Fluctuations in the spawning stock biomass and recruitment of the brazilian sardine (Sardinella brasiliensis) 1977-1997

Abstract

In the southeastern coast of Brazil, catches of the Brazilian sardine (Sardinella brasiliensis) have been decreasing from more than 200 thousand tons/year in the early '70s to about 32 thousand tons in 1990. From 1994 to 1997, catches recovered slightly (118 thousand tons), dropping then to about 20 thousand tons in 1999-2000. Extensive investigations on biology and stock assessment of Brazilian sardine have been developed in the '80s, providing stock biomass and recruitment estimates based on commercial fishing data obtained from 1977-1992. The present paper aims to update biological and stock assessment parameters from sardine data obtained during two acoustic surveys carried out in 1995 and commercial catches from the 1993-1997 period. Results from both cruises showed the weight-length relationship Wt=0.0000019. Lt3,26 (90-240 mm total length) and four age classes (mostly class II+). In the commercial catches, sardines belonged to ages 0+ and 3+ years old (mostly older than 1-year old) with 90-250 mm total length. Annual growth parameters were: Li=275 mm, K= 0.55 (1996), and Li=273 mm, K=0.50 (1997). Total mortality (Z) and natural mortality (M) coefficients were: Z= 3.8; M= 0.7 -1.2 (1996), and Z= 3.6; M= 0.6 - 1.1 (1997). The variation amplitude of M is due to the application of several different methods. Considering the historical series of 21 years of data (1977-1997), results showed that the stock went through two favorable periods (1980-84, 1989-94) and one unfavorable period (1985-89). 1997 seems to have been the beginning of a new unfavorable period, revealing recruitment cycles likewise other stocks from California and Japan.<br>Na costa sudeste do Brasil, as capturas da sardinha-verdadeira {Sardinella brasliensis) decresceram de mais de 200 mil t/ano no início dos anos 70 para cerca de 32 mil t em 1990. De 1994 a 1997, as capturas se recuperaram alcançando 118 mil t, caindo então para cerca de 20 mil t em 1999-2000. Estudos abrangentes sobre a biologia e avaliação do estoque da espécie foram desenvolvidos nos anos 80, permitindo a estimativa da biomassa e recrutamento do estoque com base em dados da pesca comercial durante 1977-1992. Os objetivos do presente trabalho foram atualizar as estimativas dos parâmetros biológicos e avaliação do estoque através de dados obtidos durante dois cruzeiros de prospecção acústica realizados em 1995 e de dados da captura comercial no período 1993-1997. Como resultados de ambos os cruzeiros, a relação peso/comprimento estimada foi: Wt=0,0000019.Lt'~6 (amplitude de comprimento total de 90-250mm) e quatro classes etárias (maior freqüência para a classe II+) estiveram presentes. Nas capturas da pesca comercial ocorreram indivíduos de idades 0+ a Ill+ anos, principalmente adultos com mais de 1 ano de idade e comprimentos entre 90-250mm. Os valores dos parâmetros de crescimento estimados foram Li = 275 mm e K = 0,55 (1996), e Li = 273 mm e K = 0,50 (1997). As taxas de mortalidade total (Z) e natural (M) foram: Z = 3,8 e M = 0,7 - 1,2 (1996), e Z = 3,6 e M = 0,6 - 1,1 (199...

Spatial analysis of egg distribution and geographic changes in the spawning habitat of the Brazilian sardine Sardinella brasiliensis

“…The spawning habitat expansion and contraction pattern described above has been compared with independent estimates of the spawning stock biomass reported by Cergole (1995) and Cergole et al (2002) (Fig. 11).…”

“… Time series of spawning stock biomass (), recruitment () and yield () estimated by virtual population analysis for Sardinella brasiliensis (adapted from Cergole et al , 2002, with permission from the Brazilian Journal of Oceanography ). …”

“…Total landings peaked in 1973 with 228 000 t followed by a sharp drop to 32 000 t in 1990 and 17 000 t in 2000. It has been suggested that unfavourable stock–recruitment relationships, including a combination of overfishing and adverse environmental factors, led to the collapse of S. brasiliensis fisheries in the SBB (Cergole et al , 2002). There are also evidences that the reproductive strategy of the fish is similar to those of small coastal pelagic fishes at eastern boundary current systems (Bakun & Parrish, 1990).…”

Regional modeling of the water masses and circulation annual variability at the Southern Brazilian Continental Shelf

“…The Southern Brazilian Continental Shelf (SBCS) is known as one of the more productive areas for fisheries in Brazilian waters [ Haimovici , ]. Many authors reported a strong relationship between the SBCS environmental variability and the Brazilian sardine ( Sardinella brasiliensis ) biological cycle and fisheries [ Matsuura , ; Sunyé and Servain , ; Cergole et al ., ; Legey and Jablonski , ; Gigliotti et al ., ; Soares et al ., ; Dias et al ., ; D'agostini et al ., ].…”

Magellanic penguins: stomach contents and isotopic profiles to assess the feeding demands of juveniles in a wintering area off Brazil

“…The sardine S. brasiliensis occurs in tropical and subtropical waters of the western Atlantic and forms compact schools in coastal waters; these sardines are captured by local fisheries (Cergol et al, 2002). The family Engraulidae is the most abundant pelagic fish family in the south-western Atlantic.…”