Question for you Tonn.. I was watching a documentary the other day: "End of the Line", which goes into depleting fish resources, and they claimed that one of the solutions (fish farming) is in fact counterproductive to rebounding a lost culture.
The reasoning is that there is more fish meal being devoured which inevitably causes problems in the food chain.
That's wrong for a number of reasons. The first and most obvious is that the majority of fish farming is not of carnivorous species. Here's some aquaculture stats for 2010 production data, from the FAO. Roughly 16 million tonnes of production was aquatic plants. Over 20 million tonnes is carp production. A little over 13 million tonnes is mollusc production. Tilapia was about 3.2 million tonnes. Atlantic salmon is 1.5 million tonnes...and there are plenty of other species in there as well.
To lump salmon aquaculture in with all other aquaculture is foolish; the vast majority is herbivorous or autotrophs. What's more, as I've told Barilko, the percentage of fish meal in aquaculture diets is actually dropping, without compromising the growth of the Atlantic salmon. It will continue to drop, as more research is done on alternative proteins. A
fellow graduate of my program is doing her Masters in Saskatchewan right now, and has been in Norway learning about marine proteins from phytoplankton. It's conceivable that in the future, the omega fatty acids and amino acids will be sourced entirely from marine algae. Fish meal is in high demand, and not just from aquaculture. I've long thought that this presents an opportunity for savvy entrepreneurs (Phytoplankton need carbon dioxide...carbon credits for start-up capital?)
Also, farmed salmon are actually more efficient at converting the fish meal in their diets into biomass. You'll frequently see figures thrown around like 4 kilograms of fish meal for 1 kg of farmed Atlantic salmon. But consider that for wild salmon, the it takes 4.5 kilograms of prey to make 0.45 kilograms of salmon. So, in actuality, your net fish consumption is lower when you eat farmed Atlantic salmon. Anyone who denies this is denying basic physiology of fishes. Though this is also part of the source of the difference in taste. Farmed Atlantic salmon are lazy couch potatoes compared to the marathon swimming wild salmon.
More than that, there is another opportunity that regulators are avoiding. Anyone who eats sea food should know about the two nasty words joined by a hyphen...by-catch. By changing the regulations to include by-catch in the quotas for all fisheries, regulators could simultaneously make ocean eco-systems stronger, while using that "undesirable" portion of the catch for producing fish oil and fish meal, which is a high value product. By-catch is not accurately reported at all, but I can tell you as someone who has been an at-sea Observer, it's not a small percentage of the catch. So, on top of the large withdrawals of the target species biomass, fishers are also removing much of the biodiversity in the by-catch that is discarded, and for the most part, dies.
I've harped on a number of times about the ridiculousness of the models that most natural resources managers use, for max sustainable yield. There's nothing sustainable about it. It's a failure. Smarter policy will go a long way towards making capture fisheries, and aquaculture more sustainable.
But really, anyone who says aquaculture is counter-productive....they're either very ignorant, or very ideological.
There are also many small hatcheries that are helping the native stocks reproduce.
Good point. I didn't even mention the rejuvenation projects.
