scottish industry / science partnership (sisp) report no 03/08 · scottish industry/science...

Fisheries Research Services

Iain M. Gibb, Peter J. Wright & Rory Campbell

JULY 2008

Identifying Critical Spawning and Nursery Areasfor North Sea Cod; Improving The Basis for CodManagement

SCOTTISH INDUSTRY / SCIENCE PARTNERSHIP (SISP)Report No 03/08

S I S PProject 14/07

Photo courtesy of SNG Ltd

SSCCOOTTTTIISSHH IINNDDUUSSTTRRYY//SSCCIIEENNCCEE PPAARRTTNNEERRSSHHIIPP ((SSIISSPP))

RREEPPOORRTT NNOO 0033//0088

IDENTIFYING CRITICAL SPAWNING AND NURSERY AREAS FOR NORTH SEA COD; IMPROVING THE BASIS FOR COD MANAGEMENT

Iain M. Gibb, Peter J. Wright and Rory Campbell SISP Project 14/07

SISP PROJECT NUMBER: 014/07


SISP Project Number: 014/07 Project code: MFP6Q04

Iain M. Gibb1, Peter J. Wright 1 and Rory Campbell 2

1Fisheries Research Services Marine Laboratory

PO Box 101 375 Victoria Road Aberdeen AB11 9DB FRS Tel: +44 (0)1224-295416 FRS Fax: +44 (0)1224-295511 FRS E-mail: [email protected]

2 Scottish Fishermen’s Federation (SFF) 24 Rubislaw Terrace Aberdeen AB10 1XE SFF Tel: +44 (0)1224-646944 SFF Fax: +44 (0)1224-647058 SFF E-mail: [email protected]

mailto:[email protected]


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EXECUTIVE SUMMARY 1. In liaison with the SFF, FRS conducted two surveys on commercial fishing boats to map

the nursery and spawning areas of cod in the north west North Sea. 2. As with previous surveys this century, juveniles were found to be patchily distributed with

coastal areas around Shetland, off Newburgh and St Andrew’s Bay identified as important nursery areas.

3. The importance of some cod nursery areas appears to have persisted over recent years,

as previous studies have also found high juvenile densities around the Shetland and St Andrew’s Bay sites.

4. Cod spawn throughout much of the northern North Sea but the recent survey indicates a

number of localised aggregations, which also reflect known historical spawning areas identified from past trawl and egg surveys.

5. Key cod spawning areas identified by fishermen in 2007 were supported by the March

survey conducted as part of this project, although high catch rates were also found in areas that had been thought to be no longer used.

6. Management should consider the localised nature of cod aggregations (juvenile and

adult) when proposing measures to promote the sustainability of the North Sea stock.


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INTRODUCTION Stock collapse has often followed the loss of population richness, which is a function of the number of reproductively distinct spawning groups. The growing evidence for different cod populations within the North Sea and VIa could mean that stock level estimates of mortality and abundance may not reflect local availability or be responsive to local management measures. Fisheries Research Services (FRS), together with other UK fishery institutes, is currently investigating the sub-stock structure of cod in U.K. waters. FRS has found that there are a number of relatively discrete resident spawning groups of cod in the coastal waters of the North Sea and west of Scotland (Wright et al., 2006 a,b; Neat et al., 2006). However, comparatively little is known about the distribution and size of spawning areas or the distribution of nursery areas that supply them, particularly offshore in the northern North Sea which is currently the main focus of the fishery. Using sophisticated laboratory analyses it is now possible to identify the links between nursery and spawning areas from the chemistry of otoliths (earbones). Mapping of inshore areas under a previous partnership agreement has provided useful information on coastal nursery sites primarily off the west coast of Scotland, but similar work is needed in the region of the North Sea exploited by Scottish fishermen. This report summarises the results and relevance of a Scottish Industry Science Partnership (SISP) project between FRS and the Scottish Fishermen’s Federation (SFF) that was intended to update and improve our current understanding of North Sea cod nursery and spawning areas.

OBJECTIVES The main objective of the project was to improve understanding of the distribution of cod spawning and nursery sites in the North Sea. The specific objectives were as follows: 1. To undertake dedicated sampling of cod nursery and spawning areas by commercial

boats. 2. To examine the links between nursery and spawning areas from samples collected by

fishermen using available analytical resources from a Scottish Government project (MF0760) in progress at FRS.

