RESUMO
Elasmobranchs are particularly vulnerable to environmental contamination, especially pollutants that may bioaccumulate and biomagnify, throughout the trophic web, such as metals. However, Elasmobranch management and conservation plans are challenging, and this group is often neglected regarding ecotoxicological analyses, particularly concerning metal detoxification mechanisms. This article discusses metallothionein (MT) mediated metal detoxification in Elasmobranchs and reflects on the current knowledge gap in this regard.
RESUMO
BACKGROUND: Parasites of deep-sea fishes from the South-East Pacific (SPO) are poorly known. Of c.1030 species of fish found in this area, 100-150 inhabit the deep-sea (deeper than 200 m). Only six articles concerning metazoan parasites of fish from deep-waters of SOP are known, and nine monogenean species have been reported. Currently, ten species are known in Acanthocotyle Monticelli, 1888 (Monogenea) and when stated, all of them are found in shallow waters (10-100 m). Acanthocotyle gurgesiella Ñacari, Sepulveda, Escribano & Oliva, 2018 is the only known species parasitizing deep-sea skates (350-450 m) in the SPO. The aim of this study was the description of two new species of Acanthocotyle from two Rajiformes. METHODS: In September 2017, we examined specimens of two species of deep-sea skates (Rajiformes), Amblyraja frerichsi (Krefft) and Bathyraja peruana McEachran & Myyake, caught at c.1500 m depth off Tocopilla, northern Chile, as a by-catch of the Patagonian tooth fish Dissostichus eleginoides Smitt fishery. Specimens of Acanthocotyle were collected from the skin of the skates. Morphometric (including multivariate analysis of proportional measurements, standardized by total length), morphological and molecular analyses (LSU rRNA and cox1 genes) were performed in order to identify the collected specimens. RESULTS: The three approaches used in this study strongly suggest the presence of two new species in the genus Acanthocotyle: Acanthocotyle imo n. sp. and Acanthocotyle atacamensis n. sp. parasitizing the skin of the thickbody skate Amblyraja frerichsi and the Peruvian skate Bathyraja peruana, respectively. The main morphological differences from the closely related species Acanthocotyle verrilli Goto, 1899 include the number of radial rows of sclerites, the non-discrete vitelline follicles and the number of testes. CONCLUSIONS: The two species of monogeneans described here are the only recorded parasites from their respective host species in the SPO. Assessing host specificity for members of Acanthocotyle requires clarifying the systematics of Rajiformes.
Assuntos
Doenças dos Peixes/parasitologia , Platelmintos/classificação , Rajidae/parasitologia , Infecções por Trematódeos/veterinária , Animais , Teorema de Bayes , Chile , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , Complexo IV da Cadeia de Transporte de Elétrons/genética , Genes Mitocondriais , Especificidade de Hospedeiro , Funções Verossimilhança , Cadeias de Markov , Método de Monte Carlo , Análise Multivariada , Oceano Pacífico , Filogenia , Platelmintos/anatomia & histologia , Platelmintos/genética , Análise de Componente Principal , RNA Ribossômico/genética , Pele/parasitologia , Infecções por Trematódeos/parasitologiaRESUMO
Recent molecular evidence has called into question the identity of skates collected in the waters off the Falkland Islands previously identified as Zearaja chilensis. NADH2 sequence data indicate that these specimens are not conspecific with those currently referred to as Z. chilensis from Chile and, in fact, represent a novel cryptic species. This study aimed to investigate this hypothesis based on morphological comparisons of specimens from the coasts of both western and eastern South America. In total, 50 specimens from Chile and 41 specimens from the Falkland Islands were collected and examined; morphometric data were generated for a subset of specimens from both areas. NADH2 sequence data were generated for a total of 19 specimens from both areas, as well as specimens of Z. nasuta from New Zealand, D. pullopunctatus from South Africa, D. oxyrinchus from the Azores, Okamejei hollandi, and O. cairae from Borneo, and O. kenojei from Japan. Based on morphological and molecular analyses, Zearaja is synonymized with Dipturus and species assigned to the former genus are transferred to the latter genus. A neotype is designated for D. chilensis and this species is redescribed. Dipturus lamillai sp. nov. is described based on specimens from the Falkland Islands. Comparison of our NADH2 data with data for mitochondrial genomes generated from tissue samples taken from two specimens originally identified as Z. chilensis, indicate that, while the sample from Chile came from a specimen of D. chilensis, that from the skate steak obtained from a restaurant in Korea actually came from a specimen of D. lamillai sp. nov. This emphasizes the importance of confirming both the provenance and identity of specimens from which sequence data are generated and submitted to GenBank if misidentifications are to be avoided.
