Spawning areas of fish on the Chatham Rise

2001-2014

Prepared for Chatham Rock Phosphate Limited

August 2014

© All rights reserved. This publication may not be reproduced or copied in any form without the permission of the copyright owner(s). Such permission is only to be given in accordance with the terms of the client’s contract with NIWA. This copyright extends to all forms of copying and any storage of material in any kind of information retrieval system.

Whilst NIWA has used all reasonable endeavours to ensure that the information contained in this document is accurate, NIWA does not give any express or implied warranty as to the completeness of the information contained herein, or that it will be suitable for any purpose(s) other than those specifically contemplated during the Project or agreed by NIWA and the Client.

Prepared by:Richard L. O'DriscollNeil W. BagleySusan Jane Baird

For any information regarding this report please contact:

Richard O'DriscollProgramme leaderFisheries Stock Assessment & Monitoring+64-4-386 0876richard.odriscoll@niwa.co.nz

301 Evans Bay Parade

Hataitai

Wellington 6021

Phone +64 4 386 0300

NIWA CLIENT REPORT No: WLG2014-58Report date: August 2014NIWA Project: CRP15301

Contents

Executive summary.......................................................................................................................5

1 Introduction ........................................................................................................................6

2 Methods .............................................................................................................................8

2.1 Data extract......................................................................................................................... 8

2.2 Spawning summaries .......................................................................................................... 8

3 Results ................................................................................................................................9

4 Discussion ......................................................................................................................... 37

5 Conclusions ....................................................................................................................... 38

6 Acknowledgements ........................................................................................................... 38

7 References ........................................................................................................................ 39

Appendix A Description of female gonad stages ............................................................ 40

Tables

Table 1: List of species with more than 20 gonad stage observations from female fish in the area bounded from 43° to 44° S and 178° E to 178° W. 7

Table 2: Staging methods and selected female stages used in this report. 9

Table 3: Summary of observations of spawning and spent fish in revised consent area. 37

Figures

Figure 1: Location of the Chatham Rock Phosphate Ltd mining and prospecting permit and licence areas. 6

Figure 2: Observations of spawning and spent alfonsino. 10

Figure 3: Observations of spawning and spent Baxter's dogfish. 11

Figure 4: Observations of spawning and spent black oreo. 12

Figure 5: Observations of spawning and spent black shark. 13

Figure 6: Observations of spawning and spent Bollon's rattail. 13

Figure 7: Observations of spawning and spent dark ghost shark. 14

Figure 8: Observations of spawning and spent hake. 15

Figure 9: Observations of spawning and spent hapuku. 16

Figure 10: Observations of spawning and spent hoki. 17

Figure 11: Observations of spawning and spent javelinfish. 18

Figure 12: Observations of spawning and spent ling. 19

Figure 13: Observations of spawning and spent long-nosed chimaera. 20

Figure 14: Observations of spawning and spent lookdown dory. 21

Figure 15: Observations of spawning and spent lucifer dogfish. 22

Figure 16: Observations of spawning and spent oblique banded rattail. 22

Figure 17: Observations of spawning and spent Oliver's rattail. 23

Figure 18: Observations of spawning and spent orange roughy. 24

Figure 19: Observations of spawning and spent pale ghost shark. 25

Figure 20: Observations of spawning and spent Ray's bream. 26

Figure 21: Observations of spawning and spent ribaldo. 27

Figure 22: Observations of spawning and spent sea perch. 28

Figure 23: Observations of spawning and spent shovelnose dogfish. 29

Figure 24: Observations of spawning and spent silver warehou. 30

Figure 25: Observations of spawning and spent smooth oreo. 31

Figure 26: Observations of spawning and spent smooth skate. 32

Figure 27: Observations of spawning and spent spiky oreo. 33

Figure 28: Observations of spawning and spent spiny dogfish. 34

Figure 29: Observations of spawning and spent stargazer. 35

Figure 30: Observations of spawning and spent white warehou. 36

Reviewed by Approved for release by

Dr Rosie Hurst Dr Julie Hall

5

Executive summaryThis report is in response to Environmental Protection Authority (EPA) request number 34 for the

best available information to identify spawning areas used by commercial fish species in the

Chatham Rock Phosphate Limited (CRP) marine consent areas and surrounding area of the Chatham

Rise. It summarises all available data on occurrence of spawning fish from research trawl and

observed commercial catch data from 1 July 2001 to 28 July 2014.

