Threats to South American River dolphins

The most shocking threat in South America today is the deliberate killing of river dolphins for bait. Hand harpoons are used to hunt botos mainly in the central Brazilian Amazon. It is likely that thousands of dolphins are killed annually in this way. The hunting is illegal and it is a really serious threat to river dolphins. It is also a cruel hunt – dolphins are harpooned and killed, others are captured and tied up by their tails until they are needed for bait.

Dead river dolphins (and also caiman) are used as bait to catch fish that feed on dead animals – picacatinga or mota fish. The dolphin carcass is put in a large wooden slatted box and lowered into the river. The fish are attracted in large numbers to feed on the carcass and can easily be caught by fishermen working close to the wooden box. Traders subsequently purchase the fish and transport them to Colombia where the majority is sold in supermarkets in the cities.

People generally know that it is illegal to kill river dolphins but since the law enforcement is non-existent they are willing to take the risk and benefit from income generated by the fishery.

Entanglement in fishing gear has also been a major threat to boto populations for many years. The overfishing of the Orinoco and Amazon river basins has lead fishermen to use increasingly desperate techniques in order to catch enough, large fish. This variety of intrusive practices has increased the occurrence of conflict between river dolphins and fishermen. Seen as competition for the dwindling fish populations, the river dolphins have suffered much persecution over recent years. They are, however, not entirely blameless as they have been fighting back, often seen stealing and damaging fishing nets!

A variety of other threats also impact on South American river dolphin populations. Habitat degredation from deforestation and water pollution are major threats. Additionally, expanding dam projects throughout the river systems have isolated already vulnerable populations. This only increases the effects existing threats have on the surviving populations of river dolphins.

Community outreach programs are of paramount importance, as is the strengthening of protection legislation and its enforcement throughout the region. WDCS is working with NGOS and individuals in Brazil and Colombia to address these very urgent threats to river dolphins. Published in July of 2010, the Action Plan for the conservation of river dolphins in South America has mapped out the future for the conservation of the species. Read our next blog entry and find out how!