Variação temporal nos parâmetros crescimento e proporção sexual do tubarão-lixa Ginglymostoma cirratum (Chondrichthyes: Gynglymostomatidae) no litoral cearense em duas décadas

Abstract

Ginglymostoma cirratum, classified as vulnerable by the IUCN and MMA, is still considered a fishery resource in several Brazilian states. In Fortaleza, one of the largest fishing landing points in Ceará, nurse shark individuals are routinely landed and sold. The species has been studied in Ceará on an ad hoc basis. Given the lack of fishing data since 2017, we sought to evaluate the population structure over this period of almost two decades (2006-2008, 2010-2011, 2015-2017 and 2022-2025). The data were evaluated according to period, size class and sex. A total of 449 individuals were sampled in 262 sampling days. Females were more abundant, totaling 136 individuals, while males had only 124 individuals sampled. Regarding the number of carcasses, this was the largest percentage sampled (42.1%), totaling 189 individuals landed and eviscerated in the four periods. Sizes ranged from 42.3 to 316 cm. The most frequent length class was 82-102 cm. One pregnant female was sampled in the first period. In all periods, only 6.3% of females were considered adults and 9.6% for males. It was possible to observe that fishing almost predominantly targets young individuals. Throughout the periods, the frequency of the species remained stable. However, it was observed that fishing is more incisive on females. To certify changes in population structure and abundance, CPUE (Catch per Unit Effort) data is required. Therefore, the study highlights the utmost importance of obtaining these data to continue research and find conservation plans for the species.