Maps of observations of spawning (ripe and running ripe) and spent females on the Chatham Rise

were produced for 29 fish species. Background data showing all positions where fish of a given

species were staged were also plotted to represent the distribution of possible observations.

Gonad stage information from within the revised consent area (excluding the withdrawn prospecting

permit area 55967) was only available for 14 of the 29 species from research trawls, and only 2 of 29

species from observer records since July 2001. No data were available for the other species, because

these were not caught and/or not staged within the revised consent area.

Individual female hake in spawning condition were observed inside the revised consent area in both

research trawl and observer data, and spent female hake were observed in the revised consent area

in research trawl data and close to the revised consent area in observer data. Spawning and spent

spiny dogfish, spent hoki, spent lookdown dory, and spent sea perch were also observed inside the

revised consent area in research trawl data. An important caveat is that most of the research trawl

data evaluated came from only one time period (January), and many species are known not be

spawning at this time of year. There were no records of spawning or spent fish of other species inside

the revised consent area, but there was evidence of potential spawning of Bollon’s rattail, dark ghost

shark, hapuku, ling, long-nosed chimaera, pale ghost shark, ribaldo, silver warehou, stargazer, and

white warehou in the surrounding area from observations of spawning or spent fish nearby. None of

the other species examined showed evidence of spawning on the mid-Chatham Rise. Black oreo,

smooth oreo, and orange roughy spawn along the flanks of the Chatham Rise, around the 1000 m

isobath.

Based on the available data, there was no evidence that the revised consent area was particularly

important as a spawning ground for any of the 29 species examined.

6

1 IntroductionOn 9 June 2014, Chatham Rock Phosphate Limited (CRP) received a request for further information

from the Environmental Protection Agency (EPA) in relation to its marine consent application to mine

phosphorite nodules from the Chatham Rise.

This report is in response to EPA request number 34 for the best available information to assess the

effects of the mining activities on fish eggs and larvae within the proposed marine consent area

(Figure 1) and on the surrounding area:

34. Identify all the spawning areas used by commercial fish species in the proposed marine

consent and surrounding area of the Chatham Rise.

Figure 1: Location of the Chatham Rock Phosphate Ltd mining and prospecting permit and licence areas. Note that prospecting permit area 55967 was withdrawn from the consent application on 1 August 2014. The combined area of prospecting permit 55971, mining permit 55549, and licence 50270 is referred to as the “revised consent area”.

Information on the areas of importance for spawning, pupping or egg-laying, and juveniles of New

Zealand fish was summarised by Hurst et al. (2000) and O’Driscoll et al. (2003). Hurst et al. (2000)

provided data for 35 important inshore fish species (defined as those which occur in under 200 m),

while O’Driscoll et al. (2003) looked at 32 important deepwater fish species (occurring from 200 to

1500 m depth) and 4 pelagic fish species. Three species (ling, hake, and silver warehou) were

included in both reports. The main data sources for both reports were published and unpublished

literature (including university theses and local body reports) and the (then) Ministry of Fisheries

research trawl survey (trawl), commercial scientific observer trawl (obs and obs_lfs) and tuna

longline (l_line) databases. The date of data extraction for spawning summaries presented by Hurst

et al. (2000) was up to 4 April 2000 for research data and to 20 December 1999 for observer data.

The date of data extraction for spawning summaries presented by O’Driscoll et al. (2003) was 30 June

2001.

