Lying in hospital with bloodied bandages over the deep gashes in his legs, Senegalese fisherman Ali Fall recalls the moment a hippopotamus tried to kill him as he hauled in nets in a local river.

"I came with another fisherman to pick up the nets I had left when the hippopotamus upended our boat. My friend got away but it bit into my left leg, then my right," said the shaken 25-year-old.

The waters of Gouloumbou in eastern Senegal, a tributary of the river Gambia and the village where Fall lives, have often run red with the blood of his peers.

In the last decade, 25 fishermen have been mauled to death in the giant jaws of these easy to provoke mammals and many more injured, village officials said.

"It's the second time I've been attacked, after their first attempt in 2014. I've cheated death twice," said Fall from his hospital bed in the nearby city of Tambacounda.

Back in Gouloumbou, which lies 500 kilometres (310 miles) east of the capital Dakar, village chief Abdoulaye Barro Watt looks out of the windows of his office, next to the river where locals continue to risk death with few other options for a livelihood in this rural area.

They were all fisherman hoping to make a living for their families," he said.

"These men are struggling to survive due to these attacks. I have written so many letters to the authorities, even the fisheries minister, to make them aware of the problem."

Gouloumbou villagers and the massive hippopotamuses once lived together in relative safety, the chief said. "We used to play with them in the river. They were harmless."

That has all changed, said fisherman Abdoulaye Sarr, sitting with a friend, Moussa Bocar Gueye. "They are evil monsters who attack us night and day. Because of them, we haven't been fishing."

Both men are from the "thiouballo" ethnic group which has long made its living from fishing but neither will be launching their "pirogue", or traditional wooden boat, onto the river today.

"It's three weeks since we last went fishing," Gueye added. "There aren't any more fish at the market."

Hippopotamuses, vegetarians that live in or near swamps and rivers, can weigh up to 1,500 kilogrammes (3,300 pounds) and spend long hours in water to protect their skin from the sun.

Easily irritated with terrifying strength, the mammals kill more humans each year than almost any other animal in Africa because of their volatile nature, according to wildlife experts.

- Protected, but deadly -

Senegal lists the hippopotamus as a protected species, so culling them is illegal. Their current number is unknown, but a survey is underway to track their presence in the country.

It is not only fishermen who fear the giant beasts. A lack of running water makes villagers dependent on the river to wash themselves and their clothes.

"I'm scared they'll attack. That's why I always stay facing the river," said Aminata Sy, a woman in her forties scrubbing her laundry.

"We don't have a well or any taps," she added, keeping a close eye on children swimming nearby.

The fishermen have pressed the government to send them motorised boats, and a first lot has been promised.

"The fisheries ministry will provide the fishermen of Gouloumbou with 20 metal pirogues (with motors), which are more resistant to attacks," said Djibril Signate, national director of inland fishing.

"We are installing a fish farming enclosure in Gouloumbou. The ministry has also distributed nets, hooks and lifejackets so they can fish in pools that are chock full (of fish)," Signate added.

Different explanations are given for the attacks.

Fishing officials say hippopotamuses are especially aggressive at this time of year when the females are giving birth.

But fisherman Sarr says a decline in superstition is responsible.

"Practising magic protected people from the river, but now they don't treat it properly, washing their clothes and dishes."

He warned, darkly, that a Malian fisherman was to blame, after cursing the village following an argument over pricing in 2007.

Whatever the cause, fisherman Fall will take no more chances.

"After I get better, I'm changing profession," he said.