Morphometry and relative growth of the Brazilian sardine, Sardinella brasiliensis (Steindachner, 1879) in the southeastern Brazilian bight

• Autor(a) principal: Perin, Simone
• Data de Publicação: 2014
• Outros Autores: Vaz-dos-Santos, André Martins
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Arquivos de Zoologia (Online)
• Texto Completo: https://www.revistas.usp.br/azmz/article/view/88073
• topic: Otolith; Sagitta; Allometric model; Population condition.

The Brazilian sardine, Sardinella brasiliensis, is a small pelagic clupeid fish distributed primarily between 22°S and 29°S, where it forms large schools. The species is an important fishery resource and is targeted by purse seine vessels operating in the area. Although an extensive literature addresses various characteristics of the species, studies of its morphometry and relative growth are scarce. The aim of the present study was to analyze the relative growth based on body and otolith morphometry to identify the patterns characterizing the population. Monthly samples were obtained during 1985 and 1987, and data on total length, total weight and otolith length, height and weight were analyzed. The allometric model of Huxley (y = axb) was fitted seasonally and by year, and regressions were compared among seasons and between years. The regression coefficient "b" was tested (t-test) to identify isometry and allometry. A total of 603 sardines, with total lengths ranging from 120 mm to 229 mm, were analyzed. The length-weight relationships tended to show positive allometry, whereas the total length-otolith measurement relationships tended to show negative allometry. The relative growth rates decreased during the year and showed the lowest values during spring in association with the peak of the spawning period. In contrast, the condition factor (coefficient "a" of the allometric regression) increased gradually during the year until spring as a consequence of the increasing weight of the fish due to gonad maturation. Comparisons between the years analyzed also show that the fish grew faster during the collapse of the stock, in 1987. The methodology used in this study allowed the detection of this effect. This study established the historical pattern of relative growth and showed that morphometry and relative growth offer efficient tools for monitoring the sardine in the study area.