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Climate change impacts on fishery resources have been widely reported worldwide. Nevertheless, a knowledge gap remains for the warm-temperate Southwest Atlantic Ocean—a global warming hotspot that sustains important industrial and small-scale fisheries. By combining a trait-based framework and long-term landing records, we assessed species' sensitivity to climate change and potential changes in the distribution of important fishery resources (n = 28; i.e., bony fishes, chondrichthyans, crustaceans, and mollusks) in Southern Brazil, Uruguay, and the northern shelf of Argentina. Most species showed moderate or high sensitivity, with mollusks (e.g., sedentary bivalves and snails) being the group with the highest sensitivity, followed by chondrichthyans. Bony fishes showed low and moderate sensitivities, while crustacean sensitivities were species-specific. The stock and/or conservation status overall contributed the most to higher sensitivity. Between 1989 and 2019, species with low and moderate sensitivity dominated regional landings, regardless of the jurisdiction analyzed. A considerable fraction of these landings consisted of species scoring high or very high on an indicator for potential to change their current distribution. These results suggest that although the bulk of past landings were from relatively climate-resilient species, future catches and even entire benthic fisheries may be jeopardized because (1) some exploited species showed high or very high sensitivities and (2) the increase in the relative representation of landings in species whose distribution may change. This paper provides novel results and insights relevant for fisheries management from a region where the effects of climate change have been overlooked, and which lacks a coordinated governance system for climate-resilient fisheries. [ABSTRACT FROM AUTHOR]

The article presents a study which aims to determine the effects of freshwater discharge from Rio de la Plata and beach morphodynamics on the population and distribution of the mole crabs (Emirita brasiliensis) in sandy beaches of Uruguay. The study gathered different data from 16 beaches between July 1999 and April 2001, as well as samples from estuaries. Mole crab samples were collected by using a sheet metal cylinder, measured, weighed and were preserved in 5% buffered formalin. Results show that mole crabs are more abundant in dissipative beaches (areas where salinity is high and phytoplanktons are abundant) compared to the reflective beaches. It suggests that further studies be made to gain more understanding on the source-sink dynamics of sandy beaches.

The Rio de la Plata and the adjacent Atlantic Ocean are covered by the most significant amount of environmental cooperation in the Southwest Atlantic. There are joint agreements between Uruguay and Argentina and their institutions, and there is a long history of bi-national fisheries management and maritime traffic organizations. However, these agreements do not cover many other activity sectors that come under different jurisdictions and regulatory instruments. Documentary sources spanning 30 years have been used to describe the spatial extent and evolution of more than 30 activities (grouped into main clusters), as well overlaps and conflicts between them. The higher number and diversity of activities were found in the coastal zone, while fisheries and spatially-defined management measures were dominant in common waters and on the continental shelf. Transport/navigation and communication cables were the most common clusters along surface and sub-bottom linear routes, respectively. The different and overlapping use of the water column and across multiple jurisdictions were the cause of sectoral conflicts, such as between fisheries-transport or fisheries-submarine cables. Under a sector-by-sector analysis, and in the absence of a comprehensive planning environment, many of these conflicts are resolved, at best, by legal proceedings. There have been significant advances in the governance and spatial organisation of fisheries and transport, while progress in conservation and infrastructure has not occurred at the same speed or by considering a broader vision of the system. Addressing the existing and increasing interferences or unresolved conflicts emphasises the need to consolidate multilevel governance frameworks and opportunities in order to advance in marine spatial planning in the Southwest Atlantic Ocean. [Display omitted] • Long-term and spatial changes in the use of marine space are assessed in Uruguayan waters. • 34 activities were mapped, with higher number and diversity in the coastal zone than offshore. • Interferences and conflicts between activities were assessed by combining maps, conflict scores and regulations. • Overlaps and interferences were found in clusters Transport, Fisheries and Cables and pipelines. • Suggestions are made to develop multilevel marine spatial planning, including shared waters with Argentina. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the relationships between beach morphodynamics and macrofauna assemblages has been critical in theoretical evolution of sandy beach ecology. However, macroscale studies that consider the concurrent effects of large-scale estuarine and morphodynamic gradients have been exceptional. The present study evaluates the combined effects of large-scale (>400km) salinity and morphodynamics on the distribution of Excirolana armata. Along a salinity gradient (from 0.10 to 34.30) generated by the Río de la Plata estuary (SW Atlantic Ocean), sixteen Uruguayan sandy beaches were analyzed over a two-year period. A conditional two-step procedure using a General Additive Model (2-step GAM) was performed in order to model occurrence (1st-step) and abundance (2nd-step) of E. armata, in relation to salinity, grain size, sand moisture, compaction and organic matter of the sand, slope, beach and swash width, and water and sediment temperature. The 1st-step GAM retained 6 physical descriptors in the model (decreasing order): mean grain size, organic matter, salinity, beach width, sand moisture and water temperature. The 2nd-step GAM showed that mean grain size, salinity, sand moisture, beach width, sand compaction and organic matter were the most important explanatory variables (in decreasing order) of abundance. Mean grain size was the main predictor in both models, suggesting an important substrate specificity of E. armata towards smallest grain sizes. A meta-analysis concerning large-scale variation in abundance of E. armata in sandy beaches of the Rio Grande ecoregion (28°S–35°S) of the Warm-Temperate Southwestern Atlantic Province gave compelling evidence of this high-substrate specificity of the E. armata. Salinity was also a key factor shaping patterns in occurrence and abundance, which increased from low to intermediate/high salinities (>20), reinforcing the notion of E. armata as a marine species with relatively high tolerance to estuarine conditions. The potential role that internal brooding gives for protection of offspring to osmotic stress is discussed. [Copyright &y& Elsevier]