CCAMLR

Durante CCAMLR-39, los Miembros de la Comisión discutieron la implementación del objetivo de la Convención, bajo el punto 8 de la agenda. La Comisión acordó establecer un grupo web para facilitar la discusión dirigida al fortalecimiento del objetivo de la Convención para allanar el camino hacia la celebración de la cuadragésima reunión de la Comisión, en la que la Comisión envíe una clara señal de unidad y cooperación para cumplir con sus obligaciones de conservación de los recursos vivos marinos antárticos. El grupo web se reunió por primera vez en febrero de 2021, con el objetivo de sostener un diálogo estratégico inclusivo con miras a determinar si la organización, en su conjunto, está haciendo todos los esfuerzos posibles por cumplir con el objetivo de la Convención y por afianzar su papel dentro del Sistema del Tratado Antártico. Estas discusiones contaron con la participación de nueve Miembros de la Comisión, a saber, Argentina, Australia, Chile, Estados Unidos, Japón, Noruega, Nueva Zelandia, Reino Unido y la Unión Europea.

Desde 2005, la captura total de kril antártico en la Subárea 48 ha ido creciendo constantemente, si bien permanece por debajo del nivel crítico de la captura de 620 000 toneladas. El análisis de los datos de la captura muestra que la intensidad de la pesca de kril aumentaba ligeramente mientras se usaban arrastres tradicionales (convencionales) (la captura de kril mediante arrastres convencionales en 2019 fue un 46 % superior a la de 2008). Sin embargo, ese aumento fue mucho más significativo con la utilización del sistema de pesca continua (la captura de kril mediante sistemas de pesca continua en 2019 fue un 460 % de la de 2008).

Tomando en cuenta la expansión progresiva del sistema de pesca continua en el Área de la CCRVMA, que puede considerarse un factor importante de posible degradación de la pesquería de kril realizada mediante arrastres tradicionales (convencionales), se propone implementar en la Medida de Conservación 51-07 un límite a las extracciones mediante el sistema de pesca continua en el Área 48, de manera que los barcos que utilicen el sistema de pesca continua puedan extraer solo un máximo del 70 % del límite de captura permisible de kril.

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.

The otolith morphology of fish species varies ontogenetically. In this study, 120 otoliths collected from the Ross Sea, the Amundsen Sea, the Weddell Sea, and the Lazarev Sea were used to analyze the morphological differences in otolith of Antarctic toothfish (Dissostichus mawsoni, TOA) across life stages by conventional measurement analysis, elliptical Fourier analysis and landmark method. The results showed that there were differences ontogenetically in otolith morphology. The shape of otolith changes from smooth and low complexity to intricate and high complexity, and the growth rate of otolith along the longitudinal axis is lower than that along the transverse axis. The characteristic parts, such as antirostrum, change significantly across life stages. Linear discriminant analysis showed the highest correct rate of classification is 85.417% from elliptical Fourier analysis, and followed by 79.167% from landmark method and 71.875% from geometric morphometrics, respectively.