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Originally Posted by vandelay
Speaking of introduced exotics, the dreaded Asian silver carp that's threatening the Great Lakes was introduced to control algae in aquaculture and wastewater treatment and is feared to compound the invasive effect of zebra and quagga mussels due to the excessive algae the mussels grow from their excreta.
But apparently the meat of silver carp is tasty. If and when, and it's really a matter of when it reaches the lake, we better learn to eat it.
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It's so much more complex than just one invasive species though. The Zebra Mussels have actually wiped out two other exotic species by cleaning the water so thoroughly. Also, several native species actually feast on Zebra Mussels, but they are so prolific and fast going in cold freshwater like the Great Lakes that no matter how fast native predators eat them, they still clog the waters.
The Zebra Mussel, by eating plankton actually wiped out the nasty Alewife problem by depriving them of their food source which was actually the same plankton the Mussels eat. The Alewives used to boom in population so erratically due seasonal algae blooms that they would suffer starvation collapse and die en masse and make beaches uninhabitable. The Lake Trout population, which would be the typical apex predator in the lakes, was also suffering population collapse at the time due to lampreys, so there was nothing to control them. So we stocked the lakes with Salmon which would predate the Alewives and control them. Then Zebra mussels came along and ate all the plankton collapsing the Alewife population and therefore the Salmon population. They also happen to be excellent food for Lake Trout which is the original species that is supposed to dominate the Great Lakes apex niche. This shifting of prey species in combination with clever conservation techniques to kill lamprey eels has helped to bring the Lake Trout population back to multidecade highs.
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Lampricides, river barriers, traps and new experimental control techniques like disrupting spawning with sex pheromones have dropped the fish kill total from 103 million pounds a year to less than 10 million, the commission says.
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http://www.mlive.com/news/index.ssf/...ey_declin.html
The collapse of the Lake Trout population in the 1940's and 50's devastated what was one of the largest fisheries in the US. At one point in time they were catching millions of pounds of Lake Trout a year which is excellent tasting and normally thrives in the lakes. Now that lampreys are eating 90 million less pounds of fish, the commercial industry is thriving again.
A lot of native species feast on the Zebra mussel including Smallmouth Bass, Lake Trout, and Crayfish, which apparently eat 105 Zebra Mussels a day per adult Crayfish. Crayfish also basically inhabit the same prey status as Zebra Mussels for Lake Trout which further boosts the Trout's numbers.
So ironically Lake Michigan is healthier now with Zebra Mussels than it was before their invasion. They are a pain for power plants and boaters, but they caused huge issues for other more noxious invaders while feeding some of the rebounding native species.
But we are way off topic so N E ways back to buildings.
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