SURVEY OF THE PELAGIC FISH RESOURCES OFF GHANA 13...

UNION ECONOMIQUE ET MONETAIRE MARINE FISHERIES RESEARCH

OUEST AFRICAINE DIVISION - GHANA (MFRD)

SURVEY OF THE PELAGIC FISH RESOURCES OFF GHANA

13 March – 17 March 2012

Marine Fisheries Research Division, Tema,Ghana

Centre de Recherches Océanographiques (CRO), Dakar, Sénégal

R.V. ITAF DEMÉ– CRO, Senegal

Roche ltée, Groupe-conseil

3075, chemin des Quatre-Bourgeois, bur. 3

Québec (Québec) Canada G1W 4Y4

1

DRAFT FINAL REPORT OF EUMOA SPONSORED

SURVEY OF THE PELAGIC FISH RESOURCES OFF GHANA

13TH – 17TH MARCH, 2012

by

RichmondQuartey*

Ebenezer Ekuban*

AbdoulayeSaaré**

*Marine Fisheries Research Division, Tema, Ghana

and

** Centre de Recherches Océanographiques de Dakar - Thiaroye, Dakar, Sénégal

2

TABLE OF CONTENTS:

1 INTRODUCTION…………………………………………………..3

1.1 OBJECTIVES OF THE CRUISE………………………………4

1.2 PARTICIPANTS…………………………………………………4

1.3 NARRATIVE……………………………………………………..5

2 METHODS………………………………………………………….7

2.1 ENVIRONMENTAL DATA…………………………………….7

2.2 BIOLOGICAL SAMPLING…………………………………….8

2.3 ACOUSTICS SAMPLING……………………………………..9

3 SURVEY RESULTS………………………………………………11

3.1 HYDRGRAPHIC CONDITIONS

3.1.1 Salinity hydrographical profiles……………………………..11

3.1.2 Temperature…………………………………………………..12

3.2 PELAGIC FISH…………………………………………………….13

4 OVER VIEW OF RESULTS…………………………………………18

Annex I List of Participants

Annex II Fishing Operations

Annex III Instruments and Fishing Gear Used

Annex IV Number and Biomass of Main Species

Annex V Size Frequency of Main Species

Annex VII List of Participants

3

1 INTRODUCTION

The survey was organized by the Centre de Recherché Océanographiques of Dakar and

sponsored by the Economic and Monetary Union of West Africa, UEMOA, under the

International program of cooperation within the West African States on agriculture (No Act

03/2001). N°05/2007/CM/UEMOA 2007. This project is the first of a series of projects and

agreements between EUMOA involving surveys with the research vessel “R.V ITAF DEME”. The

objectives of the survey had been agreed upon during discussions between the EUMOA and the

Ghana government through the Fisheries Commission under the Ministry of Food and

Agriculture and the Environmental Protection Agency (EPA) in Ghana.

The broad agricultural policy of the Economic Union of West African States is towards the

regional project for assessment of fish stocks. The guidelines of the agricultural policy of the

UEMOA (PAU) were adopted in December 2001 by the Conference of Heads of State and

Government of UEMOA, through the additional Act 03/2001. The fisheries sector was addressed

specifically in axis 2 of the PAU: "deepening of the common market in the agricultural sector and

management of shared resources.

Under the Agricultural Policy of UEMOA (PAU), a three year program was adopted in Dakar in

March 2003 to develop the fisheries sector in the UEMOA which aims to establish a process of

coordinating and harmonizing management of shared fisheries resources, for sustainable

management of these resources and to contribute to food security and poverty reduction in the

UEMOA. This program includes, among others, the definition of a plan of concerted

development of fisheries and aquaculture within the UEMOA underpinned by good knowledge of

the state of fisheries resources in the UEMOA countries. The objective of this program is to

establish a process of coordination and harmonization of the management of shared fisheries

resources for sustainable management of these resources and contribute to food security and

poverty reduction in the UEMOA area. This program consists of five (05) components namely:

the creation of the Advisory Committee on the harmonization of policies and the laws of the

Member States concerning fishing and aquaculture. The definition of a concerted plan of

fisheries and aquaculture in UEMOA is a regional strategy of negotiation of the fisheries within

the UEMOA agreements.

