A diver who was sent into the river soon after the dry dock arrived in February found living creatures on the sides and bottom of the hull. Sowles and company officials decided to see whether the cold water here would kill the organisms naturally. A second dive, about two weeks ago, showed that while most of the organisms had died, some were still alive, Sowles said. It's unclear how the company could kill or remove the foreign organisms from the dry dock, which is 750 feet long and 180 feet wide. Foreign species periodically arrive in Maine's coastal waters without notice, riding on hulls or in the ballast tanks of ships that call here from all over the world.
Most exotic organisms die in the cold Maine sea.
But a percentage of the survivors can multiply and disrupt the balance of predators and prey that support the coastal environment and economy. The green crab, for example, arrived on a European ship and decimated Maine's commercial clamming industry because of its unchecked appetite for the soft-shelled mollusk. A newer invader, the Japanese shore crab, has taken over tide pools in the mid-Atlantic and is approaching Maine. Not all foreign species are invasive. The periwinkle, for example, has become a welcome part of the ecosystem, even supporting a small cottage industry that collects and sells them as a delicacy.