MARAM_Tristan_2021_MAY_06 (Updated 2021 Gough CPUE).pdf (607.04 kB)

Updated 2021 GLMM -standardised lobster CPUE from Gough Island of the Tristan da Cunha outer group of islands

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posted on 05.07.2021, 09:23 by Susan Holloway, Doug Butterworth
The longline CPUE series for Gough island is GLMM standardised through to 2020. Year, month, area, trap-type, soak time, depth, sequential day of fishing and year-area interactions are treated as fixed effects, and year-month interactions treated as a random effect. The standardised CPUE value for the current season is higher than that of the previous season. The Gough CPUE is now just above the Itar value. A large difference exists between the nominal CPUE value for the 2020 season, compared with the standardised CPUE value. This is due to the majority of the 2020 season’s catch being taken in months for which the relative catchability is very poor, as well as longer tranches taken in these later months (which will reduce the nominal CPUE value).

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Department of Mathematics and Applied Mathematics, University of Cape Town