The feeding habits of the endemic Remo flounder, Oncopterus darwinii (Actinopterygii: Pleuronectidae), in an exposed sandy beach's surf zone in southern Brazil

The Remo flounder, Oncopterus darwinii Steindachner, 1874 is a small Pleuronectidae (~ 250 mm TL) distributed in the warm-temperate zone from Santa Catarina (28°S - Brazil) to the Gulf of San Matías (42°S - Argentina). We studied the occurrence and diet of juveniles of this flatfish (85% < 100 mm TL) for one year (August 2009 to July 2010) in a southern Brazilian sandy beach. Individuals were much more common in spring and early summer than in the other seasons. Of the 758 individuals analyzed, only 69 (9.1%) were found with empty stomachs. The Remo flounder fed predominantly on small crustaceans (gammarid amphipods, mysids and the hipiidae Emerita brasiliensis Schmitt, 1935) and no seasonal differences were found in the composition of the diet of this flatfish. However, variations in the Index of Relative Importance (IRI) were found among seasons, which most likely can be explained by a decrease in the availability of favored food items throughout the year. The pattern of distribution of O. darwinii indicates that southern Brazilian sandy beaches are used as nursery ground for this species.(AU)

The feeding habits of the endemic Remo flounder, Oncopterus darwinii (Actinopterygii: Pleuronectidae), in an exposed sandy beach's surf zone in southern Brazil

The Remo flounder, Oncopterus darwinii Steindachner, 1874 is a small Pleuronectidae (~ 250 mm TL) distributed in the warm-temperate zone from Santa Catarina (28°S - Brazil) to the Gulf of San Matías (42°S - Argentina). We studied the occurrence and diet of juveniles of this flatfish (85% < 100 mm TL) for one year (August 2009 to July 2010) in a southern Brazilian sandy beach. Individuals were much more common in spring and early summer than in the other seasons. Of the 758 individuals analyzed, only 69 (9.1%) were found with empty stomachs. The Remo flounder fed predominantly on small crustaceans (gammarid amphipods, mysids and the hipiidae Emerita brasiliensis Schmitt, 1935) and no seasonal differences were found in the composition of the diet of this flatfish. However, variations in the Index of Relative Importance (IRI) were found among seasons, which most likely can be explained by a decrease in the availability of favored food items throughout the year. The pattern of distribution of O. darwinii indicates that southern Brazilian sandy beaches are used as nursery ground for this species.

External morphology, postcranial and appendicular osteology of three southwestern Atlantic flatfishes ( Paralichthys, Paralichthyidae), and comparisons with other congeneric species

Comparisons of the external morphology and analysis of osteological features of the postcranial and appendicular skeletons of three southwestern Atlantic flatfish species of the genus Paralichthys (P. isosceles, P. orbignyanus and P. patagonicus) were carried out. Bones are described, and detailed morphological, morphometric and meristic characteristics of these flounders are given in order to provide information about the external and internal morphology of three species of Paralichthys occurring in the south-west Atlantic waters that add new information and will help regarding within the framework of a phylogenetic study of the group. Interspecific differences were found in the number of vertebrae and intermuscular bones, as well as in the morphology and morphometry of vertebrae, caudal skeletons, pectoral and pelvic girdle bones. Relationships between bones are discussed and bone characteristics compared with those found in other species of Paralichthys and in other pleuronectiform species. The position of Paralichthys isosceles within Paralichthys is discussed, along with other congeners such as P. triocellatus and P. oblongus.(AU)

Se llevaron a cabo comparaciones de la morfología externa y el análisis de las características osteológicas de los esqueletos postcraneal y apendicular de tres especies de peces planos del Atlántico sudoccidental del género Paralichthys (P. isosceles, P. orbignyanus y P. patagonicus). Se describen los huesos, y se proporcionan características morfológicas, morfométricas y merísticas detalladas de estos lenguados con el fin de aportar información sobre la morfología externa e interna de tres especies de Paralichthys presentes en el Atlántico sudoccidental. Esta nueva información contribuirá al marco de un estudio filogenético del grupo. Se encontraron diferencias interespecíficas en el número de vértebras y huesos intermusculares, así como en la morfología y morfometría de las vértebras, los esqueletos caudales, los huesos de las cinturas pectoral y pélvica. Se discuten las relaciones entre los huesos y las características óseas en comparación con las encontradas en otras especies de Paralichthys y de otros Pleuronectiformes. Se discute la posición de Paralichthys isosceles dentro del género Paralichthys, junto con otros congéneres como P. oblongus y P. triocellatus.(AU)

