For the Sake of our Dolphins The Dolphin Project of Walvis Bay is one of four environmental projects that have benefited from the Walvis Bay Municipality’s Environmental Fund. But, the research team of the Namibian Dolphin Project is still worried, because no money to monitor the dolphins, has been made available yet from Namport, or construction companies at work in the harbour. “The common bottlenose dolphins found along Namibia’s coastline should be considered quite an important population and are locally threatened by coastal development, construction and shipping; big challenges faced daily by the small, isolated, precious, community of common bottlenose dolphins of Walvis Bay. Currently, there are only around 100 animals in the population. We are concerned for their long-term welfare and capacity to cope with these challenges,” says project leader, Dr Tess Gridley of the University of Pretoria and the Namibian Dolphin Project and Sea Search. They are conducting research on the dredging being done in the harbour of Walvis Bay, as they fear that noise from the development of the harbour may block the dolphins’ communication signals, making it harder for them to communicate with each other. “There is considerable construction planned for Walvis Bay now and into the future. The major issues that have been highlighted with this are pollution, habitat degradation and habitat removal. The possible impacts can be summarised as follows: - Broad band noise - most energy concentrated at low frequencies -under 1 kHz. - Increased sedimentation - which in Walvis Bay could impact the lagoon area - but this is being monitored carefully. - Contaminant re-mobilisation - increased pollution as contaminants re-enter the water column. - Effects on prey species - resulting in less food or contaminated food sources. - Increased food availability - positive effect.” She says it is unlikely that sound from dredging will cause any hearing injury to whales and dolphins in Walvis Bay. Dredging activity and transport of dredging materials could cause displacement of whales and dolphins, though, from key habitats, and thus more likely cause behavioural changes. The container terminal and other planned developments in Walvis Bay are in the key bottlenose dolphin habitat. Therefore they are concerned about habitat loss. “It should be noted though that dredging has been ongoing in Walvis Bay periodically for many years and the dolphins may well be habituated to any sound generated. Turbidity generated during this process is being closely monitored throughout the construction of the container terminal. ” The team suggests careful monitoring throughout the construction process with a designated Marine Mammal Observer, to watch the behaviour of dolphins in the vicinity of the dredger and construction areas. It is believed that sensitive individuals, such as bottlenose dolphin mothers with calves, may use the bay less frequently if disturbed too much. Other individuals, such as young males, may be less obviously affected. Therefore it’s important to conduct studies using photo-identification to look at individual habitat use and track the movements of individuals. Research has been conducted in Walvis Bay on the bottlenose dolphins since 2008, but the Namibian Dolphin Project is reliant on small grants and charitable donations to conduct its research, which causes a standstill when funds run low. Several large grant applications to conduct monitoring work of the dredging activities and other construction activities were not successful. The Dolphin Research team is still in need of more funding to continue its research, specifically to investigate the amount of noise generated by these activities and to look at the genetic profile of the bottlenose dolphins. “We are studying the vocal behaviour of the dolphins and have recently published on their findings, we will continue this work to look at how sounds affects the vocal behaviour of bottlenose dolphins in Walvis Bay,” Gridley added. If members of the public would like to help, they can provide a donation, join the Namibian Dolphin Project Facebook site or assist at strandings. Funds are being raised through the following link: gofundme/armnrk. For further information please contact Dr Tess Gridley, University of Pretoria Post Doctoral Researcher, on nam.dolphin.project@gmail.
Posted on: Tue, 25 Nov 2014 09:16:39 +0000
Trending Topics
Recently Viewed Topics
© 2015