-unit-effort (CPUE; kg/h) is given.

Higher rank Species %FO CPUE (kg/h)CRUSTACEA Decapoda - Brachyura Brachyura spp. 55.6 5.2 ± 6.3MOLLUSCA Bivalvia Bivalvia spp. 0.7 <0.1 ± 0.3

Ostreidae spp. 44.4 4.1 ± 8.2 Cephalopoda 31.7 0.4 ± 2.0

Brachyura spp.54%

Cephalopoda14%

Ostreidae spp.31%

Bivalvia spp.1%

Figure 15. Average relative portions (by catch rate) of invertebrate bycatch taxa in the shrimp fishery

off Suriname.

Cephalopoda Brachyura spp. Ostreidae spp. Bivalvia spp.0

10

20

30

40

50

60

70

80

90

100

40

2 1 0

60

98 99 100


Figure 16. Average portions (by weight) of retained and discarded catch for the different taxa of the

fish bycatch in the shrimp fishery off Suriname.

30

3.3. The finfish trawl fishery

3.3.1. General catch and bycatch characteristicsIn the months of March, May and June 60 hauls were sampled during three

commercial fishing trips. Tow duration varied between 2:05 h and 5:15 h (3:26 ±

0:38 h; Mean ± SD). Average water depth during fishing was 32.0 ± 4.6 m. Catch

rate (CPUE) averaged 602.0 ± 337.2 kg of total catch per hour of trawling. Catches

consisted almost completely of fish, accounting for 99 ± 2 % of the total catch by

weight. The relative portions of invertebrates, jellyfish and turtle were low (< 0.1 %)

(Fig. 17). Since the bycatch consisted almost entirely of fish, the bycatch – to –

retained fish ratio and the discarded – to – retained fish ratio were similar (Table

11).

Table 11. Catch composition in finfish trawl fishery off Suriname based on 60 catch samples. For each catch fraction, including fish

retained and different bycatch fractions, the average (±SD) catch-per-unit-effort (CPUE) and relative catch portion (by weight) are

given. Further, average bycatch-to-retained fish ratios are presented.

Fish - retained Bycatch

Total Bycatch Fish - discarded Jellyfish

CPUE (kg/h) 325.6 ± 197.7 276.4 ± 182.7 273.7 ± 184.2 < 0.1

Fraction (%) 54.9 ± 15.7 45.1 ± 15.7 44.3 ± 16.1 < 0.1

Bycatch ratios

bycatch:fish retained fish discarded:fish retained jellyfish:fish retained invertebrates:fish retained

1.06 ± 1.08 1.05 ± 1.08 < 0.1

31

Target catch or Fish retained

55%

Fish discarded44%

Jellyfish, other invertebrates and turtles

1%

general catch composition in the finfish trawl fishery

Figure 17. Average relative portions (by weight) of target catch (retained fish), discarded fish and rest fraction

(jellyfish, other invertebrates and turtles).

A total of 110 species were identified in the catches of the finfish trawl fishery. The

fish fraction consisted of 98 species and the invertebrate fraction of 12 taxa. The

seven most common species (by weight) were: C. jamaicensis/similis (21 %), T.

lepturus (largehead hairtail; 12 %), O. ruber (corocoro grunt; 5 %), L. synagris (lane

snapper; 5 %), C. virescens ( 5 %), Selene brownii (Caribbean moonfish; 5 %) and

D. guttata (longnose stingray; 5 %) (Fig. 18).


T. lepturus12%

O. ruber8%

D. guttata5%L. synagris 5%C. virescens

5%

S. brownii 4%

S. barracuda4%

P. harroweri3%

M. furnieri3%

Others(fish, jellyfish, turtles,

cephalopods and benthos)28%

Catch composition - contribution by species

Figure 18. Average relative portions (by weight) of the caught organisms of the finfish fishery off

Suriname. ‘Others’ includes 100 species with low relative contributions.

32

3.3.2. Catch and bycatch composition and sizes

3.3.2.1. Retained and discarded fish

Ninety-eight fish species were identified in the catch. Twenty-one of these

were rather rare, occurring in less than 5% of the samples. Two species,

C. jamaicensis/similis and T. lepturus occurred in every sample (Table

12). Sciaenidae was the most dominant family (43 %), followed by

Trichiuridae (13 %) and Haemulidae (11 %) (Fig. 19).

Sciaenidae43%

Trichiuridae13%

Haemulidae11%

Dasyatidae7%

Lutjanidae6%

Carangidae6%

Sphyraenidae5%

Pristigasteridae4%

Ariidae3%

Others2%

fish catch composition - contribution by family

Figure 19. Average relative portions (by weight) of the caught fish families in the finfish fishery off

Suriname. ‘Others’ includes 39 families with low relative contributions.

Almost half of the fish species were always discarded, while almost one fifth was

always retained. The remaining fish species (32 %) were either retained or

discarded, depending on their size. (Fig. 20). Retained fish were mostly

representatives of the Sciaenidae, accounting for nearly 60% of all retained fish (by

weight). Haemulidae species (grunts) composed 13% of the retained fish, Lutjanidae

species (snappers) 11%. T. lepturus accounted for the highest percentage (20%) of

all discarded fish species, followed by Sciaenidae fishes (16%), Dasyatidae (16%)

and Carangidae (10%).

33

Table 12. Fish catch species identified from 60 catch samples in the finfish fishery off Suriname. For each species the frequency of

occurrence (%FO) and catch-per-unit-effort (CPUE) is given, both in terms of weight (kg/h) and numbers (#/h).

Class Order Family Species %FO CPUE (kg/h)Actinopterygii Anguilliformes

Muraenesocidae Cynoponticus savanna 5.3 < 0.1Nettastomatidae Hoplunnis macrura 3.5 < 0.1Ophichthidae Ophichthus cylindroideus 3.5 < 0.1

AulopiformesSynodontidae Synodus foetens 7.0 < 0.1

BatrachoidiformesBatrachoididae Batrachoides surinamensis 7.0 0.2 ± 1.5

ClupeiformesClupeidae Harengula jaguana 29.8 1.9 ± 5.6

Opisthonema oglinum 24.6 2.0 ± 7.8Engraulidae Anchoa spinifer 56.1 0.4 ± 0.8

Anchoviella lepidentostole 59.6 0.2 ± 0.4Pristigasteridae Pellona harroweri 94.7 22.7 ± 32.9

