ABSTRACT Artisanal fisheries in center-southern Chile targeted a large amount of southern ray bream (Brama australis), whereas other species of Bramidae are negligible in the catches. During a small-scale fishing trip targeting B. australis off the coast of Lebu Harbour (38°S) in August 2021, two specimens of other Bramidae species were also caught, but the fishermen did not identify them. The first corresponded to a sickle pomfret, Taractichthys steindachneri, the first record of the species in Chilean waters. The second specimen corresponded to the rough pomfret, Taractes asper, already reported from the Chilean coast, but with only one previous record from the eighties. We discussed how the occurrence of T. steindachneri and T. asper provide insights regarding the B. australis demography in the south Pacific.

ABSTRACT The conservation of threatened sharks requires defining the occurrence and distribution range of the species and key habitats for their survival. During surveys of mesophotic and deeper benthic habitats (50 to 340 m depth) off Rapa Nui (Easter Island, Chile, southeastern Pacific), using a remotely operated vehicle, a male bluntnose sixgill shark, Hexanchus griseus (Hexanchidae), was sighted. The estimated total length of this immature specimen was ∼146 cm. This is the first documented record of the species off Rapa Nui. The in situ evidence of this threatened deep-water shark highlights the urgency to build management strategies to protect vulnerable apex predators of coastal and deep-waters ecosystems of the recently created Rapa Nui Marine Protected Area for Multiple Uses, above all from the effects of fisheries and other human activities (e.g. bycatch, marine litter).

ABSTRACT The hapuku wreckfish Polyprion oxygeneios is recorded for the first time in Argentinian waters. Four specimens were caught off Mar del Plata (38°S, Argentina) in depths between 60 and 260 m during austral summer (three by sport fishers and one in a research cruise). Up to the present, this species was consistently misidentified with its congener, the common wreckfish P. americanus, off Argentina. These records represent a connection between previous records from Brazil and the more austral circumglobal distribution of the species.

ResumoForam avaliados os efeitos das diferentes variáveis ambientais na estrutura da comunidade de peixes em um pequeno estuário temperado. Dados biológicos e ambientais foram obtidos bimestralmente entre 2007 e 2009, ao longo do eixo principal do estuário. Análises multivariadas foram aplicadas (CLUSTER, SIMPER, CCA) para determinar a estrutura espacial da comunidade de peixes e para estimar a influência ambiental sobre ela. Um total de 48 espécies de "teleósteos" foi observado, com as famílias Characidae e Sciaenidae apresentando o maior número de espécies e sendo 90% das capturas formada por juvenis. A comunidade de peixes foi altamente dominada por uma só espécie (Micropogonias furnieri, 88,9%) e quatro espécies contribuiram com pouco mais de 1% cada para o total das capturas (Odontesthes argentinensis 5,4%, Brevoortia aurea 1,1%, Paralonchurus brasiliensis 1,1% e Mugil platanus1,0%). Retardatários estuarinos e de água doce dominaram em número de espécies, seguidos por migrantes de água doce e marinhos. Ao longo do eixo principal foram definidas três áreas distintas, cada uma apresentando assembleias de peixes com espécies e guildas funcionais distintas. A ocorrência e abrangência espacial dessas áreas estiveram ligadas à variação espacial na salinidade, que consistentemente foi influenciada pela descarga do Rio da Prata e pela precipitação local. Os resultados destacam a importância dos ambientes rasos como áreas de berçário e permitem enfatizar sua susceptibilidade às mudanças ambientais.

AbstractThe effects of different environmental variables on the fish community structure were evaluated in a small temperate estuary. The biological and environmental data were collected bimonthly between 2007 and 2009 along the main estuarine axis. Multivariate analyses were applied (CLUSTER, SIMPER, CCA) to determine the spatial structure of fish community and to estimate the environmental influence on it. A total of 48 species of "teleost" fishes were observed, with the families Characidae and Sciaenidae presenting the largest number of species, 90% of the catches being juveniles. The fish community was overwhelmingly dominated by one species (Micropogonias furnieri, 88.9%), and only four species contributed more than 1% of total catch (Odontesthes argentinensis5.4%, Brevoortia aurea 1.1%, Paralonchurus brasiliensis 1.1%, and Mugil platanus 1.0%). Estuarine and freshwater stragglers dominated in number of species, followed by freshwater migrants and marine migrants. Three areas with different fish assemblages, with distinctive species and functional guilds, were defined along the main axis. The occurrence and spatial spread of these areas were linked to spatial variation in salinity, which was consistently influenced by discharge from the Río de la Plata and local precipitation. The results highlight the importance of shallow environments as nursery areas and permit emphasis on their susceptibility to environmental changes.

