“So is this great and wide sea, wherein are things creeping innumerable, both small and great beasts.” Although diving has advanced by leagues and fathoms since the ancient writer penned these words, there remains great mystery about the strange inhabitants in the dark recesses of the ocean depths.
While many people experience thrilling encounters with the beauty below the sea’s surface, terror also lurks around the corner for the careless or unfortunate. From a whale overturning a sightseeing boat in July to jumbo squids attacking a Greenpeace sub recently, aggressive aquatic actions against humans getting a little too close for comfort in recent days has alerted divers to the necessity of caution. One of the most insidiously multiplying examples of potentially dangerous marine wildlife is the lamprey.
A squiggling, snake-like relative of the eel, the lamprey is not a fish to write home about for its beauty. Normally, they can be seen hanging limply from larger fish by their round, tentacle-toothed mouths. The needle-sharp teeth pierce the skin, and then the piston-like tongue begins siphoning blood and nutrients while secreting a saliva that prevents blood from clotting. When a lamprey is caught by a fisherman, the fight is on: the vicious creature resists capture violently to the end.
Most fish who dwell in lamprey-infested waters are endangered. In the Great Lakes region, great measures are required to prevent the fish industry from massive losses to these parasitic lampreys. Due to an influx of lampreys in Lakes Huron and Superior, trout catches in the 1960s dropped from 15 million pounds to 300,000.
Depletion of large fish is a major concern for fishermen anxious to rid the waters of these parasitic lampreys, and they are urging visitors to understand the threat. Divers swimming in the Great Lakes who do not pressure wash their gear before diving in other areas may unintentionally spread these invasive pests to other waters.
Fish are not the only ones vulnerable to lamprey attacks. Even divers who have been in the water long enough for their skin to feel attractively cold to hungry lampreys are at risk.