This Project aims at improving and strengthening the knowledge of the stocks of the member

states of the Union, by collecting the appropriate scientific data, to set coherent and effective

measures of arrangement, in the optics of a responsible fishing. It will also create continuity

4

along the African West coast and meet the need to have the best information on the stock of the

region, etc.

1.1 Objectives

Following the agreement between UEMOA and the CRO, the main objectives of the survey

were:

To estimate the biomass and map the distribution of small pelagic fish stocks off Ghana by

hydro-acoustic methods and describe the hydrographic conditions in the region over a period

of 6 days, from March 13 - 17, 2012.

To map the general hydrographic regime and to monitor the temperature, salinity at deep

water trawl stations and on hydrographical stations

Collect biological data of the main target species

To sample standard hydrographical transects for temperature, salinity and oxygen.

On the job training for local participants covering main survey routines

1.2 Participation

Participating scientists from Ghana boarded the vessel at Takoradi on the 13th of March 2012 to

join the scientists and crew of the N/O Itaf Deme.

List of scientific participants:

From: Centre de Recherches Océanographiques de Dakar-Thiaroye (CRODT), Sénégal:

Abdoulaye Sarre (Cruise leader) and Ndiaga Thiam (Fisheries biologist)

From: The Marine Fisheries Research Division, Tema, Ghana:

Richmond Quartey and Ebenezer Ekuban

1.3 Narrative

5

The survey started on the 13 March 2012 at 12:30 GMT (GMT=Local time) from Takoradi. The

vessel departed and steamed east towards Lomé at the border with Togo, where the trip ended

on the 17 March 2012.

After the disembarkation of the Ivoirians, the ship loaded Mr. Quartey and Mr. Ekuban of Ghana,

the campaign of Ghana began in the morning of March 13th and all zones were covered from

13th till 17th March.

In total, 13 transects were canvassed; 41 hydrologic stations were visited. In every region (West,

Centre and East of Ghana) measurements of current meters were performed.

The acoustical index of cogitation was recorded continuously with SIMRAD SOUNDER ER60.

The fishing operations were performed according to the detections; type of trawl-net used was

dependent on the location of these detections (at the surface or at the bottom); parallel course

tracks (acoustic transects) about 10 NM (nautical miles) apart. During this season, detections

were rare on the mid water casts. On the contrary, significant detections were regularly recorded

on demersal casts. In total 12 throws of trawl-net were performed, 5 with the mid water trawl and

7 with the demersal trawl-net.

During the survey semi-random swept-area hauls were carried out on the shelf within the depth

zones 20-30m, 31–50m, and 51-100m during daytime. Continuous acoustic registrations were

done throughout the survey. Pelagic trawling on registrations and random trawl hauls were taken

irregularly but with the aim of covering representative areas of the shelf between 20 and 100m

depth. Trawling was done irregularly either to identify echo registrations or to check ‘blindly’ if

fish were mixed with the plankton in the upper layers of the water column. Pelagic trawl with

floats was often used to catch fish close to the surface. A smaller pelagic trawl or the bottom

trawl with floats was used for sampling pelagic fish in shallow waters (depth less than 25metres).

1.4 Survey Efforts

Figure 1 shows the cruise tracks with trawl and hydrographic stations for the Ghanaian region.

6

Fig. 1 Cruise Tracks of Ghana Survey

Table1.1 Survey area and valid trawl stations by depth stratum, total trawl stations separated by

bottom (BT) and pelagic (PT), hydrographic stations (CTD) and distance surveyed in NM.

Summary of Survey Effort

Table 1.1 Survey Areas and Trawl Station

2. METHODOLOGY

2.1 Meteorological and hydrographical sampling

Area BT PT CTD Dist. Surveyed

Ghana 7 5 41 706 NM

7

Temperature, salinity, and oxygen sampling

CTD were taken in connection with most trawl stations and at predetermined hydrographic

transects. Figure 1 presents positions for CTD stations. A Seabird 911 CTD plus was used to

obtain vertical profiles of temperature, salinity and oxygen. Real time plotting and logging was

done using the Seabird Seasave software installed on a PC. The profiles were usually taken

down to a few meters above the bottom. The calibration constant calculated during surveys off

the western Gulf of Guinea was applied for the whole survey.

