Fish assemblage in a temperate estuary on the uruguayan coast: seasonal variation and environmental influence

Foi estudado a dinâmica sazonal da comunidade de peixes em relação as variáveis ambientais do estuário Pando, localizado na costa uruguaia. Os peixes foram amostrados mensalmente entre maio de 2002 e junho de 2003. Os indivíduos coletados foram identificados e classificados em estágios (jovens, adultos) e grupos funcionais. Relações entre a dinâmica da comunidade e as variáveis ambientais foram avaliadas utilizando-se técnicas uni- e multivariada. Vinte e uma espécies foram coletadas, principalmente visitantes de água doce, estuarinas e marinhas migratórias, sendo as mais abundantes e representadas por juvenis: Micropogonias furnieri, Mugil platanus, Paralichthys orbignyanus e Brevoortia aurea. A comunidade variou sazonalmente com rápidas mudanças na primavera e no outono, associadas à variações de temperatura e salinidade. Correlações significativas entre abundância e temperatura parecem estar relacionadas com a sincronizaçao de eventos dos ciclos de vida. Neste estuário a salinidade parece desempenhar um papel-chave na estrutura funcional e uso do habitat por juvenis. Este fato é relevante para a definição dos estuários como áreas de criadouro e pela influencia da salinidade sobre o ciclo da ictiofauna local.The seasonal dynamics of the fish community in the Pando estuary on the Uruguayan coast were studied in relation to environmental sampled monthly between May 2002 and June 2003. Individuals collected were identified, and classified into stages (juveniles, adults) and functional groups. Relationships between community dynamics and environmental variables were evaluated using uni- and multivariate techniques. Twenty-one species, mostly freshwater stragglers, estuarine and marine migrants were collected. The most abundant species were Micropogonias furnieri, Mugil platanus, Paralichthys orbignyanus and Brevoortia aurea and were represented by juveniles. The community varied seasonally with rapid shifts in spring and autumn associated with changes in temperature and salinity. Significant correlations between abundance and temperature may be related to the timing of life cycle events. In this estuary, the salinity appears to play a key role in the functional structure and in the use of the habitat by juveniles. This is relevant for the definition of estuaries as nursery areas: this definition is context-dependent and is determined by the salinity conditions

High site fidelity and restricted ranging patterns in southern Australian bottlenose dolphins

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Information on site fidelity and ranging patterns of wild animals is critical to understand how they use their environment and guide conservation and management strategies. Delphinids show a wide variety of site fidelity and ranging patterns. Between September 2013 and October 2015, we used boat‐based surveys, photographic identification, biopsy sampling, clustering analysis, and geographic information systems to determine the site‐fidelity patterns and representative ranges of southern Australian bottlenose dolphins (Tursiops cf. australis) inhabiting the inner area of Coffin Bay, a highly productive inverse estuary located within Thorny Passage Marine Park, South Australia. Agglomerative hierarchical clustering (AHC) of individuals’ site‐fidelity index and sighting rates indicated that the majority of dolphins within the inner area of Coffin Bay are “regular residents” (n = 125), followed by “occasional residents” (n = 28), and “occasional visitors” (n = 26). The low standard distance deviation indicated that resident dolphins remained close to their main center of use (range = 0.7–4.7 km, X ± SD = 2.3 ± 0.9 km). Representative ranges of resident dolphins were small (range = 3.9–33.5 km2, X ± SD = 15.2 ± 6.8 km2), with no significant differences between males and females (Kruskal–Wallis, χ2 = 0.426, p = .808). The representative range of 56% of the resident dolphins was restricted to a particular bay within the study area. The strong site fidelity and restricted ranging patterns among individuals could be linked to the high population density of this species in the inner area of Coffin Bay, coupled with differences in social structure and feeding habits. Our results emphasize the importance of productive habitats as a major factor driving site fidelity and restricted movement patterns in highly mobile marine mammals and the high conservation value of the inner area of Coffin Bay for southern Australian bottlenose dolphins

