Feeding habits of the congeneric species Stellifer rastrifer and Stellifer brasiliensis (Acanthopterygii: Sciaenidae) co-occurring in the coast of the state of Santa Catarina, Brazil.

The objective of the present study was to investigate the feeding habits allowing the occurrence of the congeneric species Stellifer rastrifer and Stellifer brasiensis, collected on a seasonal basis, in the operating area of the artisanal seabob-shrimp trawl fishery in Porto Belo, an important fishing area on the southern Brazilian coast. Fish were collected seasonally from November 2009 to August 2010, in isobaths of 10, 20 and 30 m. Of the 450 stomachs analyzed, 194 belonged to Stellifer rastrifer and 242 to Stellifer brasiliensis. From the totality of analyzed stomachs 33.49% were empty and 66.52% had some content. Crustacea were the predominant food category in the diet of S. rastrifer and S. brasiliensis, and the shrimp Acetes americanus was the most frequent crustacean in stomachs of both studied species. The overlapping in the diet of the species was high, however when analyzing the overlap in each season it was found that it occurred only during spring and winter. Although the most important items in the diet of these species are the same, the intake of each alternates in time, suggesting a difference in predation pressure, which leads to less direct competition in a given time.

Feeding habits of the congeneric species Stellifer rastrifer and Stellifer brasiliensis (Acanthopterygii: Sciaenidae) co-occurring in the coast of the state of Santa Catarina, Brazil / Hábitos alimentares das espécies congêneres Stellifer rastrifer e Stellifer brasiliensis (Acanthopterygii: Sciaenidae) co-ocorrendo na costa do estado de Santa Catarina, Brasil

The objective of the present study was to investigate the feeding habits allowing the occurrence of the congeneric species Stellifer rastrifer and Stellifer brasiensis, collected on a seasonal basis, in the operating area of the artisanal seabob-shrimp trawl fishery in Porto Belo, an important fishing area on the southern Brazilian coast. Fish were collected seasonally from November 2009 to August 2010, in isobaths of 10, 20 and 30m. Of the 450 stomachs analyzed, 194 belongd to Stellifer rastrifer and 242 to Stellifer brasiliensis. From the totality of analyzed stomachs 33.49% were empty and 66.52% had some content. Crustacea were the predominant food category in the diet of S. rastrifer and S. brasiliensis, and the shrimp Acetes americanus was the most frequent crustacean in stomachs of both studied species. The overlapping in the diet of the species was high, however when analyzing the overlap in each season it was found that it occurred only during spring and winter. Although the most important items in the diet of these species are the same, the intake of each alternates in time, suggesting a difference in predation pressure, which leads to less direct competition in a given time.(AU)

O objetivo do presente estudo foi investigar os hábitos alimentares que possibilitam a ocorrência das espécies congêneres Stellifer rastrifer e Stellifer brasiensis, coletados sazonalmente, na área operacional da pesca artesanal do camarão sete-barbas, em Porto Belo, uma área de pesca importante na costa sul do Brasil. Os peixes foram coletados sazonalmente de novembro de 2009 a agosto de 2010, em isóbatas de 10, 20 e 30m. Dos 450 estômagos analisadas, 194 eram de S. rastrifer e 242 de S. brasiliensis. Da totalidade dos estômagos analisados 33,49% estavam vazios enquanto 66,52% tinham algum conteúdo. Crustacea foi a categoria de alimento predominante na dieta, e o camarão Acetes americanus foi o crustáceo mais freqüente nos estômagos de ambas as espécies. A sobreposição na dieta foi alta, porém a cada estação do ano, verificou-se que a sobreposição ocorreu apenas durante a primavera e o inverno. Embora os itens mais importantes na dieta destas espécies sejam os mesmos, o consumo de cada um é alternado no tempo, o que sugere uma diferença na pressão de predação, levando a uma menor competição direta em um determinado momento.(AU)

Growth and reproduction aspects of Pimelodus maculatus Lacépède, 1803 (Siluriformes, Pimelodidae) of the Cachoeira Dourada reservoir, state of Goiás and Minas Gerais, Brazil.

