Bering Sea Marine Invasives

There are relatively few non-native species in the Bering Sea. However, Arctic regions are expected to become more susceptible to biological invasions. Changes in vessel activity and climate are predicted to increase the probabilities of successful introduction and establishment. Given the importance of the Bering Sea to Alaskans and the current lack of knowledge on this topic, evaluating the potential threat of non-native species is needed.

We conducted a risk assessment for the Bering Sea that included 1) profile reports of important non-native species; 2) a ranking system, which we used to assess the risk each species posed to the Bering Sea; 3) environmental suitability models for these species under current and future climate scenarios; 4) an analysis of shipping traffic to the region to identify ports of entry for non-native species.

Ranking system

Our ranking system evaluates the potential threat of non-native taxa to the Bering Sea. Each species is evaluated and scored independently following an in-depth literature review. Overall scores can range from 0 (least threat) to 100 (highest threat). The system contains 33 questions grouped into 5 categories. A score is calculated for each question based on the response selected. The ranking system can account for missing data by calculating the final score based only on known answers. We evaluated a total of 46 taxa that occur in the Bering Sea and nearby marine ecoregions.

Nearest Occurrence	Taxonomic Group	Scientific Name	Common Name	Rank Score	Status Report
1E- Gulf of Alaska	Mollusks - Bivalves	Crassostrea gigas	Pacific oyster	74.25
2E- Alaskan Panhandle / British Columbia	Crustaceans - Crabs	Carcinus maenas	European green crab	69.5
1W- Oyashio Current	Mollusks - Bivalves	Mytilus galloprovincialis	Mediterranean mussel	67.75
2E- Alaskan Panhandle / British Columbia	Tunicates	Didemnum vexillum	Carpet sea squirt	65.64
1E- Gulf of Alaska	Crustaceans - Barnacles	Amphibalanus improvisus	Bay barnacle	65.21
0- Bering Sea	Crustaceans - Amphipod	Caprella mutica	Japanese skeleton shrimp	64.95
1W- Oyashio Current	Mollusks - Bivalves	Venerupis philippinarum	Japanese littleneck clam	63.24
2E- Alaskan Panhandle / British Columbia	Bryozoans	Bugula neritina	Brown bryozoan	62.63
0- Bering Sea	Mollusks - Bivalves	Mya arenaria	Soft-shell clam	59.5
2E- Alaskan Panhandle / British Columbia	Bryozoans	Watersipora subtorquata complex	N/A	58.51
2E- Alaskan Panhandle / British Columbia	Tunicates	Botryllus schlosseri	Golden star tunicate	57.95
1W- Oyashio Current	Crustaceans - Barnacles	Amphibalanus amphitrite	Striped barnacle	57.5
1W- Oyashio Current	Crustaceans - Amphipod	Jassa marmorata	N/A	57.18
1E- Gulf of Alaska	Tunicates	Botrylloides violaceus	Chain tunicate	56.25
1W- Oyashio Current	Tunicates	Styela clava	Clubbed tunicate	55.25
2E- Alaskan Panhandle / British Columbia	Cnidarians - Hydrozoan	Ectopleura crocea	Pink-mouthed hydroid	54.47
2E- Alaskan Panhandle / British Columbia	Mollusks - Bivalves	Teredo navalis	Naval shipworm	54
1E- Gulf of Alaska	Tunicates	Molgula citrina	N/A	53.15
3E- Vancouver, Washington, Oregon	Tunicates	Diplosoma listerianum	Compound sea squirt	52.75
2E- Alaskan Panhandle / British Columbia	Tunicates	Ciona savignyi	N/A	52.25
1E- Gulf of Alaska	Bryozoans	Schizoporella spp.	Orange ripple bryozoan	51.78
3E- Vancouver, Washington, Oregon	Crustaceans - Crabs	Eriocheir sinensis	Chinese mitten crab	51.75
3E- Vancouver, Washington, Oregon & 3W- Sea of Japan/East Sea	Annelid - Polychaete	Polydora cornuta	Whip mudworm	51.25
1W- Oyashio Current	Crustaceans - Tanaids	Sinelobus cf. stanfordi	N/A	50.42
3E- Vancouver, Washington, Oregon	Cnidarians - Anthozoans	Diadumene lineata	Orange-striped green anemone	50.13
3E- Vancouver, Washington, Oregon	Crustaceans - Isopods	Limnoria tripunctata	N/A	50
3E- Vancouver, Washington, Oregon & 3W- Sea of Japan/East Sea	Crustaceans - Shrimp	Palaemon macrodactylus	Oriental shrimp	49.87
3E- Vancouver, Washington, Oregon	Mollusks - Gastropods	Philine auriformis	New Zealand sea slug	49.71
0- Bering Sea	Fishes	Alosa sapidissima	American shad	49.25
0- Bering Sea	Fishes	Salmo salar	Atlantic salmon	49.25
3E- Vancouver, Washington, Oregon	Annelid - Polychaete	Pseudopolydora cf. kempi	N/A	47.4
3E- Vancouver, Washington, Oregon	Crustaceans - Amphipod	Melita nitida	N/A	47.3
3E- Vancouver, Washington, Oregon	Cnidarians - Hydrozoan	Cordylophora caspia	N/A	46.84
3E- Vancouver, Washington, Oregon & 3W- Sea of Japan/East Sea	Mollusks - Gastropods	Crepidula onyx	Onyx slippersnail	46.84
3E- Vancouver, Washington, Oregon	Mollusks - Bivalves	Macoma petalum	Atlantic macoma	46.75
3E- Vancouver, Washington, Oregon	Mollusks - Gastropods	Tritia (Ilyanassa) obsoleta	Eastern mudsnail	46.41
2E- Alaskan Panhandle / British Columbia	Mollusks - Gastropods	Batillaria attramentaria	Asian horn snail	46
2E- Alaskan Panhandle / British Columbia	Tunicates	Molgula manhattensis	N/A	45
3E- Vancouver, Washington, Oregon	Mollusks - Bivalves	Petricolaria pholadiformis	False Angelwing	44.11
3E- Vancouver, Washington, Oregon	Cnidarians - Anthozoans	Nematostella vectensis	Starlet sea anemone	43.47
3E- Vancouver, Washington, Oregon	Crustaceans - Isopods	Synidotea laticauda	N/A	39.45
3E- Vancouver, Washington, Oregon	Annelid - Polychaete	Hediste diadroma	N/A	38.83
3E- Vancouver, Washington, Oregon & 3W- Sea of Japan/East Sea	Crustaceans - Copepods	Mytilicola orientalis	Red worm	36.12
3E- Vancouver, Washington, Oregon	Crustaceans - Copepods	Limnoithona tetraspina	N/A	34.26
3E- Vancouver, Washington, Oregon	Crustaceans - Ostracods	Eusarsiella zostericola	N/A	33.91
3E- Vancouver, Washington, Oregon	Crustaceans - Amphipod	Paracorophium spp.	N/A	29.15

Acknowledgments

This project was made possible through funding from the North Pacific Research Board (project #1523) and the Aleutian and Bering Sea Islands LCC (ABSI LCC). Tracey Gotthardt and Aaron Poe were instrumental in developing this project. Casey Greenstein, Lindsey Flagstad, Catie Bursche, Jaime Weltfelt, and Curtis Whisman contributed to developing the ranking system and the species status reports. Thank you to Jennifer Dijkstra, Nora Foster, Kelly Krueger, Linda Shaw, Christina Simkanin, and Peter Westley for the time and energy they put into the expert review process.