Information on spawning areas was not updated as part of the initial consent application, except for

hoki (O’Driscoll & Ballara 2014). An extract of gonad stage data from the research trawl database in

7

June 2014 showed that there were 28 fish species in the area bounded from 43° to 44° S and 178° E

to 178° W (an area that incorporates all of the revised consent area) with more than 20 gonad stage

observations from female fish (Table 1). Data on spawning were reviewed for 21 of these 28 species

by either Hurst et al. (2000) or O’Driscoll et al. (2003), but there were only sufficient data at the time

of writing these earlier reports to plot maps for 15 species. The range of species for which gonad

stage data has been collected on research surveys has increased since the early 2000s, especially as

data are now routinely collected for elasmobranchs (sharks and skates) and rattails.

Table 1: List of species with more than 20 gonad stage observations from female fish in the area bounded from 43° to 44° S and 178° E to 178° W. This area incorporates all of the revised consent area (Figure 1). Data were extracted from the research trawl database up to June 2014. Reviewed and mapped columns indicate whether spawning distribution was reviewed and plotted by Hurst et al. (2000) (H) and/or O’Driscoll et al. (2003) (O).

Species code Common name Scientific name Reviewed MappedFemale stages

available

BYS Alfonsino Beryx splendens O O 147

ETB Baxter’s dogfish Etmopterus baxteri O 41

BOE Black oreo Allocyttus niger O O 359

BSH Black shark Dalatias licha 29

CBO Bollon’s rattail Coelorinchus bollonsi 148

GSH Dark ghost shark Hydrolagus novaezealandiae O 1 021

HAK Hake Merluccius australis OH O 955

HAP Hapuku Polyprion oxygeneios H H 41

HOK Hoki Macruronus novaezelandiae O O 27 233

JAV Javelinfish Lepidorhynchus denticulatus 64

LIN Ling Genypterus blacodes OH O 4 228

LCH Long-nosed chimaera Harriotta raleighana 33

LDO Lookdown dory Cyttus traversi O O 441

ETL Lucifer dogfish Etmopterus lucifer 76

CAS Oblique banded rattail Coelorinchus aspercephalus 72

COL Oliver’s rattail Coelorinchus oliverianus 22

GSP Pale ghost shark Hydrolagus bemisi O 327

RBM/SRB Ray’s bream Brama brama O O 42

RIB Ribaldo Mora moro O O 31

SPE Sea perch Helicolenus spp H 287

SND Shovelnose dogfish Deania calcea O 165

SWA Silver warehou Seriolella punctata OH O 504

SSO Smooth oreo Pseudocyttus maculatus O O 68

SSK Smooth skate Dipturus innominatus O O 42

SOR Spiky oreo Neocytttus rhomboidalis O O 81

SPD Spiny dogfish Squalus acanthias H 1 567

STA/GIZ Stargazer Kathetostoma giganteum H H 92

WWA White warehou Seriolella caerulea O O 145

This report updates all available data on occurrence of spawning fish from research trawl and

observed commercial catch data from July 2001 to July 2014 based on extracts from the Ministry for

Primary Industries (MPI) trawl and cod databases.

8

2 Methods

2.1 Data extract

Data were extracted from MPI’s research trawl database (trawl) and observer database (cod) on the

28 July 2014. Observer data were from trawl and bottom longline. Data were extracted from 1 July

2001, a start date selected to allow us to update spawning information from O’Driscoll et al. (2003),

who presented data up to 30 June 2001.

The spatial boundary of the extract was 42° to 46° S and 173° E to 173° W for research trawl data,

and Fisheries Management Areas (FMA) 3 and 4 for observer data. Both areas covered the entire

Chatham Rise to enable us to show data surrounding the revised marine consent area.

