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Background. Although the information on fish ecology and population dynamic are fundamental for fisheries assessment and the development of sustainable management practices, there is still a gap for bycatch species, mainly in tropical coastal areas. The aim of the presently reported study was to describe the feeding habitats, mean length of maturation, and the population structure of Conodon nobilis (Linnaeus, 1758) caught as bycatch of the shrimp trawl fisheries in the south of Pernambuco, north-eastern Brazil. Materials and methods. Specimens of C. nobilis were collected monthly from August 2011 through July 2012, using an artisanal shrimp outrigger trawler from the local fleet. The population structure was analysed by sex, length, and seasons. Stomachs and gonads were removed and examined to define the length at first maturity (L50) and the feeding habits of C. nobilis in north-eastern Brazil. Results. A total of 272 specimens were caught. The sex ratio was similar among females and males in the area. The mean size at first maturity (L50) was estimated as 14.3 ± 0.65 cm. The diet of the species was mainly based on crustaceans (Penaeidae) and fish, however, it was not observed differences in the diet between juvenile and adults, and climate seasons. Conclusion. Conodon nobilis was classified as a zoobenthivore species, and showed a higher proportion of individuals caught above the L50. The information here provided, combined with other studies in the region, may contribute to the development of improved management strategies to species conservation and exploited marine habitats in northeast Brazil, which is still mostly unknown.

Background. Reproductive aspects of fishes are very useful in the development of management and conservation strategies of stocks. The information available on this subject, however, is very limited for tropical species, especially for those with low economic value, such as the barred grunt, Conodon nobilis (Linnaeus, 1758). This species is a common member of the family Haemulidae off the coasts of Brazil and it plays an important ecological role in coastal areas acting as a biological vector of organic matter. Thus, this study was intended to provide data on the reproductive parameters of C. nobilis to fill the gap in the existing knowledge. Materials and methods. Reproductive traits of C. nobilis were estimated from 410 fish collected in the coast of Alagoas, during fishery surveys carried out between December 2009 and June 2012. Length–weight relations (LWRs) for males and females were calculated from the observed length and weight by regression analysis. Data on the maturity status were used to estimate the size at first maturity for females, males, and pooled sexes. The fecundity was assessed by the volumetric method, and information on the reproductive period was retrieved from the gonadosomatic and the reproductive activity indices. Results. Sex ratio differed between sexes with mature females being more abundant than males. Although no evidence of sexual dimorphism was found in the length distribution, LWRs showed that males have a negative asymptotic growth and females present a positive asymptotic growth. The first sexual maturity for females, males, and pooled sexes was attained at 20.78, 20.57, and 20.72 cm of the total length (TL), respectively. Gonadosomatic and reproductive activity indices indicated that C. nobilis may be capable of spawning all year round with a more intense activity occurring between the rainy season in the region studied. The batch fecundity fluctuated between 1640 and 105 471 oocytes with a mean of 45 384 ± 16 737 eggs per female and was positively correlated to female size. Conclusion. Overall, C. nobilis showed an intermediate fecundity rate with reproductive activity throughout all year round. No evidence of sexual dimorphism in maturity and size distribution was found for the species. We hope that our findings may be helpful for fishery biologists in the design of effective management strategies for this ecologically important species.

Background. Although the information on fish ecology and population dynamic are fundamental for fisheries assessment and the development of sustainable management practices, there is still a gap for bycatch species, mainly in tropical coastal areas. The aim of the presently reported study was to describe the feeding habitats, mean length of maturation, and the population structure of Conodon nobilis (Linnaeus, 1758) caught as bycatch of the shrimp trawl fisheries in the south of Pernambuco, north-eastern Brazil. Materials and methods. Specimens of C. nobilis were collected monthly from August 2011 through July 2012, using an artisanal shrimp outrigger trawler from the local fleet. The population structure was analysed by sex, length, and seasons. Stomachs and gonads were removed and examined to define the length at first maturity (L50) and the feeding habits of C. nobilis in north-eastern Brazil. Results. A total of 272 specimens were caught. The sex ratio was similar among females and males in the area. The mean size at first maturity (L50) was estimated as 14.3 ± 0.65 cm. The diet of the species was mainly based on crustaceans (Penaeidae) and fish, however, it was not observed differences in the diet between juvenile and adults, and climate seasons. Conclusion. Conodon nobilis was classified as a zoobenthivore species, and showed a higher proportion of individuals caught above the L50. The information here provided, combined with other studies in the region, may contribute to the development of improved management strategies to species conservation and exploited marine habitats in northeast Brazil, which is still mostly unknown. [ABSTRACT FROM AUTHOR]

Background. Reproductive aspects of fishes are very useful in the development of management and conservation strategies of stocks. The information available on this subject, however, is very limited for tropical species, especially for those with low economic value, such as the barred grunt, Conodon nobilis (Linnaeus, 1758). This species is a common member of the family Haemulidae off the coasts of Brazil and it plays an important ecological role in coastal areas acting as a biological vector of organic matter. Thus, this study was intended to provide data on the reproductive parameters of C. nobilis to fill the gap in the existing knowledge. Material and methods. Reproductive traits of C. nobilis were estimated from 410 fish collected in the coast of Alagoas, during fishery surveys carried out between December 2009 and June 2012. Length-weight relations (LWRs) for males and females were calculated from the observed length and weight by regression analysis. Data on the maturity status were used to estimate the size at first maturity for females, males, and pooled sexes. The fecundity was assessed by the volumetric method, and information on the reproductive period was retrieved from the gonadosomatic and the reproductive activity indices. Results. Sex ratio differed between sexes with mature females being more abundant than males. Although no evidence of sexual dimorphism was found in the length distribution, LWRs showed that males have a negative asymptotic growth and females present a positive asymptotic growth. The first sexual maturity for females, males, and pooled sexes was attained at 20.78, 20.57, and 20.72 cm of the total length (TL), respectively. Gonadosomatic and reproductive activity indices indicated that C. nobilis may be capable of spawning all year round with a more intense activity occurring between the rainy season in the region studied. The batch fecundity fluctuated between 1640 and 105 471 oocytes with a mean of 45 384 ± 16 737 eggs per female and was positively correlated to female size. Conclusions. Overall, C. nobilis showed an intermediate fecundity rate with reproductive activity throughout all year round. No evidence of sexual dimorphism in maturity and size distribution was found for the species. We hope that our findings may be helpful for fishery biologists in the design of effective management strategies for this ecologically important species. [ABSTRACT FROM AUTHOR]