Invasion of the Killer Mollusks

In an alarming discovery for Bay Area ecophiles, and bad news for the Department of Fish and Game, divers found highly invasive quagga mussels in two Southern California lakes in the last three weeks.

The big concern: The mussels make it into the Bay delta, where they plunk down, reproduce like crazy, and run amok in the sensitive estuary habitat. The inch-long Ukrainian invaders work like Britta filters, sucking all the phytoplankton out of the water and leaving friendly, happy, phytoplankton-consuming zooplankton hungry — which in turn means zooplankton-consuming fish go hungry, and then the fish go away, and then everyone gets upset because hey, no more salmon.

Also, when the nutrients go, the water gets clearer, meaning algae and other marine plants bloom like crazy. That can kill fish, too, by sucking all the oxygen out of the water and turning the water acidic. But wait, there’s more! Quagga mussels suck up bad chemicals in the water, too, at very high levels. They pass that along in the food they reject — scientists gave that stuff the lovely label “pseudofeces” — multiplying the levels of things like mercury in the food chain until it eventually makes its way into us apex predators.

Quagga mussels also attach themselves to hard surfaces — boats, docks, piers, pipes and valves, and seriously foul them up in the process (unless you like the dimpled look for your boat hull). In the Great Lakes, where they’ve made themselves quite at home, the mussels run up hefty maintenance bills every year. They can live out of the water long enough to travel on a quagga-encrusted hull from one waterway to the next.

So even though the mussels are still pretty far away, there’s no time like the present for a good round of hand-wringing. Fish and Game has responded by sending dive teams to waterways near the two lakes, to look for more mussels, and by setting up checkpoints to make sure unwitting recreational boaters aren’t traveling with quaggas on board.

And if you do see one up here, best not to let it in.

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