Knowledge of the spatial distribution of juvenile cod is essential for obtaining precise recruitment data to conduct sustainable management of the eastern and western Baltic cod stocks. In this study, the horizontal and vertical distribution and density patterns of settled juvenile 0- and 1-group Baltic cod are determined, and their nursery areas are localised according to the environmental fac...

Experimental observations of acoustic propagation through a Soliton Wave Packet (SWP) show an abnormally large attenuation over some frequencies, that was found to be significantly time dependent and anisotropic. Nevertheless, by remarking the problem of signal attenuation, the approach used in most of the studies can be considered as ”static” since no additional effects were taken into account...

Monthly circulation of the South Atlantic Bight is diagnosed using a 3-D, shallow water, finite element model forced with monthly wind stress and hydrographic climatology. Temperature and salinity observations from the period 1950-99 are objectively interpolated onto the model domain, and Comprehensive Ocean-Atmosphere Data Set (COADS) wind velocities from 1975-1999 are used to prescribe the mo...

Multi-path interference due to boundary reflection in shallow water acoustic communication poses a major obstacle to reliable and high-speed underwater communication system. In this study, initially 3D variations of field data such as sound speed, temperature and salinity in horizontal transects of the Strait of Hormuz were analyzed using the ROPME data. Later, data on typical sound speed ...

The main part of the thesis is five separate research papers published in or submitted to leading journals in the field of computer vision and pattern recognition. In addition, a data capture system for hydrographic maps has been designed and implemented. It places the results of the thesis papers in context and demonstrate their importance. The five thesis papers are [1] Øivind Due Trier and T...

Eight alien freshwater snail species were introduced into Martinique Island during the last 50 years. The introduced snails include four planorbids (Biomphalaria straminea, Helisoma duryi, Amerianna carinata and Gyraulus sp.), three thiarids (Melanoides tuberculata, M. amabilis and Tarebia granifera) and one ampullarid (Marisa cornuarietis). Four of these species rapidly colonized the whole Mar...

This thesis studies the role of cross-isopycnal mixing in general circulation dynamics , from both the theoretical and observational points of view. The first two chapters discuss some theoretical aspects of cross-isopycnal mixing in the oceans. In chapter one, an integral constraint relating the interior stratification and air-sea heat fluxes is derived, based on the condition that the total m...

Quanti-qualitative changes in Dinophysis and Alexatidrium populations from the Gulf of Venice NW Adriatic Sea were studied on a short time scale (44 h cycles). Under hydrographic conditions of marked thermo-haline stratification (July 1995), D. sacculus populations assembled in the surface waters (12 24 yt isopycnals). Division processes took place mostly in the early hours of the morning and a...