Thermosalinograph

The ES38B thermosalinograph run routinely during the survey. It continuously obtained

samples of sea surface salinity and relative temperature (5 m depth) every 10 sec during the

survey.

Current speed and direction measurement (Aanderaa)

The ship-borne Acoustic Doppler Current Profiler (Aanderaa) run throughout the survey. The

Aanderaa was set to external trigger by the Simrad ER 60 acoustic system. The depth cell

interval set to 8m and the number of cells set to 50.

Meteorological

Wind direction and speed, air temperature, global radiation and sea surface temperature (5m

depth) were logged automatically every nautical mile on an Aanderaa meteorological station.

The environmental data collection was performed using a CTD brand ALEC model AST 1000.

Measurements were taken from 41 stations on the 13-transect coverage area. On the 7th

transect temperature and salinity was taken at 10, 50 and 100 meters depths. Transects 2, 5

and 6 were sampled at 10, 25, 50, 100, and 200 meters depth.

8

2.2 Biological fish sampling

The pelagic trawl catches were sampled for species composition by weight and numbers. The

deck sampling procedure is described in more detail by StrØmme (1992). The length

measurement (total length) was taken for target species. The length of each fish was recorded to

the nearest 1 cm below, and for anchovy to the nearest 1 mm below. The mantle length was

measured to the nearest 1 cm below for Sepia spp. In addition, at a few stations total length and

body weight (g) were recorded for the target species in the acoustic survey. Basic information

recorded at each fishing station i.e. trawl hauls, is presented in Annex II. A description of gear

used, acoustic instruments and their standard settings is in Annex III. The swept-area estimates

are presented in Annex IV. Pooled length frequency distributions, raised to catch per hour, of

selected species by area are shown in Annex V. Groups families included in the species

composition and swept area analysis is given in Annex VI. Fishing operations were performed

using a pelagic trawl, and a mid-water trawl employing big floats. These operations were carried

out according to the importance of concentrations encountered. Thus 12 hauls were made in

total, with 7 midwater trawls and 5 pelagic trawls. At each station, a representative sample was

taken to determine the composition, weight and number by species, size frequency for the target

species.

The length-weight relationship used to estimate biomass is:

W = L3 * condition factor (cond)

100

Where a condition factor (cond) =

0.94 was used for round sardinella,

0.97 for flat sardinella, 0.96 and

0.88 for mackerel for Carangidae, Clupeidae and associated species. with an average

size of 23 cm was used for the evaluation biomass.

2.3 Biomass Estimates

Acoustic abundance estimation

A SIMRAD ER 60 Echo sounder was used and the echograms were stored on files. The

acoustic biomass estimates were based on the integration techniques. The large scale Survey

system (LSSS, Christian Michelsen Research Center) was used for integration, analysis and

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allocation of the integrated SA-values (average area back scattering coefficient in m2/NM2). The

splitting and allocation of the integrator outputs (SA-values) was based on a combination of a

visual scrutiny of the behavior pattern as deduced from echo diagrams, LSSS analysis and the

catch composition. The mean integrator value in each sampling unit (SA-values) was divided

between the standard categories / groups of fish, as noted below, on the basis of trawl catches

and characteristics of echo traces.

-Sardinella (Sardinella aurita and S. maderansis)

-PEL 1 (clupeids other than sardinella)

-PEL 2 (carangids, scombrids, barracudas, hairtail)

-Mesopelagic fish

-Demersal fish

-Plankton

The following target strength (TS) function was applied to counter sA-values (mean integrator

value for a given area) to number of fish (sardinella, PEL 2):

TS = 20 log L – 72 dB (1)

Or in the form

CF = 1.26 – 106 –L-2 (2)

Where L is total length CF is the reciprocal back scattering strength, or the so-called fish

conversion factor. In order to split and convert the allocated sA-values (m2/NM2) to fish densities

(number per length group per NM2) the following formula was used

Where ρi= number of fish in length group i

(3)

iA i

i

Fi

nSp

p

Ci

1

10

A = area (NM2) of fish concentration

SA = mean integrator value (echo density) in area A (m2/NM2)

