Phd defence Eli Børve - the tidal travel of cod

December 15th,10.15-11.15 our colleague Eli Børve defends her PhD thesis at the University of Oslo. The focus of her thesis is on tides as important drivers for the motion in many coastal seas. The defence takes place in Aud. 1 in the Geology building at Blindern but can be followed on zoom: https://www.mn.uio.no/geo/fors... 

About the thesis

While tides mainly move water back and forth, the interaction between tidal currents and topography might induce residual currents and fluxes, providing an important transport component. The coastal sea around Lofoten and Vesterålen is an area where strong tidal currents interact with complex coastlines and topography. However, the tidally-induced transport in this region has gained little attention.

The coastal sea around Lofoten and Vesterålen in northern Norway is the main spawning ground for the Northeast Arctic (NEA) cod, the most important commercial species in Norwegian fisheries. The recruitment of this fish stock depends on ocean currents transporting NEA cod eggs and larvae from the spawning-ground to the nursing ground in the Barents Sea. Thus, understanding the processes determining transport pathways is key for identifying vulnerable areas and predicting fish recruitment for sustainable fisheries management.

This thesis shed light on the importance of tidally-induced transport in the sea surrounding Lofoten and Vesterålen. The thesis comprises theoretical and model studies investigating different transport processes, such as tidal pumping, tidal rectification and damping of tidally generated continental shelf waves, as well as a comparison study on particle transport with and without tides. The results show that tides largely impact the particle transport in the region, both by increasing the transport from a spawning-ground in Vestfjorden to the shelf and by influencing which routes the particles follow.