The gadoid outburst in the North Sea
Cushing, D.H. (1984). The gadoid outburst in the North Sea. J. Cons. - Cons. Int. Explor. Mer 41(2): 159-166
In: Journal du Conseil. Conseil International pour l'Exploration de la Mer: Copenhague. ISSN 0020-6466, meer
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| Trefwoorden |
20th century
Fish stocks
Organisms > Aquatic organisms > Animals > Aquatic animals > Marine animals > Fishes > Aquatic animals > Marine fishes > Osteichthyes > Cod
Calanus Leach, 1816 [WoRMS]
ANE, Noordzee [Marine Regions]
Marien/Kust |
| Abstract |
Cushing (1966) reported a correlation between haddock recruitment and the abundance of Calanus in the North Sea which failed with the very large year class of 1962 which started the gadoid outburst. This note reports another correlation between cod recruitment and Calanus during the gadoid outburst, but it fails if earlier observations (before 1962) are included. Comparing 1948 to 1961 with 1962 to 1978 a delay of one month in the peak of seasonal production of Calanus is demonstrated. In each year a delay in peak production of Calanus in months from the presumed date of hatching was calculated. Cod recruitment was significantly correlated with this index of delay for the period 1954 to 1977, across the periods before and during the gadoid outburst; if the mean recruitment in years with the same delay is related to the index of delay, most of the variance is accounted for. A multiple regression of cod recruitment on delay and on Calanus abundance was calculated and another of cod recruitment on delay, Calanus abundance, and March sea temperature; in the latter case three quarters of the variance was accounted for. The gadoid outburst in the North Sea was probably started by a natural change. |
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