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- Standardized CPUE and size distribution of the shortfin mako shark in the portuguese pelagic longline fishery in the AtlanticPublication . Coelho, Rui; Rosa, Daniela; Lino, PedroThis document provides fishery indicators for the shortfin mako shark captured by the Portuguese pelagic longline fishery in the Atlantic (standardized CPUEs and size distribution). The analysis was based on data collected from fishery observers, port sampling and skippers logbooks (self sampling), between 1995 and 2015. The mean sizes were compared between years, seasons (quarters), stocks (north and south) and sampling areas. The CPUEs were analyzed for the North Atlantic and compared between years, and were standardized with Tweedie and Delta GLM approaches. In general, there was a large variability in the nominal CPUE trends in the North Atlantic, and the final standardized series was flatter than the nominal. For the size distribution there were no major trends in the time series, with the sizes tending to be larger in the South Atlantic. The data presented in this document can be considered for use in the upcoming 2017 shortfin mako stock assessment, specifically the standardized CPUE for the North Atlantic and the size distribution for both hemispheres.
- Hook, bait and leader type effects on surface pelagic longline retention and mortality rates: a meta-analysis with comparisons for target, bycatch and vulnerable fauna interactionsPublication . Casaca Santos, Catarina; Rosa, Daniela; Coelho, RuiA meta-analysis of 24 publications was conducted to assess effects of hook, bait and leader type on retention and at-haulback mortality rates of target, bycatch and vulnerable species of the pelagic longline fishery. Turtles and swordfish had lower retention rates with circle hooks. In contrast, retention rates of 3 sharks and 2 tuna species were greater with circle hooks. Bait type did not seem to significantly influence the retention rates of most of the species examined. Wire leader lead to a decrease in retention rates of bony fishes and a mix for elasmobranchs. For athaulback mortality, hook type was the most influential, with 5 elasmobranch species and 6 bony fishes having a significantly lower at-haulback mortality rates when using circle hooks. Bait type and leader type did not have a significant effect on at-haulback mortality rates for most species. The results presented here should be considered preliminary. Future work will consider expanded information on fishery characteristics.
- Fishery indicators for the shortfin mako (Isurus oxyrinchus) caught by the portuguese pelagic longline fishery in the Atlantic: nominal CPUEs, catch-at-size and at-haulback mortalityPublication . Coelho, Rui; Rosa, Daniela; Lino, PedroThis paper provides an overview of fishery indicators for the shortfin mako shark captured by the Portuguese pelagic longline fishery in the Atlantic, in terms of catch-at-size, nominal CPUEs and at-haulback mortality. The analysis is based on data from fishery observers, port sampling and skippers logbooks (self sampling), from 1997-2015. In general, there was a large variability in the nominal CPUE trends for the north Atlantic, with a slight increase during the period. For the catch-at-size there were no major trends in the time series, but the sizes tended to be larger in the South Atlantic and with a larger variability. The at-haulback mortality was similar between sexes, with a trend for decreasing mortality rates with increasing specimen size. The data presented in this working document should be considered preliminary and is presented in preparation for the 2017 shortfin mako stock assessment in the Atlantic Ocean.