As dawn breaks over Ghana's Atlantic coast, artisanal fishing boats return to shore with last night's catch -- baskets of snapper, crabs, rays and a distinct-looking fish locals call "esene".

Once abundant along Ghana's shores, esene, or guitarfish -- with the flattened body of a ray and the tail of a shark -- have become increasingly difficult to find.

For conservationist Issah Seidu, 36, every landing is a reminder that time is running out to save the endangered species.

After studying terrestrial wildlife, he visited coastal fishing communities in 2018 and encountered what scientists describe as one of the world's least-known conservation crises.

"We came to these communities and saw piles of sharks, rays and guitarfish being landed without any thought about conservation," Seidu told AFP.

"That was the moment I realised somebody had to do something," said the wildlife biologist, who never dreamt of a career revolving around the sea.

Guitarfish -- relatives of both sharks and rays -- are among the world's most threatened marine fish, red-listed as "critically endangered" by the International Union for Conservation of Nature (IUCN).

Their meat is a delicacy widely eaten locally, while their fins command high prices in international markets.

Across west Africa, populations have collapsed.

Sawfish may have already disappeared from Ghana's waters and wedgefish, another close relative, have become increasingly scarce.

Seidu fears guitarfish could be next.

- Winning over fishermen - The biggest challenge has been persuading fishermen to stop catching one of their most valuable species.

Seidu's NGO AquaLife Conservancy has helped boost knowledge about conservation.

And instead of simply asking fishermen to stop, it has helped develop snail farming as an alternative livelihood.

NGO AquaLife Conservancy has helped develop snail farming as an alternative livelihood for fishermen (768x512, AR: 1.50)Today, rows of giant African snails crawl inside wooden pens in Adjoa, a coastal community where fishing families are testing the new source of income.

"The fishermen themselves selected snail farming," said Seidu -- and they cannot meet the demand.

Edward Afful, a fisherman of 20 years, says shrinking catches have left many crews struggling to recover the cost of fuel for their boats.

He now raises snails alongside fishing.

"If we had....