SPATIOTEMPORAL VARIABILITY OF TARGET-SPECIES IN TUNA AND TUNA-LIKE FISHING IN BRAZIL

Silvaneide Luzinete Rodrigues,Vívian Graziela Oliveira Carneiro,Ana Júlia Rufino De Freitas,Humber Agrelli De Andrade

doi:10.20950/1678-2305.2020.46.2.587

Silvaneide Luzinete Rodrigues, Vívian Graziela Oliveira Carneiro + Show 2 more

Open Access

https://doi.org/10.20950/1678-2305.2020.46.2.587

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Abstract

Knowing the history of fishing-target catches and identifying them is essential for fish species conservation, mainly for the conservation of migratory species, whose stock assessment data are often provided by commercial fleets. Data on the catch, effort, and geographic distribution of fishing operations found in Banco Nacional de Dados da Pesca de Atuns e Afins - BNDA (National Database of Tuna and Tuna-like Species Fishing) were herein analyzed. The ratios between catches of different Tuna and tuna-like species were calculated and the identified patterns were used to classify what would be the target-species of the Brazilian fleet in different periods between 1978 and 2018. Based on the current results, there are three different exploration phases marking the Brazilian longline fleet. The first phase (1978-1981) was featured by the prevalence of Japanese vessels, which recorded the highest presence of swordfish on catching quantity within that period (with mean target-species indicator of Dka = 0.30). The second phase took place between 1982 and 2001, and it was marked by an increased indicator for tuna species, mainly of albacore (with mean of Dka = 0.17). Finally, the third phase (2002-2018) stood out for the leasing of several vessels, increasing the effort and the volume of swordfish (with mean of Dka = 0.04), and blue shark catches (with mean of Dka = 0.19). Moreover, the recorded CPUE reflected variations in fleet targeting over the years, as well as the biomass of the analyzed species.

Highlights

The following species are among the main commercial catch targets worldwide: bigeye tuna (Thunnus obesus), albacore tuna (Thunnus alalunga), yellowfin tuna (Thunnus albacares), swordfish (Xiphias gladius) (Arrizabalaga et al, 2015; Pons et al, 2017; Erauskin‐Extramiana et al, 2019) and blue shark (Prionace glauca) – which, by the way, is the most often caught elasmobranch through pelagic longline fishery focused on tuna and tuna-like species (Fiedler et al, 2015; Coelho et al, 2018)
Data provided by Banco Nacional de Dados da Pesca de Atuns e Afins – BNDA, which is held by Secretaria de Aquicultura e Pesca – SAPA, linked to the Ministério da Agricultura, Pecuária e Abastecimento - MAPA of the Brazilian government, were analyzed
The present analysis revealed the complex background of the pelagic longline fishery carried out by the Brazilian tuna-fishery fleet, which encompasses a mosaic of vessels from different origins

Summary

Introduction

Marine species presenting wide oceanic distribution such as tuna, swordfish and shark species, are the catch-target in several countries (Hobday et al, 2017; Pons et al, 2018). The meat of these species is quite appreciated and has high commercial value. In the international market, mainly in the USA, Europe and Asia (Arrizabalaga et al, 2011; Guillotreau et al, 2017). Most stocks of these species are overfished or their catch stays within their maximum sustainable limit (Punt et al, 2015; FAO, 2020). The following species are among the main commercial catch targets worldwide: bigeye tuna (Thunnus obesus), albacore tuna (Thunnus alalunga), yellowfin tuna (Thunnus albacares), swordfish (Xiphias gladius) (Arrizabalaga et al, 2015; Pons et al, 2017; Erauskin‐Extramiana et al, 2019) and blue shark (Prionace glauca) – which, by the way, is the most often caught elasmobranch through pelagic longline fishery focused on tuna and tuna-like species (Fiedler et al, 2015; Coelho et al, 2018)

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