Species that are considered uncertain risk need a more in-depth assessment beyond the Risk Summary to better define the species’ risk to U.S. environments.
Gasterosteus islandicus, Iceland Stickleback, is a stickleback species native to Iceland. It was previously considered a subspecies of G. aculeatus but is currently recognized as its own valid species by Fricke et al. (2018). G. islandicus has never been reported as introduced or established outside of its native range, therefore history of invasiveness is uncetain. This species has a low climate match with the contiguous United States. Further information on invasiveness, taxonomy, and distribution is needed to adequately assess the risk this species poses to the contiguous United States, so the certainty of this assessment is low. The overall risk assessment category is uncertain.
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Uncertain Risk
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