Egg fecundity and maturity of North Sea cod, Gadus morhua
Oosthuizen, E.; Daan, N. (1974). Egg fecundity and maturity of North Sea cod, Gadus morhua, in: Daan, N. (1975). Oecologische gevolgen van de visserij op Noordzee-kabeljauw: een drietal studies over de voedselopname, groei en reproduktie van de kabeljauw en een geïntegreerde modelstudie van het effekt van visserij op oecologische populatiegrootheden. pp. 378-397
In: Daan, N. (1975). Oecologische gevolgen van de visserij op Noordzee-kabeljauw: een drietal studies over de voedselopname, groei en reproduktie van de kabeljauw en een geïntegreerde modelstudie van het effekt van visserij op oecologische populatiegrootheden. PhD Thesis. E.J. Brill: Amsterdam. Diff. pag. pp., more
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| Authors | | Top |
- Oosthuizen, E.
- Daan, N., more
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| Abstract |
An analysis is presented of reproduction aspects of North Sea cod, Gadus morhua L., based on samples from the population during the spawning season. Fecundity was related to size and the highest correlation was observed in the linear fecundity-weight function. The results obtained are in good agreement with former estimates in literature. Year to year variation was not found to be significant and no effects of age and condition on the fecundity could be established. Dry egg weights were not significantly correlated with length or age, but were on the average significantly lower than a previous estimate in literature suggesting that yearly variation might be significant. Maturity is reached at a smaller length and a younger age by males than by females. Comparison with literature data revealed that for both sexes maturity is reached at considerable smaller lengths in recent years than during the first quarter of the century. The following reproduction parameters were estimated: absolute fecundity, F is 569 W- 807 000 eggs; relative fecundity,F is 569 eggs/ g wet weight above Wo is 1418 g (95% confidence limitsof F is 508 and 630) ; dry egg weight, E is 0.074:6 mg/egg (Sd ± 0.0129); length at 50% maturity, L50 is 53.3 cm for males and 59.2 cm for females. |
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