Salmon fishing communities in the Pacific northwest are desperately trying to catch an invasive species of Atlantic salmon that escaped from nets over the weekend. Cooke Aquaculture, which was farming the fish, blamed the fiasco on eclipse-induced high tides—though conservation groups are skeptical.

The company estimates that between 4,000 and 5,000 fish escaped into the Pacific waters, the Seattle Times reports. The aquaculture facility held held roughly 2,600,000 pounds (1,300,000 kilograms), or 305,000 Atlantic salmon.

Tides are caused by the moon’s gravitational pull on the Earth, and to a lesser degree the sun’s, causing higher than normal sea levels when the two are aligned. The US National Oceanic and Atmospheric Administration reports that the high tides in the area were about seven feet and four inches—not too much higher than typical levels.

The farmed Atlantic salmon—in the wild, an endangered species—can grow to be up to 32 inches (81 cm) with black spots on their gills and large scales. They often exhibit wear and tear on their fins from farm nets.

Fishers from the Lummi tribe first noticed the escaped Atlantic salmon when they were out fishing for native Chinook salmon on Sunday. Chinook, or king salmon, are massive fish that can grow over 100 pounds and have the most fat (read: deliciousness) of any salmon species. They’re usually silver in color with black spots on their tails and under their jaws.

It’s unclear whether or not these Atlantic salmon will affect the Chinook salmon population. The concern is that the Atlantic salmon will outcompete Chinook salmon for food, breed with them to create hybrids, or spread diseases like sea lice.

“What my research showed is that they do escape, they do survive, they will ascend rivers, they will reproduce with each other and they will produce viable offspring that are competitively equal or superior to Pacific salmon,” John Volpe, an ecologist at the University of Victoria, told the Globe and Mail.

Salmon fishing is tightly regulated, but the Washington state Department of Fish and Wildlife has removed fishing limits on the escaped Atlantic salmon until further notice.

Quartz has reached out to Cooke Aquaculture, and will update this post with additional information if the company responds.