Assuntos
Rajidae , Animais , Ilhas MalvinasRESUMO
Zearaja chilensis has been reported from Southern Brazil in the Southwest Atlantic (SWA) to northern Chile in the Southeast Pacific (SEP), and it was listed as vulnerable by the IUCN. Recent molecular studies have called into question the conspecificity between specimens from these opposite coasts of South America, which can have implications for the conservation status of the species. To verify the identity of specimens identified as Z. chilensis, 47 individuals from SWA and 22 from SEP were examined. By comparing external morphology, spinulation pattern, clasper, egg cases, and mitochondrial cytochrome c oxidase I (COI) sequence data, differences between groups were found. Adults from SWA presented longer snout length and shorter tail than those from SEP. Dermal denticles were restricted to the rostral area in SWA skates, whereas in SEP skates most of the dorsal surface was covered with denticles. Marked differences in the morphology of several components of clasper were noticeable. Egg cases of SWA skates had thinner lateral keels than those of SEP. Molecular analysis revealed two well-defined cohesive clusters, corresponding to SWA and SEP specimens, respectively. Average K2P distance between groups was 3.4%, higher than expected for intraspecific differences, and sequences were assigned to different BINs. These integrative approaches strongly support that specimens from SWA known as Z. chilensis correspond to a different nominal species than those from SEP. Herein, Z. brevicaudata (Marini 1933) is resurrected from synonymy with Z. chilensis.
Assuntos
Mitocôndrias/metabolismo , Rajidae/classificação , Animais , Brasil , ChileRESUMO
The subclass Batoidea comprise skates, electric rays, stingrays, guitarfishes, and sawfishes, and their interrelationships are still problematical despite recent morphological and molecular phylogenetic studies. The most recent morphological phylogeny indicates that guitarfishes are a polyphyletic group, and that the phylogenetic placement of Platyrhina and Platyrhinoidis is still unclear. Several molecular studies suggest that guitarfishes (except Zanobatus) and sawfishes comprise the monophyletic order Rhinopristiformes, and that thornback rays (Platyrhinidae, Platyrhina, and Platyrhinoidis) are more closely related to the electric rays (Torpediniformes); rhinopristiforms have recently been supported by morphological data as well. The clasper musculature of batoids suggests an alternative pattern of interrelationships for thornback rays, with the m. dilatator attached to the dorsal terminal 1 cartilage by a series of tendons found only in Rhinopristiformes and Platyrhinidae, suggesting that they are closely related. Furthermore, Rajiformes, Rhinopristiformes, and Platyrhinidae exclusively share a reduced m. extensor lateralis, suggesting that these taxa form a monophyletic group. This study identifies new synapomorphies that corroborate the separate monophyly of Rajiformes, Torpediniformes, and Myliobatiformes: the m. dilatator divided into dorsal and ventral bundles and the presence of a single m. flexor are found only in Rajiformes; the extensor lateralis with a laminar shape is a derived character of Torpediniformes; and the exclusive m. flexor medialis arising on the puboischiadic bar is derived for Myliobatiformes.
