Invasive alien species in changing marine arctic economies and ecosystems.

The rate of change in Arctic marine environments in response to shifts driven by climate change threatens Arctic resilience. The growing recognition and visibility of these changes have scientific and social roots. Mitigating these consequences is therefore a social-scientific concern. Multiple scales, perspectives, and governance systems for Arctic marine environments, alongside receding climate and economic barriers to species movements and scientific research, create challenges and opportunities that differ in magnitude and breadth from marine invasions elsewhere. The receding barriers in the marine Arctic amplify the potential ecological and economic consequences from new species introductions and range expansions from adjacent biomes. While there is consensus that marine invasive species can cause severe damages to ecosystems and resource-dependent communities, which species pose what threats, and to whom, remain complex dynamic socioecological and biogeophysical economic questions. Decisions over prevention, detection, and monitoring along with institutional frameworks for cooperating and responding to threats also affect the expected severity of impacts. Technologies, and costs, for identifying and monitoring species compositions and risks are evolving, with novel research advances as well as increasingly sophisticated ecological-economic, environmental niche, and habitat suitability models. Despite advances in understanding drivers and dynamics of new species introductions, a dearth of baseline knowledge regarding Arctic marine invasions remains. Potential consequences extend beyond ecosystem changes and include legal, institutional, and social shifts. Studies on the red king and snow crab invasions in the Barents Sea from multiple disciplinary angles showcase complex social, economic, and ecological interconnections that are transforming communities and ecosystems.

Alien and cryptogenic Foraminifera in the Mediterranean Sea: A revision of taxa as part of the EU 2020 Marine Strategy Framework Directive

The human-mediated translocation of marine alien species beyond their natural ranges started as early as people began navigating the sea and is of growing concern to nature conservation. The Mediterranean Sea is among the most severely affected areas by biological invasions, a phenomenon that has been fostered by the opening and recent extension of the Suez Canal, the transport and release of ballast water, aquaculture and aquarium trade, ichthyochory and other active or passive dispersal mechanisms. The increase of marine invasions has stimulated considerable research, but for some important groups, in particular microorganisms, data are still limited. In this paper we have reviewed the current status of marine alien foraminifera in the Mediterranean Sea. Our survey includes a comrephensive taxonomic revision of previously recognized alien taxa, and new information obtained from the fossil record and from molecular studies. Our survey and reexamination of alien benthic foraminifera yielded a total of 43 validly recognized species and two species of cryptogenic taxa and reduces the number of previous recordings. The revised list includes both larger symbiont-bearing and smaller benthic foraminifera, including 16 hyaline-perforate, 3 agglutinated and 24 porcelaneous taxa. The vast majority of alien foraminifera recorded so far have become established in the Eastern and Central Mediterranean Sea, indicative for translocation and introduction via the Suez Canal pathway. Only one species, Amphistegina lobifera, causes significant ecological impacts and fulfills the criteria to be considered as an invasive alien. This species is a prolific carbonate producer, and displays extreme forms of ecosystem invasibility with capabilities to reduce native diversity and species richness. The proliferation and rates of recently observed range extensions, track contemporary sea surface temperature increases, provide strong support for previous species distribution models, and corroborate findings that rising water temperatures, global climate change and the extension of climate belts are major drivers fueling the latitudinal range expansion of larger symbiont-bearing and smaller epiphytic foraminifera. Intensified efforts to study alien foraminifera on a molecular level, in dated cores and in ballast water are required to trace their source of origin, to identify vectors of introduction and to verify their status as true aliens.

Extreme dispersal or human-transport? The enigmatic case of an extralimital freshwater occurrence of a Southern elephant seal from Indiana

Elephant seals (Mirounga spp.) are the largest living pinnipeds, and the spatial scales of their ecology, with dives over 1 km in depth and foraging trips over 10,000 km long, are unrivalled by their near relatives. Here we report the discovery of an incomplete Holocene age Southern elephant seal (M. leonina) rostrum from Indiana, USA. The surviving material are two casts of the original specimen, which was collected in a construction excavation close to the Wabash River near Lafayette, Indiana. The original specimen was mostly destroyed for radiometric dating analyses in the 1970s, which resulted in an age of 1,260 ± 90 years before the present. The existence of sediments in the original specimen suggests some type of post depositional fluvial transportation. The prevalent evidence suggests that this male Southern elephant seal crossed the equator and the Gulf of Mexico, and then entered the Mississippi River system, stranding far upriver in Indiana or adjacent areas, similar to other reported examples of lost marine mammals in freshwater systems. Based on potential cut marks, we cannot exclude human-mediated transportation or scavenging by Indigenous peoples as a contributing factor of this occurrence. The material reported here represents by far the northernmost occurrence of a Southern elephant seal in the Northern Hemisphere ever recorded. The unusual occurrence of a top marine predator >1,000 km from the closest marine effluent as a potential extreme case of dispersal emphasizes how marine invasions of freshwater systems have happened frequently through historical (and likely geological) time.

Invasions can drive marine disease dynamics

Over half the world’s human population lives near the coast, with diverse impacts on the structure and function of coastal ecosystems, including the introduction of parasites that result from shipborne trade, aquaculture, and other human-aided dispersal. The scale of these activities has accelerated through time, expanding the potential for new introductions and subsequent impacts in coastal systems. However, the extent, dynamics, and impacts of marine parasite invasions are relatively unexplored compared to free-living organisms. This chapter (1) advances a framework to consider which parasites are most likely to invade, specifically considering diverse life-history traits, (2) reviews the current baseline knowledge for transfer mechanisms and the history of marine invasions, and (3) considers the ecological and evolutionary implications of parasite invasion. While recent advances have aided our understanding of the intersection of disease and invasion ecology, a closer look at the smallest disease-causing organisms will open new avenues for understanding the full scope of parasite invasions and their role in emerging diseases.

Alien Invasive Species Impacts on Large Lake Ecosystems and Their Economic Value

Globalization of trade and travel has made possible the spread of alien species across the planet. Invasive species are presently considered as one of the major threats to biodiversity in many locations throughout the world. Thousands of AIS have been transported globally by a number of anthropogenically-mediated vectors, including ship-mediated vectors (e.g., ballast water, hull-fouling), recreational boating, live bait, aquarium trade, live food fish, and unauthorized introductions. Ballast water is one of the leading vectors for transporting and introducing species, both in Canada and around the world, and is responsible for the transport of at least one third of all documented marine invasions. Since invasive species have no regard for political boundaries, efforts to prevent invasions need to be interjurisdictional. Given, also that invasive species often travel as contaminants of trade transfers, for example, in the ballast tanks of ships, reducing the spread of invasive species via this pathway would either require constraints on where ships travel, or the installation onto all ships of expensive ballast treatment technology, thereby increasing the cost of shipped goods. As such cost benefit analysis involves trade-offs with other activities, complicating decisions about how impacts can best be managed.