We document the southern records of three species of tropical bony fishes along the coast of Buenos Aires Province, Argentina (CBAP, 36-38°S). Rachycentrum canadum, Elops saurus and Caulolatilus chrysops were caught by bottom-trawl commercial vessels. Records presented here significantly extend southward their latitudinal distribution from those previously reported. Using sea surface temperature satellite images we show a southward warm circulation event from Brazil as a putative factor to explain the occurrence of these bony fishes in the CBAP.

Se presentan tres nuevos registros de especies de peces óseos cuya distribución corresponde a aguas tropicales, capturados por buques pesqueros en la costa de la Provincia de Buenos Aires, Argentina (CPBA, 36°-38°S). Los ejemplares corresponden a las especies: Rachycentrum canadum, Elops saurus y Caulolatilus chrysops. Estos registros amplían significativamente el límite austral de su distribución. La presencia ocasional de estas especies está asociada al transporte de agua subtropical cálida proveniente de la plataforma continental brasilera. Esta hipótesis es probada mediante el análisis de imágenes satelitales de temperatura superficial del mar.

The Nile tilapia (Oreochromis niloticus) is a species widely cultivated worldwide. In recent decades it was an increasing development of fish farming of this species and the red variety in Argentina and Uruguay. From January to March 2010, four specimens of O. niloticus were captured in the south boundary of Samborombón Bay (S 36° 17´- W 56° 46´), which is the external sector of the Río de la Plata. Probably the collected specimens were released accidentally from hatcheries placed on the banks of aquatic environments in communication with the Samborombón Bay. The patterns and mechanisms of species dispersal are of significant interest, while the interactions among factors determining invasion success often remain poorly understood. Invasion success is influenced by the ability of invading specie to withstand, interactions with native species and oceanographic characteristics of the new habitat. Of four specimens obtained two were females, one in spawning stage. This is the first record of Nile tilapia from a natural environment in Argentina and could indicate the beginning of a new invasion by a non native species.

La Tilapia del Nilo (Oreochromis niloticus) es una especies cultivada en todo el mundo. En Argentina y Uruguay, la cría de tilapia ha tenido un incremento importante en las últimas décadas. Entre enero y marzo de 2010 fueron capturados cuatro ejemplares de O. niloticus en la Bahía de Samborombón (S 36º 17´- O 56º 46´), en el sector externo del Río de la Plata. Probablemente los ejemplares capturados puedan haber resultado de escapes accidentales de criaderos ubicados en ambientes en comunicación con el Río de la Plata. De los cuatro ejemplares capturados dos fueron hembras, una de ellas en etapa de desove. Este es el primer registro de Tilapia del Nilo en un ambiente natural en Argentina y podría indicar el comienzo de una invasión por una especie no nativa. Los patrones y los mecanismos de dispersión de especies son de gran interés, mientras que las interacciones entre los factores que determinan el éxito de la invasión a menudo, son poco interpretadas. El éxito de la invasión está influenciado por la capacidad de los invasores para resistir a las interacciones con especies nativas y con las características oceanográficas del nuevo hábitat, que en este caso parecerían no ser desfavorables para O. niloticus.

A male specimen of the giant manta ray, Manta birostris (Donndorff 1798), was founded at the Pando stream mouth, Uruguay (34° 48' S-55° 43' W). The disk width was 4.20 m and the total body weight was estimated in 900 kg. This finding, the first ever to be register on the coastal waters of Uruguay, extends the known distribution of the manta ray into the south-western Atlantic. The presence of this oceanic specie in estuarine waters is discussed

Se registró la presencia de un macho de la mantarraya Manta birostris (Donndorff 1798) en la desembocadura del arroyo Pando (34° 48' S-55° 43' O), Río de la Plata, Uruguay. El ancho del disco fue de 4.20 m con un peso estimado de 900 kg. Este hallazgo es el primer registro de M. birostris para las costas uruguayas y representa una ampliación, hacia el sur, del área de distribución de esta especie en el Océano Atlántico sudoccidental. Se discute, además, la ocurrencia de esta especie oceánica en aguas estuarinas