Odontognathus mucronatus 84.2 0.5 ± 0.9Elopiformes

Elopidae Elops saurus 7.0 < 0.1Lophiiformes

Antennariidae Antennarius striatus 1.8 < 0.1Ophidiiformes

Ophidiidae Lepophidium profundorum 1.8 < 0.1Perciformes

Carangidae Alectis ciliaris 3.5 < 0.1Caranx crysos 5.3 0.4 ± 3.0Caranx hippos 26.3 1.4 ± 5.8Caranx latus 1.8 < 0.1Chloroscombrus chrysurus 42.1 1.2 ± 3.3Oligoplites saliens 19.3 1.1 ±3.2Selene vormer 40.4 0.7 ± 1.7Selene brownie 94.7 30.2 ± 61.6Trachinotus goodei 1.8 < 0.1Trachinotus cayennensis 42.1 0.8 ± 2.3

Echeneidae Echeneis naucrates 5.2 0.5 ± 2.7Ephippidae Chaetodipterus faber 50.9 7.2 ± 15.0Gerreidae Diapterus auratus 61.4 1.7 ± 2.4

Eucinostomus spp. 1.8 < 0.1Haemulidae Anisotremus surinamensis 1.8 < 0.1

Anisotremus virginicus 5.2 < 0.1Conodon nobilis 35.1 0.8 ± 1.7Genyatremus luteus 31.6 0.9 ± 2.9Haemulon boschmae 12.3 1.9 ± 8.8Haemulon steindachneri 3.5 0.5 ± 3.5Haemulon spp. 1.8 0.1 ± 0.9Haemulopsis corvinaeformis 35.1 7.5 ± 27.2Orthopristis ruber 91.2 48.1 ± 73.6

Lutjanidae Lutjanus jocu 5.2 0.2 ± 1.2Lutjanus synagris 98.2 24.9 ± 36.1Rhomboplites aurorubens 40.4 2.4 ± 4.6

Mugilidae Mugil cephalus 1.8 < 0.1Mullidae Upeneus parvus 5.2 < 0.1Polynemidae Polydactylus oligodon 28.1 0.5 ± 1.1Pomatomidae Pomatomus saltatrix 12.3 < 0.1Priacanthidae Priacanthus arenatus 3.5 0.2 ± 1.5Rachycentridae Rachycentron canadum 14.0 0.7 ± 2.3Sciaenidae Ctenosciaena gracilicirrhus 96.5 12.6 ± 32.3

Cynoscion acoupa 10.5 0.3 ± 1.6Cynoscion jamaicensis/similis 100 159.7 ± 212.1Cynoscion microlepidotus 8.8 0.3 ± 1.5Cynoscion steindachneri 1.8 < 0.1Cynoscion virescens 71.9 26.2 ± 31.9Isopisthus parvipinnis 50.9 5.0 ± 7.7

34

+ Macrodon ancylodon (small) (= trie)Larimus breviceps 49.1 5.7 ± 9.3Macrodon ancylodon 45.6 8.7 ± 18.4Menticirrhus americanus 84.2 7.0 ± 8.0Micropogonias furnieri 78.9 18.3 ± 21.2Nebris microps 17.5 0.2 ± 0.9Paralonchurus brasiliensis 28.1 3.7 ± 12.4Stellifer microps 26.3 1.7 ± 6.0Stellifer rastrifer 1.8 < 0.1

Scombridae Scomberomorus cavalla 59.6 4.2 ± 7.9Scomberomorus maculatus 26.3 0.6 ± 2.9

Serranidae Diplectrum formosum 10.5 < 0.1Epinephelus itajara 1.8 < 0.1

Sparidae Calamus penna 10.5 < 0.1Sphyraenidae Sphyraena barracuda 78.9 24.8 ± 46.8Stromateidae Peprilus paru 75.4 2.6 ± 4.4Trichiuridae Trichiurus lepturus 100 71.9 ± 74.5

PleuronectiformesParalichthyidae Syacium papillosum 14.0 0.2 ± 0.6

ScorpaeniformesDactylopteridae Dactylopterus volitans 3.5 < 0.1Triglidae Prionotus punctatus 86.0 9.9 ± 17.9

SiluriformesAriidae Amphiarius phrygiatus 7.0 0.1 ± 0.6

Amphiarius rugispinis 5.3 < 0.1Aspistor quadriscutis 33.3 4.2 ± 13.0Bagre bagre 52.6 3.1 ± 4.0Notarius grandicassis 36.8 4.5 ± 10.6Sciades parkeri 3.5 0.1 ± 0.6Sciades proops 50.9 3.1 ± 5.4

TetradontiformesDiodontidae Chilomycterus antillarum 3.5 < 0.1Monacanthidae Aluterus monoceros 7.0 0.4 ± 1.8Ostraciidae Acanthostracion quadricornis 5.3 < 0.1Tetraodontidae Colomesus psittacus 5.3 0.2 ± 1.0

Lagocephalus laevigatus 8.8 0.1 ± 0.4Sphoeroides testudineus 7.0 < 0.1

Elasmobranchii

Carcharhiniformes

Carcharhinidae Carcharhinus falciformis 14.0 0.4 ± 1.3Sphyrnidae Sphyrna lewini 5.3 0.2 ± 0.8

Triakidae Mustelus higmani 35.1 0.2 ± 0.5Myliobatiformes

Dasyatidae Dasyatis americana 49.1 6.6 ± 16.0Dasyatis geijskesi 14.0 0.8 ± 2.1Dasyatis guttata 63.2 25.7 ± 36.7

Gymnuridae Gymnura micrura 35.1 0.9 ± 2.8Rhinopteridae Rhinoptera bonasus 33.3 12.9 ± 49.6

OrectolobiformesGinglymostomatidae

Ginglymostoma cirratum 1.8 0.2 ± 1.7

RhinopristiformesRhinobatidae Rhinobatos percellens 8.8 0.2 ± 1.6

TorpediniformesNarcinidae Narcine bancroftii 10.5 0.9 ± 3.8

Narcine brasiliensis 1.8 < 0.1

35

C a r a n x c r y s o sA l u t e r u s m o n o c e r o s

A m p h i a r i u s r u g i s p i n i sC h l o r o s c o m b r u s c h r y s u r u s

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A l e c ti s c i l i a r i sS e l e n e v o m e r

R h i n o p t e r a b o n a s u sA c a n t h o s t r a c i o n q u a d r i c o r n i s

O p h i c h t h u s c y l i n d r o i d e u sD i p l e c t r u m f o r m o s u m

P r i o n o t u s p u n c t a t u sD a s y a ti s a m e r i c a n a

D a s y a ti s g u tt a t aS p h y r n i d a e

O p i s t h o n e m a o g l i n u mN a r c i n e b a n c r o ft i i

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T r a c h i n o t u s g o o d e iC y n o sc i o n a c o u p aL u t j a n u s s y n a g r i s

R h o m b o p l i t e s a u r o r u b e n sM a c r o d o n a n c y l o d o n

C y n o sc i o n v i r e sc e n sM e n ti c i r r h u s a m e r i c a n u s

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O l i g o p l i t e s s a l i e n s

1001001001001001001001001001001001001001001001001001009898979797969594939190

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36

Figure 20. Average portions (by weight) of retained and discarded catch for the different fish species in the finfish trawl fishery of

Suriname.

