Dozens of Nigerian fishermen are feared dead after Chad's military launched air strikes on Boko Haram militants in the Lake Chad region, a local fishermen's leader has told the BBC.

Abubakar Gamandi Usman, chairman of Lake Chad Basin Fisheries Association of Nigeria, said several of the union's members were missing and estimated more than 40 had died.

No bodies have yet been recovered, but Usman believes some fishermen were hit by the strikes, while others drowned after attempting to flee in overloaded boats.

Authorities in Chad and Nigeria have not commented, but on Sunday, Chad's presidency said it had carried out retaliatory "intensive air strikes" on Boko Haram strongholds.

In a statement on Facebook, the presidency said it had responded to "unjustified attacks" by Boko Haram, which took place last Monday and Wednesday and targeted Chadian military bases near Lake Chad, reportedly killing at least 24 soldiers and two generals.

The Lake Chad basin is a huge region of waterways and swampland shared by Nigeria, Chad, Niger and Cameroon. It has long been a stronghold for Boko Haram and its rival faction, Islamic State West Africa Province (Iswap).

"After Boko Haram attacked Chadian forces, they retreated to islands they operate from. Fishermen also inhabit these islands," Usman told the BBC.

After Chad's air force began circling overhead on Friday, panic broke out, with both Boko Haram fighters and fishermen attempting to flee.

The search for the missing fishermen has been slow, Usman said, as some parts of Lake Chad are very deep. The local community also has limited access to canoes, as many are controlled by Boko Haram, Usman added.

"Boko Haram controls access to the fishing grounds, transporting fishermen to and from the fish market to the fishing site. Boko Haram collects taxes from these fishermen," he said.

Recently, the region has seen a rise in attacks on security forces, as well as kidnappings and raids on communities.

Chadian military operations have been accused of causing civilian deaths before - in October 2024, the air force was said to have killed dozens of Nigerian fishermen during air strikes targeting Boko Haram fighters on Tilma Island in Lake Chad.

Nigeria's military has also been accused of claiming civilian lives during operations against armed groups and jihadist fighters, though authorities often describe such deaths as unintended collateral damage.

Most recently, the armed forces denied media reports that civilians were killed during a series of air strikes in the central Niger state on Sunday.

Military spokesperson Maj Gen Michael Onoja said the operations were "executed based on credible, actionable intelligence".