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The franciscana dolphin (Pontoporia blainvillei) is the most threatened small cetacean in the southwestern Atlantic Ocean. Its incidental capture in the Uruguayan fisheries of the Atlantic oceanic coast (AOC) has been recorded since 1940 and was systematically studied from 1974 to 1994, providing the most recent by-catch per unit of effort estimate (BPUE) for the AOC region (0.0064 franciscanas per 1000m net per fishing set). The lack of new by-catch data during the past 12 years has led to a data gap in by-catch estimates for the species in Uruguay. The current study was developed in two separate stages, a first stage (July 2004 -December 2005 designed to identify fisheries that interact with franciscana, and a second stage (2006), designed to determine new BPUE and franciscana mortality estimates for the selected fisheries. During the first stage, 13 artisanal fisheries of the Uruguayan coast were visited monthly, while in the second stage five fisheries (including the Rio de la Plata estuary and the AOC) were selected for monitoring. During 2006, 26 fishermen recorded all the information related to each fishing event, allowing the estimation of fishing effort calculated in linear units multiplied by hour (FE L ). We also estimated a fishing set (FE S ) based by-catch rate which allowed the comparison with previously reported results. For 2006, the BPUE L (based on FE L ) was estimated at 0.0020 franciscanas per 1000m net per hour and the BPUE S at 0.0286 franciscanas per 1000m net per fishing set. The BPUE L was extrapolated to the surveyed fishing fleets during 2006, resulting in a mortality estimate of 289 (95% CI: 266-350) franciscanas. Based on the fishing dynamics reported herein, we consider the BPUE L the most accurate estimate of by-catch for the Uruguayan coast. This research updates the values of BPUE in the AOC after a 12-year information gap and includes the first by-catch evaluation in the Uruguayan estuarine coast. We highly recommend an abundance estimation of the species to complement the information reported herein in order to know the current status of franciscana dolphin population in Uruguay.RESUMEN: El delfín franciscana (Pontoporia blainvillei) es el pequeño cetáceo más amenazado de Atlántico Sudoccidental. La captura incidental de franciscanas en las pesquerías uruguayas de la costa del Océano Atlántico (AOC) ha sido registrada desde 1940 y relevada sistemáticamente entre 1974 y 1994; brindando el último valor de Captura Por Unidad de Esfuerzo (BPUE) en la AOC uruguaya (0,0064 franciscanas por1000m de red por lance). La ausencia de nuevos valores de BPUE durante 12 años produjo una carencia de datos sobre la captura incidental de la especie en Uruguay. El presente estudio fue realizado en dos períodos, el primero (Julio 2004-Diciembre 2005) con el objetivo de identificar las pesquerías que interactuaban con la franciscana, y el segundo período (año 2006) para determinar la BPUE y mortalidad de la franciscana en las pesquerías seleccionadas. En el primer período se visitaron mensualmente ...

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Killer whale (Orcinus orca) is frequently encountered in coastal and high productive pelagic waters, near the shelf break. In the south-western Atlantic Ocean, spatial and temporal occurrence patterns are poorly known. However, the monitoring of the interaction between killer whales and longline fishery suggests that the species is frequent in this region. We analysed the killer whale presence within the Uruguayan pelagic longline fishing zone. Data were collected from 1996 to 2007, during 2189 fishing events, by vessel skippers and on-board observers. We estimated the sighting rate (SR = sightings days/fishing days * 100) for different time scales and in 1 × 1 degree grids. Generalized linear models were used to evaluate the effect of spatial, temporal, environmental and operational variables on the species presence. Killer whales were sighted in 100 fishing days (SR = 4.5%), this occurrence being explained by distance from shore and sea surface temperature, varying among months and fishing boats. Although sightings occurred year round, they were more frequent in autumn and winter, at 150–400 nautical miles (nm) from shore (mean = 250 nm) and in waters with temperatures ranging from 19 to 24°C (mean = 22°C). Sets took place between 19°–40°S and 21°–54°W, while killer whales occurred mostly from 34°–37°S and 48°–53°W. In this region, the high productive Brazil—Malvinas Confluence Zone is located, and concentrates fishing effort and also killer whales.

ABSTRACT. 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 furnieri, 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.