Giant otter Pteronura brasiliensis density and abundance in Llanos Orientales de Colombia in the Orinoco basin

Germán Garrote,Brayan Marín,Fernando Trujillo,Beyker Castañeda,Jose Manuel Escobar,Laura Pérez,Jacinto Terán

doi:10.1017/s0030605320000058

Abstract

AbstractThe giant otter Pteronura brasiliensis, categorized as Endangered on the IUCN Red List, was once widely distributed throughout South America. By the middle of the 20th century the giant otter had become locally extinct along the main rivers of the Orinoco basin. Although some populations seem to have recovered, the paucity of information available does not permit a full evaluation of the species' conservation status. The objective of this study was to estimate the abundance and density of the giant otter population along the Orinoco river in the municipality of Puerto Carreño, Vichada, Colombia, where there is important commercial and recreational fishing. Thirty-nine linear km were surveyed, repeatedly, with a total of 315 km of surveys. Population size was estimated by direct counts of individuals. All individuals detected were photographed and identified individually from their throat pelage patterns. In total, 30 otters were identified, giving a minimum density of 0.77 individuals per km, one of the highest reported for the species in Colombia. Given the high density in this well-developed area, our results highlight the importance of this population for the conservation of the species.

Highlights

The giant otter Pteronura brasiliensis, categorized as Endangered on the IUCN Red List, was once widely distributed throughout South America
This study was carried out along the Orinoco river in the municipality of Puerto Carreño in the north-east of the Department of Vichada (Fig. )
Important commercial and recreational fishing activities occur in this area

Summary

No of surveys

Diurnal, live in groups and have irregular pale patterning on their throats that allows individuals to be identified (Duplaix, ), facilitating estimation of population size by direct counts of groups and individuals (Groenendijk et al, ). –. When we detected an individual or group of otters, we followed them until the pale throat patterns of each individual could be photographed and the size of the group established. Linear km, including the main river, its tributaries and lagoons. Six groups of giant otters and two solitary individuals were detected. Our results show that the giant otter density along the river Orinoco and its tributaries and lagoons in the Puerto Carreño area is among the highest reported for the species in Colombia (Table ), similar to the .

Study area

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