Some species, most notably salmonids, have larger fat deposits
in the belly flaps than in other parts of the fish. Distribution
of fat in many fish seems to be in descending fat levels
from the head to the tail (Icekson et al. 1998, Kolstad et al.
2004). Diet will have a significant impact on the fat content
and fatty acid profiles of aquatic animals. Aquacultured fish on
a controlled diet, for example, do not show the same seasonal
variation in fat content as wild species. It is also possible to modify
the fat content and fat type via diet. For example, adding fish
oil to fish feed will increase the fat content of fish (Lovell and
Mohammed 1988), usually proportionately to the level of fat/oil
in the diet (Solberg 2004). It has also been shown with many
species (salmon being the most investigated) that the fatty acid
composition is a reflection of the fatty acid composition in the
fish diet (Jobling 2004). Therefore, it is possible to selectively
increase the nutritional value of aquacultured fish by increasing
the level and improving the ratio of nutritionally beneficial
fatty acids (Lovell and Mohammed 1988). Conversely, one can