RESUMO

Surf zones are associated with a shelter area, nursery and feeding for several species of fish. In this study, the dietary habits of three species of fish with demersal habits (Gulf kingcroakerMenticirrhu gracilis, Whitesea catfishGenidens barbusand Barbu Polydacytlus virginicus), were verified in the surf zone area of an active urban beach of Baixada Santista, concerning structure in size, day and night abundances and overlapping diets. Atotal of 617 fish were analyzed, of which 362 were 194 were G. barbusand 61 were P. virginicus. Stomach contents, represented in Relative Importance Index diagrams, showed that the bivalve Donax gemmulais the most important food item for M. gracilis, scales of Teleostei for G. barbusand Euphausiacea for P. virginicus. In order to evaluate the similarity of the diets, the Macarthur & Levins indices and a cluster analysis with the Bray-Curtis distance were applied revealing that the diet is 44% different between G. barbusand M. gracilis, 5% between G. barbusand P. virginicusand of 84% between M. gracilisand P. virginicus. Anthropogenic waste like plastic, nylon, metal pieces, were only occasionaly observed.(AU)

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RESUMO

The majority of batoids are listed as Threatened (20.4%) or Data Deficient (41%) by the IUCN Red List. A key challenge to assessing Data-Deficient species is obtaining estimates of key life-history characteristics. Here, a Bayesian approach was used to estimate derived life-history characteristics from a growth model applied to the Data-Deficient Brazilian electric ray Narcine brasiliensis. The age of 170 specimens (107 females, 63 males) was estimated from vertebral centra, and total length, disc width, total weight and birth size were used in a joint estimation of sex-specific length-weight models and two-dimensional von Bertalanffy growth models. Estimates of age at length zero, age at maturity, longevity and mortality at age were derived simultaneously. The Bayesian joint modelling approach was robust to small sample sizes by adding a likelihood to constrain L0 and sharing parameters, such as Brody growth coefficient between length measurements. The median growth parameter estimates were a shared L0 = 38.8 mm, female L∞ = 515 mm, 𝑘 = 0.125 and male L∞ = 387 mm, 𝑘 = 0.194. Age at maturity was estimated to be 7.40-7.49 years for females and 4.45-4.47 years for males, whereas longevity was 22.5-22.6 years for females and 14.2 years for males depending on length measurement. Age-1 natural mortality was estimated to be 0.199-0.207 for females and 0.211-0.213 for males. The derived life-history characteristics indicate N. brasiliensis is earlier maturing, but slower growing relative to other Torpediniformes. These characteristics along with the species' endemism to southern Brazil and high by-catch rates indicate that one of the IUCN Red List threatened categories may be more appropriate for the currently Data-Deficient status. The Bayesian approach used for N. brasiliensis can prove useful for utilizing limited age-growth data in other Data-Deficient batoid species to inform necessary life characteristics for conservation and management.

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RESUMO

The feeding habits of cobia, Rachycentron canadum, was described along the coast of Pernambuco State, northeastern Brazil. One hundred ten specimens were caught between February 2004 and August 2006 with fork length ranging from 40.0 to 137.0 cm (mean and standard deviation: 85.8 ± 18.0 cm) and total weight between 0.4 and 29.8 kg (7.5 ± 4.4 kg). The importance of each food item in the diet was evaluated using the index of relative importance (IRI). Among the one hundred ten stomachs analyzed (52 females and 58 males), 92 (83.6%) had food items, while 18 (16.4%) were empty. Bony fish were the main food item (IRI = 98.7%), being squirrelfish (Holocentrus adscensionis) and porcupine fish (Diodon sp.) the most frequent prey items (30.7% and 8.2%, respectively). Elasmobranchs, crustaceans and cephalopods were also present in small proportions (IRI < 1% for each). No significant differences in diet were found between sexes or size classes (fork length: < or ≥ 69.8 cm; estimated L50 for the species). The present data demonstrate that cobia is a carnivorous predator along the coast of Pernambuco State, with a preference for demersal bony fish, independently of the size and sex of the individuals analyzed.