Length-distributions of the 20 most frequently occurring species were plotted,

distinguishing between retained and discarded where applicable. For some species,

only the larger sized individuals were retained, while others were discarded at any

length (Fig. 21).

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

20

40

60

80

100

120

140

Cynoscion jamaicensis/similis - discarded Cynoscion jamaicensis/similis - retained

1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 1011061111161211261311361411460

5

10

15

20

25

30

35

40

45

Trichiurus lepturus - discarded Trichiurus lepturus - retainedb

37

Length (cm)

Length (cm)

number of individuals


a

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

20

40

60

80

100

120

Lutjanus synagris - discarded Lutjanus synagris - retainedc

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

20

40

60

80

100

120

140

160

180

200

Selene brownii - discarded Selene brownii - retainedd

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 490

10

20

30

40

50

60

70

80

90

Orthopristis ruber - discarded Orthopristis ruber - retainede

38

Length (cm)

Length (cm)

Length (cm)




1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 490

5

10

15

20

25

30

35

40

Menticirrhus americanus - discarded Menticirrhus americanus - retainedf

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

5

10

15

20

25

30

35

40

Micropogonias furnieri - discarded Micropogonias furnieri - retainedg

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

5

10

15

20

25

30

35

40

45

50

Sphyraena barracuda - discarded Sphyraena barracuda - retainedh

39

Length (cm)

Length (cm)

Length (cm)




1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 490

5

10

15

20

25

30

35

Peprilus paru - discarded Peprilus paru - retainedi

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

10

20

30

40

50

60

70

80

Cynoscion virescens - discarded Cynoscion virescens - retainedj

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

10

20

30

40

50

60

Diapterus auratus - discarded Diapterus auratus - retainedk

40

Length (cm)

Length (cm)

Length (cm)




1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

2

4

6

8

10

12

14

16

Scomberomorus cavalla - discarded Scomberomorus cavalla - retainedl

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

5

10

15

20

25

30

Bagre bagre - discarded Bagre bagre - retainedm

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 970

50

100

150

200

250

300 Anchiovella lepidentostole - discarded

Anchoa spinifer - discarded

Ctenosciaena gracilicirrhus - discarded

Dasyatis guttata - discarded

Pellona harroweri - discarded

Prionotus punctatus - discarded

Odontognathus mucronatus - discarded

n

Figure 21. Length frequency distributions of the most common commercial fish species (a-m) and of the non-

commercial fish species (n).

41

Length (cm)

Length (cm)

Length (cm)





Thirteen invertebrate taxa (Table 13) were identified. The shrimp species P. subtilis and X.

kroyeri were sorted during the first two trips. During the third trip also N. schmitti, P. brasiliensis

and P. schmitti were caught, but then shrimp species were not always completely separated.

Approximately half of the invertebrate species occurred in less than 10 % of all samples.

Cephalopod species occurred the most, namely in 72 % of all samples (Table 13). Forty % of

these species by weight were discarded (Fig. 21). All the other invertebrate species were

discarded entirely. X. kroyeri (seabob shrimp) occurred in almost 30 % of the samples, where P.

subtilis (brown shrimp) only occurred in 15 % of the samples.

Table 13. Invertebrate species (shrimps excluded) identified in the finsfish fishery off Suriname. The frequency

of occurrence (%FO) and catch-per-unit-effort (CPUE; kg/h) is given for both species together. Used data for

the shrimp species are only from the first two trips, because during the third trip species were not separated.

Higher rank Species %FO CPUE (kg/h)ASTEROZOA Forcipulatida Uniophora granifera 5.3 < 0.1 Ophiurida 7.0 < 0.1 Paxillosida Luida senegalensis 12.3 < 0.1CRUSTACEA Decapoda – Anomura Dardanus fucosus 3.5 < 0.1

Neopetrolisthes maculatus 1.8 < 0.1 Decapoda - Brachyura Calappa nitida 5.3 < 0.1

Callinectes ornatus 17.5 < 0.1Calinectes spp. 19.3 < 0.1

Decapoda - Penaeidae P. subtilis 15.2 < 0.1X. kroyeri 27.3 0.5 ± 2.1

Stomatopoda - Unipeltata Squillidae spp. 1.8 < 0.1MOLLUSCA Gastropoda Haliotis spp. 1.8 < 0.1

Cephalopoda 71.9 0.8 ± 2.5

42

Shrimp19%

Cephalopods60%

Callinectes spp.7%

D. fucosus3%

C. ornatus8%

C. nitida1%

Others2%

invertebrate bycatch - contribution by taxon

Figure 22. Average relative portions (by catch rate) of invertebrate bycatch taxa in the finfish fishery

off Suriname. ‘Others’ includes six taxa with low relative contributions.

0 10 20 30 40 50 60 70 80 90 100

40 60


Axis Title

Cephalop

oda

Figure 23. Average portion (by weight) of retained and discarded Cephalopoda in the finfish trawl

fishery of Suriname.

43

Penaeus brasiliensis

shrimp mix

Nematopalaemon schmitti

0 10 20 30 40 50 60 70 80 90 100

100

29

0

0

71

100


Figure 24. Average portions (by weight) of retained and discarded shrimp species in the finfish trawl fishery of Suriname,

based on data from all three trips together. The retained part of the shrimp mix includes the species X. kroyeri, P. subtilis, P.

schmitti and not identified Penaeus spp., he discarded part includes the species X. kroyeri and P. subtilis.

44

4. DiscussionThis is the first study to give an overview of the catch and bycatch compositions in the different trawl

fisheries subsectors in Suriname, namely the seabob, shrimp and finfish trawl fishery. It wants to provide

a knowledge baseline of bycatch and discards and as such better inform these fisheries towards more

sustainable management.

