Dissertation (Metadaten)
Titel:Influence of maternal effects and environmental conditions on growth and survival of Atlantic cod (Gadus morhua L.)
Autor:Vivian Christiane Buehler
Fakultät:Mathematisch-Naturwissenschaftliche Fakultät
DDC Sachgebiet:570 Biowissenschaften, Biologie
Datum der mdl. Prüfung:02.12.2004
Referent(in):Prof. Dr. D. Schnack
Korreferent(en) Korreferentin:Prof. Dr. H. Rosenthal
Beschreibung:Commercially exploited stocks that have experienced declines in population abundance have responded by altering life history traits of growth and maturation. Cod is not only becoming mature at an earlier age but also, the majority of the stock comprises fishes with no previous spawning experience. Actual fisheries management does not take in account qualitative differences within the spawning stock. If the stock responds to continued exploitation by shifting maturity to an earlier stage, fish will spawn at smaller sizes. They will produce smaller eggs, and consequently small and less viable larvae, so that the contribution to the spawning stock biomass will be less than expected. There are many advantages for delaying maturation: Larger and heavier fish will be better conditioned for spawning, have higher fecundity and larger eggs that are more viable. Harvesting at delayed recruitment enables the stock to maintain a larger SSB with an expanded age structure while supporting a sustainable fishery.
Schlagworte:maternal effects, overfishing, fish larvae, growth, survival, Atlantic cod, otoliths, bigger-is-better, mesocosms, genetic fingerprinting
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