Introduction To River Dolphins
The dolphins that live in rivers!
Most whales and dolphins live in the sea. But there is a small, unusual group that live in fresh water. They live in some of the largest, muddiest rivers on earth - the river dolphins.
River dolphins are among the most endangered mammals on earth. Tragically, the Yangtze river dolphin or baiji in China has recently been declared extinct (in 2007). The extinction of the baiji was entirely at the hands of humans. It was the result of the destruction of its habitat - the Yangtze River - and uncontrolled, intensive fishing resulting in too many dolphins being killed in fishing equipment.
Losing the baiji forever is a shocking early warning sign of the probable outcome for the surviving river dolphin species. Very simply, if we do not do more to protect river dolphins and their river habitats, we will loose them.
WDCS aims to bring the plight of river dolphins to peoples attention and is working to protect them from further losses. This work is important both at a local level where we are working with communities sharing river habitats with the dolphins; and internationally as we need to raise support and funding for urgent river dolphin conservation action.
River dolphins are emblematic flagship species for rivers. Saving river dolphins means saving rivers. In fact river dolphins are perfect ambassadors for the need to protect rivers and the hundreds of thousands of other species – including local people – that are dependant on supplies of fresh water.
River resources, like all natural resources, are not inexhaustible. And many impacts are not reversible. Once flagship species such as river dolphins start to disappear from stretches of river, it may already be too late to make necessary amends. The good news is that if measures and actions are taken now to protect and secure a future for river dolphins, local human communities and wildlife sharing the habitat will also benefit.
Where did river dolphins come from?
River dolphins have been described as ‘living fossils’! Scientists believe that river dolphins evolved from primitive marine dolphins which remained in large freshwater river systems of South America and Asia as sea levels fell. They became the specialised river dwellers they are today.
River dolphins live in far flung places of the world and have evolved independently of each other. They do, however, look remarkably alike in many respects and share characteristics which are a reflection of common adaptations to river life.
Where are river dolphins found?
Today, river dolphins survive in two areas of the world - South America and Asia.
In South America the Amazon river dolphin (boto) and the tucuxi (sotalia) live in the mightiest river on earth - the Amazon in South America.
The Amazon is colossal in scale; it carries one fifth of all the river water on the planet and drains over 40% of South America.
River dolphins also live in the Ganges river basin of Nepal, India and Bangladesh (Ganges river dolphin); the Indus river basin of Pakistan (Indus river dolphin). In addition, there are small and isolated fresh water populations of Irrawaddy dolphins living in rivers and lakes of Cambodia, Laos, Vietnam, Thailand and Myanmar.
Why are river dolphins in so much trouble?
River dolphins are particularly vulnerable because not only are they restricted to fresh water, they are found in naturally low population numbers and are extremely vulnerable to direct threats related to human activity and to the many stresses placed on rivers. Their river homes are relatively small and restricted and are being destroyed by people.
The expansion and intensification of human activities in the Amazon region is threatening river dolphins and their habitat. Rivers are being degraded by agrochemicals, mining and industrial effluents, deforestation and hydroelectric developments. These manmade activities are reducing both the range and health of river dolphin populations. Reports indicate that the Amazon river dolphin is retreating from the upper western reaches of its distribution, probably as a result of increasingly dense human settlement in the Andean region and the ensuing over exploitation of natural resources, such as timber and fish.
Fisheries pose the most immediate and serious threat to the Amazon river dolphins. Over the past few decades, the spread of commercial fishing operations in the Amazon combined with new technologies such as nylon gillnets have resulted in a major amplification of fishing effort and as a result, the accidental mortality (bycatch) of river dolphins and other endangered wildlife, such as Amazon manatees, entangled in fishing nets is common and widespread. More alarmingly still, some fisheries (mainly in Brazil and Peru) necessitate the deliberate hunting of Amazon river dolphins, so that their carcasses can be used as bait for edible (and commercially available) fish (mota fish). This practise appears to be becoming more widespread and is a serious threat to the future of Amazon river dolphins.
Amazon river dolphins are also injured and killed by fishermen because they are perceived negatively as an animal that interferes with and damages fishing nets and competes for dwindling fish supplies in the rivers and lakes. Traditionally, cultural beliefs in the Amazon have afforded the Amazon river dolphin some protection against hunting and people do not eat river dolphin meat. However, in many regions, the dolphins have been regarded with ambivalence and even fear as an animal with supernatural powers and this may heighten the conflict with fishermen.
Dolphins, particularly calves, can become entangled in monofilament fishing nets now widely used in the Amazon. If they are not released quickly they will drown. Of course if a fisherman is close by when a dolphin is caught in a net, the dolphin is vulnerable to capture and sale for captive purposes, or a trophy animal for a high profile public figure.
Although on paper Amazon river dolphins appear to be protected by various laws and regulations, the problem is that legislation is poorly complied with and rarely enforced. More often than not, communities living in the Amazon are unaware of protective measures for river dolphins and other wildlife. River dolphins are being displaced from prime habitats in the rivers and lakes by a range of disturbances, from uncontrolled boat traffic to deliberate instances of hunting and capture. These river dolphins and their counterparts in Asia are most definitely in trouble and need help if they are survive into the future.
What is WDCS doing to save river dolphins?
For some 20 years, WDCS has continuously supported river dolphin conservation projects and initiatives run by local people in their own countries in South America and Asia. Following the catastrophic extinction of the baiji, WDCS is redoubling efforts to prevent the worlds surviving river dolphins following the baiji down the road to extinction.
In 2008, WDCS supported an important South American regional river dolphin workshop which took place in Bolivia. The workshop brought together conservation biologists, educators, researchers and some policy makers working on river dolphin issues from all range states. The workshop has resulted in a regional action plan for river dolphin conservation. Follow up work is now being done to develop national river dolphin action plans for each country, to express in more detail actions and measures needed to protect river dolphins locally.
WDCS is currently working with a number of non governmental groups (NGOs) and conservation biologists in South America and funding river dolphin conservation programmes in Colombia (Fundacion Natütama and Fundacion Omacha); and Bolivia. WDCS is also contributing to an important initiative in Ecuadorian Amazon on the Napo River.
In Asia we are currently putting together a conservation action plan following the success of the initiative in South America. This will highlight some important conservation priority actions which WDCS will seek to work with Asian groups and individuals to implement. The most pressing requirement is capacity building in Asia so that we can support local people in their efforts to secure a future for these endangered cetaceans.