Reproductive biology of Cetengraulis edentulus (Cuvier, 1829), the major fishery resource in Guanabara Bay, Brazil

Abstract

Cetengraulis edentulus is a broadely distributed engraulid in Southwest Atlantic, currently accounting for the main fish species commercially exploited at Guanabara Bay, Brazil. This study aimed to extend the knowledge on reproduction of C. edentulus at Guanabara Bay and to test whether some descriptors of reproductive activity, especially the gonadosomatic index (GSI), and the index of reproductive activity (IRA) changed among seasons. A total of 978 C. edentulus specimens were retrieved from purse seine commercial landings at Conservas Rubi S.A. company, in São Gonçalo city, RJ. Subsamples of 90-120 individuals were collected from bimonthly yields between July 2010 (winter) and June 2011 (autumn). Most fish were adults (120-170 mm TL), in response to the high selectivity of commercial fisheries. All descriptors indicated a broad spawning period (late winter to spring), peaking in November, suggesting this is the critical period to protect C. edentulus stocks from overfishing at Guanabara Bay. Fecundity averaged 12,720 oocytes and was positively related to fish size, GSI and fullness index, indicating that preserving larger individuals (TL > 160 mm) could contribute significantly to the reproductive success of C. edentulus, since they produce more oocytes.Cetengraulis edentulus é um engraulídeo amplamente distribuído no Atlântico Sudoeste, sendo um importante recurso comercialmente explorado na baía de Guanabara, Brasil. O presente estudo teve como objetivo ampliar o conhecimento sobre a reprodução de C. edentulus na baía de Guanabara e testar quais descritores da atividade reprodutiva, especialmente o índice gonadossomático (IGS) e o índice de atividade reprodutiva (IAR) se modificaram ao longo das estações do ano. Um total de 978 indivíduos de C. edentulus foram capturados pelo método de rede de cerco da frota comercial no cais da empresa Conservas Rubi S.A., na cidade de São Gonçalo, RJ. Subamostras de 90-120 indivíduos de C. edentulus foram coletados bimestralmente durante o período de julho de 2010 (inverno) e junho de 2011 (outono). A maioria dos indivíduos foram adultos (120-170 mm CT), em resposta a alta seletividade das capturas comerciais. Todos os índices indicaram um amplo período reprodutivo (final do inverno e primavera), com pico em novembro, sugerindo que este seria um período crítico para preservar os estoques de C. edentulus da sobrepesca na baía de Guanabara. A fecundidade média foi de 12720 ovócitos e foi positivamente relacionada com tamanho do peixe, IGS e índice de repleção, indicando que preservar maiores indivíduos (CT > 160 mm) poderia contribuir significativamente para o sucesso reprodutivo de C. edentulus na área, visto que esses indivíduos produzem um maior número de ovócitos.

Spatial and temporal differences in the fish assemblage structure in a subtropical estuary

“…Considering the high abundance of C. edentulus individuals caught in the summer and spring and at site 4, we can infer that these individuals may be hiding from predators and establishing their temporary niches for growth in these environments due to they are present in the Itacorubi River, an area with less influence of the tide, and because they are considered transient in the estuary. This assumption is in agreement with the breeding pattern of the species (Franco et al, 2014), which presents an extended reproductive period between late winter and spring, with more intense reproductive activity in November, entering the estuaries in the following months. A similar pattern occurred in the shallow areas of the Sepetiba Bay (Pesanha & Araujo, 2003) and a tidal river in the Pinheiros Bay (Oliveira-Neto et al, 2010).…”

Reproductive biology of the anchovy (Stolephorus commersonnii, Lacepède, 1803) and spotted sardine (Amblygaster sirm, Walbaum, 1792) from Tanga Region, Tanzania

“…Studies on the reproductive biology of fishes provide essential knowledge for stock management and conservation (King and McFarlane, 2003;Silva et al, 2005). Most studies on fish reproduction rely on the classification of gonad maturity stages, which are critical for the accurate determination of the reproductive strategy of a species (Franco et al, 2014). However, the gonadosomatic index (GSI) is used as an indicator for the sexual cycle of different fish species, through which spawning seasons can be determined (Nunes et al, 2011).…”

“…Individuals of the anchovy, S. commersonnii Lacépède, 1803 (Engraulidae) are distributed globally from 27°N to 24°S and from 38°E to 155°E in waters with a depth of less than 50 m (Gao et al, 2016). Many species of anchovies are economically important in several regions (Franco et al, 2014); essentially, they are utilized throughout the tropical Indo-Pacific region for human consumption and as tuna bait (Andamari et al, 2002). Moreover, anchovies are known to form a vital part of marine food chains and form a link between the planktonic organisms and the predators such as carnivorous fishes, marine mammals, and birds.…”

Use of a species-rich and highly eutrophic tropical estuary in the South Atlantic by Pleuronectiformes (Teleostei: Acanthopterygii)

“…In the tropical estuary of Guanabara Bay (Rio de Janeiro State, Brazil), the harvest of flatfishes is associated with intense fishing as bycatch of shrimp trawl fisheries (Jablonski et al 2006). However, very little information is available on the fish fauna of this estuary (Rodrigues et al 2007;Andrade-Tubino et al 2009;Rosenfelder et al 2012;Silva-Junior et al 2012;Franco et al 2014). The scarcity of information about the flatfish community of Guanabara Bay, a tropical estuary with a history of environmental degradation, demands a thorough assessment of the fish community.…”