Pi = proportion of fish in length group I in sample from the area

CFi = fish conversion factor for length group i

The number per length group (ρi) was then summed and the total number of fish obtained:

ρ = ∑n ρ i

i=1 (4)

The length distribution of a given species within an area was computed by simple adding of the

length frequencies obtained in the pelagic trawl samples within the area. In the case of co-

occurrence of target species, the SA value was split in accordance with length distribution and

catch rate in numbers in the trawl catches. Biomass per length group (Bi) was estimated by

applying measured weights by length (W i) when available or theoretical weights (calculated by

using condition factors), multiplied with number of fish in the same length group (Ni). The total

biomass in each area was obtained by summing the biomass of each length group:

B =∑n ρ WI

i=1

The number and biomass per length group in each concentration were then added up to obtain

totals for each region.

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3 SURVEY RESULTS

3.1 Hydrography

Hydrographical data was collected on fixed CTD stations from the Thermosalinograph and the

Aanderaa weather station that continuously collected sea surface temperature, wind speed and

direction, solar radiation, etc. during the survey.

The section worked here show a stable stratified distribution of the oceanographic parameters,

Surface salinity was between 34.2 and 34.85 0/00 with strong salinity gradient being found in the

central and western part of the shelf as shown in figure 3.1.

Fig. 3.1 Sea Surface salinity on Ghana shelf

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Temperature

Sea surface temperatures were dominated by water temperatures higher than 29oC for the

entire shelf of Ghana at the surface figure 3.

2

Fig. 3.2 Spatial Distribution of Temperature-Ghana

Fig. 3.3 Vertical sections of temperature off Tema

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4. RESULTS FROM THE ACOUSTIC SURVEY

The distribution area of the main groups of pelagic fish on the shelf off Ghana, i.e. the

sardinellas, Horse, PEL 1 (Clupeids), and PEL 2 (mainly carangids), are depicted in the following

figures (4.1 – 4.6) using the integrator values from the LSSS echo-integrator system recorded

with the ES38B kHz transducer connected to the ER60. The acoustic densities (in m2NM2) are

illustrated by a scale normally used on acoustic surveys with “Dr. Fridtjof Nansen”.

Ghana shelf

The hydro acoustic survey of Ghana section covered the shelf and slope systematically to 100m

depth during the day time, continuing offshore during the night hours. Due to lack of time and

sea conditions, we could not repeat areas where the acoustic densities were weak at night.

However, the coast of Ghana was properly covered so as to estimate its pelagic biomass. Low

to medium acoustic densities was found over most of the shelf.

Pelagic Fish

The main groups of pelagic fish encountered during the survey of Ghana illustrated with

contoured acoustic densities are shown in Figure 4.1 – 4.6

Sardinella and Achovy

Sardinella maderensis was the prominent species in this group encountered, figure 4.1, and

accounted for 81% of the total sardinella catch in this sub region.

Fig. 4.1 Distribution of S. maderensis

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Length distribution for this group was between 6cm and 9cm for both species. However very

small densities of S. aurita were encountered only at the western end of Ghana around Cape

Three point, figure 4.2.

Fig. 4.2 Distribution of S. aurita in Ghana

Table 4.1 shows that the total biomass estimates for the main groups encountered during the

survey.

MAIN GROUPS BIOMASS ESTIMATES (TONS)

S. maderensis 4550

S. aurita 1070

Anchovy 1530

Horse 8940

PEL 1 460

PEL 2 23790

Table 4.1 Biomass Estimates of the Survey

15

However a few anchovies were caught on this expedition just beyond the 30 m depth contour, as

shown in figure 4.3, with length distribution ranging from 6 cm to 8 cm and a total biomass

estimate of 1530 tons.

Fig.4.3 Distribution and concentration of anchovy in Ghana

Horse Group

D.macarellus was the most dominant species for the Horse group. It was distributed widely both

in the eastern and western portions of the shelf, figure 4.4.

Fig. 4.4 Distribution and abundance of Horse in Ghana

16

Their distribution was not so dense and to a large extent are mostly juveniles. Length distribution

for this group ranged from a minimum of 2cm to a maximum of 28cm. Assuming an average

length of 7cm for the two groups with a condition factor of 0.96, the biomass estimate of Horse is

8 940 tons.