Assuntos
Músculos/anatomia & histologia , Filogenia , Rajidae/anatomia & histologia , Rajidae/classificação , Nadadeiras de Animais/anatomia & histologia , AnimaisRESUMO
We analyzed growth and reproduction of captive-born smallnose fanskates Sympterygia bonapartii. Egg cases were obtained from oviposition of two females caught in the wild and held at Temaikèn Aquarium. Following hatching, growth was analyzed in 13 females and 21 males until sexual maturity. Pattern of oviposition activity and reproductive performance were evaluated in six of the captive-reared females. Four models were fitted to growth data, among which the logistic function was the one attaining the best fit. The highest growth rate for both sexes was recorded during the first year of life, whereas growth was significantly higher in females than in males during the second year. Size at first oviposition was 61.7 ± 3.5 cm TL, similar to wild specimens. However, captive-reared females reached maturity before two years of age, i.e. much earlier than wild skates, implying a significant phenotypic plasticity in this species. The similarity in size at maturity and the difference in age at maturity between captive and wild specimens indicate that there is a decoupling of both parameters mediated through growth rates. Captive-born skates reproduced successfully and yielded viable offspring, indicating that the environment at Temaikèn Aquarium is suitable for S. bonapartii to attain its full life cycle.(AU)
Analizamos el crecimiento y la reproducción de ejemplares de raya marmorada, Sympterygia bonapartii nacidas en cautiverio. Se obtuvieron ovicápsulas a partir de la oviposición de dos hembras capturadas en la naturaleza y mantenidas en el Acuario Temaikèn. Posteriormente a la eclosión, se analizó el crecimiento en 13 hembras y 21 machos hasta la madurez sexual. Se evaluó el patrón de oviposición y la performance reproductiva en seis de las hembras criadas en cautiverio. Se ajustaron cuatro modelos a los datos de crecimiento, entre los cuales la función logística fue la que logró el mejor ajuste. Para ambos sexos, la mayor tasa de crecimiento se registró durante el primer año de vida. Durante el segundo año, la tasa de crecimiento fue significativamente mayor en hembras que en machos. La talla de primera oviposición fue de 61,7 ± 3,5 cm LT, similar a la estimada en rayas silvestres. Sin embargo, las hembras criadas en cautiverio alcanzaron la madurez antes de los dos años de vida, es decir mucho antes que en el ambiente natural, lo que implica una plasticidad fenotípica significativa en esta especie. La similitud en la talla de madurez y la diferencia en la edad de madurez entre individuos cautivos y silvestres indican que hay un desacople de ambos parámetros mediado por la tasa de crecimiento. Los individuos nacidos en cautiverio se reprodujeron exitosamente y dejaron descendencia viable, lo que indica que el ambiente del Acuario Temaikèn es adecuado para que S. bonapartii complete su ciclo de vida.(AU)
Assuntos
Animais , Maturidade Sexual , Rajidae/crescimento & desenvolvimento , Rajidae/fisiologiaRESUMO
We analyzed growth and reproduction of captive-born smallnose fanskates Sympterygia bonapartii. Egg cases were obtained from oviposition of two females caught in the wild and held at Temaikèn Aquarium. Following hatching, growth was analyzed in 13 females and 21 males until sexual maturity. Pattern of oviposition activity and reproductive performance were evaluated in six of the captive-reared females. Four models were fitted to growth data, among which the logistic function was the one attaining the best fit. The highest growth rate for both sexes was recorded during the first year of life, whereas growth was significantly higher in females than in males during the second year. Size at first oviposition was 61.7 ± 3.5 cm TL, similar to wild specimens. However, captive-reared females reached maturity before two years of age, i.e. much earlier than wild skates, implying a significant phenotypic plasticity in this species. The similarity in size at maturity and the difference in age at maturity between captive and wild specimens indicate that there is a decoupling of both parameters mediated through growth rates. Captive-born skates reproduced successfully and yielded viable offspring, indicating that the environment at Temaikèn Aquarium is suitable for S. bonapartii to attain its full life cycle.(AU)
