1. Since 2000, an increasing number of humpback whale sightings have been recorded in northern Chilean Patagonia (mostly between 41.5 S and 44 S) from dedicated aerial and marine surveys and also opportunistic and land-based platforms during austral summer and autumn months.2. Based on local knowledge from the early years of coastal whaling suggesting the historic presence of humpback whales in the area, and more recent observations confirming feeding groups, mother-calf pairs, and philopatry, it is proposed that a proportion of the eastern South Pacific humpback whales consistently use the Chiloe-Corcovado region to feed and nurse their young.3. This mid-latitude area could be regarded as the northernmost feeding ground for humpback whales in South America, extending the previous known range some 1300 km north.4. These findings provide further evidence for alternative life-strategies other than traditional migration and highlight the importance of northern Patagonian fjords to resolve questions that are central for large baleen whale conservation and management such as the extent and characteristics of spatio-temporal habitat use and overlap with human activities.5. The need for future research on the migratory movements and population structure of this poorly understood population of humpback whales is emphasized, while an account is given of the threats they currently face.

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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...

A combination of stomach content and nitrogen (δ 15 N) and carbon (δ 13 C) stable-isotope analysis was used to assess the trophic interactions and feeding habits of three notothenioid coastal fish (Champsocephalus esox, Patagonotothen tessellata and Patagonotothen cornucola) and one exotic salmon species (Oncorhynchus tschawytscha) with diverse life habits (benthic and benthopelagic) in the Francisco Coloane Coastal Marine Protected Area, southern Chile. The stomach contents of C. esox were mainly fish; those of P. cornucola and O. tschawytscha were crustacean decapods, Munida gregaria. A cluster analysis on isotope data and stable-isotope Bayesian ellipses detected two different predator groups, one with benthopelagic habits (C. esox and O. tshawytscha) and one with benthic habits (P. cornucola and P. tessellata). These results were supported with similar isotopic trophic level of each group. We suggest that the exotic salmon O. tschawytscha is a generalist predator with a broad trophic niche that may compete with the native notothenioid C. esox, as both have equivalent trophic levels with substantial overlap. This preliminary study is the first on trophic relationships of a subtidal fish assemblage within a remote ecosystem of fjords and channels in Chile's southern Patagonia.

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The contribution of prey species to the diet and their variation over time are poorly understood processes in the trophic ecology of Southeast Pacific humpback whales (Megaptera novaeangliae). The purpose of this study was to use carbon and nitrogen stable isotopes to provide insights into the trophic ecology and to determine the inter-annual variation of the diet of the humpback whales in the Magellan Strait. During 2011 and 2012, an analysis was carried out to determine the isotopic composition of humpback whale skin. We used a Bayesian isotope mixing model to determine the relative contribution of prey species to the isotopic value of the consumer. The humpback whale had mean values of-16.3 +/- 0.6%c in delta C-13 and 14.7 +/- 1.0 parts per thousand in delta N-15 (n = 33). The delta C-13 and delta C-13 in both the whales and the Fuegian sprat (Spratrus fueguensis) were significantly higher in 2011 compared to 2012. Additionally, females had significantly higher delta N-15 values in 2012; however, mean delta C-13 and delta N-15 values of whales within each season and between age classes did not differ statistically. A variation was observed in the contribution of different prey to the whale diet between the study years, with Fuegian sprat as the predominant prey during 2011 (mean 55 +/- 12%), and crustaceans dominating the diet in 2012 (mean 82 +/- 9%). This study confirms the diet of the humpback-whale within the Magellan Strait. Furthermore, isotopic analyses suggest important inter-annual changes due to (1) changes in the proportion of the species being consumed, probably due to variations in availability (e.g., abundance) of prey; and/or (2) annual isotopic changes at the base of the food web. Further studies are required on the population dynamics of prey in order to monitor annual changes in abundance and food supply.National Commission for Scientific and Technological Research (CONICYT) Chilean Antarctic Institute (INACH) CEQUA Foundation Foundation BIOMA

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