Jorge Acevedo

Leucistic South American sea lion in Chile, with a review of anomalously color in otariids

Las coloraciones anormales en los mamiferos marinos ocurren en muy baja frecuencia. Estas coloraciones atipicas son clasificadas como albinismo, melanismo y leucismo, siendo esta ultima coloracion registrada con mas frecuencia en Arctocephalus gazella. En este articulo se documenta el primer caso de leucismo en un ejemplar de Otaria flavescens observado en la zona austral de Chile, asi como de una actualizacion de coloraciones atipicas informadas en otaridos.

Rare piebald and partially leucistic Antarctic fur seals, Arctocephalus gazella, at Cape Shirreff, Livingston Island, Antarctica

We document five cases of unusual colouration in Antarctic fur seals, Arctocephalus gazella, at Cape Shirreff, Livingston Island, from 1991–1992 to 2005–2006 austral summer seasons. This is the first time that these colour patterns have been reported for this species. These included four rare light coloured animals and one piebald individual. The incidence of this atypical colouring was low and the lack of resightings in previous and subsequent seasons suggests that these morphs are not common in Antarctic fur seals. Although the causes of these atypical light colour patterns are uncertain the subject is interesting for study and more observations on these atypical colourations are required for a proper assessment of the ecological and physiological implications of this condition in otariids can be conducted in the future.

Filopatría de la ballena jorobada (Megaptera novaeangliae Borowski, 1781), al área de alimentación del estrecho de Magallanes

Humpback whales migrate annually between high latitude feeding grounds and low latitude breeding grounds, exhibiting a marked degree of fidelity to migratory destinations. Southeastern Pacific humpback whales migrate between the reproductive area located principally off Ecuador and Colombia and the feeding area located around the Antarctic Peninsula. Previous studies suggested a second feeding area for this population in the Magellan Strait. This study evaluates the site fidelity of humpback whales to the Magellan Strait feeding area using photo-identification data obtained during 10 sighting cruises carried out in three austral summer seasons (2002-2003 to 2004-2005). If the Magellan Strait is a second feeding area for some whales of this population, a high return rate of the same animals photo- identified to this area than by chance would be expected. The site fidelity of humpback whales in different austral summer seasons shown a high return rate ( =78.9%). Furthermore no significant differences were found in the return rate between female and males or between different class/age categories. Finally, the high return rate humpback whale, indicate that Magellan Strait is another feeding ground at least for a part of the Southeastern Pacific humpback whales population.

Vagrant Antarctic fur seals, Arctocephalus gazella, in southern Chile

The Antarctic fur seal, Arctocephalus gazella, in the eastern South Pacific Ocean, first reported on Hoste Island, Cape Horn in 1973, and then on the Juan Fernandez Archipelago in 1982 and 1983, was recorded again in October and December 2009 on the southern coast of Chile. Three different individuals were seen simultaneously on a single day at Punta Dungenes, Magellan Strait, and a fourth individual was sighted at the northeastern coast of Almirantazgo Sound, Tierra del Fuego. These records represent the first sightings of live Arctocephalus gazella in southern Chile. Although it is difficult to establish both their origin and rationale for dispersion outside of their distribution range, the substantial breeding population recovery in South Georgia and food shortages during the breeding and post-breeding season are suggested as possible explanations.

Albino Weddell seal at Cape Shirreff, Livingston Island, Antarctica

To our knowledge, this paper is the first record/report of a juvenile light-coloured Weddell seal (Leptonychotes weddellii) at Cape Shirreff, Livingston Island in January 1998, determining that it was an albino individual. Based on available literature, three cases of albino seals have been reported exclusively for Harbour seal pups, and no albino has been reported for Antarctic pagophilic true seals. Therefore, this is the first confirmed case of albinism in Antarctic pagophilic true seals species, indicating that this phenomenon is indeed of a rare occurrence.

Southernmost Distribution of Common Bottlenose Dolphins (Tursiops truncatus) in the Eastern South Pacific

The common bottlenose dolphin (Tursiops truncatus) is a cosmopolitan species that does not range to latitudes greater than 45o in either hemisphere, with a few exceptions. In South American waters, this species is generally distributed in the Atlantic Ocean south to Chubut province (ca. 46o S), while in the eastern South Pacific this species has been recorded in northern and central Chile, with a few records south to 40o S. Here we summarize recent records of common bottlenose dolphins obtained during systematic marine mammal surveys in the Chilean Patagonian and Fuegian channels and fjords (the Los Lagos, Aysén, and Magallanes regions of Chile). These data suggest an extension of the documented range of the species southwards, indicating that bottlenose dolphins may have colonized new areas in the eastern South Pacific or as the result of an increase in survey efforts by scientists in the region.

