I can't help but see some merit in the proposal, considering that we currently discard a tremendous quantity of by-product that could provide more efficient returns.
However, it would require that the rate of harvest of squid be kept at constant levels to prevent the things that were mentioned above - abuses.
Case in point - North Sea Sand Lance harvest. Literally in excess of one million tons of sand eels are harvested annually for use in fish feed. This has impacted every organism in the North Sea from predatory fish to sea birds to massive whales. The harvest is growing in size every year. It doesn't take a crystal ball to see where this is heading.
Yet with some fisheries (gulf shrimp for instance) generating a 12:1 by-kill ratio, I do see merit in using what we are already discarding. The herring roe fishery in Alaska always seemed wasteful of the herring bodies to me, although in that case they are most likely jettisoned into the rich north pacific soup and ultilized by all kinds of sea creatures.
One last concern is where too much of one thing is used natural systems usually fail. Squid gut powder, sand eel meal, etc - are convenient and controllable for our human ways of thinking but in the scheme of nature too narrow of a dietary range.
Take for instance the sitka spruce re-plantings of modern logging operations. In nature, when these grow in a certain density a weevil explosion destroys the entire stand. Thus they don't occur in such densities.
In our desire to have uniform stands of s/spruces we planted acres of them together and when they reached a certain age decades later the weevils destroyed what is not supposed to happen in nature before they could be logged.
You could look at that as a weevil problem, or you could look at that as a human thinking problem. I think the latter, since nature is the ulitmate truth; the great balancing act in the universe, and we are always trying to fool her.
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