Feeding habits of a large endangered skate from the south-west Atlantic: The spotback skate, Atlantoraja castelnaui

Elasmobranch predation has important effects on marine ecosystems. Identifying the main correlates of the feeding habits of skates is of paramount importance for determining their ecological role. We tested the hypotheses that the diet of the spotback skate, Atlantoraja castelnaui, off Uruguay and northern Argentina, changes with increasing body size, between seasons and regions and that prey size increased with predator's size using a multiple-hypothesis modelling approach. A. castelnaui preyed mainly on teleosts, followed by cephalopods, elasmobranchs and decapods. Small individuals of A. castelnaui consumed decapods and large individuals ate elasmobranchs and cephalopods. The consumption of teleosts was constant along the ontogeny but differed between seasons; more demersal-benthic teleosts were consumed in the cold season, whereas more benthic teleosts were eaten in the warm season. Also, A. castelnaui consumed more cephalopods in the warm season than in the cold season. Benthic teleosts were consumed more in the south region, whereas decapods were eaten more in the north region. A. castelnaui is able to consume larger teleosts as it grows. We conclude that A. castelnaui is a versatile, mainly piscivorous, consumer that shifts its diet with increasing body size and in response to seasonal and regional changes in prey abundance or distribution.Fil: Barbini, Santiago Aldo. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lucifora, Luis Omar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Misiones; Argentin

The presence of southern fishes in the Argentinian continental shelf and adjacent areas

A list of Southern Ocean fishes captured in the Argentinian continental shelf and adjacent areas is presented. The list comprises a total of 41 species. They represent 15% of the ichthyofauna registered in the Southern Ocean. The geographic position of the samples was considered in order to show the northward displacement of some Antarctic species toward southwestern Atlantic waters.Fil: Cousseau, María Berta. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; ArgentinaFil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Figueroa, Daniel Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; Argentin

Feeding habits of the cockfish, callorhinchus callorynchus (Holocephali: Callorhinchidae) from off northern argentina

Los hábitos alimentarios de Callorhinchus callorynchus fueron investigados en las aguas costeras del norte de Argentina. Se evaluó el efecto del tamaño del cuerpo, la temporada y la región sobre la composición de la dieta de las hembras mediante un enfoque de modelado de múltiples hipótesis. Callorhinchus callorynchus se alimentó principalmente de bivalvos (55,61% PSIRI), seguido de cangrejos brachyuras (10,62% PSIRI) y de isópodos (10,13% PSIRI). Las hembras de C. callorynchus presentaron cambios en la dieta con incremento del tamaño del cuerpo, la temporada y la región. Además, esta especie es capaz de consumir bivalvos de mayor tamaño a medida que incrementa el tamaño del cuerpo. El nivel trófico fue calculado en 3,15, caracterizando a esta especie como un consumidor secundario. Concluimos que C. callorynchus presentó un comportamiento de triturador de presas duras, principalmente bivalvos, cangrejos y gasterópodos. Las hembras de esta especie cambian su dieta con el incremento del tamaño del cuerpo y en respuesta a cambios temporales y regionales en la abundancia y distribución de sus presas.The feeding habits of Callorhinchus callorynchus were investigated in coastal waters off northern Argentina. The effect of body size, seasons and regions was evaluated on female diet composition using a multiple-hypothesis modelling approach. Callorhinchus callorynchus fed mainly on bivalves (55.61% PSIRI), followed by brachyuran crabs (10.62% PSIRI) and isopods (10.13% PSIRI). Callorhinchus callorynchus females showed changes in the diet composition with increasing body size and also between seasons and regions. Further, this species is able to consume larger bivalves as it grows. Trophic level was 3.15, characterizing it as a secondary consumer. We conclude that C. callorynchus showed a behavior of crushing hard prey, mainly on bivalves, brachyuran, gastropods and anomuran crabs. Females of this species shift their diet with increasing body size and in response to seasonal and regional changes in prey abundance or distribution.Fil: Roman, Jorge Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Chierichetti, Melisa Antonela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Scenna, Lorena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Fish abundance and distribution patterns related to environmental factors in a choked temperate coastal lagoon (Argentina)