Analizamos el crecimiento y la reproducción de ejemplares de raya marmorada, Sympterygia bonapartii nacidas en cautiverio. Se obtuvieron ovicápsulas a partir de la oviposición de dos hembras capturadas en la naturaleza y mantenidas en el Acuario Temaikèn. Posteriormente a la eclosión, se analizó el crecimiento en 13 hembras y 21 machos hasta la madurez sexual. Se evaluó el patrón de oviposición y la performance reproductiva en seis de las hembras criadas en cautiverio. Se ajustaron cuatro modelos a los datos de crecimiento, entre los cuales la función logística fue la que logró el mejor ajuste. Para ambos sexos, la mayor tasa de crecimiento se registró durante el primer año de vida. Durante el segundo año, la tasa de crecimiento fue significativamente mayor en hembras que en machos. La talla de primera oviposición fue de 61,7 ± 3,5 cm LT, similar a la estimada en rayas silvestres. Sin embargo, las hembras criadas en cautiverio alcanzaron la madurez antes de los dos años de vida, es decir mucho antes que en el ambiente natural, lo que implica una plasticidad fenotípica significativa en esta especie. La similitud en la talla de madurez y la diferencia en la edad de madurez entre individuos cautivos y silvestres indican que hay un desacople de ambos parámetros mediado por la tasa de crecimiento. Los individuos nacidos en cautiverio se reprodujeron exitosamente y dejaron descendencia viable, lo que indica que el ambiente del Acuario Temaikèn es adecuado para que S. bonapartii complete su ciclo de vida.(AU)
Assuntos
Animais , Maturidade Sexual , Rajidae/crescimento & desenvolvimento , Rajidae/fisiologiaRESUMO
Objetivo: Desenvolver um sistema web para notificação de acidentes por arraias ocorridos no Estado do Amazonas. Método: Pesquisa aplicada desenvolvida em duas etapas principais: (i) especificação dos requisitos com uma profissional de imunologia; (ii) projeto e desenvolvimento de um sistema Web utilizando a plataforma JAVA e o Sistema Gerenciador de Banco de Dados MySQL; Resultados: O trabalhou resultou em um software web para gerir as notificações de acidentes com arraias cujo código fonte está disponibilizado para a comunidade sob a licença GNU (General Public Licence). Conclusão: O sistema desenvolvido poderá subsidiar estudos epidemiológicos, pesquisas sobre os tipos de ocorrência e gravidade de acidentes por arraias no Estado do Amazonas.
Objective: To develop a web system for notification of accidents with different ray species in the state of Amazonas. Method: Applied research developed in two main steps: (i) specification of requirements with an immunologist; (ii) design and implementation of a system web using the JAVA platform and MySQL database management system. Results: The work produced a web software to manage notification of accidents with rays. The source code of the system is available to the general public under the GNU general public license. Conclusion: The system developed here can be used to support epidemiologic studies and research into the different types of accidents involving rays and their severity in the state of Amazonas.
Objetivo: Desarrollar un sistema web para la notificación de accidentes por rayas ocurridos en el Estado de Amazonas. Método: Investigación aplicada desarrollada en dos fases principales: (i) obtención de requisites con una profesional del área de inmunología; (ii) diseño e implementación del sistema utilizando como plataformas de desarrollo Java y el Sistema Gestor de Bases de Datos MySQL. Resultados: El trabajo resultó en un sistema web para la notificación de accidentes por rayas, cuyo código fuente está disponible para la comunidad bajo la licencia GNU (General Public Licence). Conclusión: El sistema desarrollado puede apoyar estudios epidemiológicos, investigaciones sobre los tipos de incidencias y gravedad de los accidentes por rayas en el Estado de Amazonas.
