Examination of temporal and spatial variability of length compositions for the 1983 Division 3L cod trap fishery with reference to resulting age composition estimation / by J.W. Baird and S.C. Stevenson... : Fs70-8/87-11E-PDF

"A study was conducted during the 1983 Newfoundland cod trap fishery in NAFO Div. 3L to examine the temporal and spatial variability amongst commercial length frequency samples and to determine the impact of any differences on age composition estimation. Likelihood ratio statistics were used to evaluate the relative contributions of time and location to the overall variation. The analysis showed that both month and unit area contributed significantly to the variability in length compositions, with unit area explaining considerably more variation than month. This suggests that length frequencies should be weighted by unit area landings rather than just by monthly landings as is presently the case. In terms of age composition estimation, differences of up to 25% for some ages occurred depending on whether frequencies were weighted by month, unit area or both month and unit area. Considering these differences, researchers should consider spatial as well as temporal variability when using commercial sampling data from this fishery to estimate removals at age"--Abstract, page 2.

Lien permanent pour cette publication :
publications.gc.ca/pub?id=9.895621&sl=1

• Format MARC XML
• Format MARC HTML

Demander des formats alternatifs