Seafood is the primary source for EPA and DHA in human diets. Estimated amounts of EPA and DHA in the top seafood types consumed are shown in Table 2-8. The figures suggest that, other than salmon, the most frequently consumed types of fish are not particularly rich sources of these fatty acids.

The fatty acid concentration of farmed fish reflects the composition of the diets they are fed (Bell et al., 2003). Fish, like mammals, have a limited ability to deposit EPA and DHA in their tissues even when they are fed diets high in ALA (Tocher et al., 2003). Thus, farmed salmon need to be fed a source of EPA and DHA (e.g., fish oil) to have a fatty acid profile similar to that of wild salmon. Feeding diets that are high in fish oil for a period prior to harvest elevates levels of EPA and DHA in farmed salmon previously fed vegetable oils during part of their growing period (Bell et al., 2003).