Inshore versus offshore farming

In an effort designed to detect differences between manually fed inshore farmed rainbow trout (Salmo gairdneri R.) and automatically computerfed offshore farmed rainbow trout, an experiment (1986) was conducted at Karlshamn, Sweden, using two different sites, one inshore and one offshore. At the sheltered inshore site traditional JAMEK† (Jamek Industry A/S, Norway) cages were used, while at the exposed off-shore location a large single unit fully automated Farmocean PLAT-FARM 3500 (Farmocean AB, Sweden) was used. Out of the same population a significant number of fish were removed from the two different farms and examined for: (1) standard length vs. weight, (2) standard length vs. circumference, (3) total weight vs. viscera weight. A comparing analysis indicates that offshore farmed rainbow trout get a significantly higher ratio of useful flesh vs. viscera fat, a slimmer and more salmon-like body and in general a superior appearance. The results also indicate a lower rate of mortality amongst computerfed offshore farmed fish. Increased activity among these fish in a turbulent environment, coupled with uninterrupted feeding seems to account for these positive findings.