PEL 1

Only one member of this group was encountered during this survey. Decapterus punctatus was

encountered in the inner portion of the shelf in small quantity (fig. 4.5). Assuming an average

length of 7 cm and a condition factor of 0.96 the biomass estimate of PEL 1 was 460 tons (Table

4.1)

Fig. 4.5 Distribution and abundance for PEL 1-Ghana

PEL 2

This group was encountered in both the central portion and the western part of the shelf in wide

patches (fig 4.6). Among the carangids D. macerate was the most prominent of this group in

terms of number of occurrences. It was distributed in the inshore area within the 30 m to 50 m

depth range. Within this range also a few juvenile D. punctatus were encountered with some

medium size Moon fish, Selene dorsalis, also showing up. However, the biggest carangid

17

present in this survey was Alectis alexandrenus which gave the highest weight caught in the

entire survey. The main species widely distributed in this group is D. macerate which was caught

at two different depth ranges. The length distribution of the species is found in Annex. Assuming

an average total length of 13cm for all the species and a measured condition factor of 0.96 the

biomass estimate of PEL 2 was estimated to about 7 840 tons (Table 4.1).

Fig. 4.6 Distribution and abundance of PEL 2-Ghana

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General Over View

The biomass estimated in this work is in many respects comparable to estimates from other

previous surveys in Ghana with regards to the methodology. Any differences may be due to the

fact that all surveys have either been limited in time or restricted in area, which could lead to

overestimation or underestimation. Recruitment could possibly have changed also, with the

pelagic species whose abundance is usually linked to favorable environmental parameters. It is

likely that recent high average SST may have had an impact on the lower estimates achieved in

this survey, in addition to this survey being a short one (7 days).

However, it is going to be difficult to relate results from this survey with any previous surveys for

the simple reason that we have no records of any acoustic surveys in the Ghanaian waters in

March. The pelagic stocks are usually seasonal, and in this survey they were found mostly in

waters between the 40m to 50m depths; revealing high concentrations of Sardinella

maderensis and S. auritas and anchovies. The average length registered for these three pelagic

species was ranges from 7 – 9 cm; indicating that they are mostly juveniles yet to be recruited to

the fisheries.

The distribution pattern for the pelagic resources encountered in this survey was also noteworthy

for the time of the year. The anchovies encountered were in one cluster, and the same goes for

the S. aurita and the PEL 1. And these were found in smaller concentrations ranging between

0.46 to 1.07 x 103 tons.

However, the situation is very different for the S. maderensis, Horse and PEL 2. These were all

encountered in two different concentrations; there was an eastern group and a western group,

except for Horse, that was found in the Central part of the shelf and to the west of the shelf. For

S. maderensis, the Central concentration was greater than the Western concentration (2.56 to

1.99) x103 tons; whereas for PEL2, the Western concentration was greater than the Central

concentration (20.3 to 3.45) x 103 tons. For Horse, the concentration was found in the Eastern

and the Central parts of the shelf, with the Eastern having the greater weight i.e. 7.84 to 1.10 x

103 tons.

The depth at which these pelagic species were encountered indicate that they are not yet ready

to be recruited to the artisanal fisheries since their range extends beyond the 30 m depth

contour for artisanal fisheries, and also their sizes indicate that they are juveniles except ,

perhaps, for the anchovies.

19

REFERENCES

Toresen, R., Gjøsæter, H., and Barros, P. 1998. The acoustic method as used in the

abundance estimation of capelin (Mallotusvillosus Müller) and herring (Clupeaharengus

Linné) in the Barents Sea. Fisheries Research 34 (1998) 27-37.

MacLennan, D. N. and Simmons E. J. (1992). Fisheries Acoustics. Chapman and Hall.325p.

