Arctic charr (Salvelinus alpinus): a case study of the importance of understanding biodiversity and taxonomic issues in northern fishes

Abstract

Charrs, fishes of the genus Salvelinus (Salmonidae), comprise about 7-20þ species important in the ecosystems and fisheries of Arctic and sub-Arctic waters. Charrs vary by life-history type (anadromous vs. lacustrine), are noted for variability in morphology, colouration and feeding and habitat use across their range, and occur from temperate regions to the northernmost areas of land. Charr diversity is manifested as an often confusing array of taxonomic and functional diversity. Components of taxonomic diversity include unresolved species' complexes, subspecies, glacial lineages and genetic stocks. Features associated with functional diversity include semi-distinct life history variants and differential habitat and feeding tactics resulting in distinctive growth forms. Complex periglacial histories, allopatric and sympatric diversification processes, founder effects, hybridisation and introgression have contributed to the observed variability and complexity. The categorisation of taxonomic and functional diversity and understanding their roles, drivers and vulnerabilities underpins conservation and management efforts for taxa and their ecosystems. In that context, Arctic charr is an excellent example of diversity and the many levels of difficulties associated with determining the significance of diversity. Despite recently increased scientific efforts, resolving the nature and importance of charr diversity remains both a challenge and a priority because rapid anthropogenically driven change, especially climate change, is altering ecosystems and biodiversity faster than diversity can be inventoried, its importance understood and protective measures developed.

The role of Salvelinus in contemporary studies of evolution, trophic ecology and anthropogenic change

“…Reist et al, 2006Reist et al, , 2013Jeppesen et al, 2012). Recently, there has been a focus on anthropogenic contamination in Arctic environments, specifically related to bio-magnification of mercury as a problem in non-industrialized highlatitude areas (e.g.…”

Preference for nearshore and estuarine habitats in anadromous Arctic char (Salvelinus alpinus) from the Canadian high Arctic (Victoria Island, Nunavut) revealed by acoustic telemetry

“…The Arctic char (Salvelinus alpinus) is a facultatively anadromous salmonid with a circumpolar distribution (Johnson 1980;Nordeng 1983;Reist et al 2013). Migratory individuals leave the fresh water at ice-breakup and spend the summer in the marine environment where they feed until they migrate back to fresh water before rivers freeze (Johnson 1980;Bégout Anras et al 1999).…”

Genetic Stock Identification and Relative Contribution of Arctic Char (<i>Salvelinus alpinus</i>) from the Hornaday and Brock Rivers to Subsistence Fisheries in Darnley Bay, Northwest Territories + Supplementary Appendix Tables S1 to S4 (See Article Tools)

“…Understanding diversity in Arctic char as it pertains to life history, as well as historical and contemporary genetic variation, is important for documenting and subsequently monitoring regional biodiversity in a rapidly changing Arctic (Reist et al, 2006(Reist et al, , 2013Schwartz et al, 2007). Our genetic data lend support to the possibility that some sampling locations support Arctic char life history variants that are different from the anadromous forms in the region (see for example MacDonell, 1996MacDonell, , 1997Babaluk et al, 1998;Reist et al, 1997).…”

“…Additional work, however, is required to confirm whether LAKE-A and LAKE-B are truly landlocked stocks that are physically isolated from anadromous Hornaday River Arctic char or whether they are freshwater-resident forms that are reproductively isolated from anadromous char in the region. Documenting and further understanding Arctic char diversity in the region will be important for understanding how char biodiversity is generated and maintained (Reist et al, 2013) while providing baseline information on the distribution of char stocks in the region.…”

“…This result may be due to the existence of freshwater-resident char that opt to forego marine migrations and are reproductively isolated from their anadromous counterparts or to physical barriers to migration that prevent gene flow between these groups (i.e., LAKE-A and LAKE-B represent landlocked stocks of Arctic char). Indeed, the Arctic char exhibits marked phenotypic, ecological, and life history diversity throughout its range (Klementsen, 2010;Reist et al, 2013) and is arguably the most diverse salmonid (Muir et al, 2015). Further, freshwater-resident Arctic char have been confirmed in the Brock River system through the use of otolith microchemistry (Roux et al, 2011b) and non-anadromous forms are also known in other lakes (e.g., Seven Islands and Rummy Lakes) in the Hornaday River system (McDonnell, 1996(McDonnell, , 1997.…”