The last point is particularly important because all four farmed versions of the fish at the center of Greenberg's book are fed fishmeal -- ground up forage fish -- to provide the oils and fats required for those species to grow.
Animals that are fed fishmeal can bioconcentrate monomethyl mercury in protein matrices that are then passed on to the consumer in the fat components of derived foods [ 15].
The carcasses may be processed into animal feed and fishmeal, while the skin, cartilage, and jaws are also of value.
In channel catfish, fish fed a diet containing 48% canola meal had significantly lower growth compared to fish fed a fishmeal diet or diets containing 12% or 36% canola meal (Webster et al. 1997).
Hajen et al. (1993) reported that Chinook salmon (Oncorhynchus tshawytscha) fed a diet containing 30% rapeseed protein concentrate had the same growth rate as fish fed a fishmeal diet.
Additionally, shrimp fed high soybean protein diets with supplementation of relevant minerals had similar tissue mineralization to those fed high fishmeal diets.
Fish fed the fishmeal reference diet had the highest average weight throughout the study (Figure 1).
Sunshine bass (Morone chrysops × Morone saxatilis) fed a diet containing 20% canola meal did not have a significant difference in growth compared to fish fed a fishmeal diet (Webster et al. 2000).
In a perfect bit of carnivorous symmetry, pigs and poultry can also be fed on fishmeal.
They were fed daily with a fishmeal based feed [ 21] at 1.5% (w/w) of their body weight every day.
