Natalia Botero Acosta

Diagnosis of the Taxonomic Composition, Spatial Distribution, Social Structure and Conservation Threats of Marine Mammals in Tribugá’s Gulf

Town/RegionCountryCategoriesDate
Nuquí, Chocó ProvinceColombiaCentral and Latin America, Cetaceans, Marine18 Dec 2009

Colombian Pacific coast holds a considerable proportion of biodiversity and species endemism. This has promote the development of eco-touristic activities, which unfortunately have not yet had a positive impact on the knowledge of the basic biology and conservation threats of marine mammals inhabiting this area either seasonally or permanently.

Tribugá’s gulf is part of the breeding area of Southeast Pacific Humpback whales. Additionally, other species like the bottlenose dolphin, the common dolphin, the orca and the spotted dolphin can be frequent in this portion of Colombian Pacific coast.

In order to diagnose the taxonomic composition, spatial distribution, social structure and conservation threats of marine mammals in Tribugá’s gulf, lineal transects covering coastal and oceanic habitats will be done on a small boat, on two different climatic seasons and two transitional months. Information about coordinates, behavior, heading, social context and entanglements (if occur) will be registered on each survey. Photographs will be taken for taxonomic assertion and individual identification in species with natural marks. Conservation threats will be described by walking transects along the coast, searching for osteological remains and stranded animals, and interviews to locals and fishermen. Several diversity indexes will analyze the taxonomic composition according to the temporal and spatial variables.

To describe the possible effects of the area’s structural and environmental gradients over marine mammals spatial distribution, sightings coordinates will be examined on spatial distribution software. Presumed associations between habitat structure and observed behaviors as well as between habitat structure and the occurrence of strandings and entanglements will be tested with a frequency analysis. The same kind of test will examine those variables on a temporal scale. This investigation will promote the development of long-term research and management practices, therefore supporting the conservation and sustainable use of biological resources in the Tribugá’s gulf.

For further information contact greenheart777@gmail.com

Project Update: June 2010

Between April 23rd and May 23rd, 13 boat surveys were carried out along Tribugá’s gulf, traveling 1267.9 km. Since depth increases gradually from the coast, transects covered a significant portion of the bathymetric gradient (0 – 4000 m). Sighted species included: bottlenose dolphin (Tursiops truncatus), spotted dolphin (Stenella attenuata), spinner dolphin (Stenella longirostris) and rough-toothed dolphin (Steno bredanensis). Sightings occurred in depths between 11 and 1267m. Sighted groups often included all age classes. Groups were generally bigger in spinner dolphins (150 and 300 individuals) than in other species (2 to 60 individuals).

Environmental education activities included a marine mammals’ identification workshop with touristic operators in Coquí and workshops at primary and high schools in four locations: Arusí, Joví, Coquí and Nuquí. Touristic activities are incipient and limited to July-October humpback whales' season. Strandings seem to be very rare, so the biggest conservation threat seems to be entanglements occurring occasionally on industrial tuna fisheries.


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