20

ANNEX I List of Participants in the Campaign

Name Function Period

Abdoulaye SARRE Coordonnateur du navire From 2 to 31 March

Ndiaga THIAM Biologiste From 2 to 31 March

Mor SYLLAResponsable collecte

biologiqueFrom 2 to 31 March

Cheikh NDOURResponsable collecte

environnementaleFrom 2 to 31 March

Amadou Fallou NIANG Biologist From 2 to 31 March

Madiabel DIOP Biologist From 2 to 31 March

Richmond QUARTEY Biologist /Ghana From March 13 to 17

Ebenezer EKUBAN Biologist /Ghana From March 13 to 17

Karim Moulaye MARA commander: From 2 to 31 March

Arfang SARR Shift Supervisor From 2 to 31 March

Abdourahmane SARR Chief Engineer From 2 to 31 March

Youssou SAMB Lieutenant Fishing From 2 to 31 March

Ousseynou Faye crew From 2 to 31 March

Alassane Séne crew From 2 to 31 March

OusseynouNdiaye crew From 2 to 31 March

Mamadou Niang crew From 2 to 31 March

AdamaSy crew From 2 to 31 March

LansanaDiedhiou crew From 2 to 31 March

Mamadou NIASSY crew From 2 to 31 March

Serigne Lo crew From 2 to 31 March

Saliou Ba crew From 2 to 31 March

Abdoulaye M’Bengue crew From 2 to 31 March

Moussa Thiandoum crew From 2 to 31 March

Mbaye N’Diaye crew From 2 to 31 March

Idrissa Diémé crew From 2 to 31 March

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ANNEX II Results Fishing Operations - GHANA

ItafDeme SURVEY:2120301 STATION 12

DATE :13/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 4ｰ53

start stop duration Lon W 2ｰ25

TIME :23:20:00 23:50:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800

FDEPTH: 0 0 Gear cond : 0

BDEPTH: 30 32 Validity : 0

Towing dir: 0ｰ Wire out : 50 Speed : 2.5 kn

Sorted : 4 Total catch: 4.06 Catch/hour: 8.12

SPECIES CATCH/HOUR% OF TOT

C SAMP

weight numbers

Engraulisencrasicolus 6 1800 73.89 14

Sardinellaaurita 0.6 126 7.39 13

Sepia sp. 0.4 38 4.93

Sardinellamaderensis 0.4 8 4.93

Caranxlatus 0.2 2 2.46

Decapterusmacarellus 0.2 4 2.46

Alloteuthisafricana 0.2 24 2.46

Elagatisbipinnulata 0.1 2 1.23

Sauridabrasiliensis 0.02 2 0.25

__________ ________

Total 8.12 100


DATE :14/03/2012 GEAR TYPE: BT NO: 1POSITIONlat N 4ｰ57


TIME :16:20:00 16:50:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800





SPECIES CATCH/HOUR% OF TOTC SAMP

weight Numbers

Brachydeuterusauritus 50 2294 38.05 15

Chloroscombruschrysurus 20 834 15.22

Polydactylusquadrifilis 18 2 13.7

Sphyraenaguachancho 8 130 6.09

Pomadasysperoteti 6 2 4.57

Drepaneafricana 5.6 62 4.26

22

Selene dorsalis 5.4 540 4.11

Galeoidesdecadactylus 4 74 3.04

Trichiuruslepturus 3.8 2 2.89

Pseudotolithustypus 2 22 1.52

Ethmalosafimbriata 1.6 16 1.22

Pseudotolithusbrachygnathus 1.2 2 0.91

Panulirusregius 0.9 6 0.68

Elopslacerta 0.8 2 0.61

Alectisalexandrinus 0.7 8 0.53

Ephippionguttifer 0.6 2 0.46

Callinectes sp. 0.6 4 0.46

Ilishaafricana 0.6 16 0.46

Dentexcanariensis 0.5 2 0.38

Cynoglossussenegalensis 0.4 4 0.3

Lagocephaluslaevigatus 0.3 6 0.23

Pteroscionpeli 0.3 16 0.23

Sardinellamaderensis 0.1 6 0.08

__________ ________

Total 131.4 100




TIME :19:20:00 19:50:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers

Decapterusmacarellus 1 14 47.17

Balistescapriscus 1 8 47.17

EXOCOETIDAE 0.1 2 4.72


__________ ________

Total 2.12 100



start stop duration Lon W 1ｰ8.

TIME :05:45:00 06:15:00 30.0 (min) Purpose : 1

23

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers

Decapterusmacarellus 0.1 94 19.23 17

Diodonhystrix 0.4 8 76.92


__________ ________

0.52 100



start stop duration Lon W 1ｰ8.

