The Sound of Hope - The Story of the Humpback Dolphin

Two spectacular and contrasting oceans surround the southern part of Africa. The Atlantic side of the continent is a showcase of a cold marine environment with an impressive abundance of life on islands and below the surface. This is the realm of the Benguela Current. By contrast, on the Indian Ocean side of the African continent, the water is warmer, generating a diverse and colourful marine environment. This is the realm of the Agulhas Current. These two oceans surrounding southern Africa, plus the effects of the southern oceans, create a diverse and unique marine region with nearly 40 species of marine mammals. The coastal area around the city of Cape Town is a microcosm of the mixing zone between these two oceans and holds a remarkable level of marine biodiversity. Here, five species of dolphins and three species of baleen whale are regularly observed from shore. Ranging from Cape Town up the warm eastern coast, there lives a unique marine mammal. A shy and rare dolphin that still remains an enigma for researchers. This is the Indian Ocean humpback dolphin, the most endangered marine mammal in South Africa. There are in total four species of humpback dolphins in the world and all of them live in very shallow coastal waters. The Indian Ocean humpback dolphin is an inshore species that hug the coast along the warm waters from India to Cape Town, avoiding completely the cold Atlantic Ocean. Despite many years of research, not much is known about this unique dolphin in South African waters. Although the best estimates available suggest that there are no more than 500 individuals along the entire coast, down from around 1,000 individuals only 20 years ago. Their habitat and habits make them hard to study. They move and socialise in small groups, often hiding in the surf zone and in murky water making them difficult to find and photograph. Individuals are known to move along hundreds of kilometres of coastline and are rarely identified more than a few times in any study. This makes it almost impossible for scientists to study important individual level questions like health, survival and calving rate. The Indian Ocean humpback dolphin's preference for coastal shallow waters places them in some of the most dangerous waters. Coastal shallow seas are most intensely utilised by humans and dolphins encounter waters with heavy fishing, shipping, recreational activities and pollution entering the seas from rivers and beaches. This dolphin faces some serious threats as nearly 20% of the South African coast has some form of development within 100 metres of the shoreline. Since humpback dolphins depend on and prefer coastal zones associated with rivers and estuaries they have amongst the highest level of pollutant of any marine mammal in South Africa. Another serious threat is the devastating effect of shark nets that kills far too many humpback dolphins per year in KwaZulu-Natal removing valuable individuals from an already endangered dolphin population. Humpback dolphins may also struggle to find enough food. Marine scientists suggest that the decline in reef fish species and the over-exploitation of many estuarine-dependent fish species may limit the growth of this dolphin population. It is very difficult to assess the impacts of all these natural and human-induced threats on the declining numbers of the humpback dolphin. It is likely that the collective pressures of all these threats are the driving factor contributing to the fast decline of humpback dolphin population. These threats are associated not only with a clear drop in dolphin numbers but also changes in their natural behaviour and the increase in the number of solitary animals. The further development of South Africa's ocean economy will increase pressure on the humpback dolphin that could finally drive this unique marine mammal to extinction. To conservationists and marine scientists it was clear that something urgently needed to be done to avoid losing this enigmatic dolphin from our coastal waters. Working with such low numbers of humpback dolphins the researchers needed to innovate to obtain better data. So as a response to these threats researchers around South Africa came together and formed the SUSE consortium in May 2016 and this was with the aim to increase research capacity in humpback dolphins around South Africa. So this award-winning consortium comprises of 18 members from 15 different institutions and they come together to conserve the species at a national level in South Africa. So when we're working with such low numbers in a population it's really important that we now need to innovate to come up with new ideas for better ways to study these animals. Humpback dolphins rely heavily on vocal channels for communication and exploration of their environment. The use of acoustic monitoring offers a cost-effective option for detecting animals along the coast particularly in water with low visibility such as estuaries and sheltered bays. A key area of my research has been trying to confirm signature whistle use in these animals. Dolphins are unique among mammals in having signature whistles which are similar to a name and are used to communicate with one another. All previous efforts at acoustically monitoring dolphins have only identified vocalisations to the species level of present or absent. This study is a new approach and will allow researchers to identify individual dolphins and look at numbers, movements and even who's hanging out with who. The research team will be deploying underwater recording units throughout South Africa to detect dolphin presence. This unique and exciting new way to collect data on humpback dolphins will mean scientists are able to monitor this endangered species with very little or no interference. Also eliminating the need to be on the water and directly interacting with individuals that may influence their natural behaviour. By identifying naturally occurring vocalisations scientists will be able not only to locate the animals along the coast but also determine how far they travel and also estimate the number of individuals in the group. By recording humpback dolphin vocalisations scientists will be able to explore habitats that are remote or difficult to access via boat. Instead of being limited to studying them on a few good weather days scientists will be able to record information about the animal's movements 24 hours a day and over extended periods giving superb and more comprehensive information of the dolphin's activities. The use of underwater acoustic technology will open a new world on the secret life of the enigmatic humpback dolphin. Not a moment too soon as this information will be vital to better understand and conserve South Africa's most endangered marine mammal.