First records of three-spined stickleback Gasterosteus aculeatus in Svalbard freshwaters: An effect of climate change?

Several fish species, including three-spined stickleback, Gasterosteus aculeatus, have shown a more northerly distribution in the Norwegian Sea into the eastern part of the Arctic Ocean during the last decades. Three-spined stickleback has however never been recorded in freshwaters on Svalbard, whereas Arctic charr, Salvelinus alpinus, has been the only reproducing fish with anadromous, resident, and landlocked populations. On this background, we sampled fish by gillnetting, electrofishing, and trapping in two watercourses on the island of Spitsbergen, Svalbard, during the summers 2001 and 2006. During these surveys, three-spined sticklebacks were captured in both localities. To our knowledge, this represents the first records of the species in Svalbard freshwaters. The presence of a few adult sticklebacks does not provide evidence that breeding populations are established. However, increased temperatures associated with climate change in recent years in both Arctic marine and freshwater environments may have facilitated the appearance of the species in these localities and thus may be a first indication of the potential establishment of this species in Svalbard freshwaters. [ABSTRACT FROM AUTHOR]