Population genetic structure of the South American Bryde's whale

A genetic analysis based on mitochondrial DNA control region sequences was conducted to investigate both species identity and populations genetic structure of South American Brydes whales. The genetic analysis was based on historical, biopsy and stranding samples from Chile (n= 10) and Brazil (n= 8). For comparative purposes published sequences of the Brydes whales from different localities of the Indian and Pacific Oceans (including Peru, n= 24) were incorporated into the analysis. Results of the phylogenetic analysis identified the Brydes whales of South Ameri ca as Balaenoptera brydei. No statistically significant genetic differentiation was found between Chilean and Peruvian Brydes whales. However, striking differences were found between western South Atlantic (Brazil) and eastern South Pacific (Peru and Chile) animals. In addition, striking genetic differences were found between all South American localities and those from the western North Pacific, Fiji and Java. These results suggest movement of B. brydei in the eastern South Pacific in the latitudinal range corresponding to Chile and Peru. These results also suggest no or very limited mov ement of whales between the South Pacific and the South Atlantic Oceans. This is consistent with the notion that B. brydei is not distributed further south of approximately 40oS on both sides of South America.

Trophic Ecology of Humpback Whales (Megaptera novaeangliae) in the Magellan Strait as Indicated by Carbon and Nitrogen Stable Isotopes

National Commission for Scientific and Technological Research (CONICYT) Chilean Antarctic Institute (INACH) CEQUA Foundation Foundation BIOMAR

CARACTERÍSTICAS OCEANOGRÁFICAS Y BIOLÓGICAS DE LAS COMUNIDADES DEL PLANCTON Y NECTON DEL ÁREA MARINA COSTERA PROTEGIDA FRANCISCO COLOANE: UNA REVISIÓN

The objective of this study was to make a review of the current state of knowledge on the Coastal Marine Protected Area (CMPA) Francisco Coloane in terms of the physical and chemical oceanography, the phyto-zooplankton compositions and the fish, birds and marine mammals species present, and provide temperature and salinity data collected during a marine survey carried out the 2012 fall season. Surface temperatures fluctuate between 2.0 and 9.0°C. Salinity varies between 23 and 30.9 PSU. The most oxygenated waters and those of highest pH were recorded within Seno Ballena (320-340 µmoles Kg -1 ; 8.11 units of pH). In spring nutrient levels indicate low surface concentrations, except for phosphate, the phytoplankton is dominated by diatoms and the zooplankton is composed of copepods and meroplanktonic larvae with high abundance levels in the Jeronimo Channel. The family of fish most representative is the Nototheniidae, and among marine birds and mammals, the Magellan penguin and the humpback whale are the most sighted. The review indicates that it is necessary to make further studies on physical oceanography and the benthic community of CMPA.

Residence of the leopard seal in the Magellan Strait: a potential sub-Antarctic population inhabiting the waters of Southern Chile?

The leopard seal is widely distributed on the Antarctic pack ice, but a number of individuals are also thought to displace north from the pack ice to the sub-Antarctic Islands or venture even farther north. In Chile, the leopard seal has been reported mainly in the Fueguian Archipelago, with individuals sighted year-round; however, the data to date have been unable to determine whether it is the same individuals who remain year-round. Thus, one of the questions to be resolved is whether there is a northward dispersion of individuals from the Southern Ocean returning to the Antarctic continent, or alternatively if there is a potential sub-Antarctic population that delay or suspend their migration toward the Antarctic region. Opportunistic sightings of a solitary seal at Ballena Sound (53°41′S, 72°37′W), Magellan Region, Chile, were documented in photographs on six occasions from January to May 2012. Based on the review of the photographs, the leopard seal was identified as the same individual. This finding provides the first evidence of a long occupation by a leopard seal in the fjords and channels of Fueguian Region, suggesting the existence of a small population inhabiting the waters of Southern Chile year-round.