Este documento resume los temas tratados en la Quinta Sesión de la Asamblea de Naciones Unidas sobre el Medio Ambiente del Programa de Naciones Unidas para el Medio Ambiente que se desarrolló de forma virtual en febrero de 2021 con una agenda centrada en cuestiones administrativos y presupuestarios, habiéndose acordado la reanudación del quinto período de sesiones de la Asamblea en forma presencial en febrero de 2022 a fin de abordar los temas sustanciales de la agenda.

Marine mammal depredation on fisheries is a worldwide issue involving socio-economic and ecological consequences. The bottom longline fisheries directed to toothfish are among them, where Sperm and Killer whales star the depredation events. The SAGO Extreme System is an innovative technology developed to prevent this interaction. Based on the Autoline System and with the addition of the SAGO Extreme device and other accessories, this system implies mayor changes in the vessel and gear. On this paper the system, setting and hauling maneuvers implemented on the Uruguayan FV Ocean Azul are described. The performance of the Sago Extreme System is discussed and an intrinsic mitigation measure for preventing seabird incidental catch is presented. Marine mammal depredation on fisheries is a worldwide issue involving socio-economic and ecological consequences. The bottom longline fisheries directed to toothfish are among them, where Sperm and Killer whales star the depredation events. The SAGO Extreme System is an innovative technology developed to prevent this interaction. Based on the Autoline System and with the addition of the SAGO Extreme device and other accessories, this system implies mayor changes in the vessel and gear. On this paper the system, setting and hauling maneuvers implemented on the Uruguayan FV Ocean Azul are described. The performance of the Sago Extreme System is discussed and an intrinsic mitigation measure for preventing seabird incidental catch is presented.

The Gradual contraction of Antarctic krill fishery toward islands or concentration in some localized area has caused increased concerns. To examine the potential impact of the concentration of krill fishery, acoustic data and fishery statistics were analyzed to reveal the relationship between the actual fishing sites and the underlying krill distribution; sea ice concentration is also used to explain the movement of the krill fishery into the Bransfield Strait. The analyses demonstrated again that the krill distribution is highly patchy and dynamic; and that the contraction or concentration of the krill fishery were most likely to be a natural response of the fishery to the characteristics of Antarctic krill distribution as knowledge accumulates, and to the suitability of emerging fishing ground as sea ice concentration decreases. The analyses also showed that the krill fishery will only concentrated in areas in which there was ample krill resources, and the potential impact of the concentration of krill fishery need to be assessed against the highly patchy and dynamic nature of krill distribution, not merely by its presence. The results of the analyses further implied that when progressing the Risk Assessment Framework for allocating the Precautionary Catch Limit into smaller management units, the spatial size of the candidate management unit need to be large enough to accommodate the highly patchy and dynamic nature of krill distribution to avoid the potential to create inadvertent risks to the local krill stock or predators depending on it.

Otolith shape analysis has been often widely used for stock discrimination. Controversial results are concluded on geographical stocks between the Crozet Islands and the Kerguelen Islands, East Antarctic. In this study, six otolith shape indices (form factor, roundness, circularity, rectangularity, ellipticity, and aspect ratio) and elliptical Fourier coefficients were used to analyze the otoliths shape of Patagonian toothfish Dissostichus eleginoides (TOP) from those two regions to try to supplement the information about the stocks. Prior to analysis, the allometric effect of fish growth on the otolith morphology was examined. The principal component analysis (PCA) was used for analyzing the shape indices (SIs), the Ellipse Fourier coefficients (EFCs), and the combination of SIs and EFCs, and the success rate of classification is 51.00 %, 74.00 %, and 80.00 % for those three treatments, respectively. The overall otolith shapes of D. eleginoides from the Kerguelen Islands and the Crozet Islands are similar, although fine differences occur in the outer contours of otolith. Combined with the tagging and genetic data, the present study concluded that stock connectivity occurs for TOP between the Crozet Islands and the Kerguelen Islands. Multiple approaches, including otolith chemistry, may help elucidate the proportion and mechanism of exchange between two regions.