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

• Main Authors: Silvaneide Luzinete RODRIGUES, Vívian Graziela Oliveira CARNEIRO, Ana Júlia Rufino de FREITAS, Humber Agrelli de ANDRADE
• Format: Article
• Language: English
• Published: Instituto de Pesca 2020-10-01
• Series: Boletim do Instituto de Pesca
• Subjects: fishery effort; catch rate; fishing target
• Online Access: https://www.pesca.sp.gov.br/boletim/index.php/bip/article/view/1540/1467

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.