2.2 Spawning summaries

Data on occurrence of spawning and spent fish were summarised for the 28 species listed in Table 1

and for orange roughy. Orange roughy did not appear in Table 1 because they were not caught by

research trawls in the region around the revised consent area, but were included in this report

because they are an important fishery on the Chatham Rise. The 29 species presented here included

20 species of teleost (bony fish) and 9 species of elasmobranch (cartilaginous fish such as sharks,

skates and rays).

There were three different gonad staging methods for teleosts and four staging methods for

elasmobranchs used in the trawl database (see Appendix 1 for description of stages). Observers use a

single (5-stage) scale for teleosts (Appendix 1) and are not required to stage elasmobranchs.

Female fish with stages indicating that hyaline oocytes (clear eggs) were present were selected to

represent spawning fish. These stages are referred to as “ripe” and “running ripe” (Table 2). These

stages are known to be the best indicator of when a female fish releases her eggs and their

appearance closely matches the timing of actual spawning events. Not all fish release all their eggs in

a single spawning event, and can release eggs in batches over time. Partially spent fish were

therefore not included with the spawning fish as it is thought female fish at this stage can spawn

sometime later. Males were also not included as milt in ripe or running ripe gonads can be present in

male teleosts for long periods of time. Female fish that had released their eggs and were in a “spent”

state were used to determine when fish had completed spawning.

Sea perch differ from the other teleosts in Table 1 in that they are viviparous, meaning that eggs

hatch into larvae internally and are released live during spawning.

Elasmobranchs can be divided into two groups: species that are viviparous (bearing live young); and

species that produce eggs encased in a leathery exterior egg cases. Of the nine elasmobranch species

in Table 2, four are egg-laying (ghost shark, pale ghost shark, long-nosed chimaera, smooth skate),

and five are live-bearing (black shark, Baxter’s dogfish, Lucifer dogfish, spiny dogfish, shovelnose

spiny dogfish). Elasmobranchs were considered to be in spawning condition when pups or egg cases

were present in the uterus (Table 2). Developing pups and egg cases may be present for unknown

time before being born or laid, so our definition of spawning for elasmobranchs may include females

where actual egg-laying or pupping was not imminent. There was no discrimination in elasmobranch

staging methods between the size of pups or egg cases in the uterus.

The stages corresponding to spawning and spent females were selected for each of the staging

methods (Table 2) and locations of fish at these stages were plotted on maps of the Chatham Rise.

9

Background data showing all positions where fish of a given species were staged were also plotted in

grey to represent the distribution of possible observations.

Table 2: Staging methods and selected female stages used in this report. See Appendix 1.

Teleosts Middle depths stage method

(MD)

Deepwater stage method

(DW)

Stock monitoring stage method

(SM)

Observer stage

method

(OBS)

Ripe 4 4 3 3

Running ripe 5 5 4 4

Spent 7 6 5 5

Elasmobranchs Ghost shark staging method*

(GS)

Spiny dogfish staging method*

(SP)

Skate staging

method*

(SK)

Generic shark staging method

(SS)

Egg cases present 4 N/A 4 4

Pups present N/A 5 N/A 5

Spent - 6 - 6

*Staging methods are now obsolete and were replaced with the generic shark staging method SS in 2011.

- No staging method available.

3 ResultsFigures 2–30 show maps of the distribution of spawning (ripe and running ripe) and spent females on

the Chatham Rise for the 28 fish species in Table 1 and orange roughy arranged in alphabetical order

of common name.

Gonad stage information from within the revised consent area (see Figure 1, excluding the

withdrawn prospecting permit area 55967) was only available for 14 of the 29 species from research

trawls, and only 2 of 29 species from observer records since July 2001 (Table 3). No data were

available for the other species, because these were not caught and/or not staged within the revised

consent area.

