Marine populations are genetically structured through historical processes, environmental or physical barriers and life history characteristics. Divergent patterns of demographic history, even among closely-related species sharing climatic changes, raise questions about the influence of species-specific traits on population structure. The Southern Ocean features comparatively high biodiversity, which has been attributed to frequent local extinction-recolonization cycles that have driven benthic, Antarctic organisms into temporary refugia. In contrast, organisms in the Arctic were able to shift latitude in response to changing Pleistocene climate. We therefore hypothesize that Arctic populations were historically less constrained in their distribution than Antarctic fish populations and hence show lower levels of genetic structure. For assessing the role of lifestyle in influencing demographic history in the Southern Ocean closely related notothenioid fish with benthic (Trematomus bernacchii, T. hansoni) and semi-pelagic or even cryopelagic (T. newnesi) lifestyles were genetically analysed. In the Arctic, polar cod (Boreogadus saida), which is often found in association with sea ice, but also throughout the water column to the bottom, can be regarded as semi- or cryopelagic too. The Antarctic species were analysed by six microsatellite and one mitochondrial marker before (Van de Putte et al., 2012) and we extend these analyses with data from nine microsatellite markers in polar cod. Antarctic species showed significant genetic population structure between High-Antarctic and Peninsular regions and much lower differentiation in pelagic than benthic species. It suggests that the observed patterns are indeed related to ecological traits of Antarctic fish. In the Arctic, we hypothesize genetic structuring inside fjords in Svalbard relative to shelf specimens, which we expect to show low or absent structure as in Antarctic species with a similar lifestyle. Identifying common driving factors for population structure is important in order to enable forecasting, particularly in light of dramatically increasing rates of environmental change. Comparing population genetic patterns and exploring underlying causes from both poles may thus help to shed light on how fish populations survived in the past and may persist in the future. Reference - Van de Putte A., Janko K., Kasparova E., Maes G.E., Rock, J., Koubbi P., Volckaert F.A.M., Choleva L., Fraser K.P.P., Smykla J., Van Houdt J.K.J., Marshall C. 2012 Comparative phylogegraphy of three trematomid fishes reveals contrasting genetic structure patterns in benthic and pelagic species. Marine Genomics 8:23-34.
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RBINS Staff Publications 2018
The Belgian part of the North Sea is part of a very important seabird migration route through the Southern North Sea, which makes it an ideal area to study bird migration. Because of its shape, this part of the North Sea acts as a migration bottleneck, concentrating birds during migration. This study aims at cross-validating bird detection by meteorological and bird radars, mainly focusing on offshore and coastal migration, and suggesting refinements to the bird detection algorithms of both weather and dedicated bird radars. The Royal Meteorological Institute of Belgium (RMI) uses three C-band weather radars for meteorological observations, one of which is located in Jabbeke, at only a few kilometers from the Belgian coast. The Royal Belgian Institute of Natural Sciences (RBINS) has installed a Merlin bird radar (DeTect Inc.) on an offshore platform at 25km from the coast, to study the impact of offshore wind farms. The Merlin radar system consists of two identical radar antennas, one scanning in the horizontal pane and one in the vertical. They are operating at a range of 7.4km and 1.85km respectively, thus providing high resolution data. The measurements of the bird radar and the weather radar in Jabbeke are overlapping, which offers a unique situation to cross-validate the data of both types of radar and to extrapolate the high resolution data of the bird radar to the wider spatial scale of the weather radar. RBINS and RMI are joining forces in a two year project called RAVen (RAdar registrations of bird migration Validation through an interdisciplinary approach). It runs until mid-September 2018 and is funded by the Belgian Science Policy. First results (from spring 2016) already show a good correlation between the number of birds detected by both radars.
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RBINS Staff Publications 2017