Marine mammal bycatch by the industrial bottom trawl fishery at the Río de la Plata Estuary and the adjacent Atlantic Ocean

Fisheries interactions with non-target marine vertebrates are a worldwide problem. The impact of coastal bottom trawl fisheries on marine mammals has never been evaluated before in the Río de la Plata Estuary and the adjacent Atlantic Ocean. Our aim was estimating the bycatch per unit effort (BcPUE) and incidental mortality rates of marine mammals caused by the industrial coastal bottom trawl fisheries fleet. We evaluated the mortality of three species (i.e., franciscana dolphin Pontoporia blainvillei, South American sea lion Otaria flavescens, and the South American fur seal Arctocephalus australis); these species are facing conservation problems either at the regional or local scale. We conducted an onboard data collection program of marine mammals' bycatch involving crew members of 10 vessels (30%) of the Uruguayan coastal bottom trawl fleet between January 2009 and April 2012. A total of 102 marine mammal individuals were bycaught during 490 fishing trips involving 2,398 fishing days. Mortalities estimated for franciscana dolphin were the highest among the species affected, with values adding up to ~100 individuals for year (with scenarios of population decline in the area), followed by South American sea lion with ~77 individuals by year (0.8% of local population) and the South American fur seal with an annual mortality estimate of ~25 individuals (~0.02% of local population). BcPUE showed significant temporal variation, with franciscana dolphin BcPUE varying seasonally and those of otariids according to their breeding season. Our estimates of marine mammal bycatch by bottom trawl fisheries should constitute an important input for the sustainable management of fisheries and the conservation of marine biodiversity in the southwestern Atlantic Ocean.Fil: Franco Trecu, Valentina. Universidad de la República; UruguayFil: Szephegyi, María Nube. Universidad de la Republica; UruguayFil: Doño, Florencia. Universidad de la Republica; UruguayFil: Forselledo, Rodrigo. Universidad de la Republica; UruguayFil: Reyes, Federico. Universidad de la Republica; UruguayFil: Passadore, Cecilia. Universidad de la Republica; Uruguay. Flinders University; AustraliaFil: Crespo, Enrique Alberto. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Inchausti, Pablo. Universidad de la República; Urugua

Marine mammal bycatch by the industrial bottom trawl fishery at the Río de la Plata Estuary and the adjacent Atlantic Ocean.

Fisheries interactions with non-target marine vertebrates are a worldwide problem. The impact of coastal bottom trawl fisheries on marine mammals has never been evaluated before in the Río de la Plata Estuary and the adjacent Atlantic Ocean. Our aim was estimating the bycatch per unit effort (BcPUE) and incidental mortality rates of marine mammals caused by the industrial coastal bottom trawl fisheries fleet. We evaluated the mortality of three species (i.e., franciscana dolphin Pontoporia blainvillei, South American sea lion Otaria flavescens, and the South American fur seal Arctocephalus australis); these species are facing conservation problems either at the regional or local scale. We conducted an onboard data collection program of marine mammals’ bycatch involving crew members of 10 vessels (30%) of the Uruguayan coastal bottom trawl fleet between January 2009 and April 2012. A total of 102 marine mammal individuals were bycaught during 490 fishing trips involving 2,398 fishing days. Mortalities estimated for franciscana dolphin were the highest among the species affected, with values adding up to ~100 individuals for year (with scenarios of population decline in the area), followed by South American sea lion with ~77 individuals by year (0.8% of local population) and the South American fur seal with an annual mortality estimate of ~25 individuals (~0.02% of local population). BcPUE showed significant temporal variation, with franciscana dolphin BcPUE varying seasonally and those of otariids according to their breeding season. Our estimates of marine mammal bycatch by bottom trawl fisheries should constitute an important input for the sustainable management of fisheries and the conservation of marine biodiversity in the southwestern Atlantic Ocean

Hacia un monitoreo continuo de variables oceanográficas en el Parque Nacional Isla de Flores, Uruguay