Growth and reproduction parameters of the yellow-mandi, Pimelodus maculatus Lacépède, 1803 (Siluriformes, Pimelodidae), were determined for the Cachoeira Dourada reservoir (GO/MG). The field work occurred throughout February 2007 to January 2008 (with the exception of December 2007). Gill nets with mesh sizes from 1.5 to 10 centimeters were placed in three different areas in the reservoir and were collected 24 hours later. A total of 538 specimens were captured, amongst which 242 were females, 219 were males and 77 could not have their sex determined. Sex ratio differed from 1:1 only during July 2007 and January 2008, with males and females predominating in each of those months. Males occupied the medium length classes (18.9 to 24.3 cm) while females were most abundant in the superior classes (from 27 to 37.8 cm).The growth constant K was statistically equal for males (K=0.1851) and females (K=0.1708), however, females P. maculatus may have a greater investment in reproductive tissue, a fact indicated by the elevated values of Kn and GSI during the summer. Bearing in mind that P. maculatus reproduces in the rainy season, a greater gain in weight is expected during the months before the reproduction season, and that after it occurs the fish loses fat and weight as a consequence of metabolic effort. Still, the absence of juveniles may be an indication that the species did not find in the reservoir the proper conditions for reproduction and growth of its fry.

Growth and reproduction aspects of Pimelodus maculatus Lacépède, 1803 (Siluriformes, Pimelodidae) of the Cachoeira Dourada reservoir, state of Goiás and Minas Gerais, Brazil / Aspectos da dinâmica populacional e reprodutiva de Pimelodus Maculatus (Siluriformes, Pimelodidae) no reservatório de Cachoeira Dourada (GO-MG), Brasil

Growth and reproduction parameters of the yellow-mandi, Pimelodus maculatus Lacépède, 1803 (Siluriformes, Pimelodidae), were determined for the Cachoeira Dourada reservoir (GO/MG). The field work occurred throughout February 2007 to January 2008 (with the exception of December 2007). Gill nets with mesh sizes from 1.5 to 10 centimeters were placed in three different areas in the reservoir and were collected 24 hours later. A total of 538 specimens were captured, amongst which 242 were females, 219 were males and 77 could not have their sex determined. Sex ratio differed from 1:1 only during July 2007 and January 2008, with males and females predominating in each of those months. Males occupied the medium length classes (18.9 to 24.3 cm) while females were most abundant in the superior classes (from 27 to 37.8 cm).The growth constant K was statistically equal for males (K=0.1851) and females (K=0.1708), however, females P. maculatus may have a greater investment in reproductive tissue, a fact indicated by the elevated values of Kn and GSI during the summer. Bearing in mind that P. maculatus reproduces in the rainy season, a greater gain in weight is expected during the months before the reproduction season, and that after it occurs the fish loses fat and weight as a consequence of metabolic effort. Still, the absence of juveniles may be an indication that the species did not find in the reservoir the proper conditions for reproduction and growth of its fry.(AU)

O presente estudo procurou averiguar os parâmetros de crescimento e reprodução do mandi-amarelo, Pimelodus maculatus Lacépède, 1803 (Siluriformes, Pimelodidae), no reservatório de Cachoeira Dourada (GO/MG). As coletas ocorreram de fevereiro de 2007 a janeiro de 2008 (exceto em dezembro de 2007), em três pontos do reservatório, com auxílio de baterias de redes com malhas variando de 1,5 a 10,0 cm entre nós adjacentes durante 24 horas. Foi capturado um total de 538 indivíduos dentre os quais 242 fêmeas, 219 machos e 77 de sexo indeterminado. A proporção sexual diferiu de 1:1 em julho de 2007 e janeiro 2008, com o predomínio de machos e fêmeas, respectivamente. Os machos concentraram-se nas classes de comprimento medianas (18,9 a 24,3 cm) enquanto que as fêmeas nas superiores (de 27 a 37,8 cm). A constante de crescimento K foi estatisticamente igual entre machos (K=0.1851) e fêmeas (K=0.1708), no entanto, P. maculatus fêmeas parecem ter um maior investimento em tecido reprodutivo, fato indicado pelos elevados valores de Kn e IGS durante o verão. Tendo em vista sua desova durante o período chuvoso, é esperado um maior ganho de peso nos períodos que antecedem a reprodução e que após esse processo haja uma perda de gordura ou peso devido aos gastos metabólicos envolvidos. Ainda, a ausência de captura de P. maculatus juvenis pode ser uma indicação de que a espécie não encontrou na área condições adequadas para tal.(AU)

