The more stirring the better: cichlid fishes associate with foraging potamotrygonid rays

One hunting tactic of freshwater rays (Potamotrygonidae), termed undulate the disc and stir substrate, is here reported to attract cichlids at two sites in the upper Paraná River. The ray species involved in such association are Potamotrygon falkneri and P. motoro, whose activity attract four cichlid species, namely Crenicichla britskii, Satanoperca pappaterra, Cichla kelberi, and Geophagus proximus, the two latter non-native species to the study area. The cichlids approach a ray when it begins to stir the substrate and form sediment clouds, and remain close to the ray during this activity only. The association is here regarded as following behavior even if very transient.Uma tática de caça das raias de água doce (Potamotrygonidae), chamada de ondular o disco e agitar o substrato, é aqui relatada como atrativa para Cichlidae em dois locais da bacia do alto rio Paraná. As espécies de raias envolvidas nesta associação são Potamotrygon falkneri e P. motoro, cuja atividade atrai quatro espécies de ciclídeos, Crenicichla britskii, Satanoperca pappaterra, Cichla kelberi e Geophagus proximus, as duas últimas exóticas à área de estudo. Os ciclídeos se aproximam de uma raia quando esta começa a remexer o substrato e formar nuvens de sedimento, e permanecem na proximidade da raia apenas durante esta atividade. A associação é aqui considerada como comportamento de seguir, ainda que transitório.499501Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Reef fishes of the Anchieta Island State Park, Southwestern Atlantic, Brazil

This paper presents a checklist of the reef fish fauna of the Anchieta Island State Park, a no-take zone in which no extractive activities are allowed, in Ubatuba, Southeastern Brazil. Data was obtained between 2011 and 2013, mainly through underwater observations with snorkelling and SCUBA, and secondarily using scientific fishing (trawling). Published and unpublished data were also verified and compiled. A total of 103 reef fish species, distributed in 78 genus and 50 families was recorded. Haemulidae was the richest family (n=7 species), followed by Epinephelidae (n=6), Pomacentridae, Carangidae and Tetraodontidae (n=4 each). Haemulon was also the most speciose genera (n=5), followed by Stegastes, Acanthurus and Mycteroperca (n=3 each). Sixty-nine species (67%) are included in global and regional Red Lists. Twenty-five species (24.2%) are within the categories Critically Endangered (CR), Endangered (EN), Vulnerable (VU) and Near-Threathened (NT). The network of Marine Protected Areas in Southeastern Brazil is still incipient, and the considerable number of threatened species in the Anchieta Island State Park clearly indicates the importance of the study area for the conservation of coastal and reef fishes.CNPqFAPERJCAPESUniv Estadual Paulista, Inst Biociencias, Sao Vicente, SP, BrazilUniv Fed Sao Paulo, Inst Mar, Lab Ecol & Conservacao Marinha, Santos, SP, BrazilUniv Fed Rio de Janeiro, Inst Biol & SAGE COPPE, Rio De Janeiro, RJ, BrazilUniv Fed Paraiba, Ctr Ciencias Aplicadas & Educ, Rio Tinto, PB, BrazilUniv Estadual Paulista, Campus Expt Registro, Registro, SP, BrazilUniv Fed Sao Paulo, Inst Mar, Lab Ecol & Conservacao Marinha, Santos, SP, BrazilWeb of Scienc

UMA ÁREA DE VIDA RESTRITA AUMENTA A VULNERABILIDADE DA RAIA-DE-FOGO, Potamotrygon motoro, A PESCA EM UM HOTSPOT DE BIODIVERSIDADE DA REGIÃO NEOTROPICAL