3. To provide a more comprehensive map of the distribution of cod spawning and nursery

sites in the North Sea, by combining fishermen’s observations of running and undersized cod with those of research surveys.

To achieve the first of these objectives, two charter surveys were commissioned by FRS in liaison with the fishing industry. After the due process of tendering, contracts were offered to the Fishing Vessels Ocean Bounty and Genesis to carry out surveys of cod nursery and spawning areas respectively. The nursery area charter was completed in September 2007, and the spawning area charter in March 2008. The cruise reports from both surveys are included at the end of this report as Appendices (Appendix 1: Ocean Bounty; Appendix 2: Genesis). The second objective will be achieved during an ongoing Scottish Government project using otolith samples collected on both surveys. These otoliths will be chemically analysed by ICP-MS, and the results published in due course. The third objective involved researching archival information on the nursery and spawning areas of cod. Data on the distribution of spawning cod


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(stage 3 maturity) was collated from all available research vessel surveys conducted by FRS and the International Council for the Exploration of the Sea (ICES) within the relevant geographical areas. Data on juvenile distributions were also collated from previous survey data, particularly from dedicated inshore surveys. A chart of the location of running cod by fishermen (www.scotland.gov.uk/Resource/Doc/1061/0055424.pdf; see Figure 4) was reviewed and augmented by survey data, enabling the production of a more comprehensive map. Identification of Cod Nursery Areas Little reliable historic information on the nursery areas which supply resident spawning groups in the North Sea is available, as is the case for information on the level of exchange of juveniles between nursery areas. In a recent study however, there was strong evidence that nursery areas around Scotland were isolated in nature, with little or no inter-mixing between nursery patches more than 200 km apart (Gibb et al., 2007). This study mapped the density distribution of 0-group cod in 2001 and 2002-2004. The 2001 data was compiled from inshore surveys of the west and east coast of Scotland (including the Shetland Isles) conducted in partnership with the fishing industry in November-December 2001. The 2002-04 inshore surveys were dedicated nursery ground surveys onboard FRV Clupea conducted in August-September in all three years. Data from the Scottish 3rd quarter surveys of the North Sea were used to provide information for offshore areas. Cod abundances in 2007 collected as part of this SISP project were assimilated into this dataset, and the map of nursery areas updated (Figure 1). The grid resolution of the map was set at a quarter ICES statistical rectangle in order to reflect the fine scale inshore sampling grid and the patchiness of juvenile distribution. The combined survey data demonstrates that whilst 0-group cod occur extensively over much of northern North Sea, the majority are confined to a few small coastal areas and overall densities are scarce, with median densities around 10 cod.km-2. All densities exceeding this value occurred within 60 km of the coast. In the study of Gibb et al. (2007), substantially elevated densities of >100 cod.km-2 were only found within the Moray Firth, Shetland and St. Andrews Bay, east of Scotland. Concentrations of >1000 cod.km-2 were restricted to at most 2 quarter ICES statistical rectangles. In this SISP study, concentrations of >100 cod.km-2 were found in St Andrews Bay and off Newburgh while concentrations of >1000 cod.km-2 were only observed around Shetland. Such temporal persistence within the St Andrews Bay and Shetland areas indicates they have remained important nursery areas. Within the Gibb et al. (2007) study, presence in tows was related to depth with around 60% of tows in depths <90 m containing 0-group cod compared to less than 10% in depths >180 m. In the sites where cod were present, density was negatively related to depth from 11 – 175 m. This situation was similarly reflected within this SISP survey, where cod were found in depths <54 m. Indeed, 99 % of the total cod caught were found in depths less than 26 m. Differences in density may also have been related to exposure. Exposed coastlines were generally found to be areas of low juvenile abundance, while several well sheltered areas (especially around Shetland) were found to have high juvenile abundance. Thus, from all available data, juvenile 0-group cod are largely located in very discrete concentrations around the Scottish coast in the north west North Sea. Whilst there were many similarities in juvenile cod distribution among surveys there were also some important differences. For example, the large density of juvenile cod found within the Moray Firth (Smith’s Bank) in 2003 was not seen in either the 2004 or 2007 surveys. Similarly, larger densities found at Newburgh in 2007 were not reflected by the 2002-04 distributions. Hence, local abundance at some nursery areas may vary substantially from year to year. The combined data for the four years does however indicate that relatively few sites may be critical