External morphology, postcranial and appendicular osteology of three southwestern Atlantic flatfishes ( Paralichthys, Paralichthyidae), and comparisons with other congeneric species

Comparisons of the external morphology and analysis of osteological features of the postcranial and appendicular skeletons of three southwestern Atlantic flatfish species of the genus Paralichthys (P. isosceles, P. orbignyanus and P. patagonicus) were carried out. Bones are described, and detailed morphological, morphometric and meristic characteristics of these flounders are given in order to provide information about the external and internal morphology of three species of Paralichthys occurring in the south-west Atlantic waters that add new information and will help regarding within the framework of a phylogenetic study of the group. Interspecific differences were found in the number of vertebrae and intermuscular bones, as well as in the morphology and morphometry of vertebrae, caudal skeletons, pectoral and pelvic girdle bones. Relationships between bones are discussed and bone characteristics compared with those found in other species of Paralichthys and in other pleuronectiform species. The position of Paralichthys isosceles within Paralichthys is discussed, along with other congeners such as P. triocellatus and P. oblongus.(AU)

Se llevaron a cabo comparaciones de la morfología externa y el análisis de las características osteológicas de los esqueletos postcraneal y apendicular de tres especies de peces planos del Atlántico sudoccidental del género Paralichthys (P. isosceles, P. orbignyanus y P. patagonicus). Se describen los huesos, y se proporcionan características morfológicas, morfométricas y merísticas detalladas de estos lenguados con el fin de aportar información sobre la morfología externa e interna de tres especies de Paralichthys presentes en el Atlántico sudoccidental. Esta nueva información contribuirá al marco de un estudio filogenético del grupo. Se encontraron diferencias interespecíficas en el número de vértebras y huesos intermusculares, así como en la morfología y morfometría de las vértebras, los esqueletos caudales, los huesos de las cinturas pectoral y pélvica. Se discuten las relaciones entre los huesos y las características óseas en comparación con las encontradas en otras especies de Paralichthys y de otros Pleuronectiformes. Se discute la posición de Paralichthys isosceles dentro del género Paralichthys, junto con otros congéneres como P. oblongus y P. triocellatus.(AU)

Reproductive biology of the flatfish Etropus crossotus (Pleuronectiformes: Paralichthyidae) in the Paranaguá Estuarine Complex, Paraná State, subtropical region of Brazil

The present work studied the reproduction of the flatfish Etropus crossotus in the Paranaguá Estuarine Complex, Paraná State, subtropical region of Brazil. Monthly collections of biological material occurred from October 2008 to October 2009, at seven sampling sites, through ten-minute otter trawl surveys in the shallow infralittoral areas of the estuary. Temperature, water salinity, photoperiod, and rainfall data were also recorded. Ovarian histology was used to: 1 - describe ovarian development microscopically, 2 - make the quantitative analyses of both sexes more precise. The maturation curve, the frequency of gonadal maturation states and the condition factor verified that the reproductive period occurred from October to January. The frequency of young and adult individuals established that the recruitment period occurred in January and February. There were no significant differences in the sex ratio during the study period. The studied species completes its entire life cycle in an estuary and its reproduction is well-synchronized with the temporal variations implicit in subtropical regions.(AU)