The influence of population structure and reproductive aspects of the genus Stellifer (Oken, 1817) on the abundance of species on the southern Brazilian coast / A influência da estrutura populacional e dos aspectos reprodutivos na abundância de espécies do gênero Stellifer (Oken, 1817) no litoral sul brasileiro

The differences between abundance and the relationship with aspects of population and reproductive Stellifer rastrifer, Stellifer stellifer and Stellifer brasiliensis were analysed. Data were collected monthly trawl directed for capture of seabob shrimp in Armação do Itapocoroy, an important fishing area on the southern Brazilian coast. The chi-square test showed that the population of S. rastrifer presented values of capture significantly higher than others in all evaluated periods. The frequency distribution of total length curves combined with records of the size at first maturity (L50) showed that S. rastrifer is a species with a majority of the adults effectively participating in the reproductive period. The frequency of occurrence of individuals in reproduction monthly examined together with changes in the gonadosomatic index (GSI) and the reproductive activity index indicated that spring was the main breeding season for the three species. However, it was observed that the reproductive period of S. rastrifer was more pronounced and more extensive than that of its congeners, apparently providing it with ecological advantages and enabling a more effective population balance given the pressure exerted by fishing in the study area.

As diferenças nas abundâncias numéricas e a relação dessas com os aspectos reprodutivos e populacionais de Stellifer rastrifer, Stellifer stellifer e Stellifer brasiliensis foram analisadas. Os dados foram coletados em arrastos mensais destinados à captura do camarão sete-barbas em Armação do Itapocoroy, uma importante área pesqueira do litoral sul brasileiro. O teste de qui-quadrado demonstrou que a população de S. rastrifer apresentou valores de captura significantemente superiores que as demais em todos os períodos avaliados. A distribuição em classe de tamanho sobreposta ao valor de primeira maturação sexual (L50) evidenciou que S. rastrifer foi a espécie com a maior proporção de indivíduos capturados considerados adultos, ou seja, que efetivamente participam do evento reprodutivo. A frequência de ocorrência mensal dos estádios de maturação sexual analisada conjuntamente com as variações do índice gonadossomático e do índice de atividade reprodutiva indicaram que a principal estação reprodutiva para as três espécies foi a primavera, Entretanto, observou-se que o período reprodutivo de S. rastrifer foi mais acentuado e mais extenso do que o de suas congenéricas, aparentando lhe fornecer vantagens ecológicas e possibilitando um equilíbrio populacional mais eficaz frente à pressão exercida pela pesca na área de estudo.

Evaluation and management of blue crab Callinectes sapidus (Rathbun, 1896) (Decapoda-Portunidae) fishery in the Estuary of Cananéia, Iguape and Ilha Comprida, São Paulo, Brazil.

The Estuary of Cananéia, Iguape and Ilha Comprida is a part of the Estuarine Lagoon System of Cananéia, Iguape and Paranaguá, on the south coast of São Paulo State, Brazil. It has been recognised for its high standards of environmental conservation. The objective of this paper was to assess the blue crab (Callinectes sapidus) fishing in the region, from January 1998 to December 2006, and obtain supportive data to implement technical rules for the rational exploitation and resulting conservation of this resource. The results show a remarkable decrease in the fisheries' abundance index (CPUE) up to 2005, from 9.4 to 4.0 kg/hour, mainly caused by an increase in fishing effort, from 1,960 to 13,776 hours on a yearly basis. With the decrease in the fishing effort in 2005 and 2006, the abundance index reacted positively, indicating a recovery of the exploited population. Due to the lack of appropriate regulation limiting the fishing effort and organising the fluctuating admission rates of new fishermen, there is a noticeable increase of the effort, above the sustainable level. Therefore, there is a need for measures to limit and control the admission of fishermen in this activity. One of the measures to be considered is the establishment of regular periods where fishing the species is prohibited (called 'defeso'), each year, especially from September to January. Another measure is to create a fishermen registry and special licenses, to limit the number of new entrants. Such actions require, for their implementation, a co-managed initiative, involving the blue crab fishermen themselves, governmental agencies and resource management researchers, and the integration of ecological, socioeconomic and cultural dimensions.