Las mediciones continuas de variables ambientales en zonas costeras son fundamentales para comprender la compleja dinámica de los procesos oceanográficos y atmosféricos, así como mejorar la comprensión del medio marino para fines operativos y de conservación que se puedan integrar en un proceso de planificación espacial marina. En Uruguay se han llevado adelante distintos esfuerzos para la generación de este tipo de información in situ, pero en su mayoría no lograron mantenerse en el tiempo, principalmente por los altos costos operativos y de mantenimiento de sensores específicos. En este trabajo se presentan los resultados preliminares de más de un año de mediciones continuas de temperatura y salinidad en el Río de la Plata, obtenidos a partir de soluciones de bajo costo y un fuerte trabajo de coordinación multiinstitucional entre la academia y organismos del Estado. Las mediciones fueron obtenidas a partir de la instalación de sensores DST-CTD en el Parque Nacional Isla de Flores, un sitio clave para el muestreo de la zona exterior del Río de la Plata. Se destaca el valor de contar con este tipo de información, y se discute la importancia y complejidad de la implementación de un sistema de monitoreo continuo a largo plazo

Rumo ao monitoramento contínuo de variáveis oceanográficas no Parque Nacional Ilha de Flores, Uruguay

Continuous measurements of environmental conditions in coastal zones are key to understanding oceanographic and atmospheric processes, as well as improving our understanding of the marine environment for operational and conservation purposes that can be integrated into a marine spatial planning process. Several efforts have been made in Uruguay in order to achieve these goals, but they have not sustained over time due to high operative and maintenance costs of specific sensors. This work presents the first results of more than a year of continuous measurements of temperature and salinity in the Río de la Plata obtained using a low cost solution and through a high-commitment multi-institutional teamwork between the academy and state agencies. Measurements were obtained with a DST-CTD sensor installed in Flores Island National Park, a key sampling point for the external zone of Río de la Plata. The relevance of having this type of information is presented and the need for the implementation of a continuous long-term monitoring system is discussed.Las mediciones continuas de variables ambientales en zonas costeras son fundamentales para comprender la compleja dinámica de los procesos oceanográficos y atmosféricos, así como mejorar nuestra comprensión del medio marino para fines operativos y de conservación que se puedan integrar en un proceso de planificación espacial marina. En Uruguay se han llevado adelante distintos esfuerzos para la generación de este tipo de información in situ, pero en su mayoría no lograron mantenerse en el tiempo, principalmente por los altos costos operativos y de mantenimiento de sensores específicos. En este trabajo se presentan los resultados preliminares de más de un año de mediciones continuas de temperatura y salinidad en el Río de la Plata, obtenidos a partir de soluciones de bajo costo y un fuerte trabajo de coordinación multiinstitucional entre la academia y organismos del Estado. Las mediciones fueron obtenidas a partir de la instalación de sensores DST-CTD en el Parque Nacional Isla de Flores, un sitio clave para el muestreo de la zona exterior del Río de la Plata. Se destaca el valor de contar con este tipo de información, y se discute la importancia y complejidad de la implementación de un sistema de monitoreo continuo a largo plazo.Medições contínuas de variáveis ​​ambientais nas áreas costeiras são essenciais para entender a complexidade na dinâmica dos processos oceanográficos e atmosféricos, e para melhorar nossa compreensão do ambiente marinho para fins operacionais e de conservação que podem ser integrados num processo de planejamento espacial marinho. No Uruguai, diferentes esforços foram feitos para gerar esse tipo de informação in situ, mas a maioria não pôde ser conservada ao longo do tempo, principalmente devido aos altos custos operacionais e de manutenção de sensores específicos. Este trabalho apresenta os resultados preliminares de mais de um ano de medições contínuas de temperatura e salinidade no Rio de la Plata, as quais foram obtidas a partir de soluções de baixo custo e um forte trabalho de coordenação multi-institucional entre a academia e as agências estaduais. As medidas foram obtidas com sensores DST-CTD instalados no Parque Nacional Isla de Flores, uma importante locação para amostragem da área externa do Rio de la Plata. O valor de ter esse tipo de informação é destacado e discute-se a importância e a complexidade da implementação de um sistema de monitoramento contínuo de longo prazo

