Analysis of Pre-recruit Data from Surveys for Greenland Halibut in NAFO Subarea 2 and Divisions 3KLMNO by
Research survey data are analyzed to predict relative year-class strength from 1975 to 2000. Log-additive models with fixed year-class strength and survey-age effects that have common variance among pre-specified groups (e.g. group = survey-age combinations) and zero covariance between groups are ut...
Main Authors: | , , |
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Other Authors: | |
Format: | Text |
Language: | English |
Published: |
2002
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Subjects: | |
Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.597.7513 http://archive.nafo.int/open/sc/2002/scr02-021.pdf |
Summary: | Research survey data are analyzed to predict relative year-class strength from 1975 to 2000. Log-additive models with fixed year-class strength and survey-age effects that have common variance among pre-specified groups (e.g. group = survey-age combinations) and zero covariance between groups are utilized to model the error structure of the data. Variance estimation of each group is iteratively re-weighted. Likelihood ratio tests reduce the number of variance parameters estimated. The most parsimonious model indicates that the 1993, 1994, and 1995 estimates of year-class strength are predominant over the time period, and the two most recent year class strength estimates, the 1999 and 2000 cohorts are also relatively strong. |
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