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|Effects of the invasive red king crab (Paralithodes camtschaticus) on soft-bottom fauna in Varangerfjorden, northern Norway|
|Oug, E.; Cochrane, S.K.J.; Sundet, J.H.; Norling, K.; Nilsson, H.C. (2011). Effects of the invasive red king crab (Paralithodes camtschaticus) on soft-bottom fauna in Varangerfjorden, northern Norway. Mar. Biodiv. 41(3): 467-479. dx.doi.org/10.1007/s12526-010-0068-6|
|In: Marine Biodiversity. Springer: Berlin. ISSN 1867-1616, more|
Benthos; Ecosystem disturbance; Predation; Sedimentary environments; Paralithodes camtschaticus (Tilesius, 1815) [WoRMS]; ANE, Norway [gazetteer]; Marine
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The red king crab (Paralithodes camtschaticus) was introduced from the northern Pacific to the Russian Murman coast during the 1960s and 1970s. Over the subsequent decades, the crab has become established in northern Norwegian waters, where it continues spreading westward. The crab is an active predator on benthic fauna, especially feeding in deep soft-bottom environments. The present studies, carried out in the Varanger area close to the Russian border in 2007-2009, indicate that soft-bottom epifauna and infauna have become markedly reduced in crab-invaded areas. For infauna, quantitative data from 1994 were used as a basis to compare faunal composition before and after the crab became abundant in the area. It appeared that echinoderms, non-moving burrowing and tube-dwelling polychaetes, and most bivalves were reduced, whereas some small-sized polychaetes and small bivalves had increased. In situ sediment profile imagery (SPI) was used to examine sediment structure and biogenic activity. At several locations, the sediment habitat quality was degraded due to hypoxic conditions and low biological activity below surface layers. It is suggested that the crab has removed organisms performing important functions such as bio-irrigation and sediment reworking. Hence, it appears that the crab may reduce the functional diversity of the resident species assemblages, which may have overall implications for ecosystem function, production and responses to other environmental stressors.