Unwanted guests: What’s hitching a ride on your vessel?

All those barnacles, mussels, sea squirts, worms and weeds that foul your hull are more than just a costly nuisance — they are an environmental threat. The unintentional transport and introduction to new areas of nonnative aquatic plants and animals is a growing global environmental and economic concern. Once a new species arrives and settles in a foreign area, it is virtually impossible to remove or control it. The poster child for invaders into U.S. waters is the freshwater zebra mussel — estimated to cause millions of dollars of damage annually. Salt water has its own vast clientele. There are many other species in coastal areas just waiting for the perfect new home — encrusting worms, flower-like hydroids and anemones, sponges, and crabs.

Boats moving along coastlines or across oceans can transport these aliens thousands of miles and deposit them in new environments. The ballast water of commercial vessels has been blamed for much of the transport, but hull fouling on private yachts is the primary route for many marine invaders. In New Zealand and Hawaii, for example, an estimated 70% of introduced species arrived by private ship — particularly sailboats.

These plant and animal invaders can threaten local flora and fauna, clog industrial structures, foul aquaculture facilities and be generally unsightly. It is often assumed that the widespread use and efficacy of antifouling coatings has sidelined fouling as a transport vector. It has not! Hull fouling continues to be a rampant, but manageable, problem. Fouling tends to be concentrated in seawater intakes, sea chests, keels, propellers and propeller shafts — havens for these seemingly benign creatures. Control of these hitchhikers is possible.

At the University of Connecticut’s department of marine biology, NOAA’s National Sea Grant is funding our study of the potential transport of these hitchhikers between Florida and New England waters in an effort to establish hull maintenance protocols that can reduce or eliminate potential invaders.

The complex communities of potential invaders on your hull may not slow you down or even be noticed — but could unwittingly contribute to an environmental disaster. You can help stem the wave of invasions by keeping your hull free of fouling plants and animals — especially when planning to enter new waters. It pays to have a clean bottom! If you would like to participate in the survey, please contact me: robert.whitlach@uconn.edu.

By Ocean Navigator