Cetacean Society International
Whales Alive! - Vol. XIII No. 2 - April 2004
CSI has been fortunate to have found and supported several superb young scientists / conservationists in Latin America. As one example we would like to share a slightly shortened report of a project we helped to fund, and some photos we received recently from Francisco Viddi and Sandra Ribeiro, of the Universidad Austral de Chile in Valdivia. In perspective, what we think of as exotic they find normal; very few people have ever seen Burmeister's porpoise alive, and Francisco is getting underwater photographs and showing the elusive porpoise to schoolchildren! But thankfully, their perspectives on the oceans and its problems are not so different from our own.
Ecology and Conservation Of Dolphins In Southern Chile
By Francisco Viddi and Sandra Ribeiro
Most of the planet is covered by ocean waters, by far the largest ecosystem on Earth. Of this great ecosystem only a small percentage are coastal habitats. Situated at the confluence of land, sea and air, the coastal ocean, its structure and processes composed of terrestrial, freshwater, marine and atmospheric elements, is exploited by humans for food, recreation, transport, waste disposal, and other needs. The current high density and projected increases in population have caused and will threaten the seas by the diverse range of human-derived impacts such as depletion of natural resources from over-exploitation and fishing, alteration of physical habitat, chemical pollution and eutrophication, invasion of exotic species, increased boat traffic and global climate change.
Marine biodiversity has been threatened to the point of bringing some species to extinction, while many others remain under severe conservation threats. Because they are usually much less readily observed, marine species status is in general more difficult to assess and monitor than terrestrial ones. One group considered of special concern as a whole are marine mammals, the archetypal "charismatic megafauna" of the sea. Some species belonging to this group are also one of the best-known cases of overexploitation; they were intensively killed and hunted during last century for their fur, blubber and meat. In the present, one of the main concerns for coastal cetaceans is the loss of critical habitats, important areas for highly essential biological activities, due to the exponential increase of human population in coastal areas.
Although in Chile there is a poor perception of nature, threats to biodiversity are recognized among the major environmental problems in the country. There are 41 cetacean species inhabiting Chilean waters, representing 47% of all species in the world. There are 16 dolphin species and two porpoise species. Despite this very important cetacean diversity, little is known about the biology of these animals, so little can be said about their conservation status. From this very important diversity, the Chilean dolphin is the only endemic species in Chile, distributed from Valparaiso (33° S) to Navarino Island, Cape Horn (55° S), while Peale's dolphin is only found in Argentinean and Chilean waters. They are coastal species, inhabiting sheltered bays, channels, fjords and exposed coast. The current conservation status of both is listed by the IUCN as Data Deficient. They are among the most unknown dolphin species. They are also listed in Appendix II of CITES (Convention of the International Trade of Endangered Species), CMS (Convention for Migratory Species) and IWC (International Whaling Commission). Basic knowledge on their biology and ecology is still very scarce and there is no data available on abundance, population structure and dynamics, home range size and movement patterns.
Anecdotal information suggest that since 1930, and especially between 1970 and 1990, the abundance of dolphins was severely reduced by extensive hunts to use their meat as bait in the king crab and false king crab industry in southern Chile. Today the main concern for the conservation of coastal dolphin species is the incidental catch in local fisheries, and the progressive destruction of potential critical areas, mainly due to mussel and salmon aquaculture activities, which have expanded rapidly in the sheltered bays, channels and fjords of southern Chile.
The overall aim of our project is to establish a long-term programme on the conservation of small cetaceans, mainly focused on Chilean and Peale's dolphins through research and environmental education in local communities. This is part of a larger, long term project on marine conservation that considers small cetaceans as flagship and umbrella species.
The specific aims are to describe dolphins' habitat selection patterns, geographic movements and site fidelity; to estimate individual home range size and core areas on a spatio-temporal scale; to estimate population abundance and density; to analyse and describe social dynamics, behavioural patterns and genetic population; to identify dolphin conservation threats for raising environmental awareness of marine ecosystems for local communities and authorities through environmental education, considering the small cetaceans as flagship species; and to provide field training to students and local community members.
From our preliminary results, important areas were recognized for dolphins in the study areas, as well as many mother-calves pairs, high residency of identified individuals and a very specific habitat selection. The small cetaceans we found showed extremely interesting habitat segregation between them. These habitat selection patterns might be a response to certain environmental features such as water depth, water clarity and proximity to the coast and rivers. Our results are of great importance since the information we gathered showed a very important diversity of small cetaceans within a small area.
Potential human impacts have also been identified in the research areas, such as extensive aquaculture farming for mussels and salmon, which are taking place in all areas surveyed and overlapping greatly with dolphin distribution. These farms produce high levels of pollution and cause increased boat traffic and garbage, factors that could negatively impact dolphin populations, both directly and indirectly. In southern Chiloé for example, it was seen that the high coverage of mussel farming is restricting dolphins of using available space. Intense boat traffic was seen to affect dolphin normal behavioural patterns. From fine-scale land based surveys it was possible to recognize negative reaction from dolphins towards the presence of boats.
Work on public awareness and training has been developed in three areas: Valdivia, Comau fjord and Reñihue fjord. Talks have been made to present the project's objective to the general and specialized public, dissemination of current results, update of fieldwork progress and conclusions. The main objective of the environmental education component of this project is to begin a long-term programme to raise public awareness at the local, regional and national level on marine conservation issues considering the dolphin species as flagship and umbrella species. Raising as well awareness about their locally resident dolphin populations, the environment they live in and the threats that they might be facing.
Specific objectives are to work to give an understanding on marine ecosystem processes, marine ecology, links to the terrestrial environment and coastal conservation. The focus of the classes and workshops have been on the role that every organism plays in the marine environment, how human activities have influenced and affect ecological processes and the importance of conservation and respect towards all living creatures. Workshops, classes, talks and outdoors activities have been developed for schoolchildren and teachers from local communities.
This project is identifying ecologically important areas (core areas) for Chilean and Peale's dolphins, as well as for other small cetaceans, such as Burmeister's porpoises. Threats affecting their population will also be identified. The information generated will assist the formulation of coastal management policies, marine conservation action plan and habitat protective measures. The involvement of the local community, students and local government officials will ensure the long-term conservation impact of the project. Detailed field surveys conducted will generate information on the status and geographical distribution of the small cetaceans. Data analysis and modeling of habitat requirements and behavioural patterns will focus attention on ecologically important habitats and population fitness. This will also determine restricted areas for aquaculture expansion and will be used as a baseline for recommendations on the establishment of future marine protected areas.
By considering dolphins as flag species and by implementing a conservation campaign regarding the marine environment by an educational approach and the presentation of our results to the local community, schools, NGOs, universities and the scientific community; we intend to increase awareness and involvement in marine conservation issues.