http://www.scotland.gov.uk/Resource/Doc/1061/0055424.pdf


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nursery areas worth protecting. The planned work on the otolith microchemistry of both juveniles and adults will further test this nursery concept by estimating the relative contribution of these juvenile habitats to the overall adult population. This is important in understanding the role of these small concentrations to sustaining adult populations. Identification of Cod Spawning Areas Historic information on Atlantic cod spawning areas of the northern North Sea can be inferred from the catches of mature sized adults in ICES and Scottish research surveys (Hedger et al., 2004), but the ability of cod to migrate large distances immediately prior to spawning can limit the usefulness of such data. More accurate information is provided by dedicated egg surveys or surveys designed to determine the densities of spawning adults. Egg surveys were conducted in the region of this study in 1950s (Saville, 1959; Raitt, 1967; see Figure 2), 1992 (Heath et al., 1994) and most extensively in 2004 (Fox et al., 2008; Figure 3). These egg surveys indicated some clear spawning concentrations, although it was also apparent that cod used to spawn over much of the region. The main concentrations indicated by these surveys were off the Butt of Lewis, west of Orkney and Shetland and off the Moray and Tay Firths. Unlike the 1950s the largest egg concentrations in 1992 and 2004 were found between Shetland and Norway. The recent surveys of adult cod distribution are in broad agreement with historically observed concentrations in the North Sea off the north east coast of Scotland and between Shetland and Viking bank. Therefore, it seems likely that these adult concentrations have persisted during the marked decline of the North Sea stock. This suggests a persistence of spawning concentrations, as has been documented in some other North Atlantic cod stocks (Ruzzante et al., 2001). The main difference between sample periods appears to be the higher densities of eggs between Shetland and Viking bank in the 2004 survey. This area has also become more important to the fishery in recent years. The addition of the 2007 spawning aggregations supplement such findings, with aggregations found over the same Shetland-Viking Bank area as found by Heath et al. (1994). This area is also reflected in the recent Scottish Government map of spawning areas of cod (Figure 4). The most important area in terms of actual densities during the March 2007 survey was at the 110 mile holes. This area is not exclusively reflected in any previous spawning ground maps derived from the egg or trawl survey data, although adjacent areas have been identified as important areas from the estimated egg production by ICES rectangle for 2004 (Figure 3). The present project provides a useful comparison with information about cod spawning areas previously gathered as part of an investigation of fishermen’s knowledge carried out by FRS and the University of Aberdeen in 2002. Twenty five fishermen, skippers of demersal fishing vessels fishing in the northern North Sea and to the west of Scotland were interviewed on a range of topics and asked about the location and timing of cod spawning. Most commented generally and eight volunteered information on cod spawning areas. Fishermen reported that cod in spawning condition can be found dispersed over relatively large areas of the northern North Sea, some identifying particular areas as important spawning areas. Significant aggregations of spawning fish were found to the east of Shetland, north of 60º. The area south west of Shetland as previously identified by fishermen was also reflected in good catch rates by this recent survey. The north east coast of Scotland between Fraserburgh and Banff was identified by several fishermen as a traditional cod spawning area, but one which is no longer used by the fish. They commented that stock in this area had been fished out in the early 1990s by the seine netters and not recovered since. The recent survey obtained relatively high catch rates of


