Sustainability of Harvested Pacú (Colossoma macropomum) Populations in the Northeastern Bolivian Amazon

Abstract

The pacú (Colossoma macropomum) is an important commercial and subsistence fish resource in Amazonia. Pacú depend on the unique hydrology of the Amazon Basin, in particular the occurrence of annual floods, and require a healthy and intact flooded forest ( várzea) for food resources during the wet season. From March to December of 1999, 128 pacú were collected and aged ( by means of otoliths) from subsistence harvests in the town of Bella Vista, located at the juncture of the San Martín and Blanco rivers in northeastern Bolivia. The age structure of the harvested population implied a healthy and lightly exploited stock and suggested that sustainable harvest is occurring. Population parameters at our site were similar to the neighboring, lightly exploited Mamoré River system but differed slightly from heavily exploited stocks in Brazil. Pacú harvested near Bella Vista are of special concern because of poaching and the increasing regional demand for fish, and because the várzea habitat on which the pacú depends is currently threatened by cattle production, development activities, and land‐tenure conflicts. As development increases throughout Amazonia, careful management of pacú fisheries and the flooded forest on which they depend will be of critical importance.

Extremely long-distance seed dispersal by an overfished Amazonian frugivore

“…Approximately 90 per cent of this reserve consists of floodplain forests, other wetlands, rivers and lakes; flooding occurs annually from January to June and floodwaters can reach up to 6 m deep [11,35]. Colossoma is among the largest species of fishes in tropical South America, and can weigh 20-30 kg and measure more than 1 m in length [31,33]. Colossoma is common at our field site primarily because fishing pressure is low within the reserve.…”

“…Overfishing has reduced population sizes by 90 per cent in some areas over the past several decades, decreased individual fish size and altered the age structure of populations [31,33,34]. Colossoma individuals consume enormous numbers of seeds of a diverse array of plant species across the range of the species [9].…”

Conservation and Development in Amazonian Extractive Reserves: The Case of Alto Juruá

“…There is much concern about the sustainability of current fishing practices, particularly on the main trunk of the Amazon River where human population is relatively dense (Goulding & Ferreira 1996, Ruffino 2001, Jesús & Kohler 2004. Remote regions with fewer human residents still have relatively robust fish populations (Chernoff et al 2000, Silvano et al 2000, Reinert & Winter 2002. IIRSA investments in hydrovias will probably lead to higher population densities along rivers and to an increase in overfishing if appropriate management procedures are not implemented.…”

Floodplain fish communities in river systems in Bolivia: Current knowledge and addressing future research challenges

“…Rivers are also important corridors for the exchange and sale of agricultural and nontimber products and a key source for financial income (Salonen et al 2011). Fish diversity loss will undoubtedly have an adverse effect on the survival of local communities; therefore any conservation approach must rely on local knowledge and the participation of local communities to be effective (Reinert & Winter 2002).…”

“…Indigenous people make up 36 linguistic groups and 59% of the Bolivian population. Local communities are strongly dependent on the provisioning ecosystem service of fish to sustain their livelihoods (Lauzanne et al 1990, Reinert & Winter 2002, FAO 2011. Importantly, indigenous groups have an invaluable ecological understanding of these systems, including the fish communities present, and historically have used their knowledge to obtain fish resources in ways that can be considered as sustainable as they do not disrupt the natural dynamics of the river floodplain system (Pérez-Llorente et al 2013).…”