4.1. Seabob trawl fisheryIn the seabob trawl fishery, an average bycatch:seabob ratio of 0.81 was found. In general, it is estimated

that bycatch and shrimp are caught at ratios of 5:1 in temperate and subtropical regions, and 10:1 in the

tropics (see Andrew and Pepperell, 1992 and references therein; EJF, 2003; Gillett, 2008). These ratios

might be highly variable even within a fishery (Ye et al., 2000; Tonks et al., 2008), and considerable bias

might be induced by different methods used to estimate bycatch-to-shrimp ratios (Ye, 2002; Diamond,

2003). Nevertheless, we can conclude that the Suriname seabob fishery is highly selective for a tropical

shrimp trawl fishery.

Because tropical shrimp trawling mainly targets Penaeid shrimp of the genus Penaeus (FAO, 1999), the

high bycatch ratios that are typically reported, largely result from fisheries for Penaeus sp. In contrast to

the seabob shrimp X. kroyeri, these species live further offshore, beyond the 30 m isobath on sandy

bottoms (Guéguen, 2000; Willems et al., 2015b). Off Suriname, X. kroyeri is known to reach densities up

to ca. 1400 individuals m-2, while the maximum observed densities for Penaeus sp. was only 40 indiv. m-2

(Willems et al., 2015b). Assuming similar densities of bycatch species (either fish or invertebrates) in

areas trawled for Penaeus sp. or X. kroyeri, the high densities in which X. kroyeri typically occurs, result in

low bycatch levels, relative to fisheries targeting Penaeus sp. Low bycatch levels in X. kroyeri trawl

fisheries were also observed in South-Eastern Brazil. Fish:seabob ratios here averaged 0.57 (similar to

our observed fish:seabob ratio of 0.61), decreasing to 0.38 after the introduction of different types of

BRDs (Cattani et al., 2012). In the same area, Silva et al. (2012) report that X. kroyeri on average

constitutes 75% of the catch by numbers. It seems that, unlike other penaeid shrimp, X. kroyeri allows for

a relatively selective fishery due to its high densities on the trawling grounds.

Despite this relative selectivity, 41% of the catch of the Suriname seabob fishery consists of bycatch, the

majority of which is discarded (37% of the total catch). Southall et al. (2011), however, report that 31% of

the catch is bycatch, about one-third of which is discarded. It is unclear why our findings differ from these

results, as CPUE of the seabob fleet has remained relatively constant over the years (Pérez, 2014), and

practices of discarding or retaining species doesn’t seem to have changed either (J. Jagroop, pers.

comm.).

Invertebrates only made up a small part (3% by weight) of the bycatch. This is consistent with the finding

that the epibenthic community off Suriname up to ca. 30 m depth is species-poor, and largely dominated

45

by the target species X. kroyeri (Willems et al., 2015b). In contrast, the area trawled for X. kroyeri is home

to species-rich assemblages of demersal fishes, dominated by species of the Sciaenidae family (Willems

et al., 2015a). Although these fish assemblages constitute of up to 61 species, they are characterized by

a few abundant, and many rare species (Willems et al., 2015a), a pattern that is reflected in the bycatch

of seabob fisheries. While 54 fish species were identified from the catch samples, only eight species

made up 75% of the fish bycatch (by weight). Tropical shrimp trawl fisheries are known to catch a high

diversity of bycatch species (Kelleher, 2005; Gillett, 2008). Still, the observation that a few species are

numerically dominant seems a common feature of demersal fish assemblages on soft-bottom

(sub-)tropical shelves (e.g. Rocha and Rossi-Wongtschowski, 1998; Chaves et al., 2003), and the

bycatch composition of seabob trawl fisheries operating on these shelves (e.g. Bernardes Junior et al.,

2011; Silva et al., 2012; Branco et al., 2015).

On the inner Suriname shelf (up to 40 m depth), the demersal fish community changes drastically around

the 30 m isobath, from an inshore Sciaenid fish community on mud and sandy mud, to a deeper shelf

community on offshore sandy bottoms (Willems et al., 2015a). Operating between 18 and 33 m depth, the

seabob fishery overlaps with the ‘coastal’ and ‘transition’ demersal fish assemblages as described by

Willems et al. (2015a). However, the relative composition of the most abundant bycatch species differed

from the species composition of both assemblages. The difference between these fish assemblages and

the ‘bycatch assemblage’ could be assigned to the fact that the gear used to characterize these

assemblages (try-net of 4.3 m horizontal spread; Willems et al., 2015a) differs from the commercial

seabob trawls, which have a much larger horizontal (ca. 21 m) and vertical opening (ca. 2 m; B.

Verschueren, pers. comm.). Further, in contrast to the try-net, these trawls are equipped with TEDs and

BRDs, affecting the catch composition (e.g. Polet et al., 2010; Willems et al., 2016a). On the other hand,

seabob trawl fisheries do not operate randomly, but actively seek for high densities of seabob shrimp

(Pérez, 2014). These ‘hot spots’ are known be ephemeral in nature, changing quickly in space and time

(S. Hall, pers. comm.). Most likely, a typical ‘assemblage’ of demersal fishes is associated with these

shifting patches of high shrimp densities. This is the ‘bycatch assemblage’ as observed in the current

study, largely dominated by the sciaenids S. microps and C. jamaicensis/similis. Their association with

high X. kroyeri densities is not immediately obvious, as both species had rather low contributions of this

shrimp (around 15% gravimetrical contribution) to their diet (Willems et al., 2016b).

4.2. Shrimp trawl fisheryFor the shrimp trawl fishery, we found an average bycatch-to-shrimp ratio of 4.8:1. Older data on the

Penaeus spp. fishery off Guyana, Suriname and French Guiana, reported a ratio as high as 40.2:1

(Cummins and Jones, 1973 in Andrew and Pepperell, 1992). While the average ratio for tropical shrimp

fisheries has been estimated at 10:1 (Andrew and Pepperell, 1992), more recent studies show that

bycatch ratios in these fisheries are highly variable. This is illustrated by some studies from the shrimp

trawl fisheries in Brazil (genera: Metanephrops, Penaeus, Pleoticus and Plesionika), reporting different

46

bycatch-to-shrimp ratios: 34:1 (Ubatuba region Brazil; Keunecke et al., 2007), 13:1 (Santa Catarina Brazil;

Kotas, 1998 in Vianna & Almeida, 2005) and 5:1 (Northeast Brazil; Isaac, 1999 in Vianna & Almeida,

2005). A similar variability was recorded in shrimp fisheries around the Arabian Peninsula (genera:

Megrokis, Metapenaeopsis, Metapenaeus, Parapenaeopsis, Penaeus and Trachysalambria), where ratios

ranged from 5:1 to 15:1 (Ye et al., 2000; Al-Baz & Chen, 2015; Al-Mamry et al., 2015) and in Australia’s

Northern Prawn Fishery (genera: Metapenaeus, Metapenaeopsis, Penaeus and Trachypenaeus): 19:1

and 16:1 (Brewer et al., 1998). Variation in these ratios depends on several factors: fishing ground, depth,

season, fishing gear, shrimp species, … (Stobutzki et al., 2001; Hall & Mainprize, 2005; Dell et al., 2009

and references therein). The average bycatch-to-shrimp ratio observed in the present study (ca. 5:1) was

at the lower side of the range compared to tropical shrimp trawl fisheries targeting Penaeus spp.

worldwide.