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spawning cod within a few hauls in this area, suggesting that such areas may be recovering. The main difference between the 2002 fishermen’s report and the recent survey was the classification of an area to the far east of Orkney (between 0º and 1ºW) as another past spawning ground, no longer used. It was within this particular area that the recent survey obtained the highest catch rates of adult fish in spawning condition. Implications for Management A recurrent feature of stock declines has been the collapse of the spatial distributions of fish and loss of the distinct sub-stocks (Melvin and Stephenson, 2007). There is evidence that a diverse sub-stock structure is necessary to ensure the long term health and productivity of fish stocks, but maintaining this has not been recognised as an objective of fisheries management. Recent studies into population genetic structuring of cod within the North Sea have suggested that cod from Viking represent an isolated cod population. To a lesser degree, but still on an evolutionary scale, northern North Sea and west of Scotland samples can be separated from Faeroe Plateau and Faeroe Bank cod populations (Nielsen et al., in review). Whilst there is no genetic evidence for structuring in Scottish coastal cod, non-genetic markers (tagging; Neat et al., 2006, otolith shape; Galley et al., 2006 and otolith chemistry; Gibb et al., 2007) further indicate a high degree of segregation between spawning areas in the Scottish east coast and Shetland in addition to the north east North Sea. Together with recent studies of stock structuring the evidence of localised concentrations from this study indicate that fishing may have a greater impact in some areas more than others. This is particularly an issue for 0-group concentrations. Hence, some of the coastal nursery areas we identified appear to be particularly vulnerable and may deserve special protection to reduce the potential impact of discarding and other forms of gear related mortality in these areas. Clearly, large by-catches of undersized fish have no commercial advantage to fishermen. Protection could take the form of temporary closures based on real time evidence of discarding although in some locations high densities of cod appear to be common from year to year. This project also confirms that some of the major historical spawning areas for the North Sea cod are still active, but some localised populations may now be reduced. These populations could be at particular risk of severe depletion and may require targeted conservation measures.

ACKNOWLEDGMENTS We are indebted to the skipper and crew of the Ocean Bounty and Genesis for their enthusiastic co-operation with this project. We also acknowledge and thank the SFF for its support and advice throughout the project. FRS work is supported by the Scottish Government ROAME MF0760. Previous work referenced within this project was conducted as part of a contract with the European Union METACOD Q5RS-2001-00953 and the Scottish Executive projects MF0756 and MF0465. It does not necessarily reflect the views of the European Commission and in no way anticipates any future opinion of the Commission.


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REFERENCES Brander, K. M. 1994a. The location and timing of cod spawning around the British Isles. ICES Journal of Marine Science 51: 71-89. Brander, K. 1994b. Spawning and life history information for North Atlantic cod stocks. International Council for the Exploration of the Sea, Rapport des Recherches Collectives, 205. Fox, C. J., Taylor, M., Dickey-Collas, M., Fossum, P., Kraus, G., Rohlf, N., Munk, P., van Damme, C. J. G., Bolle, L. J., Maxwell, D. L. and Wright, P. J. 2008. Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means. Proceedings of the Royal Society B. (doi:10.1098/rspb.2008.0201). Galley, E. A., Wright, P. J. and Gibb, F. M. 2006. Combined methods of otolith shape analysis improve identification of spawning areas of Atlantic cod. ICES Journal of Marine Science 63 (9): 1710-1717. Gibb, F. M., Gibb, I. M. and Wright, P. J. 2007. Isolation of Atlantic cod (Gadus morhua) nursery areas. Marine Biology : 1185-1194. Heath, M., Rankine, P. and Cargill, L. 1994. Distribution of cod and haddock eggs in the North Sea in 1992 in relation to oceanographic features and compared with distributions in 1952-1957. ICES Marine Science Symposium 198: 244-253. Hedger, R., Mckenzie, E., Heath, M., Wright, P., Scott, E., Gallego, A. and Andrews, J. 2004. Analysis of the spatial distributions of mature cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) abundance in the North Sea (1980–1999) using generalised additive models. Fisheries Research 70: 17–25. Melvin, G. D. and Stephenson, R. L. 2007. The Dynamics of a Recovering Stock: Georges Bank Herring. ICES Journal of Marine Science 64: 69-82. Neat, F. C., Wright, P. J., Zuur, A. F., Gibb, I. M., Gibb, F. M., Tulett, D., Righton, D. A. and Turner, R. J. 2006. Residency and depth movements of a coastal group of Atlantic cod (Gadus morhua L.). Marine Biology 148: 643-654. Nielsen, E. E., Wright, P.J., Hemmer-Hansen, J., Poulsen, N. A., Gibb, I. M. and Meldrup, D. (in review). Population structure of cod (Gadus morhua L.) in the North Sea and west of Scotland; the role of sampling loci and individuals for inferring micro-geographical differentiation. Marine Ecology Progress Series Raitt, D. F. S. 1967. Cod spawning in Scottish waters. Preliminary investigations. ICES CM 1967/F: 29 (mimeo). Ruzzante, D. E., Taggart, C. T., Doyle, R. W. and Cook, D. 2001. Stability in the historical pattern of genetic structure of Newfoundland cod (Gadus morhua) despite the catastrophic decline in population size from 1964 to 1994. Conservation Genetics 2: 257-269. Saville, A. 1959. The planktonic stages of the haddock in Scottish waters. Marine Research 1959 (3): 1-23.

