The earliest records of non-native marine and estuarine invertebrates in Alaska date to the late 1800s and early 1900s. However, most marine and estuarine non-native invertebrates were detected much more recently, with over 75% of first records occurring after 1990. Crustaceans (amphipods and crabs) and tunicates have been the groups most commonly detected to date.

Geography and Climate

Alaska is the United States' northernmost and largest state, residing between 51°N and 71°N with a landmass covering 570,380 square miles. It is also considered both the westernmost and easternmost state, since the Aleutian Island chain crosses the International Dateline. Alaska has nearly 47,000 miles of tidal shoreline including numerous islands and is surrounded by the North Pacific Ocean, the Bering Sea, the Chukchi Sea, and the Beaufort Sea. Along Alaska's various coastlines, climate varies considerably with latitude, water temperatures, currents, continental geography, and sea ice extent. The southeastern and southwestern regions of Alaska (bordering the Pacific Ocean and Gulf of Alaska) experience a maritime climate, while the coastal climate transitions to subarctic and arctic from the Bering Sea up to the Chukchi and Beaufort Seas. Marine bioregions that border Alaska are NEP-I, NEP-II, NEP-III, and the Polar Arctic.

Overview

With its extensive coastline, northern latitude, and shipping patterns heavily influenced by the oil and gas industries, Alaska is a unique state in regard to marine and estuarine non-indigenous species (NIS). Although Alaska has relatively few records of NIS compared with other states on the west coast of North America, marine and estuarine NIS detections in Alaska are increasing. Coastwise transfer of NIS from other, more heavily invaded eastern Pacific regions is a significant pathway for introductions and major human activities at risk of transferring NIS to Alaska include shipping (via both ballast water and hull fouling), aquaculture, and the live bait trade. Climate change may encourage northward spread of NIS into Alaska as increasing sea temperatures lower the barriers for NIS already established at lower latitudes. The emergence of Arctic shipping routes as sea ice recedes may also create additional pathways for NIS to become established in Alaskan waters.

Taxonomic GroupNameYearInvasion StatusPopulation Status
FishesAlosa sapidissima1893DefiniteEstab
Crustaceans-AmphipodsAmpithoe valida1995DefiniteEstab
TunicatesBotrylloides violaceus1999DefiniteEstab
TunicatesBotryllus schlosseri2001DefiniteEstab
AlgaeCampylaephora kondoi*1967DefiniteEstab
Crustaceans-AmphipodsCaprella mutica1995DefiniteEstab
Crustaceans-CrabsCarcinus maenas2022DefiniteEstab
AlgaeCaulacanthus okamurae1996DefiniteEstab
AlgaeChroodactylon ornatum*1998DefiniteEstab
TunicatesDidemnum vexillum2010DefiniteEstab
Cnidarians-HydrozoansEctopleura crocea2003DefiniteEstab
AlgaeGracilaria vermiculophylla2017DefiniteEstab
TunicatesMolgula citrina2008DefiniteEstab
Mollusks-BivalvesMya arenaria1905DefiniteEstab
Crustaceans-IsopodsOrthione griffenis2017DefiniteEstab
AlgaeSargassum muticum1974DefiniteEstab
BryozoansSchizoporella japonica1998DefiniteEstab
AlgaeStirkia sinicola*1998DefiniteEstab
ProtozoansTrochammina hadai*1989DefiniteEstab
* = Species summary still under review.