Reproductive biology of the largehead hairtail Trichiurus lepturus (Teleostei: Trichiuridae): implications to the fisheries management on shallow coastal waters in northeastern Brazil

The largehead hairtail Trichiurus lepturus is an important fishery resource and a source of income for artisanal fishers in northeastern Brazil. In the region, this species has recently attracted the attention of investors considering its export to Asian countries. The aim of this research was to obtain data regarding reproductive biology to manage populations, as certain fishing gears usually caught juveniles. Specimens were obtained monthly from August 2017 to July 2018 from fixed traps in the municipality of Bitupitá, Ceará state, Brazil. A total of 437 specimens were sampled, ranging from 30.2 to 98.5 cm, including 255 females and 182 males. The sex ratio was 1:1.4 (M:F), with females predominating in larger length classes. The reproductive period occurs between August and December, coinciding with the dry season in the region. The species exhibits asynchronous oocyte development and batch spawning, with an average fecundity of 51,209 oocytes per batch. The results of this study are fundamental for characterizing and understanding the reproductive biology of T. lepturus, given its commercial importance in the region and the potential for increased catches targeting export markets. It was also observed that 37% of the specimens captured were below L50. This study represents an initial step in filling the knowledge gap in northeastern Brazil with reproductive data, enabling the establishment of management priorities for this important species.