TIME :09:40:00 10:10:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers

Lutjanusfulgens 50 146 31.06

Pagruscaeruleostictus 23 52 14.29

Lethrinusatlanticus 23 78 14.29

Pseudupeneusprayensis 16.4 382 10.19


Chromis sp. 9 164 5.59

Acanthostracionquadricornis 8.2 30 5.09

Acanthurusmonroviae 4.4 12 2.73

Epinephelusaeneus 2.2 2 1.37

Apsilusfuscus 2 32 1.24

Dasyatischrysonota 1.8 2 1.12

Balistespunctatus 1.4 2 0.87

Bodianusspeciosus 1.2 2 0.75

Lagocephaluslaevigatus 1 2 0.62

Aluteruspunctata 0.8 4 0.5

Syaciummicrurum 0.8 8 0.5

Pagellusbellottii 0.6 2 0.37

Chaetodonhoefleri 0.5 4 0.31

Fistulariatabacaria 0.4 6 0.25

24

Trachinocephalusmyops 0.4 4 0.25

Xyrichtysnovacula 0.04 4 0.02

Priacanthusarenatus 0.04 2 0.02

__________ ________

Total 160.98 100


DATE :15/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 5ｰ3.


TIME :16:25:00 16:55:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers


Euleptorhamphusvelox 0.5 4 67.57


Psenes sp. 0.02 2 2.7


__________ ________

0.74 100




TIME :03:55:00 04:25:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers

25

Caranxlatus 0.002 2 0



Caranxcrysos 0.5 2 92.59

__________ ________

0.54 100




TIME :05:05:00 05:35:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800




Sorted : 0 Total catch: 0.00 Catch/hour: 0


weight Numbers

N O C A T C H 0 0 0

__________ ________

0




TIME :11:10:00 11:40:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers

Octopus vulgaris 6 4 19.66

26

Pagruscaeruleostictus 5.6 136 18.35

Epinephelusaeneus 5.4 6 17.69

Balistespunctatus 3.6 8 11.8

Fistulariatabacaria 1.5 58 4.91


Balistescapriscus 0.9 2 2.95

Pseudupeneusprayensis 0.8 28 2.62

Pagellusbellottii 0.7 4 2.29

Sepia officinalishierredda 0.6 30 1.97


Citharichthysstampflii 0.6 12 1.97

Grammoplitesgruveli 0.5 4 1.64



Loligo vulgaris 0.4 86 1.31

Chloroscombruschrysurus 0.3 2 0.98

Arnoglossusimperialis 0.3 20 0.98

Priacanthusarenatus 0.3 6 0.98

Bothuspodasafricanus 0.1 2 0.33


_________ ________

Total 30.52 100



start stop duration Lon E 0ｰ17

TIME :20:15:00 20:45:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers

Engraulisencrasicolus 0.02 2 9.09


Decapterusmacarellus 0.002 2 0

__________ ________

0.22 100


DATE :17/03/2012 GEAR TYPE: BT NO: 1POSITIONlat N 6ｰ1.

start stop duration Lon E 1ｰ9.

TIME :11:50:00 12:20:00 30.0 (min) Purpose : 1

27

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers

Diodonhystrix 6.8 14 24.73

Aluteruspunctata 5 14 18.18

Ephippionguttifer 3.8 4 13.82

Rhinobatosrhinobatos 3.8 4 13.82

Balistescapriscus 2.6 6 9.45



Zanobatusshoenleinii 0.7 2 2.55

Xyrichtysnovacula 0.6 10 2.18

Pagruscaeruleostictus 0.6 2 2.18


__________ ________

Total 27.5 100



start stop duration Lon E 1ｰ9.

