|Title:||Application of Fishery-independent Data as an Alternative Source for Determining Relative Abundance Indices of Blue Marlin, Makaira nigricans (Actinopterygii: Perciformes: Istiophoridae) in the North-eastern Indian Ocean||Authors:||Setyadji, Bram
|Keywords:||BINOMIAL REGRESSION-MODEL;BYCATCH;CATCH;CPUE;TUNA||Issue Date:||May-2022||Publisher:||CENTRAL FISHERIES RESEARCH INST||Journal Volume:||22||Journal Issue:||5||Source:||TURK J FISH AQUAT SC||Abstract:||
The present study aimed to determine the abundance index of blue marlin, Makaira nigricans (Lacepede, 1802) utilizing fishery-independent data, i.e., scientific observer, and attempted to bridge the research's gap for low coverage information in the northeastern Indian Ocean. A total of 2,984 set-by-set observer data from 2006-2018, spatially disaggregated by one-degree blocks, were obtained from the Indonesian scientific observer program following commercial longline fleets. A delta-lognormal model was chosen to fit the dataset, using catch as the response variable with seven covariates. A backward procedure based on AIC, BIC and R-2 were used to select the best model. Overall, the delta-Gamma performs better when modelling data with a high proportion of zeros than other traditional models. The blue marlin CPUE trend is relatively stable over time, despite the inter-annual fluctuations, which are likely a result of natural variation in the population as opposed to operational changes or inter-annual environmental variation. Given the low spatial coverage compared to logbook data, scientific observer data performed well and produced a robust abundance index of blue marlin in the northeastern Indian Ocean.
|Appears in Collections:||14 LIFE BELOW WATER|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.