Population structure of Trichiurus lepturus Linnaeus, 1758 captured on the southern coast of Pernambuco, Northeastern Brazil Thaíza Maria Rezende da Rocha Barreto, Danilo Francisco Corrêa Lopes, Flávia Lucena Frédou, Ana Rosa da Rocha Araujo

Abstract

The objective of this study was to evaluate the population structure of Trichiurus lepturus captured as bycatch of the trawl fishery targeting Penaeidae shrimps off the coast of Sirinhaém, on the southern coast of the state of Pernambuco, in the Northeast region of Brazil. The data used for this study correspond to collections made between August 2011 and September 2014 by the Laboratory for Studies of Anthropogenic Impacts on Marine and Estuarine Biodiversity (BIOIMPACT) of the Department of Fisheries and Aquaculture (DEPAq) of the Federal Rural University of Pernambuco (UFRPE). A total of 235 specimens were analyzed, of which 95 were females, 80 were males and 65 were undetermined. Females ranged in total length from 13.1 to 97.0 cm (40.85 cm ± 10.9), and males ranged from 16.0 to 58.1 cm (36.85 cm ± 6.82). In general, females were longer than males. The relationships between total length and total weight showed positive allometry for females (b = 3.601) and grouped sexes (b = 3.277), and isometric for males (b = 3.044). The length at first sexual maturity was estimated for females and males as 41.65 cm and 34.3 cm, respectively. Due to the growing economic importance of the species in Brazil, the results of this study indicate that the swordfish stock in the region requires greater attention in order to ensure the maintenance of future stocks.