Individual female hake in spawning condition were observed inside the revised consent area in both

research trawl and observer data, and spent female hake were observed in the revised consent area

in research trawl data and close to the revised consent area in observer data (Figure 8). Spawning

and spent spiny dogfish (Figure 28), spent hoki (Figure 10), spent lookdown dory (Figure 14), and

spent sea perch (Figure 22) were also observed inside the revised consent area in research trawl data

(Table 3). There were no records of spawning or spent fish of other species inside the revised consent

area, but there was evidence of potential spawning of Bollon’s rattail (Figure 6), dark ghost shark

(Figure 7), hapuku (Figure 9), ling (Figure 12), long-nosed chimaera (Figure 13), pale ghost shark

(Figure 19), ribaldo (Figure 21), silver warehou (Figure 24), stargazer (Figure 29), and white warehou

(Figure 30) in the surrounding area from observations of spawning or spent fish nearby (Table 3).

None of the other species in Table 3 showed evidence of spawning on the mid-Chatham Rise. Black

oreo (Figure 4), smooth oreo (Figure 25), and orange roughy (Figure 18) spawn along the flanks of the

Chatham Rise, around the 1000 m isobath.

10

Figure 2: Observations of spawning and spent alfonsino.

11

Figure 3: Observations of spawning and spent Baxter's dogfish.

12

Figure 4: Observations of spawning and spent black oreo.

13

Figure 5: Observations of spawning and spent black shark.

Figure 6: Observations of spawning and spent Bollon's rattail.

14

Figure 7: Observations of spawning and spent dark ghost shark.

15

Figure 8: Observations of spawning and spent hake.

16

Figure 9: Observations of spawning and spent hapuku.

17

Figure 10: Observations of spawning and spent hoki.

18

Figure 11: Observations of spawning and spent javelinfish.

19

Figure 12: Observations of spawning and spent ling.

20

Figure 13: Observations of spawning and spent long-nosed chimaera.

21

Figure 14: Observations of spawning and spent lookdown dory.

22

Figure 15: Observations of spawning and spent lucifer dogfish.

Figure 16: Observations of spawning and spent oblique banded rattail.

23

Figure 17: Observations of spawning and spent Oliver's rattail.

24

Figure 18: Observations of spawning and spent orange roughy.

25

Figure 19: Observations of spawning and spent pale ghost shark.

26

Figure 20: Observations of spawning and spent Ray's bream.

27

Figure 21: Observations of spawning and spent ribaldo.

28

Figure 22: Observations of spawning and spent sea perch.

29

Figure 23: Observations of spawning and spent shovelnose dogfish.

30

Figure 24: Observations of spawning and spent silver warehou.

31

Figure 25: Observations of spawning and spent smooth oreo.

32

Figure 26: Observations of spawning and spent smooth skate.

33

Figure 27: Observations of spawning and spent spiky oreo.

34

Figure 28: Observations of spawning and spent spiny dogfish.

35

Figure 29: Observations of spawning and spent stargazer.

36

Figure 30: Observations of spawning and spent white warehou.

37

Table 3: Summary of observations of spawning and spent fish in revised consent area. Y indicates observations within the revised consent area; N indicates no observations within revised consent area; * indicates no observations in revised consent area, but observations nearby; - indicates no information.

Research trawl Observer

Common name Staged Spawning Spent Staged Spawning Spent

Alfonsino Y N N N - -

Baxter’s dogfish N - - - - -

Black oreo N - - N - -

Black shark N - - - - -

Bollon’s rattail Y N * - - -

Dark ghost shark Y * N - - -

Hake Y Y Y Y Y *

Hapuku N - - N * -

Hoki Y * Y Y * Y

Javelinfish N - - - - -

Ling Y * * N * *

Long-nosed chimaera N * * - - -

Lookdown dory Y * Y N * *

Lucifer dogfish N - - - - -

Oblique banded rattail N - - - - -

Oliver’s rattail N - - - - -

Orange roughy N - - N - -

Pale ghost shark Y * N - - -

Ray’s bream Y N N N - -

Ribaldo N - * N - *

Sea perch Y * Y N * *

Shovelnose dogfish N - - N - -

Silver warehou Y N * N * *

Smooth oreo N - - N - -

Smooth skate Y N N - - -

Spiky oreo N - - N - -

Spiny dogfish Y Y Y - - -

Stargazer N * * N * *

White warehou Y N N N * *

4 DiscussionThis updated analysis of gonad stage data from research trawls and observed commercial catch from

July 2001 to July 2014 suggested that spawning of hake, ling, spiny dogfish, lookdown dory, sea