The aim of this study was to assess the influence of environmental factors on the fish distribution and abundance in Mar Chiquita coastal lagoon. Seasonal fish sampling stations were distributed along the lagoon and grouped in three zones from a mixo-oligohaline waters zone with high contribution of freshwater to a mixo-eurihaline waters zone with high marine water influence. A mixo-mesohaline waters zone characterized the middle part of the lagoon. The results showed that the fish composition was dominated by marine estuarine dependent (ED) species in all three zones and in all seasons: Odontesthes argentinensis, Brevoortia aurea, Mugil liza and Micropogonias furnieri were the most representative species. The following important ecological category was freshwater fishes (FW), with Platanichthys platana and Jenynsia multidentata being the most representative species. According to the best model selected, by fitting generalized linear models, abundance of ED increased as water temperature increased during summer and autumn in all three zones. The highest abundance was recorded in the mixo-eurihaline waters zone. On the other hand, FW abundance increased with high rainfall and also when easterly winds blew. In conclusion, a differential habitat use by the species that occur in the Mar Chiquita coastal lagoon was observed. A few ED species dominated the fish composition but FW species also made use of the lagoon during periods of heavy rainfall.O objetivo deste estudo foi avaliar a influência de fatores ambientais sobre a distribuição e abundância de peixes na lagoa costeira Mar Chiquita. Estações sazonais de amostragem de peixes foram distribuídas ao longo da lagoa e agrupadas em três zonas de uma zona de águas Mixo-oligohalino com elevado aporte de água doce para uma zona de águas Mixo-eurihaline com alta influência da água do mar. Uma zona de águas Mixo-mesohalino caracteriza a parte do meio da lagoa. Os resultados mostraram que a composição dos peixes foi dominada por espécies marinhos estuarinos dependentes (ED) em todas as três zonas e em todas as estações: Odontesthes argentinensis, Brevoortia aurea, Mugil liza e Micropogonias furnieri foram as espécies mais representativas. A categoria seguinte mais importante foi peixes de água doce (FW), com Platanichthys platana e Jenynsia multidentata sendo as espécies mais representativas. De acordo com o melhor modelo selecionado pelo ajuste de modelos lineares generalizados, a abundância de ED aumentou de acordo com a temperatura da água durante o verão e outono, em todas as três zonas. A maior abundância foi registrada na zona de águas mixo-eurihalinas. Por outro lado, a abundância de FW aumentou com o aumento da pluviosidade e também quando os ventos de direção leste sopraram. Em conclusão, a utilização diferencial do habitat pelas espécies que ocorrem na lagoa costeira Mar Chiquita foi observada. Poucas espécies ED dominaram a composição de espécies de peixes, enquanto FW fizeram uso da lagoa quando as condições de alta pluviosidade foram observados

Age, growth, maturity and extinction risk of an exploited and endangered skate, Atlantoraja castelnaui, from off Uruguay and northern Argentina

The spotback skate Atlantoraja castelnaui (Arhynchobatidae) is a large and threatened skate species subjected to fishing pressure, endemic to the Southwest Atlantic that occurs from Rio de Janeiro, Brazil, to San Jorge Gulf, Argentina. The age, growth, age at maturity and the maximum intrinsic rate of population increase rmax of A. castelnaui were studied using 152 specimens collected from off Uruguay and north Argentina (35°–42° S), between June 2013 and February 2020. Vertebrae from 143 individuals were used for ageing (females: n = 83, size range 404–1300 mm total length, TL; males: n = 60, size range 400–1270 mm TL). Maximum ages determined for females and males were 30 and 28 years, respectively. To fit growth models, non-linear and Bayesian estimation approaches were considered. For the first approach, a set of four candidate growth (size-at-age) models were fitted: three-parameter von Bertalanffy, two-parameter von Bertalanffy with fixed L0, Gompertz and Logistic. In the second approach, von Bertalanffy, Gompertz and Logistic were fitted. For non-linear estimation, model selection indicated that the entire set of candidate growth models were supported by the data. The von Bertalanffy was selected as the best model for Bayesian estimation. There were no differences in growth between sexes. For the sexes combined, the von Bertalanffy growth model by Bayesian method was considered the most adequate to describe the growth of A. castelnaui (growth mean parameters ± S.D.: L∞ = 1210.29 ± 40.68 mm; k = 0.12 ± 0.01 years−1; L0 = 179.20 ± 11.62 mm). The age at maturity was estimated at 16.21 and 14.04 years for females and males, respectively. The maximum intrinsic rate of population increase rmax was estimated as 0.252 years−1. Life-history traits and rmax provided in the present study suggest that this species has a relatively low productivity and may be vulnerable to an intense fishing pressure.Fil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Sabadin, David Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Roman, Jorge Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Scarabotti, Pablo Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: LUCIFORA, Luis Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

First documented occurrence of Selene vomer (Carangidae) in Mar Chiquita coastal lagoon, Argentina

Un jeune spécimen de Selene vomera été capturé dans la lagu-ne côtière Mar Chiquita (Argentine). Il s’agit du premier signale-ment de ce Carangidae dans cette lagune. Les données morphomé-triques et méristiques relatives au spécimen sont incluses dans la diagnose. La présence d’espèces d’origines tropicales est fréquente dans les eaux côtières du nord de l’Argentine, probablement due à un apport d’eau subtropicale à l’ouest du courant de Malvinas.Fil: Ruocco, Natalia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; ArgentinaFil: Barbini, Santiago Aldo. Comision Provincial Por la Memoria de la Provincia de Buenos Aires.; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Mabragaña, Ezequiel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas; Argentina. Comision Provincial Por la Memoria de la Provincia de Buenos Aires.; ArgentinaFil: Figueroa, Daniel Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; ArgentinaFil: Díaz de Astarloa, Clara María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentin

Endemism in the skates from the Argentine-Uruguayan Common Fishing Zone

La Zona Común de Pesca ArgentinoUruguaya es una región de hidrología compleja ubicada en una región de transición, la composición de la Familia Rajidae que la habita es muy rica, contando con una superposición de cuatro géneros endémicos, único ejemplo a nivel mundial. La historia de esta región a nivel de eras geológicas es muy joven, pero exhibe una evolución traumática pese a su corta edad, y esto se ve refl ejado en la integración, composición y distribución de los géneros de la Familia Rajidae.The Argentine-Uruguayan Fishing Zone is a region of complex hydrology, located in a transition place, the composition of Family Rajidae that inhabits here is very rich, with an overlap of four endemic genera, only worldwide example. The history of this region at the level of geologic time is very young, but exhibits a traumatic evolution despite his young age, and this is refl ected in the integration, composition and distribution of the genera of the family Rajidae.Fil: Figueroa, Daniel Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; ArgentinaFil: Barbini, Santiago Aldo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scenna, Lorena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; ArgentinaFil: Belleggia, Mauro. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Delpiani, Gabriela Elina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Spath, María Cecilia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Big fish (and a smallish skate) eat small fish: diet variation and trophic level of Sympterygia acuta, a medium-sized skate high in the food web

The bignose fanskate, Sympterygia acuta, is a small-to-medium-sized species endemic to shallow coastal waters of the Southwest Atlantic. Sympterygia acuta displays a clear seasonal reproductive cycle, characterized by maximum egg-laying activity in spring and hatching in summer. We hypothesized that diet and feeding activity change with maturity stage and season and that, given its smallish size, the trophic level is low. Using a multiple-hypothesis modeling approach, the diet of S. acuta in relation to sex, body size, maturity stage, region (i.e. north and south) and season was analysed; and a potential relationship between feeding activity and the seasonal reproductive cycle was assessed. Sympterygia acuta fed on a broad spectrum of prey, but teleosts were more important (47.97% index of relative importance, %IRI), followed by decapods (39.84%IRI), cumaceans (8.31%IRI) and isopods (1.89%IRI). Maturity stage was a strong determinant of the ontogenetic diet shift of S. acuta, and relationships between number of prey consumed with season and region were found.. Feeding activity was higher in the cold season than in the warm season, and was less important in the south region than in the north region. Unexpectedly, the specific trophic level was high (3.87). Sympterygia acuta shifts its diet with maturity stage, possibly by a combination of an improved ability to capture prey and a change in energy demand of mature individuals. Despite being a small-to-medium-sized skate, S. acuta showed a trophic level similar to that of large-bodied marine predators. It reduces its feeding activity seasonally because in the warm season this species may experience an increased predation risk from large sharks.Fil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Lucifora, Luis Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentin

Feeding habits of the Rio skate, Rioraja agassizi (Chondrichthyes: Rajidae), from off Uruguay and north Argentina

The feeding habits of the Rio skate, Rioraja agassizi, from off Uruguay and north Argentina were evaluated using a multiple-hypothesis modeling approach. Relationships between number of preys and sex, maturity stage, body size, season and region were assessed by building generalized linear models. R. agassizi fed mainly upon crustaceans (shrimps, crabs and amphipods) and teleosts, but also upon isopods, cumaceans, lancelets and polychaetes. Ontogenetic diet shifts were found: small R. agassizi consumed amphipods, cumaceans and isopods and large individuals on shrimps, crabs and teleosts. The consumption of crustaceans (amphipods, shrimps, crabs, isopods and cumaceans) was higher in the north (34° - 38°S) than in the south area (38° - 41°S). R. agassizi consumed more teleosts in the cold season and preyed more on lancelets in the warm season. Prey size increased with increasing body size of R. agassizi, but large individuals also consumed small prey. Ontogenetic shifts may be related to body size rather than other life-history traits. R. agassizi adapts its feeding habits in response to regional and seasonal changes.Fil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Lucifora, Luis Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentina. Centro de Investigaciones del Bosque Atlantico; Argentin

List of cartilaginous (Sharks, Rays, and Chimaeras, Chondrichthyes) hosted in the Ichthyological Collection of the National Institute of Investigation and Fisheries (INIDEP)

Se presenta una lista de especies de peces cartilaginosos (tiburones, rayas y quimeras: Clase Chondrichthyes) que se encuentran almacenadas en la Colección Ictiológica de Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP). El material colectado proviene de campañas de investigación científica y pesca comercial. Para cada ejemplar preservado en la colección se brinda información referente a su clasificación taxonómica, a su captura y a caracteres propios de cada ejemplar. Dos holotipos y sus respectivos paratipos y un paratipo de una nueva especie de la región forman parte de la colección, que cuenta en total con el 50,47 % del total de condrictios registrados hasta ahora en el área.A list of cartilaginous fish species (sharks, skates and chimeras: Clase Chondrichthyes), which are stored in the Ichthyological Collection of Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), is presented. The specimens were collected from scientific research cruises and from commercial fishing. For each specimen stored in the collection, references about the taxonomic classification, the catch and the characters of each specimen are given. Two holotypes and their respective paratypes and a paratype of a new species in the region are part of the collection, with a total of 50.47% of the total registered chondrichthyan so far in the area.Fil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Cousseau, María Berta. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; Argentin