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Derivation of Pacific Cod Age Composition Using Length‐Frequency Analysis
Author(s) -
Foucher R. P.,
Fournier D.
Publication year - 1982
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8659(1982)2<276:dopcac>2.0.co;2
Subject(s) - gadus , composition (language) , statistics , fishery , mathematics , oceanography , geography , environmental science , biology , geology , fish <actinopterygii> , linguistics , philosophy
A computer program was developed to estimate age composition from length‐frequency samples of Pacific cod (Gadus macrocephalus) landed in British Columbia from Hecate Strait. Age groups were identified by fitting estimates of mean length at age and their standard deviations to the growth pattern determined by results of tagging experiments and research‐cruise catches. Compared to the more traditional method of graphical analysis using probability paper, better fits were obtained between observed frequencies and those expected from the parameters estimated. Obvious differences were found between computer and scale‐method estimates of age composition and mean lengths at age. Discrepancies among the scale interpretations tended to favour the computer method. Estimates of mean length at age produced by computer analysis of samples from the winter fishery on the White Rocks Ground (central Hecate Strait) were similar to those previously estimated from research‐cruise and tag‐return data.