O hábito alimentar do beijupirá, Rachycentron canadum, foi descrito ao longo da costa do Estado de Pernambuco, Nordeste do Brasil. Foram capturados 110 exemplares entre fevereiro/2004 e agosto/2006, com comprimento furcal ou zoológico variando entre 40,0 e 137,0 cm (média e desvio padrão: 85,8±18,0 cm) e peso total entre 0,4 e 29,8 kg (7,5±4,4 kg). Foi avaliada a importância de cada item alimentar na dieta utilizando o índice de importância relativa (IIR). Dentre os 110 estômagos analisados (52 fêmeas e 58 machos), 92 (83,6%) com algum item alimentar e 18 (16,4%) vazios. Os peixes ósseos foram os principais itens consumidos na dieta alimentar (IIR = 98,7%), entre os quais a mariquita (Holocentrus adscensionis) e o baiacu (Diodon sp.) foram as presas mais consumidas (IIR = 30,7% e 8,2%, respectivamente). A dieta foi composta, ainda, por elasmobrânquios, crustáceos e cefalópodes (IIR <1% cada). Não foram encontradas diferenças na dieta entre os sexos e classes de tamanho (< ou ≥ 69,8 cm de comprimento furcal, L50 estimado para a espécie). Os dados analisados demonstram que, na costa de Pernambuco, o beijupirá é um predador carnívoro com preferência por peixes ósseos demersais, independente do tamanho e sexo dos indivíduos analisados.

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RESUMO

The surf zone is a highly dynamic environment subject to seasonal fluctuations which could impose restrictions to the development of juvenile fish. The allometric condition factor index (K) provides a value of ‘well-being’ for fish, been used to compare populations under different environmental conditions. The aim of this study concerned on evaluate the effect of seasonality on surf-zone juvenile fish’ K. Along two years the K values of the main fish species were analyzed. The temperature and abundance were also reported. We compared data between cold and hot seasons to test the effect of seasonality. A total of 955 individuals were collected, totaling 20 species. Despite the surf zone instability, most fish species showed a stable K regardless of season. We found that the condition factor in neritic Atherinella blackburni, Mugil brevirostris, Trachinotus carolinus and Trachinotus goodei did not vary. Only a demersal species, Menticirrhus littoralis, shown the lowest condition factor in the hot season, coinciding with maximum water temperature. We discussed how the surf zone provides conditions for the development of fish and reinforce the importance of this environment as a breeding site.

A zona de arrebentação é um ambiente altamente dinâmico, sujeito a flutuações sazonais que podem impor restrições ao desenvolvimento de peixes juvenis. O fator de condição alométrico (K) fornece um valor de ‘bem-estar’ para peixes, usado para comparar populações sob diferentes condições ambientais. O objetivo deste estudo foi avaliar o efeito da sazonalidade sobre o K de peixes juvenis da zona de arrebentação. Durante dois anos, os valores de K para as principais espécies de peixes foram analisados. A temperatura e abundância também foram avaliadas. Nós comparamos os dados entre as estações fria e quente para testar o efeito da sazonalidade. Foram coletados 955 indivíduos, totalizando 20 espécies. Apesar da instabilidade da zona de arrebentação, a maioria das espécies demostraram um K estável independentemente da estação. Verificamos que o K para os neríticos, Atherinella blackburni,Mugil brevirostris, Trachinotus carolinus e Trachinotus goodei não variam. Apenas o demersal Menticirrhus littoralis apresentou o K mais baixo na estação quente, coincidindo com a maior temperatura da água. Nós sugerimos que a zona de arrebentação oferece condições para o desenvolvimento dos peixes juvenis ao longo do ano e reforçamos a importância deste ambiente como berçário.

