Dolphins in Bangladesh
By Elisabeth and Rubaiyat Fahrni Mansur

The endangered Ganges River dolphins, locally known as shushuk, occur throughout the river system of Bangladesh. They are most commonly seen near confluences.

In 2002, Brian Smith, Associate Conservation Zoologist for Wildlife Conservation Society and Asia Coordinator for IUCN SSC Cetacean Specialist Group, opened our eyes to the world of cetaceans. Having spent considerable time in the Sundarban, the world's largest contiguous mangrove forest, as nature guides and wildlife photographers, we were unaware of the amazing diversity of marine mammals in Bangladesh waters.

After the initial Sundarban dolphin survey, we continued to collect data on the distribution and abundance of the "endangered" Ganges River dolphin or shushuk (Platanista gangetica), Irrawaddy dolphin (Orcaella brevirostris), Indo-Pacific humpback dolphin (Sousa chinensis) and finless porpoise (Neophocaena phocaenoides) present in the estuarine waters, with the help of the captains of our tourist vessels.

During a dedicated cetacean survey of the Bangladesh coastal waters in 2004, we recorded large groups of Indo-Pacific bottlenose dolphins (Tursiops aduncus), pantropical spotted dolphins (Stenella attenuata) and spinner dolphins (S. longirostris), as well as a possible resident population of Bryde's whales (Balaenoptera edeni) and fin whales (B. physalus). The high number of different cetacean species observed at a 900 plus-meter undersea canyon known as the Swatch-of-No-Ground, was especially exciting. It was during this survey that Brian encouraged Rubai to initiate a study of the bottlenose dolphin population using photo-identification at the Swatch. With funding from WDCS, only limited reference literature at hand, and no prior experience in photo-identification, Rubai started his first field session in the winter of 2005/2006.

The crew of The Guide Tours Ltd. found and rescued this emaciated Ganges River dolphin, whose rostrum had been entangled in monofilament net.

It soon became clear that we needed to gain further experience in this field, to maximize the success of our study. While planning a visit to our grandparents in the United States this summer we started looking for possible photo-id projects to join. After contacting numerous individuals and organizations without success, we finally received an e-mail from Randall Wells of the Sarasota Dolphin Research Program. We could not believe our luck - an invitation to join and train with the longest-standing bottlenose dolphin research project in the world!

And so our summer turned into a truly memorable study tour. From the moment we arrived in Sarasota, we were completely overwhelmed by the hospitality, generosity, and professional cooperation at by the staff of the Sarasota Dolphin Research Program and Mote Marine Laboratory. Everybody was interested in our work and willing to share their experience and knowledge. We had opportunities to join Elizabeth Berens and her team on their fishing vessel, discuss opportunities regarding turtle by-catch studies with Dr. Tony Tucker, exchange ideas for an educational outreach program with Dr. David Niebuhr, learn about the long-standing Mote stranding network, proper preservation of bones as well as the basics of ACCESS database software. We spent time with Jessica Powell and the dolphin care team, and Dr. Colin Simpfendorfer helped us by analyzing shark bites on our study animals. We were also invited to join Kim Bassos-Hull and her team for the survey of Charlotte Harbor—definitely a highlight of our summer. What better way to learn about photo-id techniques than being in the field with this professional and dedicated team? The time spent with Kim, Aaron Barleycorn, Robin Perrtree, Katie McHugh, Anna Sellas, Sue Hofmann as well as several interns and volunteers, talking about dolphins and research, was truly exhilarating. We shared our lovely accommodation with Gene and Lorry Stover, which on its own was a unique experience—a life-lesson in humor and humanity.

The collaboration between professional and dedicated researchers with the Sarasota Dolphin Research Program was a totally new experience for us, an example of how passionate people can work together to make a real difference. Although the techniques and means need to be adapted to our circumstances, we returned to Bangladesh with valuable experiences, new friendships, and most importantly a supporting network of professionals, for which we are very grateful. The upcoming field season in the Sundarban and at the Swatch-of-No-Ground will profit from our experiences and we are greatly indebted to Randall Wells and his team.

Farther offshore in habitat influenced by freshwater inputs the Indo-Pacific humpback dolphin is found.

A relatively short distance from the Sundarban mangrove forest is the Swatch-of-No-Ground, where a burst of biological productivity created by upwelling currents supports large groups of Indo-Pacific bottlenose dolphins. The 900 plus-meter deep offshore undersea canyon supports extraordinary cetacean diversity. The canyon sides drop off abruptly, causing a distinct color-change.