Norwegian fjords contain sub-populations of roundnose grenadier, a deep-water fish
A new field study, published in MEPS, shows that deep Norwegian fjords house sub-populations of roundnose grenadiers, with little connections to coastal populations.
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The roundnose grenadier Coryphaenoides rupestris is a benthopelagic fish occurring in deep waters along the continental, island, and seamount slopes in the North Atlantic and along the Mid-Atlantic Ridge. It is a slow-growing and late-maturing fish species. This new study has investigated the connectivity of C. rupestris between three fjords and two coastal locations in Norway using eight microsatellite DNA markers. The data show a clear genetic heterogeneity across the study area (FST = 0.0297, p < 0.001), suggesting several populations occur at the scale of fjords or finer. Population structuring in C. rupestris along the Norwegian coast seems to be influenced by geographic distance and the complex bathymetry of the coast. Fjord sills and geographic distance appear to limit its dispersal and migration. C. rupestris is an overfished species that has been Red-Listed as Critically Endangered. Based on these new results, monitoring practices and conservation efforts should consider each of these population units independently.
This work is based on the Master thesis of Aurelien Delaval and represents collaboration between the UiB and the IMR.
Reference:
Delaval, A., G. Dahle, H. Knutsen, J. Devine, and A. G. V. Salvanes. 2018. Norwegian fjords contain sub-populations of roundnose grenadier Coryphaenoides rupestris, a deep-water fish. Marine Ecology Progress Series 586:181–192. doi: 10.3354/meps12400.
