Tracking whales and dolphins in Tanzania’s Indian Ocean waters

Thursday February 26 2015

Captain and acoustic specialist research assistant Magreth Kasuga scans the ocean for dolphins and whales off the coast of Zanzibar. Inset, Top: A Humpback whale and calf at the Pemba channel; Below: A dolphin off the coast of Pemba Island in Tanzania. PHOTOS | COURTESY

It’s exciting talking to Dr Gill Braulik who, for the past 18 years, has been following dolphins and whales around the Indian Ocean.

In a few days time, she will set sail for a six-week journey in a catamaran with her team of seven scientists — an all-female crew — to survey the Tanzanian coastline for dolphins and whales. She will survey 3,000 kilometres including the waters off the islands of Pemba and Mafia. It’s the first time that such a survey is being carried out in Tanzanian waters.

For most people, dolphins are the legendary friendly creatures that lead troubled vessels to safety and whales are the huge but agile water-spurting creatures.

Both creatures are very family oriented and move in groups of parents and calves. Dr Braulik, travelled the globe to raise the profile of these enigmatic ocean-wandering creatures and study their declining populations.

Her first stint, on which she spent 10 years, was in Pakistan. There she studied the blind Indus River Dolphin (platanista gangetica minor) found only in the Indus River, one of Asia’s longest rivers flowing through India, China and the entire length of Pakistan.

“When we started we didn’t know if there were any left,” says the ocean wanderer. There was dire need for scientific information to guide conservation efforts. “I trained the first batch of Pakistani dolphin researchers who now run the show and started the first national programme on dolphin conservation in the country,” she said.


In 2001, the team carried out the first assessment covering 1,600 kilometres in Pakistan. This was repeated in 2006 and then five years later in 2011.

The assessment revealed a population of around 1,500 freshwater dolphins, which has been stable over the years despite the challenges the animals face. About 150 years ago, the dolphins’ range covered the entire 3,500 kilometres of the Indus River. Today, this range has declined by 80 per cent.

“The bigger picture for these dolphins is not good,” continues Dr Braulik. There are 16 huge dams built on the central Indus, farmers use the river heavily for irrigation and much of the water is diverted before it drains into the ocean. Pockets of dolphins survive between the dams on the river.

Specialising in dolphin and whale research is a career Dr Braulik chose early in life. She was attracted to this field because there were many areas of the ocean untouched by scientific research, and particularly on these mammals, who are our closest relatives in the ocean. Like us, whales and dolphins are warm blooded, and give birth to live young ones who suckle the mothers’ milk from mammary glands.

As we chat with her at the ocean front of the Zanzibar Serena Inn, Dr Braulik scans the waters and says, “You can usually see humpback dolphins near the shoreline here.”

Tanzanian coastline

Tanzania’s 800-kilometre long Indian Ocean coastline is dotted with fishing communities. However, the people here do not know what species of dolphins and whales roam these waters because no surveys have been done.

“We will be seven scientists aboard the 50-foot catamaran recording visual and acoustic information,” says Dr Braulik of their forthcoming trip. The captain and acoustics specialist is Magreth Kasuga, a Tanzania research assistant on the Whale and Dolphin Evaluation Project. 

Kasuga has been working with Dr Braulik, training in marine mammal science and is taking on a greater role in the coming survey, of supervising the observers and managing the data. During the six weeks at sea, they will only touch land twice for refuelling and restocking supplies. The crew will set sail from Stone Town in Zanzibar, for Mtwara on the border of Tanzania and Mozambique in the south and end up in Tanga near the Kenyan border.

“It will be a broad scale overview of species and hotspots. This will tell us which are the endangered species to help us target our conservation efforts. At this point, apart from Zanzibar where there is a long term project run in partnership with the University of Dar es Salaam, we know very little about dolphins and whales in the rest of Tanzania’s waters,” says Dr Braulik.

Dr Braulik and her team recently also conducted a two-week survey of whales and dolphins in the Pemba Channel Conservation Area, Tanzania’s newest and biggest marine conservation area established in 2009 with an area of 1,000 square kilometres.

“It was fantastic,” she enthuses. The team recorded five species of dolphins — the most exciting being large numbers of humpback dolphins rarely seen. “These are the most threatened because they are found near coastlines and therefore are closest to humans, meaning they are subject to getting caught in fishermen’s nets.

“We saw Spotted and Bottlenose dolphins and lots of Spinner dolphins and two Humpback whales — both females with calves,” continues the researcher.

Humpback whales

Humpback whales migrate from the Antartic, where they feed on krill, all the way to the eastern shores of the African continent, using the shoreline as a guide to the safe and warm waters of Somalia, Kenya, Tanzania and Mozambique, where they give birth and breed. As a general rule, whales migrate long distances each year between feeding and breeding grounds — as much as tens of thousands of kilometres.

In Tanzania, the whales arrive in July and the last ones leave in October; this means the whale migration coincides with the world famous wildebeest migration of the Mara and Serengeti national parks.

“Humpback whales are a priority species for the Wildlife Conservation Society,” says Dr Braulik. For two centuries, Humpback whales were hunted — to near extinction — for their fat and meat till a moratorium by the International Whaling Commission was put in place. Like vultures, their population declined by 95 per cent. Although some whale populations disappeared forever, today, others are on the rebound, spelling a conservation success story.

Dr Braulik tells of expanding her study horizons beyond Tanzania. “There is a new dolphin project we are currently planning to collaborate with Global Vision International and Watamu Marine Association in Kenya on conservation of sea animals that move between countries. It will involve taking pictures of dorsal fins of dolphins and whale tails because they are unique, like our fingerprints,” she added.

The collaboration could expand to Madagascar, Mozambique and other eastern seaboard of the continent to compare data and map a safe passage for the cetaceans.

Climate change and cetaceans

Until a few years ago, a sighting off a gray whale in the southern hemisphere would have been dismissed. But on May 4, 2013, marine tour operators working in Walvis Bay, Namibia, reported an “odd looking whale, possibly a gray whale” to local researchers running the Namibian Dolphin Project.

After studying the pictures, it proved to be a gray whale (eschrichtius robustus), which is normally recorded only in the Pacific, making it the first confirmed record of the species off the African coastline. With the ice caps melting at the Poles, water passages are now opening, allowing for the sea creatures to move into new areas from as far away as the Arctic.

Threats and challenges

“The challenges are the same for these creatures everywhere,” says Dr Braulik. An initial survey along the Tanzanian coastline reveals that local fishermen do not hunt dolphins, but they get caught in nets and are sometimes eaten and the oil from the blubber is used to paint the wooden boats and dhows to guard against wood rot and wood worm.

But what’s really worrying about happenings off the Tanzanian coast is that local fishermen are using dynamite to blast the coral reefs, which kills not only the fish they want, but the reef itself and threaten creatures like dolphins, whales and turtles.

Fishermen tell of days long gone when they used to conduct dolphin hunts at sea from the Kisimkazi landing in Zanzibar, but from where now tourist boats are chasing dolphins for picture-perfect shots of the graceful cetacean.

“An ocean empty of dolphins and whales would change the ocean considerably. These creatures are at the top of the food chain. Taking them out of the sea would have a knock-on effect on the entire ecosystem including fish, on which people depend,” says Dr Braulik.