Assuntos
Masculino , Informática Médica , Rajidae , Sistemas de InformaçãoRESUMO
The yellownose skate Zearaja chilensis is endemic to South America. The species is the target of a valuable commercial fishery in Chile, but is highly susceptible to over-exploitation. The complete mitochondrial genome was described from 694,593 sequences obtained using Ion Torrent Next Generation Sequencing. The total length of the mitogenome was 16,909 bp, comprising 2 rRNAs, 13 protein-coding genes, 22 tRNAs and 2 non-coding regions. Comparison between the proposed mitogenome and one previously described from "raw fish fillets from a skate speciality restaurant in Seoul, Korea" resulted in 97.4% similarity, rather than approaching 100% similarity as might be expected. The 2.6% dissimilarity may indicate the presence of two separate stocks or two different species of, ostensibly, Z. chilensis in South America and highlights the need for caution when using genetic resources without a taxonomic reference or a voucher specimen.
Assuntos
DNA Mitocondrial/genética , Genoma Mitocondrial/genética , Mitocôndrias/genética , Análise de Sequência de DNA/veterinária , Rajidae/genética , Animais , Composição de Bases/genética , Sequência de Bases , Tamanho do Genoma/genética , Sequenciamento de Nucleotídeos em Larga Escala , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , RNA de Transferência/genética , América do SulRESUMO
Se analizaron un total de 2.782 individuos de Dipturus chilensis capturados por la flota arrastrera dirigida a la merluza (Merlucius hubbsi) que operó entre 50 y 400 m de profundidad durante los años 2005, 2006 y 2007 en la Zona Común de Pesca Argentino-Uruguaya. Las hembras presentaron un tamaño medio y mediano mayor que los machos y mayores proporciones en las capturas. Las relaciones entre la longitud total y el ancho del disco y entre la longitud total y el peso total de los individuos no presentaron diferencias significativas entre sexos. En los tres años analizados, no se encontraron variaciones significativas de la talla media y mediana. La talla a la cual fue retenido por la red de arrastre el 50% de los individuos, fue menor a la talla que madura el 50% de los individuos en la mayoría de las épocas. Las mayores capturas de individuos inmaduros como de hembras demuestran que la operación de pesca dirigida a la merluza afecta el potencial reproductivo de una especie categorizada como vulnerable por la UICN.
A total of 2,782 individuals of Dipturus chilensis captured by the Uruguayan industrial fleet whose target species is the hake (Merlucius hubbsi), that operated between 50 to 400 m of depth during the years 2005, 2006 and 2007 in the Argentinean-Uruguayan Common Fishing zone were analyzed. Females showed a higher mean and median size than males and a highest proportion in the catches. The relationships between the total length and width of the disc and between total length and total weight did not differ significantly between sexes. For the three years analyzed, no significant decrease was found for mean length and median length. The length at which 50% of individuals were retained by the trawl net was smaller than the 50% mature estimated total lengths. Higher catches of immature individuals demonstrate that the fishing operation targeting hake affect the reproductive potential of a species categorized as vulnerable for IUCN.
Analisaram-se um total de 2.782 indivíduos da Dipturus chilensis capturados pela frota de arrasto dirigida à pesca da merluza (Merlucius hubbsi) que operou entre 50 e 400 m de profundidade durante os anos 2005, 2006 e 2007 na Zona Comum de Pesca Argentino-Uruguaia. As fêmeas apresentaram um tamanho médio e mediano maior do que os machos e tiveram uma maior proporção nas capturas. As relações entre o comprimento total e a largura do disco e entre o comprimento total e o peso dos indivíduos não apresentaram diferenças significativas entre os sexos. Para os três anos analisados, não se encontrou uma diminuição significativa no tamanho médio e mediano. A mediana foi menor do que o tamanho em que 50% dos indivíduos estiveram maduros. A maior captura de indivíduos imaturos demonstra que a operação de pesca dirigida à merluza afeta o potencial reprodutivo de uma espécie categorizada vulnerável pela IUCN.