perch, Bollon’s rattail, dark ghost shark, hapuku, long-nosed chimaera, pale ghost shark, ribaldo,

silver warehou, stargazer, and white warehou may occur in and/or around the revised consent area

(Table 3). Maps in Hurst et al. (2000) and O’Driscoll et al. (2003) from data before 2001 also show

observations of ling, hake, white warehou, silver warehou, stargazer, and lookdown dory in spawning

condition on the mid-Chatham Rise.

Most of our information about spawning in the revised consent area comes from relatively few

observations. Another important caveat is that most of the research trawl data evaluated came from

only one time period (January), and many species are known not be spawning at this time of year.

38

Information about timing of spawning was summarised by Hurst et al. (2000) and O’Driscoll et al

(2003), and was not updated in this report. Data from commercial fisheries on the Chatham Rise are

available throughout the year, but there has been very little commercial effort within the revised

consent area (O’Driscoll & MacGibbon 2014).

In Chatham Rise trawl surveys from 2005–14, densities of juveniles of dark ghost shark, hake, ling,

lookdown dory, spiny dogfish, and white warehou within the revised consent area were higher than

average densities of juveniles of these species across the whole Chatham Rise (O’Driscoll et al. 2014).

The higher densities of juveniles is further evidence that some spawning of these species may occur

in and around the revised consent area.

Prospecting permit area 55967, which was withdrawn from the revised consent application on 1

August 2014, appears to be an important spawning area for ling (Figure 12), sea perch (Figure 22),

and possibly hapuku (Figure 9). There were 6388 female ling in ripe and running ripe condition

(stages 3 and 4) reported by observers on the Chatham Rise from July to October in 1989–2014. Of

these, 1972 were inside the prospecting permit 55967. This suggests that about one-third of the

observed Chatham Rise ling spawning occurs in this area. However, we note that the observer

sampling used to derive these numbers was not spread evenly and randomly across the Chatham

Rise ling population, because fishing (particularly bottom longlining) was concentrated in areas

where ling densities were relatively high (Baird 2014).

As noted by O’Driscoll & Ballara (2014), no hoki in spawning condition have been reported from the

revised consent area (Figure 10). Occasionally, spent hoki were reported by observers and in

research trawls within the revised consent area, but it is sometimes difficult to distinguish hoki in this

gonad state from resting fish. There were also a few hoki reported in spawning condition close to the

revised consent area (Figure 10). These may have been errors in staging, or may indicate female hoki

that have held on to the ripe eggs as they have not been able to release them (a condition known as

atretic). Spawning hoki on the Chatham Rise are mainly caught west of the Mernoo Bank and are

associated with known east coast South Island spawning areas (O’Driscoll & Ballara 2014).

Although spawning and spent hake were observed within the revised consent area, most of the hake

spawning on the mid Chatham Rise appears to occur in deeper water to the north of the revised

consent area (Dunn 2002, O’Driscoll et al. 2003).

5 ConclusionsAn updated analysis of gonad stage data from research trawls and observed commercial catch

suggested that spawning of hake, ling, spiny dogfish, lookdown dory, sea perch, Bollon’s rattail, dark

ghost shark, hapuku, long-nosed chimaera, pale ghost shark, ribaldo, silver warehou, stargazer, and

white warehou may occur in and/or around the revised consent area. Although available data were

sparse, there was no evidence that the revised consent area was an important spawning ground for

these, or any of the 29 species examined.