O presente trabalho estudou a reprodução do linguado Etropus crossotus no complexo estuarino de Paranaguá, região subtropical do Brasil. Coletas mensais de material biológico ocorreram de outubro de 2008 a outubro de 2009, em sete pontos amostrais, através da realização de dez minutos de arrasto de porta no infralitoral raso do estuário. Ainda, foram obtidos dados de temperatura e salinidade da água, fotoperíodo e pluviosidade para caracterização do ambiente. A histologia de ovário foi utilizada para: 1- descrever microscopicamente o desenvolvimento ovariano, 2- conferir precisão aos resultados das análises quantitativas de ambos os sexos. Através da curva de maturação, da frequência de estádios de maturação gonadal e do fator de condição verificou-se que o período reprodutivo ocorreu de outubro a janeiro. A partir da frequência de indivíduos jovens e adultos constatou-se que o período de recrutamento ocorreu em janeiro e fevereiro. Não se obteve diferenças significativas na proporção sexual ao longo do período estudado. A espécie estudada completa todo o seu ciclo de vida em estuários e sua reprodução mostrou-se bem sincronizado às variações temporais implícitas em regiões subtropicais.(AU)

Reproduction of the flatfish Achirus lineatus (Pleuronectiformes: Achiridae) in Paranaguá Bay, state of Paraná, a subtropical region of Brazil

The present study characterizes the oogenesis and the ovarian maturation scale, and determines the reproductive period, type of spawning, recruitment period, and population variations in the reproductive process of the flatfish Achirus lineatus (Linnaeus, 1758). Specimens were sampled on a monthly basis in the shallow near shore area of the Paranaguá Bay, state of Paraná, Brazil, from March 2006 to February 2007. The specimens collected were measured for morphometric data (total length and total weight) and their gonads were exposed for macroscopic evaluation. The gonads were subsequently removed, weighed and processed for microscopic analyses. Six phases of the ovarian follicle development were defined, as well as five ovarian development stages. Growth patterns differed between the sexes: negative allometry for females and positive allometry for males. Based on the seasonal assessments of the distribution of individual GSI values, the distribution of stages of gonadal development, individual body size, sex ratio, the ratio of juveniles to adults, and histological examination of the ovaries, reproduction was found to occur in the spring (spawning in batches), and recruitment in the autumn. These results show that A. lineatus is an estuarine-resident species that uses the study area for reproduction and recruitment, providing an argument in favor of the need to conserve the estuarine environment in order to preserve stocks.

Reproduction of the flatfish Achirus lineatus (Pleuronectiformes: Achiridae) in Paranaguá Bay, state of Paraná, a subtropical region of Brazil

The present study characterizes the oogenesis and the ovarian maturation scale, and determines the reproductive period, type of spawning, recruitment period, and population variations in the reproductive process of the flatfish Achirus lineatus (Linnaeus, 1758). Specimens were sampled on a monthly basis in the shallow near shore area of the Paranaguá Bay, state of Paraná, Brazil, from March 2006 to February 2007. The specimens collected were measured for morphometric data (total length and total weight) and their gonads were exposed for macroscopic evaluation. The gonads were subsequently removed, weighed and processed for microscopic analyses. Six phases of the ovarian follicle development were defined, as well as five ovarian development stages. Growth patterns differed between the sexes: negative allometry for females and positive allometry for males. Based on the seasonal assessments of the distribution of individual GSI values, the distribution of stages of gonadal development, individual body size, sex ratio, the ratio of juveniles to adults, and histological examination of the ovaries, reproduction was found to occur in the spring (spawning in batches), and recruitment in the autumn. These results show that A. lineatus is an estuarine-resident species that uses the study area for reproduction and recruitment, providing an argument in favor of the need to conserve the estuarine environment in order to preserve stocks.

Reproduction of the flatfish Achirus lineatus (Pleuronectiformes: Achiridae) in Paranaguá Bay, state of Paraná, a subtropical region of Brazil

The present study characterizes the oogenesis and the ovarian maturation scale, and determines the reproductive period, type of spawning, recruitment period, and population variations in the reproductive process of the flatfish Achirus lineatus (Linnaeus, 1758). Specimens were sampled on a monthly basis in the shallow near shore area of the Paranaguá Bay, state of Paraná, Brazil, from March 2006 to February 2007. The specimens collected were measured for morphometric data (total length and total weight) and their gonads were exposed for macroscopic evaluation. The gonads were subsequently removed, weighed and processed for microscopic analyses. Six phases of the ovarian follicle development were defined, as well as five ovarian development stages. Growth patterns differed between the sexes: negative allometry for females and positive allometry for males. Based on the seasonal assessments of the distribution of individual GSI values, the distribution of stages of gonadal development, individual body size, sex ratio, the ratio of juveniles to adults, and histological examination of the ovaries, reproduction was found to occur in the spring (spawning in batches), and recruitment in the autumn. These results show that A. lineatus is an estuarine-resident species that uses the study area for reproduction and recruitment, providing an argument in favor of the need to conserve the estuarine environment in order to preserve stocks.