Assuntos

RESUMO

The surf zone is a highly dynamic environment subject to seasonal fluctuations which could impose restrictions to the development of juvenile fish. The allometric condition factor index (K) provides a value of ‘well-being for fish, been used to compare populations under different environmental conditions. The aim of this study concerned on evaluate the effect of seasonality on surf-zone juvenile fish K. Along two years the K values of the main fish species were analyzed. The temperature and abundance were also reported. We compared data between cold and hot seasons to test the effect of seasonality. A total of 955 individuals were collected, totaling 20 species. Despite the surf zone instability, most fish species showed a stable K regardless of season. We found that the condition factor in neritic Atherinella blackburni, Mugil brevirostris, Trachinotus carolinus and Trachinotus goodei did not vary. Only a demersal species, Menticirrhus littoralis, shown the lowest condition factor in the hot season, coinciding with maximum water temperature. We discussed how the surf zone provides conditions for the development of fish and reinforce the importance of this environment as a breeding site.(AU)

A zona de arrebentação é um ambiente altamente dinâmico, sujeito a flutuações sazonais que podem impor restrições ao desenvolvimento de peixes juvenis. O fator de condição alométrico (K) fornece um valor de ‘bem-estar para peixes, usado para comparar populações sob diferentes condições ambientais. O objetivo deste estudo foi avaliar o efeito da sazonalidade sobre o K de peixes juvenis da zona de arrebentação. Durante dois anos, os valores de K para as principais espécies de peixes foram analisados. A temperatura e abundância também foram avaliadas. Nós comparamos os dados entre as estações fria e quente para testar o efeito da sazonalidade. Foram coletados 955 indivíduos, totalizando 20 espécies. Apesar da instabilidade da zona de arrebentação, a maioria das espécies demostraram um K estável independentemente da estação. Verificamos que o K para os neríticos, Atherinella blackburni,Mugil brevirostris, Trachinotus carolinus e Trachinotus goodei não variam. Apenas o demersal Menticirrhus littoralis apresentou o K mais baixo na estação quente, coincidindo com a maior temperatura da água. Nós sugerimos que a zona de arrebentação oferece condições para o desenvolvimento dos peixes juvenis ao longo do ano e reforçamos a importância deste ambiente como berçário.(AU)

Assuntos

RESUMO

The feeding habits of cobia, Rachycentron canadum, was described along the coast of Pernambuco State, northeastern Brazil. One hundred ten specimens were caught between February 2004 and August 2006 with fork length ranging from 40.0 to 137.0 cm (mean and standard deviation: 85.8 ± 18.0 cm) and total weight between 0.4 and 29.8 kg (7.5 ± 4.4 kg). The importance of each food item in the diet was evaluated using the index of relative importance (IRI). Among the one hundred ten stomachs analyzed (52 females and 58 males), 92 (83.6%) had food items, while 18 (16.4%) were empty. Bony fish were the main food item (IRI = 98.7%), being squirrelfish (Holocentrus adscensionis) and porcupine fish (Diodon sp.) the most frequent prey items (30.7% and 8.2%, respectively). Elasmobranchs, crustaceans and cephalopods were also present in small proportions (IRI < 1% for each). No significant differences in diet were found between sexes or size classes (fork length: < or ≥ 69.8 cm; estimated L50 for the species). The present data demonstrate that cobia is a carnivorous predator along the coast of Pernambuco State, with a preference for demersal bony fish, independently of the size and sex of the individuals analyzed.(AU)

