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The objectives of the present study were to characterize the benthic invertebrate communities at the Marine Protected Area (MPA) Namuncurá/Burdwood bank (created by the National Law 26875, year 2013) and their different sub-areas, to compare these benthic communities with nearby sub-areas, and to detect sites that meet the criteria of Vulnerable Marine Ecosystems (VMEs) to highlight the importance of this particular and rich sub-Antarctic region. We used quali- and quantitative data obtained from research cruises developed by Argentina in 2016 and 2017. The results showed that Porifera was the most important component (in terms of wet biomass) of these benthic communities, followed by Cnidaria and Echinodermata. The evidences regarding general composition of the main taxonomical groups of the benthic invertebrate community did not support the maintenance of the original zoning of the MPA (core, buffer, and transition), considering that only a weak differentiation was found among the sub-areas designed in the creation Law. Additionally, the analyzed evidences also demonstrated that this MPA was different from other neighboring areas. Vulnerable and fragile organisms recorded in many locations led to the detection of fourteen sites located inside the MPA Namuncurá that meet the characteristics of VMEs (wet biomass of ≥ 10 kg 1200 m−2 of vulnerable and fragile species). These evidences reinforce the conservation value of these particular and susceptible sub-Antarctic benthic communities, composed of both Antarctic and Magellanic species. [ABSTRACT FROM AUTHOR]

Eutrophication increases the biomass of opportunistic green macroalgae that covers intertidal zones, and macroalgal blooms may affect the intertidal invertebrate community and predation of invertebrates by shorebirds. In San Antonio Bay, Argentina, eutrophication from the discharge of wastewater from a coastal town produces periodic macroalgal blooms. Our aim was to assess if macroalgal blooms affect the foraging behaviour and diet of the American Oystercatcher (Haematopus palliatus). A macroalgal transplant experiment was performed in order to evaluate how epifaunal species respond to a macroalgal canopy. The availability of prey for Oystercatchers, and their foraging behaviour and diet, were analysed in two paired channels with different nutrient loadings. Oystercatchers generally ate the most profitable prey and avoided prey with a profitability value lower than the mean rate of energy intake. During the macroalgal blooms, Oystercatchers avoided two prey species with high profitability values, shifting their foraging strategy and feeding onto a suboptimal prey but with a high encounter rate. Our results suggest that nutrient loadings and the macroalgal blooms that they generate have effects on the diet and foraging behaviour of Oystercatchers, which results in an increase of the average rate of energy intake of Oystercatchers foraging along the channel subject to a macroalgal bloom. [ABSTRACT FROM AUTHOR]