Assuntos
Animais , Biometria , Demografia , Rajidae/anatomia & histologia , Argentina , Oceano Atlântico , UruguaiRESUMO
Se analizaron un total de 2.782 individuos de Dipturus chilensis capturados por la flota arrastrera dirigida a la merluza (Merlucius hubbsi) que operó entre 50 y 400 m de profundidad durante los años 2005, 2006 y 2007 en la Zona Común de Pesca Argentino-Uruguaya. Las hembras presentaron un tamaño medio y mediano mayor que los machos y mayores proporciones en las capturas. Las relaciones entre la longitud total y el ancho del disco y entre la longitud total y el peso total de los individuos no presentaron diferencias significativas entre sexos. En los tres años analizados, no se encontraron variaciones significativas de la talla media y mediana. La talla a la cual fue retenido por la red de arrastre el 50% de los individuos, fue menor a la talla que madura el 50% de los individuos en la mayoría de las épocas. Las mayores capturas de individuos inmaduros como de hembras demuestran que la operación de pesca dirigida a la merluza afecta el potencial reproductivo de una especie categorizada como vulnerable por la UICN.(AU)
A total of 2,782 individuals of Dipturus chilensis captured by the Uruguayan industrial fleet whose target species is the hake (Merlucius hubbsi), that operated between 50 to 400 m of depth during the years 2005, 2006 and 2007 in the Argentinean-Uruguayan Common Fishing zone were analyzed. Females showed a higher mean and median size than males and a highest proportion in the catches. The relationships between the total length and width of the disc and between total length and total weight did not differ significantly between sexes. For the three years analyzed, no significant decrease was found for mean length and median length. The length at which 50% of individuals were retained by the trawl net was smaller than the 50% mature estimated total lengths. Higher catches of immature individuals demonstrate that the fishing operation targeting hake affect the reproductive potential of a species categorized as vulnerable for IUCN.(AU)
Analisaram-se um total de 2.782 indivíduos da Dipturus chilensis capturados pela frota de arrasto dirigida à pesca da merluza (Merlucius hubbsi) que operou entre 50 e 400 m de profundidade durante os anos 2005, 2006 e 2007 na Zona Comum de Pesca Argentino-Uruguaia. As fêmeas apresentaram um tamanho médio e mediano maior do que os machos e tiveram uma maior proporção nas capturas. As relações entre o comprimento total e a largura do disco e entre o comprimento total e o peso dos indivíduos não apresentaram diferenças significativas entre os sexos. Para os três anos analisados, não se encontrou uma diminuição significativa no tamanho médio e mediano. A mediana foi menor do que o tamanho em que 50% dos indivíduos estiveram maduros. A maior captura de indivíduos imaturos demonstra que a operação de pesca dirigida à merluza afeta o potencial reprodutivo de uma espécie categorizada vulnerável pela IUCN.(AU)
Assuntos
Animais , Rajidae/anatomia & histologia , Biometria , Demografia , Oceano Atlântico , Argentina , UruguaiRESUMO
Squamation patterns and skeletal anatomy (neurocranium, visceral arches, synarcual cartilage, scapulocoracoid, puboischiadic bar, and mixopterigium) of Dipturus mennii Gomes & Paragó, 2001 are described as a contribution to our limited knowledge of the anatomy of species of Dipturus Rafinesque, 1810. The hyoid and branchial arches, as well as the synarcual cartilage, are described for the first time in this species. We provide morphological comparisons of this species with Dipturus trachyderma (Krefft & Stehmann, 1975), a species that may be confused with D. mennii; we further corroborate, through anatomical features, that these species warrant separate taxonomic recognition. The main differences between D. mennii and D. trachyderma were found in squamation of the nuchal and middisc region, neurocranium, pectoral girdle, and principally the clasper skeleton. The morphology of the pelvic girdle is similar in both species. Dipturus is characterized by having the ventral terminal cartilage J-shaped (as opposed to the Z-shaped ventral terminal cartilage in Zearaja, whose species were, until recently, placed in Dipturus). Additional characters that may be derived for Dipturus include the anterior rostral groove and elevated rostral proportions
