Fishmeal in Aquaculture
Dr. David CarpenterProfessor of Environmental Health and Toxicology and Director of the Institute for Health and the Environment, University of Albany
The EPA has issued advisories for the consumption of Great Lakes fish on the basis of PCBs, dieldrin and toxaphene. We applied these advisories in calculating the numbers of meals of farmed salmon that should be eaten per week from different places, from different countries, from different supermarkets. In the most severe restriction advice would be for salmon primarily from the Baltic Sea area - from Norway and Scotland, where the consumption should be limited to not more that one meal every other month. For all of the farmed salmon, there were significant advisories. Now we did find that the farmed salmon from Northern Europe was more contaminated than that from Chile or British Columbia.
One conclusion from our study is that the source of the contaminants is the food that the farmed salmon are fed. This is not a totally negative conclusion because it means that we can get the contaminants out of the farmed salmon for the most part by finding a clean food to feed them.
But another conclusion from this that I think is very important is that we have sufficiently contaminated our oceans, that now, if we concentrate the fish meal and fish oil from trash fish that nobody wants to eat, then shove it to fish in a cage and push their weight gain, we can develop animals that are dangerous to eat because of the accumulations of toxins.
Dr. Ron HardyDirector Aquaculture Research Institute University of Idaho
Unfortunately, the entire planet has residual levels of contaminants, particularly PCBs and long-lived compounds like dioxins, so it's almost impossible to find any product from the sea that doesn't have these compounds in it. Our challenge is to find areas where the contaminant level is low and get products from those sources, not from polluted sources.
The sustainability of farming of carnivorous fish will depend on the conversion of sourcing of feed ingredients from limited or finite resources such as fishmeal, there's only so much in the world, to sustainable sources such as those produced from plants and grains and oil seeds. So as we go forward with sufficient research and practice with these ingredients, there's no question that farming of these carnivorous species is sustainable. That is providing that we switch to sustainable feed ingredients.
Everybody knows that the populations of fish in the ocean have been declining, and not just recently but for a long time. The implications have been that the declines are associated with the rise of aquaculture with the increased production and removal of forage fish to provide feed for aquaculture. This really isn't true. The decline in fish abundance throughout the sea is caused by overfishing, not because the fish have been removed to make fishmeal and oil for aquaculture feeds.
Ulf WijkstromChief of the Fishery Development Planning Service in the Fisheries Department FAO, Rome
Fishmeal production today worldwide is something like between 5 and 7 million tons per year. A very large share of that comes from small pelagic species off the western coast of South America.
Now we estimate that at the end of the last decade, something like 2 million tons of fishmeal went into aquafeeds and 1.4 million tons of fish oil.
Now what will happen? We have done a recent study of this and found this, looking at fishmeal and fish feeds - the inclusion rates, the conversion rates, the rate at which the animal can absorb the fishmeal, etc. Using those factors and looking into the future, we predicted that we will run out of fish oil for aquafeeds before we run out of fishmeal.
The world production of fish oil is something like between 1 and 1.5 million tons per year, and that could be finished before 2015, just in the use for aquafeeds. Fishmeal would last a bit longer, but it could run out sometime before 2030. That is, all of the present fishmeal production could at that time possibly be used for aquafeeds.