Originally Posted by pathalla
I never heard of anyone eating them, they tend to be pretty small, but numerous.
Actually, here they are quite toxic... they accumulate toxins at a rate 10X greater than native species. Divers in the Great Lakes have a love/hate relationship with these friggin' things. As Pathalla points out, they filter vast amounts of sediment and the water here is more clear than ever... at least in the 32 years I've been diving here. We regularly get 70' visibility, and I have seen it as high as 100 feet. (Compared to an average of perhaps 20-25 feet a few years ago...) In warm water areas, the increased light penetration will cause an increase in algae blooms however.
The downsides (which IMHO far outweigh our Carribbean vis.) are that they completely cover our wrecks if they are above the lowest thermocline... typically about 70'. (I have read studies reporting a density of 70000... yes, thousand... per sq. metre in Lake Erie) They are slowly moving into the colder waters however. In Tobermory, they are still fairly light, but in Kingston and the western end of the St. Lawrence River, the wrecks are covered to perhaps a foot deep.
The other really bad news is that they also consume massive amounts of plankton... the primary food of our native fish when they are young. The sport fisheries in Lake Erie are particularly effected I understand. (I'm not a fisherguy...)
So far, only a few ducks eat them, but obviously they can only get the shallow ones. There is a new non-native specie of blennie which apparently eats them. They have no predator however, and in areas they are thick, and crowding out native species as well.
We might as well get used to these immigrants... they are part of an ongoing stream.... lamprays, carp, Brits....