Seventy-five percent of the catch of the Suriname shrimp fishery consists of bycatch. Eighty-one percent

of this bycatch (59 % of the total catch) is discarded. Because most bycatch in tropical shrimp trawl

fisheries is discarded (Kelleher, 2005), discard ratios correspond to bycatch ratios. Although more than

half of the catch is discarded in the Suriname shrimp fishery, this number is again relatively low compared

to similar fisheries. Examples include a study by Keunecke et al. (2007), reporting that 92 % of the total

catch was discarded in the pink shrimp trawl fishery in the Ubatuba region (Brazil), while in the Kuwait

shrimp trawl fishery more than 98 % of the bycatch was discarded at sea (Ye et al., 2000).

Invertebrate bycatch made up 29 % by weight of the bycatch or 23 % by weight of the total catch. This is

high relative to other tropical shrimp trawl fisheries. Keunecke et al. (2007) observed 29 species of

crustaceans in the northern coast of São Paulo (Brazil; depth 31 – 51m), and invertebrates (jellyfish

included) accounted for ± 13 % of the catch (by weight). Tonks et al. (2008) sampled 68 invertebrate taxa

in the Jozeph Bonaparte Gulf (northwestern Australia; 35 – 70m), representing 7.7 % of the biomass.

Willems et al. (2015b) reported that the density and diversity of epibenthic invertebrates increases when

going offshore on the Suriname shelf. Although this study only sampled up to 34m depth, the high

average fishing depth of the sampled hauls in the shrimp fishery (74 m) might be a reason for the

relatively high amounts of invertebrates in the catches. Because most invertebrates in the current study

were only identified to higher taxomic levels, no conclusions can be made about the species diversity.

Fish bycatch made up 49 % of the total catch in the shrimp trawl fishery. Nearly 30 % of the fish fraction

was retained with the sciaenid C. jamaicensis/similis as the most important retained species. Also in other

tropical penaeid fisheries the fish fraction dominated the total catch: e.g. 73 % of the bycatch weight in

Australia’s Northern Prawn Fishery (knowing that the target catch only represented 2 % of the total catch;

Stobutzki et al., 2001), and 75 % of the total catch by weight in the pink shrimp trawl fishery in the

Ubatuba region (Brazil) (Keunecke et al., 2007). The fact that bycatch is dominated by fish seems a

characteristic of tropical penaeid shrimp trawl fisheries (Hall, 1999).

47

Twelve different fish families were identified from the shrimp trawl catches. In different tropical prawn

fisheries around the world a high diversity was observed: 359 teleost and elasmobranch species from 100

families (Northern and Torres Strait Prawn Fishery of Australia; Stobutzki et al., 2001), 91 bony fish

species from 38 families (southeastern coast Brazil; Vianna & Almeida, 2005), 209 species from 52

families (southeastern Gulf of California Mexico; Madrid-Vera et al., 2007), 112 teleost species from 61

families (Northern Prawn Fishery Australia; Tonks et al., 2008), 97 bony fish species from 36 families

(Arabian Sea Oman; Al-Mamry et al., 2015), 61 species from 31 families (Santa Catarina Brazil;

Rodrigues-Filho et al., 2015). The low number of fish families observed in our study could be related to

the high average fishing depth (74 m), as Willems et al. (2015a) showed that demersal fish diversity on

the Suriname shelf (up to 34 m) decreases with depth. Other studies on the shrimp trawl fisheries of

tropical waters sampled depths often below or around 30 m (Evans & Wahju, 1996; Vianna & Almeida,

2005; Al-Mamry et al., 2015; Rodrigues-Filho et al., 2015). Some studies (Madrid-Vera et al., 2007; Tonks

et al., 2008) examined hauls at greater depths: e.g. 8-76 m and 45-68 m. As mentioned above these

studies also observed a high diversity, but this may be due to the fact that samples were taken over a

larger depth range. Further, the low number of fish families observed in our study might relate to the fact

that data originated from only two fishing trips, limiting the spatio-temporal spread of the data.

Fishes of the Mugilidae family dominated the fish bycatch (ca. 50% by weight), followed by Sciaenidae

(15 %) and Lutjanidae (11 %). Willems et al. (2015a) found that the coastal fish assemblages (sampled at

20-27m depth) of the shallow internal shelf waters of Suriname were dominated by Sciaenidae and that

the deeper occurring offshore assemblages (sampled at 34m depth) were characterized by the absence

of Sciaenidae and the presence of Haemulidae, Lutjanidae, Synodontidae and Triglidae. Mugilidae were

not represented in the shallow internal shelf waters of Suriname (<40m; Willems et al., 2015a). Why

Mugilidae and Sciaenidae were dominant in the sampled hauls remains unclear, as currently there is no

information about fish assemblages at the depths where the hauls were taken. Mugilidae are usually

demersal, travel in schools and feed on fine algae, diatoms, and detritus of bottom sediments. Sciaenidae

are bottom dwelling carnivores and feed on benthic invertebrates and small fish (Cervignon et al., 1993;

Froese & Pauly, 2017). As such, they should be able to feed on juvenile mullets and shrimps. The

sampled depths will probably be at the outer habitat limit of a lot of sciaenid species (Froese & Pauly,

2017). Cynoscion jamaicensis/similis, the most important retained species, is known to occur at those

depths and feeds on fishes, crabs and shrimps. Lutjanidae are known to live at these depths and they can

occur over all types of bottoms (Froese & Pauly, 2017). In tropical prawn trawl fisheries that fish shallower

than 30 m, the Sciaenid family is often the most dominant one (Ambrose et al., 2005; Vianna & Almeida,

2005; Rodrigues-Filho et al., 2015), similar to the seabob shrimp fishery of Suriname. In deeper waters off

the Gulf of California (USA) (Madrid-Vera et al., 2007) another similar abundant family, next to

Sciaenidae, was the Haemulidae (4th most abundant family in our study by weight). Other families that

occurred in deeper waters (Gulf of California (USA) and the Joseph Bonaparte Gulf (Australia) (Madrid-

48

Vera et al., 2007; Tonks et al., 2008) were not, or at negligible abundance, present in our study:

Synodontidae, Rhinoprenidae, Trichiuridae, Engraulidae and Polynemidae.