6 AcknowledgementsResearch trawl and observer data were used with permission from Ministry for Primary Industries.

39

7 ReferencesBaird, S.J. (2014). Ling longline effort and catch data summary relevant to Chatham Rise

Phosphate Ltd mining permit and licence areas. NIWA Client Report WLG2014-11

prepared for Chatham Rock Phosphate Limited, March 2014. 28 p.

Dunn, A. (2002). A descriptive summary of the biology and fishery of New Zealand hake

(Merluccius australis). NIWA Client Report WLG2002-29 prepared for Ministry of

Fisheries, September 2002. 44 p.

Hurst, R.J.; Stevenson, M.L.; Bagley, N.W.; Griggs, L.H.; Morrison, M.A.; Francis, M.P; Duffy,

C.A. (2000). Areas of importance for spawning, pupping or egg-laying, and juveniles of

New Zealand coastal fish. Final Research Report prepared by NIWA for Ministry of

Fisheries Research Project ENV 1999/03 Objective 1, December 2000. 57 pp + figs.

Unpublished report held by Ministry for Primary Industries, Wellington.

O’Driscoll, R.L.; Ballara, S.L. (2014). The Chatham Rise and hoki: role in hoki biology and

distribution. NIWA Client Report WLG2014-15-rev prepared for Chatham Rock

Phosphate Limited, March 2014. 33 p.

O’Driscoll, R.L.; Booth, J.D.; Bagley, N.W.; Anderson, O.F.; Griggs, L.H.; Stevenson, M.L.;

Francis, M.P. (2003). Areas of importance for spawning, pupping or egg-laying, and

juveniles of New Zealand deepwater fish, pelagic fish, and invertebrates. NIWA Technical

Report 119. 377 p.

O’Driscoll, R.L.; Edwards, C.T.T; Bagley, N.W. (2014). Fish distribution on the Chatham Rise

from trawl surveys. NIWA Client Report WLG2014-32 prepared for Chatham Rock

Phosphate Limited, June 2014. 95 p.

O’Driscoll, R.L.; MacGibbon, D.J. (2014). Estimated commercial catches in the Chatham Rock

Phosphate consent area 2003/04 to 2012/13. NIWA Client Report WLG2014-57

prepared for Chatham Rock Phosphate Limited, July 2014. 18 p.

Page, M. (2014). Effects of total suspended solids on marine fish: eggs and larvae on the

Chatham Rise. NIWA Client Report WLG2012-61-rev prepared for Chatham Rock

Phosphate Limited, April 2014. 22 p.

40

Appendix A Description of female gonad stagesDescription of generic female stage methods used in this report. More detailed staging sheets

refined by species or for species groups are used at sea.

TELEOSTS:

Middle depths stage method for females (MD)

Stage 1 Immature female - Ovaries small and translucent. No developing oocytes.

Stage 2 Resting female - Ovaries are developed, but no developing eggs are visible.

Stage 3 Maturing female - Ovaries contain visible developing eggs, but no hyaline eggs present.

Stage 4 Mature/ripe female - Some or all eggs are hyaline, but eggs are not extruded when

body is squeezed.

Stage 5 Running ripe female - Eggs flow freely from them ovary when body is pressed.

Stage 6 Partially spent female - Ovary partially deflated, often bloodshot. Some hyaline and

ovulated eggs present and flowing from a cut ovary or when the body is squeezed.

Stage 7 Spent female - Ovary bloodshot; ovary wall may appear thick and white. Some

residual ovulated eggs may still remain but will not flow when body is squeezed.

