Alliance for a Living Ocean

2007 Long Beach Boulevard
North Beach Haven, New Jersey 08008
Mail: PO Box 95, Ship Bottom, NJ 08008
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Those Other Inhabitants of the Bay
by Donald Launer

Don Launer is a member of Bay Watch, holds a USCG captain's license, and is a frequent contributor to boating magazines. He is author of the book, "A Cruising Guide to New Jersey Waters". E-mail address is: [email protected].

We've all seen bulkhead companies tearing out old bulkheads and installing new ones and this activity seems to have escalated during the last few years. But why?

Since the 1976 Federal Clean Waters Act, reduced pollution has meant a resurgence of marine life, including marine borers that feed on bulkheads, wharves, docks and wooden boats. The irony of having cleaner waters is that all wood in contact with the water is now being attacked at an alarming rate. Huck DeVenzio, of Hickson Corporation, manufacturer of Wolman-CCA* says, "When waterways were badly polluted, substandard treated wood could last a deceptively long time - there weren't many wood-destroying organisms living in the polluted water. As water was cleaned up, the lack of proper wood treatment became more obvious; wood-destroying organisms became more prevalent and insufficiently protected wood didn't last long."

A perfect example of the dramatic affect of cleaner water is in New York Harbor. Until a couple of decades ago professional mariners termed New York Harbor a "clean port," not because of the water purity, but because Shipworms and Isopods, which destroy wooden ships, barges and pilings, were unable to live in the polluted waters. As long as the waters remained polluted, the wooden boats and piers were spared. At that time manufacturing plants along the banks of the Hudson and New York Harbor dumped waste chemicals into the water and the city disposed of more than 300 million gallons of raw sewage a day into the river and harbor. Finally public awareness of the problems caused activism to replace complacency, and the federal, state and city governments were prompted by citizen groups to adopt stringent environmental regulations. Now, with the waters of New York Harbor cleaner than they have been in over 75 years, Shipworms and Gribbles (Limnoria) are returning with a vengeance. Marine life is proliferating, even the species we would rather do without.

As with most marine life forms, proliferation of wood-eating organisms is cyclical, and can depend on water quality, salinity, predators and other wide-ranging influences. These cycles are most pronounced in estuaries such as Barnegat Bay, where these cyclic variations are much more dramatic than in the open ocean.

In the era when all boats and ships were made of wood, the Shipworm was a scourge that could result in your ship literally sinking from under you. Frequently ships' crews had to abandon their craft because it was too rotten to sail any farther. In 1502, during the 4th voyage of Columbus to the Caribbean, his ships survived a hurricane, lightning, water spouts and coral reefs, but two of his four ships had to be abandoned because of Shipworm infestation.

But what are these little critters that can cause us so much grief? The Shipworm is not a worm at all, but rather a highly specialized mollusk, or clam. Its shell is greatly reduced in size and is modified into a rasp for grinding the wood that provides the cellulose for its unique diet. The Shipworm, which only lives in salt water, invades new wood when it is in its microscopic larval stage. In this stage they are free-swimming, and their initial entrance hole into wood may be so tiny it's hard to detect. Wood treated with creosote, which is a distillate of coal tar is the oldest and most widely known preservative and deterrent. More recently, Wolmanized* wood is the product of choice. Wolmanized wood, which comes in varying degrees of chemical saturation, offers good protection till, after a couple of decades, the active ingredient has been leached out. Once inside the edible wood the Shipworm begins eating and growing and some species can attain a length of over three feet. Since the Shipworm remains in the interior of the wood structure, its worm-like body is protected from predators and the first hint of problems comes after the interior of the wood is nearly completely devoured and the outside wooden shell of the piling, bulkhead or boat-planking disintegrates. This is the same attack plan as the land-based termite, so it's not surprising that the Shipworm has been called "the termite of the sea."

Another destroyer of wood is the Gribble (Limnoria). This tiny salt water isopod most often attacks the surface of wood. You may have seen pilings where in one location their diameter is reduced, in an hourglass-type configuration. You can blame this on an infestation of the eighth-inch long Gribble, which usually confine themselves to one particular place on a piling.

Most bulkheads that have been destroyed are now being replaced with vinyl bulkheading material. Although more expensive than either creosoted or Wolmanized wood, it provides the dual advantages of an extended life - probably about 50 years - and a minimal impact on the immediate aquatic environment.

But our relationship with these wood-eating critters isn't all bad. These same animals that can give us so much grief are also responsible for eliminating trees and branches that are washed down into our navigable waterways during storms - providing a natural clean-up system.

*Wolman[R] CCA is a trade name of the Hickson Corporation. The "CCA" defines the preservative Chromated Copper Arsenate, which is widely used to pressure-treat utility poles, foundation pilings, dock pilings and bulkheads. The preservative undergoes a chemical change and becomes "fixed" in the wood, helping it to resist attack by termites, fungi and Shipworms and Gribbles.