http://www.springerlink.com/content/100441/?p=d3a999aa26aa4bc4ae0c81f8492a880c&pi=0


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Wright, P. J., Galley, E. A., Gibb, I. M. and Neat, F. C. 2006a. Fidelity of adult cod to spawning grounds in Scottish waters. Fisheries Research 77: 148-158. Wright, P. J., Neat, F. C., Gibb, F. M., Gibb, I. M. and Thordarson, H. 2006b. Evidence for metapopulation structuring in cod from the west of Scotland and North Sea. Journal of Fish Biology 69 (Supplement C): 181-199.

Figure 1: Density (n.km-2) distribution of 0-group cod in the North Sea (Gibb et al., 2007). Circles represent trawl stations. Area codes: SH=Shetland, MF=Moray Firth, BU=Buchan and CL=Clyde. The box denotes the only square that has changed (to a higher density of 100-1000) with the addition of the 2007 Ocean Bounty data.

Figure 2: Cod stage 3-6 eggs m-1 in the North Sea and west coast of Scotland in the 1950s (Saville,1959; presented by Raitt, 1967), 1968 and 1976 (Brander, 1994a, b).

Figure 3: The distribution of stage I cod eggs from the 2004 ichthyoplankton survey. The area of the solid circles is proportional to the daily production of cod eggs at each station. Crosses indicate where a plankton sample was collected but no stage I cod eggs were found. Dashed contour lines show the bathymetry in meters. (Fox et al., 2008)

Figure 4: Real Time Closure (RTC) Cod Spawning Map, 24th December 2007, with overlaid log catch rates from this project’s Genesis cruise 2207H. (black circles: catch rates of cod varied from 0 – 4890 per hour).

APPENDIX 1

CRUISE REPORT FOR THE COD NURSERY AREA SURVEY R1/3 Not to be cited without reference to FRS Marine Laboratory, Aberdeen Charter Fishing Vessel Ocean Bounty (PD182) Cruise 2007H REPORT 17-26 September 2007 Personnel Iain Gibb (SIC) Objectives 1. To identify important cod nursery areas in the North Sea as part of SISP project. 2. To biologically sample all 0-group cod for length, sex and maturity. Otoliths will

be extracted at sea and preserved dry in plastic vials for later ICP-MS analysis. 3. To collect live 1-group cod from St Andrews Bay/Bell Rock. Out-turn days per project: MFP6Q04 – 10 days Narrative All gear and scientific equipment was loaded onto the vessel in Peterhead on the morning of Monday 17 September. After the installation of gear was complete, the vessel departed at 1600 and made passage to St Andrews Bay/Bell Rock to trawl for live 1-group cod the next morning. Despite a total of 5 trawls deployed in this area there were no catches of live 1-group cod. The vessel remained in this area until a sample size of 100 juvenile cod was achieved. After this, the vessel carried out a survey of juvenile cod nursery areas, in areas of known high juvenile density and in consultation with the vessel’s skipper. A total of 23 further trawls were made in Buchan, Moray Firth, Orkney and Shetland (Figure 1). Trawl duration ranged from 15-80 minutes, averaging 40 minutes. Zero catch rates of juvenile cod were seen in the Moray Firth and Orkney tows, however, sample sizes of at least 100 juvenile cod were successfully achieved in the Buchan, Tay and Shetland areas (Table 1). Average bottom water temperature, as derived from a minilog attached to the trawl headline was 13.0 in the Tay, 12.5 in Buchan, 12.4 in the Moray Firth, 12.0 off Orkney and 11.2 in Shetland. All cod were biologically sampled for length and otoliths

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removed and preserved dry in plastic microtubes for future ICP-MS analysis. All gear was unloaded in Peterhead on 26 September. Thanks to the skipper and crew of the Ocean Bounty for their co-operation with this survey. Ian Gibb 20 December 2007

Figure 1: 2007H trawl locations showing juvenile abundance. Catch rates varied from 0 – 636 cod per hour.