4.2. Finfish trawl fisheryIn the finfish trawl fishery, almost half of the total catch (45 %) was discarded, and can therefore be

considered as bycatch. This was confirmed by a report of P. Charlier (1999), that determined that

approximately half of the catch was discarded in this fishery. Published research on bycatch and discards

on tropical multi-species trawl fisheries seems scarce. A study of Raeisi et al. (2011) on cutlassfish

fisheries in the Persian Gulf reported a bycatch ratio of 38%, while 12% of the total catch was discarded.

Looking at more temperate regions, bycatch in bottom trawl fisheries in the north-eastern Mediterranean

Sea is well-reported. Discard rates in this fishery varied from 31-33 % (Gurbet et al., 2013; Gökçe et al.,

2016; Soykan et al., 2016) to 37.5-44 % (Machias et al., 2001; Doganyilmaz Özbilgin et al., 2006). In

other parts of the Mediterranean Sea (Adriatic and Catalan Sea) a study of Sánchez et al. (2007) showed

discard rates in the same range, 39-48 %. Two studies on bottom trawl fisheries off the Black Sea coast

of Turkey presented similar discard rates (31-42 %; Ceylan et al., 2013; Yildiz & Karakulak, 2016).

Generally, the amount and composition of bycatch will be determined, by latitude, depth and sediment,

among other factors (Raeisi et al., 2011; Feekings et al., 2012; Ceylan et al., 2013). Discard patterns will

depend on the catch compositions, but are also determined by social and economic factors (Catchpole et

al., 2005). Consequently, discard rates may vary dramatically between regions and fisheries. Low discard

rates around 10 % were for example found in the demersal trawl fishery for hake and sole off South Africa

(Walmsley et al., 2007). On the other hand, in the beam and bottom trawl fisheries that operate in the Irish

Sea, North Sea and Northeast Atlantic, discard rates might be as high as 70% of the total catch (Borges

et al., 2005; Ulleweit et al., 2010). Overall, Kelleher (2005) reviewed that for the demersal finsfish trawl

fisheries worldwide discard rates range between 0.5 and 83 %. The same study reported discard rates

between 22 and 33 % in the trawl fisheries off central and southern Brazil (area closer to Suriname,

although a larger latitude range). In conclusion, the finfish trawl fishery of Suriname is characterized by a

relatively high discard rate, which can be attributed to the non-selective fishing technique, and the lack of

BRDs.

Invertebrates made up less than 1 % of the catch by weight. Most taxa were completely discarded, except

for the cephalopods and shrimp from which a certain amount was retained (40 % of the cephalopoda, 100

% of P. brasiliensis and 29 % of the shrimp mix). Raeisi et al. (2011), who studied cutlassfish trawl

fisheries in the Persian Gulf, also found a relatively low invertebrate fraction as their proportion made up

3.3 % of the total bycatch weight (which was 27.2 % of the total catch). Further away from the tropics, a

study of Gökçe et al. (2016) showed that the north-eastern Mediterranean invertebrates made up a much

larger part of the catch, namely 35.6 %.

49

Fish made up 99 % of the total catch, which was confirmed by the report of Charlier (1999) where the

total catch consisted for 98 % out of fish The dominance of the fish fraction was also found in other finfish

trawl studies, ranging from 64.4 to 98.1 % (Walmsley et al., 2007; Raeisi et al., 2011; Gökçe et al., 2016).

As commercial fisheries can only retain fish above the minimum landing size (MLS), the larger mesh size

(80 mm; compared to shrimp and seabob trawlers, 45 mm) of the finfish trawl net’s codend will allow the

escape of a large part of invertebrates, and as such explain the dominance of the fish fraction. Further, no

less than 98 fish species from 47 families were identified in the catch, which indicates a high level of

diversity. Charlier (1999) observed 41 different taxa in the finfish trawl fishery of Surinam for the period

1993 – 1995. This, and even higher levels of diversity, were also found during trawl surveys in other

tropical regions, for example on the continental shelf and upper slope off El Salvador (148 species from

54 families; Fuentes et al., 2015) and on the Campos Basin continental shelf and slope off Brazil (220

species; Costa et al., 2015) and in the Albatross Bay Gulf of Carpentaria Australia (237 species from 68

families; Blaber et al., 1990). The high diversity level in the first two studies probably also relates to the

large depth range were samples were taken (20-240 m for the first study and 13-2030 m for the second

study, compared to 24-39.3 m in the current study). Studies of bottom trawl fisheries operating in the

Mediterranean Sea found relatively lower, but still high levels of diversity, ranging from 52 to 135 species

(Machias et al., 2001; Doganyilmaz Özbilgin et al., 2006; Gurbet et al., 2013; Gökçe et al., 2016; Soykan

et al., 2016).

The five dominant teleost families caught during the current study were Sciaenidae, Trichiuridae,

Haemulidae, Lutjanidae and Carangidae. As mentioned above, physical characteristics of the seabed and

the associated fish assemblages change around the 30 m isobath (Willems et al., 2015a). The depth were

the samples were taken (24 to 39 m) varies around this isobath. As such members from the sciaenid

family, who dominated the coastal assemblage, and members of the Lutjanidae, who dominated the

offshore fish assemblages were both represented in the samples. Sciaenidae are confined to shallow

coastal and estuarine areas and are mainly found over muddy bottoms (Willems et al., 2015a).

Additionally, a study of the sciaenids from the tropical waters of Goa concludes that juveniles prefer rather

sandy habitats, where adults prefer rocky habitats (Hegde et al., 2016). As the average length of the most

dominant fish species, the sciaenid C. jamaicensis/similis, was less than 25 cm, the occurrence of mainly

juveniles on the finfish fishing grounds could be explained. Members of the Lutjanidae family could be

found over all bottom types, but prefer coral reefs or vegetated sandy areas (Froese & Pauly, 2017).

Looking at the other families, T. lepturus (Trichiuridae) lives generally around muddy bottoms of shallow

coastal waters. A study of Mahmoodzadeh et al. (2015) in the Oman Sea revealed that the highest

biomass of Haemulidae was found below 30 m and the biomass decreased by increasing depths.

According to Froese & Pauly (2017), this family can be found in coastal waters over sandy, rock or mud

bottoms. Carangidae could be found on mud, sand & gravel or soft bottoms (STRI, 2017).

