Passive Acoustic Monitoring of Marine Mammals in the Corcovado Gulf: Chile

Alex Bocconcelli, Biology

2014 MMC Funded Project

Abstract

The proposed work will build on a recently started collaboration between WHOI (DTAG Laboratory in AOP&E and Marine Mammal Center in Biology) and the Melimoyu Ecosystem Research Institute (MERI) in Santiago, Chile, to explore various aspects of the ecology and behavior of marine mammals in the Corcovado Bay area, Chile.  This area supports a high diversity of marine mammals, including blue whales, humpback whales, minke whales, Peale’s dolphins, Chilean dolphins, killer whales, false killer whales, bottlenose dolphins, Cuvier’s beaked whales, South American sea lions, southern fur seals, southern elephant seals, and marine otters.  MERI previously deployed several acoustic recording units in the Corcovado Bay area, and analysis of data from these recorders is in the early stages.  Preliminary analyses show numerous vocalizations of blue whales, indicating the importance of this area as habitat for this endangered species.  In order to enhance the potential of the passive acoustic monitoring (PAM) data, WHOI (A.  Bocconcelli and L.  Sayigh, PIs) recently received funding from MERI to carry out a field effort in March 2014 that included tagging, photo identification, and behavioral observations of blue whales.  Five WHOI-developed DTAGs were deployed on four blue whales for a total of 22 hours and 42 minutes.  In addition to tag and observational data, skin and fecal samples were collected for a collaborator at the University of Chile in Santiago, adding another dimension to the ecological scope of these data.  Finally, behavioral observations and acoustic recordings of several other species of marine mammals were carried out as well.

Based on the results of this cruise and previous work done by MERI, critical habitat areas for blue and humpback whales in the Corcovado Gulf were identified: the Moraleda Channel, the Guaitecas Islands, and Bahia Low (Buchan et al., 2014).  In these remote locations both blue and humpback whales were sighted feeding (and defecating) close to each other for many days, and juveniles of both species were also observed.  However, it was also noted that there was a great deal of anthropogenic activity in these and adjacent areas, including aquaculture and inter-island boat traffic to support it (there are no local residents, thus crew and supplies must be continuously ferried from the main island of Chiloe’).  Sea farming for salmon in Chile accounts for 30% of the world’s production, and 90% of this industry is concentrated in the proposed study area south of Chiloe’ Island.  The salmon sea farming industry is poorly regulated, which has caused severe friction with local residents, established commercial fishermen, and conservationists.