Estimates of larval survival of cod by releases of genetically marked yolk‐sac larvae
In the spring of 1995, 18 million genetically marked yolk‐sac cod larvae Gadus morhua were released into a 2.9‐km 2 , nearly land‐locked fjord in western Norway. Four quantitative surveys were conducted, 11, 33, and 63 days, and 1 year after the first release. Almost 100% of the collected cod larvae...
| Published in: | Journal of Fish Biology |
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| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
1997
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1111/j.1095-8649.1997.tb06103.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1997.tb06103.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1997.tb06103.x |
| Summary: | In the spring of 1995, 18 million genetically marked yolk‐sac cod larvae Gadus morhua were released into a 2.9‐km 2 , nearly land‐locked fjord in western Norway. Four quantitative surveys were conducted, 11, 33, and 63 days, and 1 year after the first release. Almost 100% of the collected cod larvae were successfully identified to GPI‐1 * genotype. The marked cod larvae constituted 18% of all sampled cod larvae in the first survey and 9% in the two next. The average rate of mortality was estimated to be 23% day −1 for the first 10 days after release and 12% day −1 during the next month after release. After 1 year (April 1996), the number genetically marked I‐group cod in the fjord was estimated to be <120. The effect of the historical programme of large‐scale releases of yolk‐sac larvae on recruitment were evaluated and found to be small. |
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