50

Compared with this fishery’s data from the nineties (P. Charlier, 1999), a change in catch composition

could be observed. Back then the catch was dominated by L. synagris (Lutjanidae; 25 %), followed by

Haemulidae (12 %) and Dasyatidae (10 %). The decline of Lutjanidae is probably due to intensive fishing

on L. synagris and other snappers during the last two decades. Meanwhile it has also been suggested

that T. lepturus could have played a role in this decline, as this species is a voracious predator who could

have excluded other species by trophic competition (Martins & Haimovici, 1997).

4.4. Comparison of the three Suriname trawl fisheriesThe highest bycatch-to-target catch ratios in the Suriname trawl fisheries were observed in the shrimp

trawl fishery (5:1) followed by the finfish trawl fishery (1:1) and the seabob trawl fishery (0.8:1). All three

trawl fisheries differ in their target species, fishing area and fishing gear. The three factors that are likely

to affect bycatch ratios the most are the codend mesh size, the fishing area and depth, and the use of

BRDs. Based on the minimum mesh size of the trawl codend (45 mm for seabob and shrimp and 80 mm

for finfish), a higher ratio could be expected for seabob and shrimp trawl fisheries, compared to finfish.

While shrimp fisheries had indeed the highest bycatch ratios, seabob trawlers, with the same mesh size,

had the lowest. As discussed earlier, the target species X. kroyeri occurs in much larger densities on the

seabob fishing grounds than the Penaeus sp. on the shrimp fishing grounds. Secondly, even though

finfish and shrimp trawl vessels are allowed to fish in the same waters (from 15 fathoms or 27 m depth

onwards), samples for the finfish trawl fishery were taken adjacent to the seabob fishing grounds,

whereas samples for the shrimp trawl fishery were taken in deeper waters (around 40 fathoms or 74 m

depth). In these waters, next to the presence of different fish species, a higher diversity of invertebrates

can be expected (Willems et al., 2015b), causing high invertebrate bycatch ratios as observed in our

study. Thirdly, seabob trawlers use a square-mesh panel BRD which also contributes to a lower bycatch

rate, as the BRD allows small fishes to escape (Brewer et al., 1998; Polet et al., 2010; FAO & LVV, 2016).

The retained bycatch fraction was highest (16 %) for the shrimp trawl fishery, followed by the seabob

trawl fishery (4 %) (Fig. 23). The difference is most likely caused by the fact that in the shrimp trawl

fishery, the target species is less abundant relative to commercially valuable fish, compared to the seabob

trawl fishery. Defining target catch in the finfish trawl fishery is problematic, because the fishery retains a

wide range of species and sizes. As such, ‘bycatch’ can be defined as all the catch that is discarded, and

bycatch and discard rates are therefore the same (Fig. 23).

51

SEABOB SHRIMP FINFISH0

10

20

30

40

50

60

70

80

90

100

41

75

4537

59

45

Bycatch Discard rate

Figure 23. Bycatch and discard rates of the different trawl fisheries in Suriname. Both rates are percentages of the total catch.

Target catch Invertebrate fraction Fish fraction0

10

20

30

40

50

60

70

80

90

100

59

3

3125 29

4955

<1

99

SEABOB SHRIMP FINFISH

Figure 24. Invertebrate and fish fractions of the different trawl fisheries in Suriname.

The highest fraction of invertebrates was found in the shrimp trawl fisheries (Fig. 24). In each trawl fishery

only a negligible portion of the invertebrate fraction was marketed. The only commercial interesting

invertebrate in the seabob trawl fishery was F. subtilis. For the shrimp and finfish trawl fisheries only part

of the cephalopods (and shrimp in the finfish trawl fishery) were landed and processed.

52

%

Figure 25. Diagram of the fish families caught in the different trawl fisheries of Suriname. Each set represents another subsector. Each set and each intersection is given another colour. The intersection between the seabob and shrimp trawl fisheries (shaded) is empty. The three points in the intersection between the seabob and finfish trawl fisheries represent the following families: Ephippidae, Pristigasteridae, Rhinobatidae, Synodontidae, Tetraodontidae, Triakidae and Trichiuridae.

The highest diversity of fish at the family and species level was found in the finfish trawl fishery (98

species from 47 families). Diversity decreases at greater depths (Bianchi, 1991; Bianchi, 1992; Fuentes

et al., 2015), as indicated by the smaller amount of fish families noticed in the samples of the shrimp trawl

fishery. The families represented in all three subsectors (Carangidae, Haemulidae, Sciaenidae,

Stromateidae and Triglidae) (Fig. 25) are generally known to occur in a depth range from 1 to 70 m (or

even deeper waters; EOL, 2017; Froese & Pauly, 2017). Cynoscion jamaicensis/similis, a fish species

from the Sciaenidae family, was caught in all three fisheries, but was only retained in the shrimp (95 %)

and finfish (81 %) trawl fisheries. Due to the low average length of the species in the seabob fishery (9.3

cm), it was not retained. Cynoscion jamaicensis/similis had an average length of 19.7 cm in the finfish

trawl fishery (with an average length of 24.7 cm for the retained individuals). Nearshore regions are used

as nursery grounds, this is why mainly juveniles were caught in the seabob shrimp fishery (Hegde et al.,

2016). Three other representatives of the Sciaenidae family (C. virescens, M. ancylodon and N. microps)

were only found in the seabob and finfish trawl fishery and not in the shrimp trawl fishery, probably

because those species prefer shallower waters. In the finfish trawl fishery, the retention percentage for

each of these three species was much higher than in the seabob trawl fishery (C. virescens 97 % vs. 29

% retained, M. ancylodon 97 % vs. 60 % retained, N. microps 100 % vs. 53 % retained). Again, for these

species the minimum retention size (± 25 cm) determined the discard rate, as the average length of these

species was greater in the finfish trawl fishery (C. virescens 42.7 cm vs. 13.0 cm, M. ancylodon 26.1 cm

53

vs. 19.1 cm, N. microps 31.4 cm vs. 17.8 cm). This is probably due to the fact that juveniles prefer regions

closer to the shore (Hegde et al., 2016).

Two species of Haemulidae were represented in both seabob and finfish trawl fisheries (Haemulidae were

not determined to species level in the shrimp trawl fishery): Haemulon boschmae and O. ruber. The first

species was completely discarded in both fisheries (maximum length (Froese & Pauly, 2017) < MLS), the

second species only in the seabob trawl fishery, where in the finfish trawl fishery it was discarded for 33

%. Also here juveniles are found closer to the shore (Froese & Pauly, 2017). Prionotus punctatus

(Triglidae) was completely discarded in all fisheries. Although this species can reach a maximum length of

45 cm, it is not commercially important. Peprilus paru (Stromateidae) was completely discarded in the

seabob trawl fishery (average length 3.8 cm), partly retained in the finfish trawl fishery (56 %; average

length 18.0 cm) and completely retained in the shrimp trawl fishery. This species, with a maximum length

of 30 cm, prefers depths between 50 and 70 meters and juveniles occur in shallow coastal waters (Froese

& Pauly, 2017). This explains the high retention percentage for the shrimp trawl fishery.