O hábito alimentar do beijupirá, Rachycentron canadum, foi descrito ao longo da costa do Estado de Pernambuco, Nordeste do Brasil. Foram capturados 110 exemplares entre fevereiro/2004 e agosto/2006, com comprimento furcal ou zoológico variando entre 40,0 e 137,0 cm (média e desvio padrão: 85,8±18,0 cm) e peso total entre 0,4 e 29,8 kg (7,5±4,4 kg). Foi avaliada a importância de cada item alimentar na dieta utilizando o índice de importância relativa (IIR). Dentre os 110 estômagos analisados (52 fêmeas e 58 machos), 92 (83,6%) com algum item alimentar e 18 (16,4%) vazios. Os peixes ósseos foram os principais itens consumidos na dieta alimentar (IIR = 98,7%), entre os quais a mariquita (Holocentrus adscensionis) e o baiacu (Diodon sp.) foram as presas mais consumidas (IIR = 30,7% e 8,2%, respectivamente). A dieta foi composta, ainda, por elasmobrânquios, crustáceos e cefalópodes (IIR <1% cada). Não foram encontradas diferenças na dieta entre os sexos e classes de tamanho (< ou ≥ 69,8 cm de comprimento furcal, L50 estimado para a espécie). Os dados analisados demonstram que, na costa de Pernambuco, o beijupirá é um predador carnívoro com preferência por peixes ósseos demersais, independente do tamanho e sexo dos indivíduos analisados.(AU)

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RESUMO

A female specimen of choicy ruff, Seriolella porosa, is reported for the first time in Brazilian waters, 384 mm total length captured by the bottom trawl commercial fishery on August 12th, 2007, at 36 meters local depth off the São Paulo coast, southeastern Brazil (23º49"56""S; 45º53"24""W). The occurrence may be uncommon, probably associated with a branch of cold water of the Malvinas current.

RESUMO

A female specimen of choicy ruff, Seriolella porosa, is reported for the first time in Brazilian waters, 384 mm total length captured by the bottom trawl commercial fishery on August 12th, 2007, at 36 meters local depth off the São Paulo coast, southeastern Brazil (23º49'56''S; 45º53'24''W). The occurrence may be uncommon, probably associated with a branch of cold water of the Malvinas current.

É reportada pela primeira vez em águas brasileiras a ocorrência de um exemplar de fêmea de savorin, Seriolella porosa, de 348 cm CT capturado por arrasto comercial de parelha no sudeste do Brasil em 12 de agosto de 2007, a 36 metros de profundidade local (23º49'56''S; 45º53'24''W). A ocorrência deve ser incomum, provavelmente associada com um braço da corrente das Malvinas.

Assuntos

RESUMO

A female specimen of choicy ruff, Seriolella porosa, is reported for the first time in Brazilian waters, 384 mm total length captured by the bottom trawl commercial fishery on August 12th, 2007, at 36 meters local depth off the São Paulo coast, southeastern Brazil (23º49"56""S; 45º53"24""W). The occurrence may be uncommon, probably associated with a branch of cold water of the Malvinas current. 

RESUMO

An analysis of published data on oceanic seabirds diets, show the predominance of muscular cephalopods with superficial distribution in the oceanic layers, but also important are the gelatinous and ammoniacal species restrict to layers below 300 m from the surface. In principle, it could be not expected that deep-sea cephalopods are common prey for seabirds like several authors have been concluded. It is proposed in this study that an indirect source, important and easily attainable, have been appeared with the beginning of tuna longline operations. The habit to feed upon viscera of the fishes captured by tuna longliners, that discard the gut contents to the water, may explain the probable equivocal conclusions that deep dwelling cephalopods are natural prey of oceanic seabirds.

Uma análise de dados publicados sobre dietas de aves marinhas oceânicas mostra a predominância de cefalópodes musculares e de distribuição mais superficial nas camadas oceânicas, mas também são importantes as espécies gelatinosas e amoniacais restritas a camadas abaixo dos 300 m da superfície. A princípio, não deveria se esperar que cefalópodes de profundidade fossem considerados presas comuns de aves marinhas oceânicas como reportados por muitos autores. É proposto neste estudo que uma fonte indireta, importante e de fácil obtenção, surgiu com o início das atividades dos barcos atuneiros que operam com espinhel. O hábito de ingerir restos de vísceras de peixes capturados em barcos espinheleiros pode explicar as prováveis conclusões equivocadas de que cefalópodes de profundidade são presas naturais de aves marinhas oceânicas.