Red swamp crawfish turning up in Alaska

Warming oceans have brought news of many new and invasive species in Alaska and the Pacific Northwest.

The Alaska Department of Fish and Game reports that crawfish, also known as crayfish or crawdads, a species of freshwater crustaceans related to shrimp and lobster, have been caught twice in the last four years in gillnets in the Kenai River, a long way from their native habitat of the swamps of Louisiana and other areas of the southern United States.

Luckily, those specimens were dead, apparently tossed in the river from a “crawfish boil” party.

More alarming, red swamp crawfish have apparently established a breeding population in the Buskin River and Buskin Lake in Kodiak.

ADFG reports that according to Robert Romaire and Ray McClaine, aquaculture professors with Louisiana State University, red swamp crawfish have been introduced to places with similar climates to Southcentral Alaska. 

“Invasive populations of red swamp crawfish are now found in the northwestern United States, Great Britain, Germany, and Switzerland,” Romaire said. In these locations, McClaine said, “invasive red swamp crawfish have caused many environmental and economic problems because they out-compete native crawfish and damage rice crops.” 

In Alaska, there are no native crawfish or rice crops, but Romaire said, “Red swamp crawfish could easily become established in Alaska,” which they apparently are doing.

They could feed on salmon eggs and alter aquatic plant communities that provide shade and protection for juvenile trout and salmon. They could also directly out-compete trout and salmon for aquatic insects and other invertebrate prey.

While they are not considered invasive species, fish that normally inhabit waters farther south are turning up in Alaska and British Columbia.

The Times Colonist in Victoria, B.C., reports that a recent study turned up 37 more species of fish in the Salish Sea since 1980.

Among the newcomers are the Pacific viperfish, northern flashlightfish and longsnout prickleback.

There are other species more frequently being spied in the waters of Alaska, including what NOAA calls “tropically inclined” sunfish, spotted 40 miles off of Icy Point in Southeast Alaska.

Also, Ketchikan is experiencing its largest plankton bloom in at least 30 years; Auke Lake’s out-migrating pink salmon left earlier this year than they ever have; water temperatures in the Gulf of Alaska are a degree to several degrees warmer than normal, and whales have floated belly-up in Kodiak. 

Cristy Fry can be reached at realist468@gmail.com.

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