Ambicolored specimens of the flounder Paralichthys orbignyanus (Pleuronectiformes: Paralichthyidae)

Two ambicolored specimens of Paralichthys orbignyanus were reported for the estuarine area of the arroyo Pando (Uruguay). One of the specimens showed an almost fully coloration on the blind side, excepting the cephalic region, while the other one was partially pigmented. This is the first record of ambicoloration in P.orbignyanus.

Dois espécimes anficoloridos de Paralichthys orbignyanus foram coletados na área estuarina do arroyo Pando (Uruguai). Ambos apresentam pigmentação completa no lado oculado. Um deles, no entanto, exibe coloração em quase toda a extensão do lado cego, com exceção da região cefálica. O outro exemplar tem pigmentação desde a nadadeira caudal até a metade do corpo. Este é o primeiro registro desta anomalia na espécie P. orbignyanus.

Ambicolored specimens of the flounder Paralichthys orbignyanus (Pleuronectiformes: Paralichthyidae)

Two ambicolored specimens of Paralichthys orbignyanus were reported for the estuarine area of the arroyo Pando (Uruguay). One of the specimens showed an almost fully coloration on the blind side, excepting the cephalic region, while the other one was partially pigmented. This is the first record of ambicoloration in P.orbignyanus.

Dois espécimes anficoloridos de Paralichthys orbignyanus foram coletados na área estuarina do arroyo Pando (Uruguai). Ambos apresentam pigmentação completa no lado oculado. Um deles, no entanto, exibe coloração em quase toda a extensão do lado cego, com exceção da região cefálica. O outro exemplar tem pigmentação desde a nadadeira caudal até a metade do corpo. Este é o primeiro registro desta anomalia na espécie P. orbignyanus.

ENSAIOS DE INDUÇÃO DE DESOVA DO LINGUADO (Paralichthys orbignyanus VALENCIENNES, 1839) / Induced spawning of the brazilian flounder (paralichthys orbignyanus valenciennes, 1839)

Paralichthys orbignyanus is one of the most valuable flatfish in the southern coast of Brazil, due to its large size and high quality of flesh. So far, biological studies about this species are very rare, and it is not employed for cultivation. This study, undertaken from August 23, 1993 to September 29, 1993, presents the first induced spawning to obtain eggs and larvae of that species in laboratory. Mature adults were caught near Lagoa da Conceição (Florianópolis - SC). Females weighed 1,780 to 3,100 g, and males, 980 to 1,360 g. A total of four couples were injected with Human Chorionic Gonadotropin (HCG): 500 to 1,150 IU/kg for females, and 300 to 400 IU/kg for males. One female did not respond to the treatment and the other ones spawned after a latency period of 46 to 69 hours. Eggs were obtained through artificial fertilization from two females. The total productions of ovulated eggs were 224,000 and 280,000/kg of female, and the larval productions, was 40,500 and 83,200/kg of female, respectively. The best fertilization and hatching rates were 90%. The incubation time varied from 42 to 53 hours. The mean diameter of egg had 790 um, and the unique oil droplet, 116 µm. The mean Total length of hatched larva was 2.0 mm. Experiments of larviculture were not successful, larvae were unable to feed and starved after nine days. The tested hormonal treatment was effective for the

