Arctic Yearbook 2015 - Page 181

181 Arctic Yearbook 2015 of ecological consequences of the invasions and their spread are well founded – the RKC fishery in the Barents is particularly lucrative at the moment, while for SC there is also a growing interest from the seafood and fishery industries (Grimsmo 2015; Olsen 2015; Ripman 2015). With SC estimated to produce between 25,000-75,000 tons per year within the next ten years (Hvingel & Sundet 2014), this attractive economic gain may hasten activities that should be delayed for improved information regarding the potential damages to the benthic habitat. The economic gains may even promote decisions that delay the research in order to avoid knowing the true ecosystem costs, creating additional bias in the types of scientific research undertaken. Climate change induced invasions Indirectly, climate change impacts, considered the main underlying cause of northward habitat migration, must also be addressed in efforts to maintain existing Arctic ecosystem function at risk from invasions. Habitat migration is fraught with uncertainties while often uncontrollable at local or even regional scales, which is an indicative example of why the benefits of the colder “Old Arctic” cannot be easily replaced. This initiates discussions on examining related costs within different contexts (economic behavior, climate change mitigation costs, etc.) in terms of endeavors to more appropriately distribute them amongst global inducers of climate change and/or among the above mentioned “development players,” rather than, through inaction, pushing the costs on to ecosystems and those who rely on their current services. Climatic changes have significant ramifications in Arctic marine ecosystems while the realm of impact categories differs across the scale of analysis and evaluation approaches. When it comes to marine invasions, two major types of introductions are being identified: the ones that pertain to species already ecosystem adapted (Arctic or sub-Arctic species) and the ones that pertain to species that have managed to adapt to Arctic climatic conditions and/or are able to survive in the ecosystem thanks to the increasing temperature of the water (usually northward moving species). Transarctic invasions are not a new phenomenon. Historical experience underlines such invasions about 3.5 million years ago, during the warm mid-Pliocene epoch when hundreds of marine lineages managed to colonize out through the Bering Strait, resulting in enriched Arctic and North Atlantic biotas (Vermeij & Roopnarine 2008). According to Reid, Edwards & Johns (2008) there is mounting evidence that interoceanic exchange is already re-occurring, with the presence of a Pacific planktonic diatom (Neodenticula seminae) in the Labrador and Irminger Seas that is generally found in the North Pacific and the Bering Sea. Reid, Edwards & Johns (2008) thus consider the return of the species in the N orth Atlantic as a sign of trans-Arctic migration, potentially leading to invasions of large scale similar to the ones that took place in the Pliocene trans-Arctic interchange. Indicatively, as the literature points out (Vermeij & Roopnarine 2008), 56 molluscan lineages that are currently present in the Bering and Chukchi seas, as well as the Pribilof Islands and Anadyrski Gulf, and that did not participate in the aforementioned trans-Arctic expansion are considered potential invaders. The SC may indeed be one such current example. Current theory suggests that the species has moved to the Barents Sea through natural dispersal routes from the Pacific Arctic (Sokolov 2015), while it certainly did not come from Greenland (Agnalt 2015). Kourantidou, Kaiser & Fernandez