Comparison of larval, age-0 juvenile and age-2 recruit abundance indices of walleye pollock,Theragra chalcogramma, in the western Gulf of Alaska
Abundance indices were formulated from historical data on larvae, age-0 juveniles and age-2 recruits of walleye pollock, Theragra chalcogramma, in the western Gulf of Alaska.Indices were examined for linear and rank correlations to determine when year-class strength is established. Age-0 juveniles a...
| Published in: | ICES Journal of Marine Science |
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| Main Authors: | , |
| Format: | Text |
| Language: | English |
| Published: |
Oxford University Press
1992
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| Subjects: | |
| Online Access: | http://icesjms.oxfordjournals.org/cgi/content/short/49/3/297 https://doi.org/10.1093/icesjms/49.3.297 |
| Summary: | Abundance indices were formulated from historical data on larvae, age-0 juveniles and age-2 recruits of walleye pollock, Theragra chalcogramma, in the western Gulf of Alaska.Indices were examined for linear and rank correlations to determine when year-class strength is established. Age-0 juveniles and recruits were significantly correlated, and the rank ordering of year-class strength did not change significantly between these life stages.The same situation was observed between larvae and age-0 juveniles. However, the levels of larval and age-2 recruit abundance were not significantly correlated and the rank ordering was not significant; the cause for this dissociation was 2 years of very high larval abundance that resulted in below average year classes. Years of low larval abundance resulted in weak year classes as age-0 juveniles and age-2 recruits. These data indicate that larval surveys may be useful to predict year-class failures (when larvae are not abundant), although not necessarily strong year classes; age-0 juvenile surveys can detect relatively strong or weak year classes. |
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