Paralichthys orbignyanus é um dos linguados com maior interesse comercial no litoral sudeste-sul do Brasil, por seu tamanho e qualidade da carne. Até o momento foi pouco estudado, não sendo aproveitado em cultivo. Neste trabalho, desenvolvido entre 23/8/1993 e 29/9/1993, fizeram-se as primeiras induções de desova para obtenção de ovos e larvas desta espécie em laboratório. Indivíduos maduros foram capturados nas imediações da Lagoa da Conceição (Florianópolis - SC). As fêmeas tinham peso entre 1780 e 3100 g e os machos, entre 980 e 1360 g, formando quatro casais. Foram injetados com gonadotrofina coriônica humana (HCG), em doses únicas de 500 a 1150 UI/kg para fêmeas, e 300 a 400 UI/kg para machos. Uma fêmea não respondeu ao tratamento e as demais ovularam após um período de 46 a 69 horas, obtendo-se ovos, através de desova artificial, com duas fêmeas. A produção total de óvulos foi de 224.000 e 280.000/kg de fêmea, e a de larvas, de 40.500 e 83.200/kg de fêmea, respectivamente. As maiores taxas de fecundação e de eclosão foram de 90%. O tempo de incubação dos ovos foi de 42 a 53 horas. O diâmetro médio dos ovos embrionados foi de 790 µm e o da gota de óleo, única, de 116 µm. Ao eclodir, a larva tinha um comprimento médio de 2,0 mm. Nos cultivos, as larvas não conseguiram se alimentar e sobreviveram apenas nove dias. O tratamento hormonal proposto foi efetivo na indução do ling

INDUCED SPAWNING OF THE BRAZILIAN FLOUNDER (PARALICHTHYS ORBIGNYANUS VALENCIENNES, 1839) / ENSAIOS DE INDUÇÃO DE DESOVA DO LINGUADO (Paralichthys orbignyanus VALENCIENNES, 1839)

Paralichthys orbignyanus is one of the most valuable flatfish in the southern coast of Brazil, due to its large size and high quality of flesh. So far, biological studies about this species are very rare, and it is not employed for cultivation. This study, undertaken from August 23, 1993 to September 29, 1993, presents the first induced spawning to obtain eggs and larvae of that species in laboratory. Mature adults were caught near Lagoa da Conceição (Florianópolis - SC). Females weighed 1,780 to 3,100 g, and males, 980 to 1,360 g. A total of four couples were injected with Human Chorionic Gonadotropin (HCG): 500 to 1,150 IU/kg for females, and 300 to 400 IU/kg for males. One female did not respond to the treatment and the other ones spawned after a latency period of 46 to 69 hours. Eggs were obtained through artificial fertilization from two females. The total productions of ovulated eggs were 224,000 and 280,000/kg of female, and the larval productions, was 40,500 and 83,200/kg of female, respectively. The best fertilization and hatching rates were 90%. The incubation time varied from 42 to 53 hours. The mean diameter of egg had 790 um, and the unique oil droplet, 116 µm. The mean Total length of hatched larva was 2.0 mm. Experiments of larviculture were not successful, larvae were unable to feed and starved after nine days. The tested hormonal treatment was effective for the

Paralichthys orbignyanus é um dos linguados com maior interesse comercial no litoral sudeste-sul do Brasil, por seu tamanho e qualidade da carne. Até o momento foi pouco estudado, não sendo aproveitado em cultivo. Neste trabalho, desenvolvido entre 23/8/1993 e 29/9/1993, fizeram-se as primeiras induções de desova para obtenção de ovos e larvas desta espécie em laboratório. Indivíduos maduros foram capturados nas imediações da Lagoa da Conceição (Florianópolis - SC). As fêmeas tinham peso entre 1780 e 3100 g e os machos, entre 980 e 1360 g, formando quatro casais. Foram injetados com gonadotrofina coriônica humana (HCG), em doses únicas de 500 a 1150 UI/kg para fêmeas, e 300 a 400 UI/kg para machos. Uma fêmea não respondeu ao tratamento e as demais ovularam após um período de 46 a 69 horas, obtendo-se ovos, através de desova artificial, com duas fêmeas. A produção total de óvulos foi de 224.000 e 280.000/kg de fêmea, e a de larvas, de 40.500 e 83.200/kg de fêmea, respectivamente. As maiores taxas de fecundação e de eclosão foram de 90%. O tempo de incubação dos ovos foi de 42 a 53 horas. O diâmetro médio dos ovos embrionados foi de 790 µm e o da gota de óleo, única, de 116 µm. Ao eclodir, a larva tinha um comprimento médio de 2,0 mm. Nos cultivos, as larvas não conseguiram se alimentar e sobreviveram apenas nove dias. O tratamento hormonal proposto foi efetivo na indução do ling