http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Distributional ecology and conservation status of river dolphins (Inia geoffrensis and Sotalia fluviatilis) in portions of the Peruvian Amazon
xvii, 233 leaves : illustrations, maps ; 28 cm.
River dolphins (Inia geofftensis and Sotaliafluviatilis) were studied in the mainstem of the Amazon and Marai!6n rivers, from Iquitos, Peru, to approximately 230 km upriver and including tributaries in both the Peruvian and Ecuadorian drainages. A single stretch (142 km) of the relatively pristine Samiria River, within the Pacaya-Samiria National Reserve, was selected for in-depth study. Data from sightings made during eleven expeditions between March 1991 and August 1993 were analyzed in combination with data on survey effort and environmental features. In addition to applying standard statistical tests of significance, a Geographic Information System (GIS) was used for exploring relations between dolphin occurrence and fine-scale habitat characteristics. Three principal lines of enquiry were pursued: (1) to describe the overall distribution and relative abundance of the two dolphin species within the study area, (2) to estimate the absolute abundance of river dolphins in the core study area, and (3) to correlate dolphin distribution and movement with the presence or absence of confluences, sand banks, and sharp turns in the main river channel. Encounter rates (animals observed/km of survey effort) in the large white-water rivers were broadly similar to rates recorded in other sections of the Amazon and Orinoco rivers. In all areas, Sotalia consistently occurred in larger groups than Inia. About 700 dolphins were estimated to inhabit the Samiria River system during fegh Water (roughly half Sotalia:half Inia). Both species strongly prefeffed confluences and other habitats with complex water flow, although there were seasonal (water level) differences in the strength of that preference. Depth appears to be important in attracting dolphins.
"Major Subject: Wildlife and Fisheries Sciences".
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