Deepwater stage method for females (DW)

Stage 1 Immature/resting female

Stage 2 Early maturation female

Stage 3 Mature female

Stage 4 Ripe female

Stage 5 Running ripe female

Stage 6 Spent female

Stage 7 Atretic female

Stage 8 Partially spent female

Stock monitoring staging method for females (SM)

Stage 1 Immature/Resting

Stage 2 Maturing

Stage 3 Mature/Ripe

Stage 4 Running Ripe

41

Stage 5 Spent

Observer staging method (OBS)

Stage 1 Immature/Resting

Stage 2 Maturing

Stage 3 Mature/Ripe

Stage 4 Running Ripe

Stage 5 Spent

ELASMOBRANCHS:

Generic shark staging method (SS)

Stage 1 Immature - Ovaries small and undeveloped. Oocytes not visible, or small (pin-head

sized) and translucent whitish

Stage 2 Maturing - Some oocytes enlarged, up to about pea-sized or larger, and white to cream

Stage 3 Mature - Some oocytes large (greater than pea-sized) and yolky (bright yellow)

Stage 4 Gravid I - Uteri contain eggs or egg cases but no embryos are visible

Stage 5 Gravid II - Uteri contain visible embryos. Not applicable to egg laying sharks and skates

Stage 6 Post-partum - Uteri flaccid and vascularised indicating recent birth

Skate staging method (SK)

Stage 1 Immature

Stage 2 Maturing

Stage 3 Mature

Stage 4 Spawning - egg cases present

Ghost shark staging method (GS)

Stage 1 Immature - Oocytes barely visible and whitish. Uterus threadlike with thin epithelial

wall. Oviducal gland marked by a minor widening of the oviduct.

Stage 2 Maturing - Oocytes small and whitish. Uterus threadlike and uterine wall thin. Oviducal

gland slightly swollen and differentiated from uterus but without visibly contrasting

tissue zones.

42

Stage 3 Mature - Oocytes large, yellow, and vascularised. Uterus wide and uterine wall thick,

especially near uterine openings where it is muscular and resistant to compression.

Oviducal gland fully developed, bulbous and may exhibit contrasting tissue zones.

Stage 4 Mature and gravid - Fully or partially developed egg case present in one or both uteri.

Spiny dogfish stage method (SP)

Stage 1 Immature - Ovaries small and appear gelatinous or granulated when cut with no eggs

visible to the eye. Uterus is uniformly thin and tubular. Oviducal gland indistinct from

anterior uterus.

Stage 2 Maturing - Ovaries enlarged with eggs visible, but these are white and small in size (3

to 14 mm in diameter). Uterus somewhat enlarged compared with Stage 1, esp. near

the posterior end of the uterus, but still thin and tubular. Oviducal gland distinct from

anterior uterus, but only partly formed.

Stage 3 Mature - Ovaries enlarged, with large yellow eggs present, the largest of which are 15

mm in diameter or larger. Uterus enlarged, but with no large yellow mass or embryos

within and does not appear flaccid (c.f., Stage 6). Oviducal gland distinct from anterior

uterus, enlarged, and kidney-shaped.

Stage 4 Gravid (i) - Ovaries enlarged, with large yellow eggs present, the largest of which are 15

mm in diameter or larger. Uterus enlarged and filled with a large yellow mass

("candle"). As development proceeds, the candle divides into individual yolk balls, but

the developing embryos within are not visible to the eye. Oviducal gland distinct from

anterior uterus, enlarged, and kidney-shaped.

Stage 5 Gravid (ii) - Ovaries enlarged, with large yellow eggs present, the largest of which are

15 mm in diameter or larger. Uterus enlarged. The developing embryos are visible to

the eye. Early to mid-term embryos may have large yellow yolk sacs attached, while

late-term embryos will have absorbed their yolk sacs. Oviducal gland distinct from

anterior uterus, enlarged, and kidney-shaped.

Stage 6 Post-partum - Ovaries enlarged, with large yellow eggs present, the largest of which

are 15 mm in diameter or larger. Uterus also enlarged, but empty and flaccid (c.f.,

Stage 3). Oviducal gland distinct from anterior uterus, enlarged, and kidney-shaped.