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The eastern South Pacific humpback whale population winters primarily off Colombia and Ecuador, extending northward to the coasts of Panama and Costa Rica. It migrates south to the Fueguian Archipelago and Antarctic Peninsula waters for feeding during the austral summer. In recent years, however, humpback whales have also been observed feeding in the Corcovado Gulf, in the northern Chilean Patagonian channels, during the austral summer and fall. We examine photographically identified humpback whales in order to determine interchange or isolation of these aggregations. The apparent absence of movements of identified humpback whales among the 3 summering areas, and the differences in the proportion of white/black coloration on the fluke, suggest that each locality corresponds to a discrete feeding area for eastern South Pacific humpback whales.KEY WORDS: Humpback whale · Eastern South Pacific · Corcovado Gulf · Fueguian Archipelago · Southern Ocean · Feeding ground Resale or republication not permitted without written consent of the publisherEndang Species Res 22: 33-38, 2013 ado Gulf (43°53' S). Corcovado Gulf is located 1080 km north of the Magellan Strait, suggesting that this corresponds to another discrete feeding area for this population (Haro 2009, Hucke-Gaete et al. 2013). An alternative interpretation would be that the Corcovado Gulf may correspond to a transitory area during the whales' migration further south to the Fueguian Archipelago or the Antarctic Peninsula. Here we examine the relationship between photographically identified humpback whales in order to determine the degree of interchange or isolation among these 3 summer aggregations. Such information on possible sub-structuring of the population and stock identity is required to ensure appropriate use of capture-recapture models for reliable estimation of population size in the ESP, and to resolve central questions on one of the least understood humpback whale populations. MATERIALS AND METHODSIndividual humpback whales were identified from photographs, based on unique pigmentation patterns and/or permanent scars on the ventral side and marks on the trailing edge of the fluke (Katona et al. 1979). Only medium-to high-quality fluke photographs were used in the comparisons, based on focus, angle, clarity, contrast, and recognition (distinctive patterns, marks, or scars) (Mizroch et al. 1990, Friday et al. 2000. Six photo-identification catalogs were used, covering 3 relevant localities: Corcovado Gulf (CG), Fueguian Archipelago (FA), and Antarctic Peninsula (AP). In addition, some identified whales from Wide Channel (49°50' S) to Smyth Channel (52°44' S), north of Magellan Strait, were included as part of the FA region. The surveyed areas are described in Table 1 The only abundance estimate for this population on feeding grounds was obtained for the Bransfield Strait area, with a derived abundance of 865 individuals (95% CI = 656 to 1141). However, this represents only a fraction of the AP feeding unit (Secchi et al. 2011). Populati...

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Latitudinal preferences within the breeding range have been suggested for Breeding Stock G humpback whales that summer in different feeding areas of the eastern South Pacific. To address this hypothesis, humpback whales photo‐identified from the Antarctic Peninsula and the Fueguian Archipelago (southern Chile) were compared with whales photo‐identified from lower latitudes extending from northern Peru to Costa Rica. This comparison was performed over a time span that includes 18 austral seasons. A total of 238 whales identified from the Antarctic Peninsula and 25 whales from the Fueguian Archipelago were among those photo‐identified at the breeding grounds. Our findings showed that humpback whales from each feeding area were resighted unevenly across the breeding grounds, which suggests a degree of spatial structuring in the migratory pathway. Humpback whales that feed at the Antarctic Peninsula were more likely to migrate to the southern breeding range between northern Peru and Colombia, whereas whales that feed at the Fueguian Archipelago were more likely to be found in the northern range of the breeding ground off Panama. Further photo‐identification efforts and genetic sampling from poorly sampled or unsampled areas are recommended to confirm these reported connectivity patterns.

Se realizó un estudio poblacional sinóptico en poblaciones de Macrocystis pyrifera considerando distintos regímenes de exposición al oleaje en el Estrecho de Magallanes. Para un mejor manejo y análisis de la información obtenida, se utilizó el análisis SIG (Sistema de Información Geográfica). Los estudios se llevaron a cabo en Bahía Porvenir (53º 18' S; 70º 24' W), Tierra del Fuego. Los muestreos se realizaron en transectas perpendiculares a la línea de costa, utilizándose tres cuadrantes de 1 m 2 de área. Se estudiaron dos poblaciones, una localizada en una zona expuesta al oleaje y la otra en una zona protegida. Entre ambas poblaciones se compararon los siguientes parámetros biológicos: biomasa húmeda (kg m-2), densidad de estipes m 2 , porcentaje de individuos juveniles y adultos, y longitud de los individuos (m). La población situada al interior de la bahía presentó mayores valores de biomasa (p< 0,037), pero de igual forma una gran variabilidad entre individuos, marcándose diferencia dentro de una misma población, situación que no se observó en la población expuesta (p> 0,995), donde existió una uniformidad de relación a la biomasa por m 2. La utilización de SIG en estudios de esta naturaleza facilita la visualización, monitoreo y análisis de la distribución de las poblaciones, en contraste con los métodos utilizados convencionalmente en estudios de campo.

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