Escape from troubled shores: finding of a shallow-water boreal gastropod Onoba aculeus on the high Arctic shelf

Abstract

Abstract The species composition and distribution of marine invertebrates varies greatly in different bathymetric regions. Nevertheless, the process of exchange between faunas of different depths has occurred repeatedly throughout the evolution of marine biodiversity. In high latitudes, this process should occur most actively due to absence of strong temperature stratification. The presence of physiological adaptations that allow northern shallow-water organisms to live at greater depth has been demonstrated in a series of experiments. However, known cases of recent colonization by species confined to a highly productive shallow-water zone in unusually deeper Arctic habitats are almost absent. The present study describes finding of population of the gastropod Onoba aculeus (Gould, 1841) in two samples from the lower continental shelf of the Arctic Ocean. Onoba aculeus is a shallow-water amphiatlantic species widely distributed in the temperate regions. The finding reported here is at the same time, the northernmost, easternmost, and most remote from the coast location. We assume that the detection of molluscs indicates the presence of an abundant isolated population in the region.