RESUMO
Squamation patterns and skeletal anatomy (neurocranium, visceral arches, synarcual cartilage, scapulocoracoid, puboischiadic bar, and mixopterigium) of Dipturus mennii Gomes & Paragó, 2001 are described as a contribution to our limited knowledge of the anatomy of species of Dipturus Rafinesque, 1810. The hyoid and branchial arches, as well as the synarcual cartilage, are described for the first time in this species. We provide morphological comparisons of this species with Dipturus trachyderma (Krefft & Stehmann, 1975), a species that may be confused with D. mennii; we further corroborate, through anatomical features, that these species warrant separate taxonomic recognition. The main differences between D. mennii and D. trachyderma were found in squamation of the nuchal and middisc region, neurocranium, pectoral girdle, and principally the clasper skeleton. The morphology of the pelvic girdle is similar in both species. Dipturus is characterized by having the ventral terminal cartilage J-shaped (as opposed to the Z-shaped ventral terminal cartilage in Zearaja, whose species were, until recently, placed in Dipturus). Additional characters that may be derived for Dipturus include the anterior rostral groove and elevated rostral proportions
RESUMO
Squamation patterns and skeletal anatomy (neurocranium, visceral arches, synarcual cartilage, scapulocoracoid, puboischiadic bar, and mixopterigium) of Dipturus mennii Gomes & Paragó, 2001 are described as a contribution to our limited knowledge of the anatomy of species of Dipturus Rafinesque, 1810. The hyoid and branchial arches, as well as the synarcual cartilage, are described for the first time in this species. We provide morphological comparisons of this species with Dipturus trachyderma (Krefft & Stehmann, 1975), a species that may be confused with D. mennii; we further corroborate, through anatomical features, that these species warrant separate taxonomic recognition. The main differences between D. mennii and D. trachyderma were found in squamation of the nuchal and middisc region, neurocranium, pectoral girdle, and principally the clasper skeleton. The morphology of the pelvic girdle is similar in both species. Dipturus is characterized by having the ventral terminal cartilage J-shaped (as opposed to the Z-shaped ventral terminal cartilage in Zearaja, whose species were, until recently, placed in Dipturus). Additional characters that may be derived for Dipturus include the anterior rostral groove and elevated rostral proportions
RESUMO
Specimens of Rioraja agassizi were collected monthly off Santos, Southeast Brazil, between latitudes 23º37'S and 27º40'S, from March, 2005 to March, 2006. A total number of 278 males and 1023 females were captured. Observed depth range was 10-120 m, being the species absent above 120 m. Sex ratio significantly favored females. The entire length range of R. agassizi was observed. Females ranged in length from 16.0 to 59.4 cm and males from 13.0 to 47.2 cm. Mean female length was significantly higher than that of males. For grouped length distributions, asymmetry patterns were observed in both sexes. Length-width functions were sexually dimorphic. Males with lengths < 24.5 cm were relatively wider than females. Length-total weight curves were significantly different than length-gutted weight ones, in both sexes. Females were heavier than males for a given TL class. The angular coefficient b was significantly <3 (negative allometry) in the males, and also for the females with exception of spring when b was >3 (positive allometry). The monthly variation of the condition factor showed significant differences in both sexes
