Swimming in circles alongside a fishing boat, two short-haired otters speed across a river in southern Bangladesh that feeds into the Sundarbans, the world’s largest mangrove forest.
The fishermen lower a net close to the riverbanks and the animals splash into the water.
The rare technique relies on coordination between man and trained otters, a centuries-old partnership that has already died out in other parts of Asia.
“Our job depends on the otters,” says Shashudhar Biswas, a fisherman in his 50s, whose family has trained the animals for generations. The otters do not catch the fish, but instead chase them toward the net next to the boat.
“The otters manage to spot fish among the plants, then the fish swim away and we stay close with our nets. If we did it without them, we wouldn’t be able to catch as many fish,” says Shashudhar’s son Vipul, standing as he steers the boat along the leafy canal.
Fishing is usually done during the night when the fishermen can expect to catch between four and 12kg of fish, shrimp and crabs.
The family earns around US$250 a month selling their catch at the local market.
However, in recent years, once-abundant fish are increasingly scarce and the nets dragged up are often empty.
“The kinds of fish we used to find with our father, we don’t see here anymore,” says Vipul.
Natural fish populations have crashed in recent years, says Mohammed Mostafa Feeroz, a zoology professor at Dhaka’s Jahangirnagar University, because “the fish simply cannot breed.”
“Over-sedimentation, water pollution from oil and the use of pesticides in [rice] paddy fields, as well as over-catching are all having an impact,” Feeroz said.
Feeroz has been studying otter fishing in Bangladesh for 25 years. Over this period the number of families involved has dropped from 500 to 150.
“Go back 50 years, and the practice has declined by about 90 percent,” he says.
If the trend continues, he believes otter fishing will be “completely wiped out” within the next two decades.
Though still in his 20s, Vipul is equally pessimistic.
“If there are no fish, then there’s no point in having the otter-fishing system,” he says.
“Just look at my family’s situation. My brothers and sisters, they all want to study. They don’t want to get into the river and catch fish. If they study, then they will obviously move out of the village to find better jobs, or they will buy fish from the wholesaler and sell them,” he adds.
He worries that his only source of income will soon no longer be profitable.
Each month almost half of his earnings are spent on feeding his five otters — two fully trained adults and three young apprentices — who eat 3 to 4kg of fish a day.
Wildlife experts fear it is not only the livelihoods of the fishing families that are under threat.
Short-haired otters are an endangered species in Bangladesh; otter fishing plays a key role in their conservation, Feeroz says.
“The captive population here is very healthy because of the fishing,” he says.
Sometimes fishermen release otters into the wild, which strengthens that population, research shows.
“However, as the practice gradually decreases, the wild population will face increased pressure,” he adds.