Joint project EWOS-OSV-RV: Environmental optimization of cage farms

In this country, recent monitoring has indicated unfavourable DO concentrations in salmon cages on several localities along the west coast (e.g. in the counties Møre og Romsdal and Rogaland where in-cage DO as low as 50% of saturation has been measured du ring summer). In major salmon producing regions abroad, especially in Western Canada and in the Region X in Chile, DO deficit is a real problem due to high temperature and algal blooms. DO deficit lasting for a certain time, especially at high temperature , will reduce feed intake and growth (based on own and other's results) and increase the risk for disease outbreak. During the project period (2003-05) running monitoring of environmental key parameters, such as DO, current temperature and salinity, will be conducted at EWOS' cage-based research farms in Rogaland (localities Grotnes and Oltesvik). Comparative monitorin g will be performed both inside and outside fish cages, and with and without DO addition (OSV technology). In order to achieve more basic knowledge, performance of big salmon exposed to different DO levels (from 40 to 100% of saturation) will be conducted in tanks supplied temperated seawater (15 degreed C, 30 ppt) at EWOS' research station in Dirdal.