Most of the seabirds caught in the nets have been razorbills
Hundreds of seabirds have died this summer after becoming entangled in fishing nets in Filey Bay on the North Yorkshire coast, the RSPB has warned.
The salmon and sea trout fishery was closed for two weeks by the Environment Agency because of the high numbers of bird casualties reported by the RSPB.
But it was reopening on Thursday after the voluntary closure agreed with local fishermen came to an end.
The RSPB said it was "extremely concerned" many more birds would die.
"The timing could not be worse, with the fishery due to reopen at a particularly sensitive time when there are likely to be large numbers of the birds using Filey Bay," said Kate Tanner, a marine policy officer with the RSPB.
"RSPB observers have witnessed horrific scenes of scores of seabirds floundering and drowning in nets set by the fishermen just offshore.
"We welcomed the temporary voluntary closure of the fishery, but we now have to work with all those involved to find a long-term solution to this terrible situation."
The RSPB has been working with the Environment Agency, which licenses the fishery, and Natural England, the government's statutory nature conservation agency, to solve the problem.
The RSPB wants to support a sustainable fishery in Filey Bay, but is concerned that it would be compromised if the large-scale death of seabirds could not be prevented.
So far the majority of the seabirds caught have been razorbills, but it is possible that other locally-nesting seabirds, such as guillemots and puffins, may be caught up in the nets too.
They are thought to have come from colonies in the nearby Flamborough Head protected sites, including the RSPB's Bempton Cliffs nature reserve.
David McCandless, the North East Sea Fisheries Committee's Chief Fishery Officer, said: "It's a difficult situation.
"The fishermen are equally unhappy about the seabird deaths but need to continue because this is a very important part of their livelihood.
"Only a small number of fishermen are involved - there are only about seven or eight licences for Filey Bay - but they are unable to move to areas where the birds aren't feeding.
"Under the terms of the licences there is no flexibility - they have to operate in particular places."