National Day for Nature Conservation commemorates the Year of the Dolphin in Portugal
The Quercus and the Projecto Delfim want to raise awareness of the danger that bottlenose dolphins may become extinct in Sado. On the occasion of National Day for Nature Conservation, 28 July, the associations Quercus and Projecto Delfim offered a 3 hour guided tour of the estuary of the Sado River. This area is essential for the sedentary population of bottlenose dolphins, which has suffered a serious decline during the last decades. According to a researcher of Projecto Delfim one of the stress factors is related to small and fast boats, and "water-motorcycles".
This initiative is a contribution to the Year of Dolphin 2007 where professionals provide information on this protected species. It is a symbol of the region, and at the same time of concern for biologists and environmentalists regarding its chances to survive. For bottlenose dolphins, the estuary of the Sado River and the adjacent coastal zone constitute the natural habitat of the only sedentary population of bottlenose dolphins (Tursiops truncatus) in continental Portugal. They are among the largest wild mammals of Portuguese fauna. The monitoring carried out by the Projecto Delfim, in partnership with the Institute of Applied Psychology, revealed a population of 27 individuals at present. This means a reduction of 50 % in less than 30 years.
The survey discovered that the survival rate of young animals had decreased, and pointed out that the population is critically endangered in the medium term. It concludes that the population decline is a result of the abnormal increase of mortality among calves. This might have been caused by poisoned breast milk due to chemical pollution, which in turn affects their immune system. This fact is probably aggravated by the existing low genetic diversity of the population.
Nevertheless four calves, which were born during the last the two years and which will be monitored, still allow for some hope. This however will only make sense if the authorities adopt determined policies to ensure the restoration of the estuary’s ecology and thereby safeguard the dolphin population.
Further information:
http://www.quercus.pt
http://www.projectodelfim.pt
The survey discovered that the survival rate of young animals had decreased, and pointed out that the population is critically endangered in the medium term. It concludes that the population decline is a result of the abnormal increase of mortality among calves. This might have been caused by poisoned breast milk due to chemical pollution, which in turn affects their immune system. This fact is probably aggravated by the existing low genetic diversity of the population.
Nevertheless four calves, which were born during the last the two years and which will be monitored, still allow for some hope. This however will only make sense if the authorities adopt determined policies to ensure the restoration of the estuary’s ecology and thereby safeguard the dolphin population.
Further information:
http://www.quercus.pt
http://www.projectodelfim.pt