TIME :14:05:00 14:35:00 30.0 (min) Purpose : 1

LOG : 0.00 0.00 0.0 Region 2800






weight Numbers

Alectisalexandrinus 21.6 44 63.49 20

Brachydeuterusauritus 9 34 26.46 24

Selene dorsalis 1.42 16 4.17 21

Decapteruspunctatus 1.2 472 3.53 22


__________ ________

Total 34.02 100

ANNEXE III Scientific Equipment and Gear

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Scientific Equipment

Simrad Sounder ER 60 Simrad Integrator BI60 1 Transducer38 kHz ES38B 1 Transducer 120 kHz ES120-7 PlanometerTAMAYA One Japanese CTD brand ALEC A Current meter Anderaa 1 Mid water trawl (Norwegian type) 2 Demersal trawls 1 FURUNO net recorder 3 Reversing thermometers 3 Mechanical weighing scales(10,50 et 100 kg) An Electronic precision balance range 10 kg 5 Fisher meters 2 Calipers Keys determination (Blache, Cadenat et Stauch, 1970 - Bellemans, Sagna et Scilabba,

1988) Instruments for animal biology.

Description of fishing gear

The main gear is a pelagic trawl society Akraham*(Norway) whose dimensions are detailed

below.

The secondary device is a standard trawl fish 31.82m long, 33.9m with the length of the

beadto24.5 m headline, 45 mm stretched mesh size at the pocket.

The company is the manufacturer Akraham approved research vessel Fridtjof Nansen (Norway).

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PELAGICTRAWLUSED

Annex IV Number and Biomass of main Species

30

species CLUSL02 ENGEN01 PODBR01 CARDE04 CARDE04 CARDE04

Sardinellamaderensis

Engraulisencrasicolus

Brachydeuterusauritus

Decapterusmacarellus



sample 13 14 15 16 17 17

Totnumber

63 60 78 7 47 9

weight 0.3 0.2 1.7 0.5 0.05 0.37

length

2 13 8

3 34 1

4

5

6 2 6 1

7 31 29

8 29 25 2

9 1 23

10 22

11 7

12 2

13 4 2

14 3 1

15 6 1

16 2 1

17 5 1

18 1 1

19

20

21

31

species CARDE04 CARDE04 CARAL01 CARDE01 CARDE04 CARSL01 PODBR01



Alectisalexandrinus

Decapteruspunctatus


Selenedorsalis

Brachydeuteru

auritus

Totnumber

16 14 22 59 35 8 17

weight 0.01 0.2 10.8 0.15 0.2 0.71 4.5

Length(cm)

2 2

3 6 1

4 8 3 5 2

5 3 8 8 3

6 6 13 4

7 5 23 17

8 10 1

9

10

11

12 6

13 5

14 5

15 1

16

17 1

18 1 1

19 1 1

20 1

21

22 2

23 1

24 1

25

26

27

28

29 1

30

31

32 1

33

34 2

35 5

36 2

37

38

39

40 1

41

42

4143

44 1

45 2

32

46

47 1

33

Annex V Length Frequencies of Main Pelagic Species

Length freq. dist. – Decapterus macarellus Length freq. dist.- Sardinella maderensis

Length freq. dist.- Engraulis encrasicolus Length freq. dist. – Brachydeuterus auritus

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Length freq. distribution - Alectisalexandrines Length freq. distribution - Selene dorsalis

35

Annex VI Families/ genera in the catch analysis

Group Taxon SpeciesSardinellaaurita S. auritaSardinellamaderensis S. maderensisChinchards Trachurussp. T. trecae

D. rhonchus, D. macarellus, D.punctatus

Anchois Engraulis encrasicolusAutres pélagiques 1 Clupeiformes1 Ilishaafricana

Engraulis encrasicolusAutres pélagiques 2 Carangidae2 Sélène dorsalis

ChloroscombruschrysurusAlectisalexandrinus

Scombridae EuthynnusalletteratusSardasardaScomberjaponicus

Sphyraenidae Sphyraenaguachancho

AutresTrichiuruslepturusZeus faber

Demersaux Sparidae3 DentexangolensisD. macrophthalmusD. congoensisD. canariensisD. barnardiPagellusbellottiiSparuscaeruleostictusS. pagrus africanus

autres taxii PseudupeneusprayensisBig-eyegrunt Brachydeuterusauritus

Ariomma bondiPomadasysincisusGaleoidesdecadactylus

Mesopelagiques Myctophidae3Autres mesopelagiques

Plancton Calanoidae Calanussp.Euphausiidae Meganyctiphanessp.Autre plancton

SURVEY OF THE PELAGIC FISH RESOURCES OFF GHANA 13...

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