SEATTLE -- More seal pups are showing up dead along Alki Beach and a marine mammal group says fishing practices may be at fault.

Members of the conservation group Seal Sitters are pointing their fingers at Native Americans who string their nets in areas where seals beach themselves.

If a seal gets caught in a tribal fisherman's net and dies, it is classified as an accident under treaty rights.

But seal deaths at Alki have more than doubled in the past year, according to a report by the National Oceanic and Atmospheric Association. And Seal Sitters claim trial fishing practices are partially to blame.

"It's not nature taking its course. It's humans taking our course," said Brenda Peterson of Seal Sitters.

Seven seal pups have been found dead at Alki so far this year. Three were found last year.

Peterson's group wants more accountability among Native American fishermen, who have exclusive treaty rights to Alki Beach. At minimum, the group wants fishermen to stay and watch the nets so they could help free the seals who get caught.

"There is no plan at this time to require fishermen to do that. (I'm) not saying that wouldn't change," Peterson said.

The debate comes just weeks after a seal controversy involving a tribal fisherman.

Last month, some people at Alki caught sight of a seal tangled up in a fisherman's net. Those witnesses said the seal struggled for hours before the fisherman showed up. Once the seal was freed, the fisherman allegedly banged the seal against the side of his boat twice.

"We lost quite a few pups from that particular fisherman in October and we don't want it to happen again."

Tribal leaders investigated and said the fisherman did nothing wrong.

"The seal was determined to be dead when it was brought in the boat," said Robert Purser with Suquamish Tribal Fisheries.

But marine mammal advocates say the photos taken by witnesses depict the opposite.

"Every witness I spoke with, including our biologist, and the fishermen on the beach said that pup was alive," Peterson said.

Members of Seal Sitters say they support the tribes' right to fish, but they believe the fishermen should be held accountable for their behavior in the water.

"There is a treaty we have with the animals and the wildlife in this region that we, to the best of our ability, protect them from harm," said Peterson.