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AEBR-369-2025-Spatial-distribution-and-connectivity-of-blue cod-spawning-stock-in-Marlborough-Sounds.pdf
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AEBR-369-2025-Spatial-distribution-and-connectivity-of-blue cod-spawning-stock-in-Marlborough-Sounds.pdf (7.3 MB)
Abstract
Blue cod are a popular species of fish for recreational, commercial and customary fisheries in Aotearoa New Zealand. Blue cod stocks in many places have experienced significant declines compared to historical levels , particularly in the Marlborough Sounds.
Fisheries New Zealand is exploring measures to restore the blue cod population within the Marlborough Sounds, by identifying areas where fishing pressure could be reduced to increase abundance of spawning mature blue cod.
In this project, we use information from blue cod monitoring surveys, pooled with data that describe the types of habitat blue cod prefer, to predict the distribution of female biomass – a good index of spawning potential. Female biomass is predicted for two scales: across the full Marlborough Sounds area, including outer coastal areas; and for an inner sounds area including Pelorus and Queen Charlotte Sounds only. Areas with high female biomass occurred mostly on the outer coast around D’Urville Island and in outer Queen Charlotte Sound, however areas that had the right combination of habitat characteristics to support spawning were also predicted within the inner sounds. The impact of historical fishing on female biomass was unable to be realistically included in our analysis due to a lack of information on historical catch and so the areas we identify as important for spawning are based on present day relationships between female biomass and habitat characteristics.
Using information on local currents, we then determined the connectivity of sites of importance for spawning with juvenile habitats and explored how larvae from each site may be retained within the inner sounds. There was very low larval transport between spawning in coastal areas and the inner sounds, suggesting that spawning areas within each sound would be required to restore local stocks.
We use this information to identify and rank ten areas that hold good potential for the restoration of blue cod spawning within the inner Marlborough Sounds.
Document date
Thursday, 23 October 2025
Document type
V 1.3
File format
Adobe PDF
File size
7.3 MB
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AEBR-369-2025-Spatial-distribution-and-connectivity-of-blue cod-spawning-stock-in-Marlborough-Sounds.pdf
Uploaded date
Thursday, 23 October 2025
Search tags
ISSN:
1179-6480;
ISBN:
978-1-991407-23-8;
AUTHOR:
Brough, T.;
Beentjes, M.P.;
Leunissen, E.;
Collins, C.;
Morrison, M.;
AEBR:
369/2025;
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