In this study a telemetry-based approach was used to examine the movements and the habitat utilization of Potamotrygon motoro, a widespread species of potamotrygonid stingray of South America. The investigation included 13 individuals that were tagged with acoustic transmitters and manually monitored from March to September 2017 in the Bita river, a biodiversity hotspot of the Orinoco basin, Colombia. Stingrays used an area ranging from 0.00360 to 11.86735 km2 (average 2.57742 km2). Within this area, telemetry data identified a higher zone of activity in which 50% of the individuals remained during the study, suggesting that P. motoro is a small-range species with strong site fidelity. As the species is highly targeted by ornamental fisheries in the Orinoco basin, this information may be useful to identify critical habitats and help to guide conservation strategies, based on a fish-oriented management. Given the wide distribution of P. motoro into South America, results may also be useful to neighboring countries such as Brazil, Peru and Venezuela, where a similar use is observed for the species.Keywords: movement ecology; habitat use; acoustic telemetry; Potamotrygonidae; Orinoco basin.Neste estudo, foi utilizada uma abordagem baseada na telemetria para examinar os movimentos e a utilização do habitat de Potamotrygon motoro, uma espécie de raia da família Potamotrygonidae amplamente distribuída pela América do Sul. Para tal, 13 indivíduos foram marcados com transmissores acústicos e monitorados manualmente de março a setembro de 2017 no rio Bita, um hotspot de biodiversidade da bacia do Orinoco, na Colômbia. As raias utilizaram uma área que variou de 0,00360 a 11,86735 km2 (média de 2,57742 km2). Dentro dessa área, os dados de telemetria identificaram uma zona de atividade mais alta na qual 50% dos indivíduos permaneceram durante o estudo, sugerindo que P. motoro é uma espécie que ocupa uma pequena área de vida com forte fidelidade de sítio. Como a espécie é altamente visada pela pesca ornamental na bacia do Orinoco, essas informações podem ser úteis para identificar habitats críticos e ajudar a orientar estratégias de conservação, com base em um manejo “peixe-orientado”. Dada a ampla distribuição de P. motoro na América do Sul, os resultados também poderão ser úteis para países vizinhos, como Brasil, Peru e Venezuela, onde uma utilização semelhante é observada para a espécie.Palavras-chave: ecologia do movimento, uso do habitat, telemetria acústica, Potamotrygonidae, bacia do Orinoco

Venom gland transcriptome analyses of two freshwater stingrays (Myliobatiformes : Potamotrygonidae) from Brazil

Stingrays commonly cause human envenoming related accidents in populations of the sea, near rivers and lakes. Transcriptomic profiles have been used to elucidate components of animal venom, since they are capable of providing molecular information on the biology of the animal and could have biomedical applications. In this study, we elucidated the transcriptomic profile of the venom glands from two different freshwater stingray species that are endemic to the Paraná-Paraguay basin in Brazil, Potamotrygon amandae and Potamotrygon falkneri. Using RNA-Seq, we identified species-specific transcripts and overlapping proteins in the venom gland of both species. Among the transcripts related with envenoming, high abundance of hyaluronidases was observed in both species. In addition, we built three-dimensional homology models based on several venom transcripts identified. Our study represents a significant improvement in the information about the venoms employed by these two species and their molecular characteristics. Moreover, the information generated by our group helps in a better understanding of the biology of freshwater cartilaginous fishes and offers clues for the development of clinical treatments for stingray envenoming in Brazil and around the world. Finally, our results might have biomedical implications in developing treatments for complex diseases

Considerações sobre a reprodução de duas espécies de raias (Myliobatiformes, Potamotrygonidae) na região do Alto Rio Paraná, Sudeste do Brasil

This article presents preliminary information about the reproduction of two species of freshwater stingrays of the genus Potamotrygon, found in the Upper Parana River (Southwest Brazil), where these animals are exotic. Males of P. motoro and P. falkneri become sexually mature around 270 mm and 260 mm of disc width (DW), respectively. Females become sexually mature around 330 mm of DW in P. motoro and 325 mm in P. falkneri. In both species, females are bigger and heavier than males, reaching about 700 mm of DW and 20 kg. Copulating has not been recorded, but one courtship ritual has been observed during the dry season. Mature males present a different dentition from females and young males, which is probably related to their reproductive behavior instead of to their feeding habit. The female fertility has varied from one to three offspring. A miscarriage has been observed at different stages of embryonic development always when pregnant females were captured. In spite of the great history of anthropization of the study area, it seems that hydrological cycles are related to the reproduction of stingrays. Nevertheless, it would be necessary to conduct deeper studies to verify or not this influence