Growth parameters, longevity, and mortality of the seabob shrimp Xiphopenaeus spp. (Decapoda: Penaeidae) in four important fishing regions of southeastern Brazil

Abstract

We investigated and compared growth parameters, longevity, mortality (total, natural, and fishing), and exploitation rates of the seabob shrimp Xiphopenaeus spp. in four important fishing regions of southeastern Brazil. The hypothesis that the growth and mortality characteristics of distinct populations differ along a latitudinal gradient was tested. Sampling was performed monthly in Macaé, Ubatuba, Santos/São Vicente, and Cananéia over a 1‐ to 2‐year period. Growth and longevity parameters were estimated by the von Bertalanffy growth equation models. Total mortality (Z) was estimated by length‐converted catch curves. Growth parameters differed between sexes: males reached smaller sizes, showed larger growth coefficients (k) and higher mortality, and lived less than females in the four studied regions. Rather than finding a latitudinal gradient, our results support the hypothesis that distinct local environmental characteristics and fishing pressures alter the growth and population dynamics of Xiphopenaeus spp. in different areas. Our study indicates that the stocks of Xiphopenaeus spp. are overexploited, highlighting the importance of management plans to prevent the collapse of stocks and maintain them at sustainable levels for long‐term exploitation.

Growth, longevity and mortality of pink-shrimps Farfantepenaeus brasiliensis and F. paulensis in southeastern Brazil

“…Therefore, juveniles and pre-adults who have not yet migrated to the adult stock and have not reproduced are vulnerable to the seabob fisheries, which occur at up to 20 m deep, especially if the closed season is not suitable for the species. Miazaki et al (2021) recorded a high exploitation rate for Xiphopenaeus spp. in the same area, reinforcing pink shrimps' vulnerability.…”

“…age) t; CL ∞ is the asymptotic length, k is the growth coefficient and t 0 is the theoretical age at zero length (von Bertalanffy 1938). These growth parameters were estimated for the different cohorts using Solver supplement in Microsoft Excel, varying in the equation: CL ∞ , k and t 0 , which minimizes the sum of residuals between the lengths observed in the field and those calculated by the von Bertalanffy model (Miazaki et al 2021). Cohorts that presented a coherent biological rhythm in relation to longevity, k and CL ∞ , were chosen.…”

“…In the southeastern region, both species are frequently targeted due to their large sizes and high commercial value. They are also captured as bycatch of the seabob shrimp X. kroyeri in shallow marine areas (Mantelatto et al 2016), whose population in Ubatuba is already overexploited (Miazaki et al 2021). We believe these factors may be influencing and shaping populational parameters of pink shrimps in the sampling area.…”

Ficha de Xiphopenaeus kroyeri

“…Branco, resultados não publicados). Em comparação latitudinal da longevidade realizada por Miazaki et al (2021) com dados obtidos na região de Macaé/RJ, Ubatuba, Santos e Cananéia no litoral paulista com estudos publicados nos estados de Sergipe e Santa Catarina nos últimos 10 e verificaram uma tendência de diminuição deste parâmetro populacional, ou seja, em média houve um decréscimo de em torno de 6 a 7 meses de vida para ambos os sexos.…”

“…No litoral paulista, a taxa de explotação também se mostrou preocupante, todas acima de 0,75, sendo a média obtida para ambos os sexos em Ubatuba de 0,78, em Santos de 0,84 e em Cananéia de 0,77. Já mortalidade por pesca a região de Santos também foi mais elevada sendo de 17,0, em Ubatuba de 10,5 e Cananéia de 11 (Miazaki et al, 2021) Souza ( 2018) estudando a produção pesqueira no litoral paulista, de acordo com a segmentação geográfica, apresentou informações regionalizadas dos litorais sul, central e norte, considerando a produção total em Kg, nas três regiões, observou uma queda de 65,12%, no período de 2008 a 2016.…”