Ovarian development in the Amazonian red discus, Symphysodon discus Heckel (Osteichthyes: Cichlidae)

O acará disco, Symphysodon discus, é um ciclídeo neotropical originário da bacia Amazônica e seu corpo apresenta formato discoidal. Embora esta espécie seja popularmente utilizada em aquariofilia e exportada como peixe ornamental, ainda é pouco estudada. Este trabalho teve como objetivo estudar os aspectos morfológicos e histológicos do desenvolvimento ovariano do acará disco. Para este estudo foram utilizadas 40 fêmeas de S. discus, de tamanhos diferentes, em várias fases de desenvolvimento gonadal. Os ovários foram pesados e examinados macroscopicamente para observar os estádios de maturação. Para as observações microscópicas dos ovários foi utilizada coloração de hematoxilina-eosina. Os resultados da análise macroscópica apresentaram os estádios de desenvolvimento ovariano imaturo, em maturação, maduro e parcialmente esvaziado. A análise microscópica dos ovários revelou cinco estádios e cinco fases de desenvolvimento ovariano. Os ovários das fêmeas maduras apresentaram todas as diferentes fases de desenvolvimento ovocitário, indicando a desova múltipla para a espécie estudada.

Ovarian development in the Amazonian red discus, Symphysodon discus Heckel (Osteichthyes: Cichlidae).

The Neotropical red discus fish, Symphysodon discus, originates from the Amazonian basin and has a discoid body. Although this species is popularly used in aquaria and is exported as an ornamental fish, it has not been intensively studied. The purpose of this work was to study the morphological and histological aspects of the ovarian development in the red discus. Forty females of S. discus of varying body sizes and different stages of gonadal development were used in this study. The ovaries were weighed and examined macroscopically in order to observe the maturation stages. Histological staining of hematoxilin-eosin was used for microscopic observations of the ovaries. Macroscopic observations showed immature, maturing, mature and partially spent stages of ovarian development. Microscopic examination of the ovaries revealed five stages and five phases of ovarian development. The ovaries of the mature females showed all the different phases of oocyte development, indicating the multiple spawning habit of this species.

CURVA DE RENDIMENTO DA PESCADA FOGUETE, Macrodon ancylodon (BLOCH, 1801) DA COSTA CENTRO DO ESTADO DE SÃO PAULO / CURVA DE RENDIMENTO DA PESCADA FOGUETE, Macrodon ancylodon (BLOCH, 1801) DA COSTA CENTRO DO ESTADO DE SÃO PAULO

The purpose of this paper is the analysis of the relationship between total annual catch and fishing intensity of the pescada foguete (king weakfish) caught along the center coast of São Paulo State (Brazil, 24°S). We obtained:C = (67.7 - .00355E)E where: C = total annual catch(kg)(1959-1971), and E = fishing intensity (total number of hauls, 3.5 hours of trawling, during the year). C  is maximum (322 767 )for E = 9 535 hauls per year.

CURVA DE RENDIMENTO DA PESCADA FOGUETE, Macrodon ancylodon (BLOCH, 1801) DA COSTA CENTRO DO ESTADO DE SÃO PAULO / CURVA DE RENDIMENTO DA PESCADA FOGUETE, Macrodon ancylodon (BLOCH, 1801) DA COSTA CENTRO DO ESTADO DE SÃO PAULO

The purpose of this paper is the analysis of the relationship between total annual catch and fishing intensity of the pescada foguete (king weakfish) caught along the center coast of São Paulo State (Brazil, 24°S). We obtained:C = (67.7 - .00355E)E where: C = total annual catch(kg)(1959-1971), and E = fishing intensity (total number of hauls, 3.5 hours of trawling, during the year). C  is maximum (322 767 )for E = 9 535 hauls per year.