20 years of zebra mussels (and still counting)

The latest edition of the Ohio Sea Grant's "Twineline" magazine has an excellent summary of the invasion by the highly destructive zebra mussel.

It may be hard to believe but this tiny invasive mussel has been causing havoc in Lake Erie for 20 years and is far from ended in the damage it has caused.

The "Twineline" article notes that Lake Erie's temperate conditions were nearly perfectly suited for the zebra mussel, whose genetics indicates it came from various European sources.

That proved bad for Lake Erie because it only enhanced the mussel's ability to swarm all over Lake Erie.

While a European zebra mussel would mature in three to five years and produce upwards of 50,000 eggs, in Lake Erie a mussel would mature in 11 months and produce up to 1 million eggs annually.

Soon - as anglers and boaters and others quickly found out - zebra mussels were everywhere, on everything and in everything.

So much so that by 1994 they were costing the region between $5 billion and $10 billion annually, clogging water intake systems, coating boat hulls and cutting fishing lines that came close to the bottom.

The mussels also alrgely killed off native mussels. The zebra mussels covered the natives, preventing the latter from opening and filtering water.

Worse, another invasive species, the round goby, found the zebra mussel quite tasty.

This proved bad because the zebra mussel's high fat content stored up heavy toxins that had been locked in the lake's sediments.

This toxic brew only accumulated in the gobies which when eaten, passed on to its chief predator - the smallmouth bass.

PCBs concentrations in zebra mussels increased from 100 parts per billion to a hefty 1,800 parts per billion in bass, the "Twineline" article notes.

All of which helped give rise to the still-on-going efforts to curtail the import of all invasive species into the Great Lakes.

It's a never-ending battle with one of the first skirmishes being with the terrible and terribly small zebra mussel.

- Jeffrey L. Frischkorn
jfrischkorn@news-herald.com