Carangidae were also found in all three fisheries, but not represented by similar species. The only

representative of this family in the shrimp trawl fishery was S. setapinnis, which was completely

discarded. Although this species is described as “good food fish and marketed fresh” (Froese & Pauly,

2017), it is not landed in Suriname by shrimp trawlers. The species Caranx hippos, S brownie and Selene

vormer were caught in both seabob and finfish trawl fisheries. Selene vormer was completely discarded in

both fisheries. Both species are probable not commercially important. Caranx hippos, commercially

important in haul seine, gillnet and trawl fisheries (Carpenter & De Angelis, 2016), with an average length

of 44.0 cm in the seabob and 62.5 cm in the finfish trawl fishery, was completely discarded in the seabob

trawl fishery and almost completely retained in the finfish trawl fishery (91 %). This was probably due to

the low amount of individuals (2) caught in the seabob trawl fishery.

The families only represented in the the seabob trawl fishery (Fig. 25) are probably only found there

because of their preference to live in shallow waters or due to the anatomy of the individuals of the

Achiridae, Cynoglossidae or Muraenidae families, making it easier for them to escape through the larger

meshes of the finfish trawl codend.

Bothidae, Bramidae, Scorpaenidae and Soleidae were only found in the samples of the shrimp trawl

fishery (Fig. 25). These families occur from the coast to several 100 meters deep, but can probably not

escape through the codend of the shrimp trawl nets. The fact that these families are not found in the

seabob trawl nets, might be due to their preference for coarser sediment or due to their ability to escape

through the BRD. Species of these families were (almost) completely discarded, probably due to a lack of

commercial interest.

4.5. Some aspects concerning bycatch management and discard reductionSeveral fish species in the bycatch of one fishery off Suriname are of commercial interest to other

Suriname fisheries. As such, the mortality of bycaught and discarded commercial fishes might have a

54

socio-economic impact, negatively affecting other fleets that target these species. For example the

species C. jamaicensis/similis is not only a dominant fish species in the discussed trawl fisheries, but is

also targeted in the artisanal fishing fleet off Suriname. More information about the natural resources in

the different fisheries should be gathered and fishermen should be interviewed to better understand the

nature of possible conflicts and to address future management.

Due to the lack of stock assessments or mass-balance models (e.g. Ecopath with Ecosim; Christensen

and Pauly, 2004), it is currently impossible to quantify the ecological and socio-economic effects of

discarding. Therefore, a precautionary approach to bycatch management is recommended, which implies

that bycatch should further be reduced, in the absence of models to define safe limits of bycatch mortality.

Bycatch might also particularly affect species with a low natural resistance to fishing mortality, such as

elasmobranches (e.g. Stevens et al., 2000). Several ray and shark species which are globally

endangered and listed on the IUCN Red List of Threatened Species occurred in bycatch of both seabob

and finfish trawl fisheries, including Dasyatis geijskesi and Rhinoptera percellens (‘near threatened’),

Dasyatis guttata, Gymnura micrura and Narcine brasiliensis (‘data deficient’), and Mustelus higmani

(‘least concern’). Urotrygon microphthalmum (‘least concern’) was only found in the samples of the

seabob trawl fishery, Rhinoptera bonasus (‘near threatened’), Dasyatis americana (‘data deficient’),

Carcharhinus falciformis (vulnerable), Sphyrna lewini (endangered) and Narcine bancroftii (critically

endangered) only in the samples of the finfish trawl fishery (IUCN, 2017). While the use of TEDs in the

seabob trawl fishery has proven to significantly reduce their capture (Willems et al., 2016a), our results

show that most of these species are still regularly caught in this fishery. To further reduce the bycatch of

elasmobranches, the use of TEDs with reduced bar spacing (Trash-and-Turtle Excluder Devices or

TTEDs) was evaluated and has shown promising results (LVV and FAO, 2017). The finfish trawl fishery is

currently not obligated to use TEDs. Hence, next to elasmobranches, still a certain amount of turtles ends

up in the net. To address the bycatch problem of Endangered Threatened and Protected (ETP) species,

TEDs will be introduced in this fishery. Therefore, TEDs are being tested by WWF Guianas (in association

with LVV and the National Oceanic and Atmospheric Administration of the U.S. (NOAA)) in the framework

of the REBYC-II LAC project.

Bycatch reduction could be achieved through changes in the operational characteristics. For example

through the use of a trynet, and constant communication on shrimp catches among boats, the seabob

trawl fishery off Suriname operates in a way that maximizes shrimp CPUE (Pérez, 2014). Further,

temporal closure of a fishery during spawning season could also help to protect target stocks from

mortality. Fishing capacity can also be reduced in terms of engine power. Because in the finfish trawl

fishery the installed engine power is sometimes higher than 500 hp, the maximal permitted engine power

of 500 hp will be strictly imposed from January 2019. Bycatch reduction could also be accomplished by

additional technical gear adaptations (LVV Fisheries Department, 2013). BRDs have shown to cause a

55

34%-reduction in fish bycatch (by weight) (Polet et al., 2010). The Nordmøre-grid, a square-mesh panel

BRD is already obligated in the seabob fishery and will further be optimized. In the shrimp trawl fishery

experiments with different BRDs will be conducted in the near future (LVV Fisheries Department, 2013).

Additional benefits of bycatch reduction might include reduction of fuel consumption due to reduced drag

of codends through the water (Suuronen et al., 2012), and reduce the workload of catch sorting on deck.

Acknowledgements

We thank captain Stephen Hall and crew from FV Neptune-6, captain Joseph … and crew from FV Vier

Gebroeders, captain Harpal … and crew from FV Minerva, captain Jan … and crew from FV Berendina-

Hermina, captain … … and crew from FV Starshrimper and captain … … and crew from FV Ranmar 61

for their support in data collection on board. The Suriname Ministry of Agriculture, Livestock and Fisheries

(LVV), the World Wildlife Fund (WWF) and the Anton De Kom University of Suriname are acknowledged

for supporting the research in various ways. We further thank the Heiploeg Group, Heiploeg Suriname

N.V., Holsu N.V., Marisa Fisheries, Suvveb N.V. and Mr. Moti for the financial and logistic support of the

research.

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