Not All Invasive Species Are Bad

The specter of a seaborne Japanese invasion of the West Coast — very real to those of us alive during World War II but thankfully long exorcised — was resurrected last week by Oregon State University scientists. This time, however, the presumed invaders were not foreign soldiers but an army of alien marine species riding flotsam from the 2011 Japanese earthquake and tsunami.

News media warned of the “extinction” of local creatures due to the dozens of potentially invasive marine invertebrates discovered by the scientists on a damaged dock that floated over from Japan and washed ashore in Oregon. Warning-wise, it was overkill. Right on Connecticut’s own doorstep — or beaches, if you will — is proof that labeling an invasive as an ecological bogeyman is sometimes a knee-jerk reaction.

Two years ago, researchers at Brown University in nearby Providence, RI, asserted that the little Asian shore crab, established along the Atlantic shore since 1988 and swarming the tidal region of Long Island Sound, “gets along just fine with native species.” 

Granted, like many little guys — it’s no bigger than a silver dollar — the Asian crab has a chip on its shoulder and has a nasty bite, but it has not clobbered the food web or resident crabs, as direly predicted. Moreover, any sea-going angler worth his salt knows that “Asians” beat native crabs as blackfish bait.

That's not to say that all invasives are benign and, indeed, many are supremely destructive, even dangerous. Some of the worse come from Asia. The emerald ash borer beetle, another Asian invader, has killed perhaps 100 million ash trees since arriving in North American more than a decade ago.

Introduced from the pet trade, Burmese pythons flourishing in Florida’s Everglades are gobbling up bobcats, raccoons, wading birds and virtually anything else they can subdue and swallow. Although it hasn’t happened yet, humans — even full-grown adults — fit that description.

Nevertheless, many invasives have sparked scare stories but turned out to be as threatening as the Wizard of Oz. Back in the 1970s, I wrote a book for kids on the walking catfish (Clarias batrachus), an escapee from aquariums that was supposed to decimate native fish. Much more recently, the Asian snakehead fish was supposed to pose the same threat. The catfish and snakehead dominated headlines for months, even years. Heard about either lately? Too much of the Boy Who Cried Clarias can desensitize public recognition when a truly dangerous invasive rears its head.

Furthermore, the definition of an “invasive” can depend on one’s point of view. The scientific community generally seems to agree that an animal that spreads from one area to another on, say, a floating log is naturally extending its zoogeographical range. A floating dock seems to be something else again.

It could be said that several fish that are among the most sought after by anglers are invasive, at least in a state such as Connecticut where they were introduced. The largemouth bass, the smallmouth bass, bluegill, white crappie and black crappie don't qualify as natives. They were liberated here — and in a zillion other places — to enhance sport fishing. Some have been around for a long time,  since the middle of the 19th Century in the case of bass, but the white crappie was not reported here until 1960. Once introduced , all these fish spread like crazy so that many anglers are surprised to find they are immigrants.

For sure, a guard must be maintained against harmful invasives. It sometimes seems, however, that environmental officialdom can become obsessed with the subject. Several years ago, I took the UCONN Cooperative Extension System Course to be a certified master gardener. I remember thinking at one point that it seemed we were spending more time on invasive plants than any other subject. For hours, it seemed, a lecturer droned on and on about purple loosestrife, an invasive Old World plant that is choking wetlands. Frustrated and drowsy, I thought, “Enough with the loosestrife, teach me how to grow a tomato.”

UPCOMING OUTDOOR EVENTS

Westbrook Inshore Striped Bass Open Fishing Tournament, June 30-July 1. Anglers of all ages can register for this catch-and-release tourney at the Westbrook Marine Center, 533 Boston Post Rd. or Atlantic Outboard, 475 Boston Post Rd. both Westbrook. Telephone 860-399-6773. More information: www.atlanticoutboard.com.

2012 Nutmeg State Games Shooting Competition,  July 12-15, Blue Trail Range, Wallingford. Olympic-style multi-sport event.