Photo-identification and satellite telemetry connect southern right whales from South Georgia Island (Islas Georgias del Sur) with multiple feeding and calving grounds in the southwest Atlantic

The sub-Antarctic waters of South Georgia Island (Islas Georgias del Sur, SG/IG) are a regularly visited feeding ground for southern right whales (Eubalaena australis, SRW) in the southwest Atlantic. Satellite telemetry and photo-identification records were compared to better understand the role of SG/IG in the SRW migratory network. We present the first insights from SRW satellite-tracked from the SG/IG feeding ground, habitat use patterns in the Scotia Arc, and movements to Antarctic habitats. Photo-identification comparisons to calving and feeding areas across the South Atlantic and a review of sightings of cetaceans reported from Bird Island (west of SG/IG) since 1979 illuminate long-term habitat use patterns in SG/IG. We present the first recorded migratory movement between SG/IG and multiple countries: Argentina, Uruguay, and Brazil. Photo-identification (1) linked SG/IG to a female SRW with a long-term sighting history in Brazil, and (2) provided the first match between SG/IG and the western Antarctic Peninsula, suggesting the latter could extend the feeding area for southwest Atlantic SRW. Satellite tracking and opportunistic sightings suggest that shelf and coastal waters west of SG/IG represent an important multi-season SRW feeding habitat and add to our overall understanding of habitats and ranges occupied by recovering southwest Atlantic SRW

Data from: Genetic relatedness delineates the social structure of southern Australian bottlenose dolphins

Social relationships represent an adaptive behavioural strategy that can provide fitness benefits to individuals. Within mammalian societies, delphinids are known to form diverse grouping patterns and show a variety of social systems. However, how ecological and intrinsic factors have shaped the evolution of such diverse societies is still not well understood. In this study we used photo-identification data and biopsy samples collected between March 2013 and October 2015 in Coffin Bay, a heterogeneous environment in South Australia, to investigate the social structure of southern Australian bottlenose dolphins (Tursiops cf. australis). Based on data from 657 groups of dolphins we used generalized affiliation indices, and applied social network and modularity methods to study affiliation patterns among individuals and investigate the potential presence of social communities within the population. In addition, we investigated genetic relatedness and kinship relationships within and between the communities identified. Modularity analysis revealed that the Coffin Bay population is structured into two similar sized, mixed-sex communities which differed in ranging patterns, affiliation levels and network metrics. Lagged association rates also indicated that non-random affiliations persisted over the study period. The genetic analyses suggested that there was higher relatedness, and a higher proportion of inferred full-sibs and half-sibs, within than between communities. We propose that differences in environmental conditions between the bays and kinship relationships are important factors contributing to the delineation and maintenance of this social structure

Fishing strategies and spatial dynamics of artisanal fisheries in the Uruguayan Atlantic coast

Artisanal fisheries in Uruguay involve directly or indirectly more than 5000 people and constitute the main source of income in several coastal communities. However, and despite its economic and environmental importance, this activity is poorly documented. As such, this scarcity of information constrains the understanding and effective management of artisanal fisheries. This study aims to characterize different strategies of marine artisanal fisheries on the Uruguayan Atlantic coast and describe the spatial distribution of fishing effort. Based on a Principal Components Analysis we identified four fishing strategies targeting different species (mainly whitemouth croaker Micropogonias furniert, narrownose smooth-hound shark Mustelus spp., angel shark Squatina spp. and Brazilian codling Urophycis brasiliensis), exhibiting different seasonal patterns and fishing gear usage. Finally, the above outlined strategies showed differences in spatial utilization of the fishing area. Our results provide a spatially explicit framework for the management of Uruguayan marine artisanal fisheries