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56

56.5

57

57.5

58

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LATI

TUD

E

Log N.hr-1

0.0 - 0.1

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1.6 - 2.2

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Table 1: Summary information of 0-group cod samples Area Bay No 0-group

cod Length Range (cm)

Bell Rock 0 - Tay St Andrew’s Bay 142 8.9-16.9

Buchan Newburgh Bay 100 9.4-17.3 Brora Point 0 - Covesea Skerry 0 - Dunrobin Bay 0 -

Moray Firth

Smith Bank 0 - East Orkney 0 - Papa Westray Bay

0 - Orkney

Stronsay Firth 0 - Horewick 0 - Mousa Sound 0 -

Shetland

Whiteness Voe 159 9.9-17.5

GRAND TOTAL 401

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APPENDIX 2

CRUISE REPORT FOR THE COD SPAWNING AREA SURVEY Not to be cited without reference to FRS Marine Laboratory, Aberdeen Charter Fishing Vessel Genesis (BF 505) Cruise 2207H REPORT 18-28 March 2008 Personnel Iain Gibb (SIC) Francis Neat Declan Tobin Objectives 1. To identify important cod spawning areas in areas IVa and IVb. 2. To tag spawning cod from west Shetland for investigations of their movements.

Tagging will involve both conventional and data storage tags. 3. To biologically sample all cod (and haddock from three areas) for length, sex and

maturity. Otoliths, genetic samples and ovary sections will be extracted at sea and preserved in vials for later analysis.

4. To collect live cod eggs from Buchan and Viking areas and return them to local

ports for transportation to Ardtoe field station. Out-turn days per project: MFP6Q04 – 11 days Narrative All gear and scientific equipment was loaded onto the vessel in Peterhead on the morning of Tuesday 18 March. After the installation of gear was complete, the vessel departed at 1300 and made passage to the Moray Firth to trawl for spawning cod in order to collect live cod eggs. Despite 3 hauls of up to an hour duration conducted during the day, only 2 females were found in running state, and fertilisation was not possible. The vessel then sailed through the night for Papa Bank. Weather conditions the following day were good, and the day was dedicated to cod tagging. 5 hauls were conducted, and a total of 12 cod were successfully tagged with electronic tags and released back to the capture area. The vessel then set sail for Sumburgh Head areas at 2300. Fishing activities were conducted throughout the 20th, working North East from

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Sumburgh Head. Due to deteriorating weather conditions the vessel docked in Lerwick at 2130. A small amount of mending work was required from the last haul and this was conducted in port. The vessel stayed in port during Friday 21st due to severe gales but departed first thing on the 22nd, making passage for the Bressay Grounds where fishing operations resumed at 1300. Five hauls were conducted before the vessel made passage to the Ninian Field where 8 hauls were conducted the following day. Not enough cod in spawning state were found to make egg collection viable from this area. The vessel then made an overnight passage down to the East Bressay grounds, where 7 hauls were conducted throughout the 24th. Again, no cod in spawning state were located and so the emphasis was then changed to haddock, where a suitable number of spawning individuals were located, stripped and fertilised onboard. The vessel then made an overnight passage to the 110 Mile Holes where the highest catch rate of the cruise was attained during the next 24 hours (4890 cod hr-1). After sampling on the 26th the vessel then made an overnight passage to Fraserburgh where the fertilised haddock eggs collected from the East Bressay grounds were returned at 0500. FRS transport then transferred them to Ardtoe. The vessel immediately resumed the survey in the Buchan area on the 27th, haddock were sampled again but no viable eggs were available for fertilisation. The cruise ended in Macduff on the morning of the 28th March. Tow positions during the cruise were determined from information supplied by the skipper and previous FRS surveys. Exploratory tows were made in consultation with the skipper. No sampling was conducted within the Norwegian sector due to diplomatic clearance not been given before or within the time frame of the cruise. A minilogger was attached on the net headline to record water temperature throughout the tows and the onboard Scanmar system was used to monitor net dynamics during each haul. Catch rates of cod are shown in Figure 1. Grateful thanks are extended to the skipper and crew of the MV Genesis for their co-operation with this survey.

Fish tagging A total of 17 cod were tagged with DST tags.

Biological and genetic sampling A total of 1143 cod were sampled for biological, otolith and genetic studies during the cruise. A total of 150 haddock were also sampled from three areas for genetic studies. Iain Gibb, April 2008

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Figure 1: 2207H trawl locations. Catch rates of cod varied from 0 – 4890 per hour.

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scottish industry / science partnership (sisp) report no 03/08 · scottish industry/science...

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