Species News

Continuing with the theme of "river" dolphins, it's now time to learn more about the lesser known finless porpoise (Neophocaena phocaenoides).

The charming finless porpoise is very much a coastal species, predominantly found in salt water areas of the Indo-Pacific region. However, a small and endangered population of the porpoise inhabits the infamous Yangtze River and its tributaries. For this reason we have included the porpoise in the river dolphin series of blogs! Very little is known of the species, as is common with most of the cetaceans covered in this series of blogs, but the plight of the baiji (Yangtze river dolphin) from the Yangtze River has drawn obvious attention towards the oddly named “river pig”.

Much debate has occurred over recent years over the genetic distinction of a number of sub-species of finless porpoise. Many populations are geographically isolated and this has led to the rise of the currently recognised three sub-species. Of which, the Chinese population of freshwater dwelling porpoises is one – Neophocaena phocaenoides asiaeorientalis.

As with other species of porpoise, N. phocaenoides is not known to be overly acrobatic and shies away from boats and human disturbance. The tragedy of the Yangtze River population is that the levels of human disturbance and boat traffic in the region are so high that many individuals now readily approach boats. They have therefore become more vulnerable to the usual suspects of by-catch in fishing gear and direct boat collision. Unfortunately, their ‘cute’ looks and approachable behaviour have also led to the river population being exploited for the aquarium trade. In conjunction with all the same impacts that pushed the baiji to extinction in recent years, this represents some the most irresponsible of practices the aquarium trade takes part in worldwide.



However, the tragic loss of the baiji has spurned more rapid action in conserving the finless porpoise population of the Yangtze River. The Tian-e-Zhou Oxbow Nature Reserve, an area of wetland in the Yangtze basin near Shishou City, was originally intended for the baiji. More recently it has been adopted as a ‘safe haven’ for the finless porpoise in which 28 individuals live. This is an example Chinese conservationists wish to follow in the fight to conserve the river dwelling populations by using other sanctuaries and reserves that were previously set up for the baiji.

The Tian-e-Zhou population is by no means a strong population and with the only other ‘stronghold’ of finless porpoises in China (in Poyang Lake) coming under threat from dredging activities, their future looks bleak. Chinese conservationists have, however, insisted that the population can be saved if sufficient action is taken immediately. Sand dredging in Poyang Lake has provided a quick and sizeable cash injection into the area. Whilst the lake holds a quarter of all finless porpoises found in China, the boats are the primary cause of an extremely high porpoise death toll. If sufficient protection is put in place for the porpoises and the dredging activities are more strictly controlled, the future of the Poyang finless porpoises may well be restored.

As with many other species of cetacean, their future may rely on tourist revenue replacing the income streams created from the impacting practices, such as sand dredging and fishing. This in itself holds many obstacles but WDCS will be at the forefront of ensuring new cetacean watching programmes are conducted responsibly and to the benefit of the animals the world over.

Despite its appearance, the franciscana (Pontoporia blainvillei) cannot claim to be a true river dolphin. It typically inhabits shallow salt water areas and is distributed from the coastal waters of south-east Brazil, down to the central Argentinean region. Their long, slender beaks (at a whopping 15% of their body length, it is proportionally the longest of all cetaceans), broad flippers and rounded foreheads suggest a close relationship to all other river dolphins found in South America. However, they are classified as an entirely different family, the Pontoporiidae. One of the smaller species of cetaceans, they are characteristically inconspicuous and hard to spot in the wild due to their avoidance of boats and un-acrobatic tendencies. It is not often that cetaceans are referred to as prey species, but the franciscana has been known to be on the menu for orcas and a variety of shark species.

In keeping in common with the true river dolphins covered in this series of blogs, the future of the franciscana is under threat. Classified as ‘Vulnerable’ on the IUCN Red List, the overall population is decreasing rapidly, due mainly to by-catch in fishing gear. Franciscana populations are suffering additional pressure from reduced fish stocks as fishing fleets target many of the species they rely on for food. Further impacts on population size come also from ingesting foreign objects (predominantly from fishing gear), and chemical pollution. Some population estimates have been made and can appear relatively high. However, it is predicted that there has been at least a 30% reduction in population size over the past 3 generations (36 years) in a decline that has not slowed. The sheer scale of accidental by-catch is so high in most areas, that it is un-sustainable on its own merit. When combined with the other threats facing the franciscana, it is not hard to see the reasons for such a decline.



In response to this decline, a variety of organisations (both governmental and non-governmental) have compiled an action plan for the fraciscana dolphins residing in Brazilian waters. The Chico Mendes Institute for Biological Conservation drew up the final plans to halt the fall in population numbers over a 5 year period, finishing in 2015. The plan approaches the conservation of the franciscana on all fronts. Measures will be introduced to minimise the impacts of fishing and other practices on the dolphins and a large scale effort to understand the population structure will be implemented. Alongside this, the identity of the dolphins will be promoted throughout the regions of Brazil in which they occur and communication of their conservation will be improved. The hope is that political and international co-operation towards conserving the franciscana will significantly improve over the 5 years.

Last year WDCS answered an emergency call for help from river dolphin experts in Bolivia – Enzo Aliaga-Rossel and Mariana Escobar. They reported on a group of Bolivian river dolphins that had become hopelessly trapped in a section of river cut off from the main river during falling water levels and increasing sedimentation.

Bolivian river dolphins are special and vulnerable – they are the only cetaceans found in Bolivia which is a land-locked country in central South America. WDCS responded immediately to help.

The dolphins were trapped in an area where water levels would continue to fall and fish supplies would dwindle. After some careful research and consideration the only possible solution was to relocate the dolphins back into the main river. This was complicated and risky as it meant catching and moving the dolphins overland.

Our partners, Enzo and Maria went on to organize a team, which carried out an exceptional and pioneering rescue. 20 Bolivian dolphins were safely moved via boat and truck to the main river. The group included juveniles and even a newborn calf which was released with its mother. The dolphins were each treated with a great deal of respect and care. Their bodies were protected from harm using mattresses and also wet sheets to keep the sun of them and their temperature down.



Follow up monitoring in the area is now planned to ensure the long term success of the rescue.

River dolphins do spread out into the flooded forest and use lakes and smaller tributaries which are available to them in the high water season. As the water falls the dolphins naturally make their way back to the deeper main river channels. There is a genuine concern that incidents like this one in Bolivia could become more widespread in the Amazon if climate change impacts on the high and low water cycle. This time the dolphins were very fortunate that there was expertise and an incredible commitment to helping them from Enzo, Maria and WDCS.