Espécimes de Rioraja agassizi foram mensalmente coletados em águas ao largo de Santos, sudeste do Brasil entre as latitudes 23º37'S e 27º40'S, desde março de 2005 até março de 2006. Um total de 278 machos e 1023 fêmeas foi capturado. A amplitude de profundidade de ocorrência foi 10-120 m, estando a espécie ausente em profundidades >120 m. A razão sexual favoreceu as fêmeas. A amplitude completa de comprimentos de R. agassizi esteve representada e oscilou nas fêmeas entre 16.0-59.4 cm comprimento e nos machos entre 13.0-47.2 cm. O tamanho médio das fêmeas foi significativamente maior do que dos machos. A distribuição de freqüência de comprimentos por amostras agrupadas foi assimétrica em ambos os sexos. As curvas da relação comprimento-largura foram sexualmente dimórficas. As fêmeas foram mais largas que os machos em todas as classes de comprimento maiores do que 25 cm. As curvas comprimento-peso total foram significativamente diferentes das curvas comprimento-peso eviscerado em ambos os sexos. As fêmeas foram mais pesadas do que os machos para uma determinada classe de comprimento. O coeficiente angular b foi <3 nos machos (alometría negativa) e nas fêmeas, mas com exceção da primavera, onde a alometría foi positiva (b>3). O fator de condição variou significativamente ao longo do ano em ambos os sexos
Assuntos
Animais , Biodiversidade , Peixes/anatomia & histologia , Peixes/classificaçãoRESUMO
O presente estudo foi realizado no litoral entre a divisa dos Estados do Paraná e Santa Catarina, em duas comunidades pesqueiras artesanais que integram os municípios de Guaratuba (PR) e Itapoá (SC). Foram acompanhadas as atividades pesqueiras das comunidades, entre julho de 2001 e março de 2003, com o objetivo de: listar as espécies de elasmobrânquios capturadas pelas comunidades em questão; avaliar o uso comercial das espécies; observar a ocorrência sazonal das espécies nos desembarques; estimar a freqüência relativa de captura por aparelho de pesca; e inferir sobre a biologia reprodutiva das espécies. Durante o período estudado foram capturados: Carcharhinus falciformis, Galeocerdo cuvier, Rhizoprionodon lalandii, R. porosus, Sphyrna lewini, S. zygaena, Squatina guggenheim, Narcine brasiliensis, Rhinobatos percellens, Zapteryx brevirostris, Rioraja agassizii, Dasyatis americana, D. guttata, D. hipostigma, Gymnura altavela, Myliobatis goodei, Rhinoptera bonasus e R. brasiliensis. Quanto à comercialização das espécies, foi observado que todos os tubarões capturados na área de estudo são comercializados, dentre as raias, apenas Rhinobatos percellens e Zapteryx brevirostris. Nos desembarques, a ocorrência de elasmobrânquios foi maior durante o inverno e a primavera. A maioria das capturas ocorreu com redes de emalhe, o arrasto camaroneiro pouco capturou. Os dados do presente trabalho indicaram a utilização da área estudada para o parto das espécies G. cuvier, R. lalandii, R. porosus, S. lewini, N. brasiliensis e R. agassizii; para o crescimento de todas as espécies amostradas; e para a gestação de R. percellens e Z. brevirostris. É sugerido que medidas que visem a proteger as espécies sejam tomadas, sem trazer prejuízos e conflitos para as comunidades de pescadores.
This study was done in the South coast of Parana State and North coast of Santa Catarina State, Brazil, in two artisanal fishermen communities. Between July, 2001 and March, 2003 the fishing activities were observed aiming to: report the elasmobranchs caught species; report which species are commercialized; observe the seasonal occurrence of the species in the landings; estimate the frequency of capture by different fishing gears; and infer about the reproductive biology of the species. During the studied period were captured: Carcharhinus falciformis, Galeocerdo cuvier, Rhizoprionodon lalandii, R. porosus, Sphyrna lewini, S. zygaena, Squatina guggenheim, Narcine brasiliensis, Rhinobatos percellens, Zapteryx brevirostris, Rioraja agassizii, Dasyatis americana, D. guttata, D. hipostigma, Gymnura altavela, Myliobatis goodei, Rhinoptera bonasus and R. brasiliensis. It was observed that all sharks and only two ray species (R. percellens and Z. brevirostris) are commercialized. In the landings, elasmobranchs were more frequent during winter and spring. Most catches were done by gillnets, while just a few captures were done by shrimp trawls. The data indicated that the studied area is used by G. cuvier, R. lalandii, R. porosus, S. lewini, N. brasiliensis and R. agassizii to give birth; by all species for growing; and during the gestation of R. percellens and Z. brevirostris. It is suggested that actions aiming to protect the species must be taken, without harming and conflicts for the fishermen communities.