Scientists Study Bryde's Whales in Gulf of Thailand

While other baleen whales have been extensively studied, the Bryde’s (pronounced "broo-dus") whale remains a bit of a mystery. The comparatively scant attention the whales have received from scientists is due in part to the fact that they are not easy to track. They are rarely photographed. Sleek and fast, they are primarily fish eaters and can dive a thousand feet, often staying down for 5 to 15 minutes. They generally travel alone or in groups of two or three. They prefer tropical and subtropical waters, but other details - concerning their movements, where exactly they mate and just how many exist - are sparse. The total population of Bryde’s whales today is estimated at about 90,000.

The whales, however, are a familiar sight to Thai fishermen and villagers along the upper Gulf of Thailand. Many fishermen and others, in fact, revere them. According to Dr. Kanjana Adulyanuosol of Thailand’s Marine and Coastal Resources Research Center (MCRC) in Samut Sakhon Province, "Many Thai people respect the whales as 'gods of the sea' - owing perhaps to their huge size and mysterious life history." She adds that "In some areas, if a dead whale is found, the body is buried following a Buddhist ceremony similar to that conducted for humans. In the past, when the skeletons of the whales were found, people brought them to deposit in the temples or government institutions. About a hundred whale skeletons, both Bryde's and Omura's whales, are kept in Buddhist temples and institutions - including a 100-year-old specimen in Nakhon Si Thammarat Province in southern Thailand."

Dr. Adulyanuosol and Mr. Surasak Thaongsukdee, her colleague at the MCRC, seek to solve some of the mystery surrounding the Bryde’s whale. Since 2003, the Department has conducted boat surveys, photo identifying the whales and observing behaviors to learn more about their habitats and feeding grounds. Generally, however, only a few whales - four or five yearly - show themselves. Dr. Adulyanuosol and her colleagues were delighted, therefore, in early 2011 to see a large pod of about 35 individuals in the upper Gulf, including seven pairs of mothers and calves.

The researchers speculate that the sudden influx has to do with an unusual abundance of the anchovy, sardine and mackerel upon which the Bryde's whales prey - though the whales may also be consuming small crustaceans. The scientists (as well as a host of whale watchers who descended on the area) have gotten a good view of the whale’s feeding behaviors: "A single whale or a group of whales commonly perform lunge feeding within 3-20 kilometers off the coasts, where the water depth is about 10-15 meters. In some cases they feed in very shallow areas about 5-6 meters deep. They also performed bubble-net feeding." In 2011, MCRC staff observed several instances of mating behaviors, as well as a mother with a very young calf - leading them to believe that the Bryde’s both breed and give birth in the Gulf.

The research center hopes to further study the whales’ migration patterns and behaviors, as well as do satellite tagging and genetic studies. Thai scientists have collaborated with Japanese and Taiwanese researchers to do molecular work on Bryde’s whale bones, and are currently analyzing the data for publication. Not all of their output is so technical; recently the MCRC published Little Enden and the Happy Sea, an online children’s book about a Bryde’s whale calf’s journey to find a place where all animals and people could live well together. (The book is in Thai, but the Center will publish an English version, as well.)

By taking advantage of the unique opportunity in the Gulf of Thailand to observe so many Bryde’s whales in one place, the MCRC scientists hope to discover and communicate new information concerning this elusive species, and thereby increase public awareness of the need to protect them and their habitats.