Disease Documented in Lake Champlain Northern Pike

Esocid lymphosarcoma , a disease found in Northern Pike and Muskellunge, has been confirmed in Northern Lake Champlain. During February and March ice-fishermen on Northern Lake Champlain encountered strange lesions on Northern Pike, a condition that many anglers have never seen before.

Fish Health Biologist Thomas Jones with the Vermont Fish & Wildlife Department was aided by several ice-fishermen in obtaining infected fish. Dr. Paul Bowser, of Cornell University provided laboratory confirmation of the diagnosis of Esocid lymphosarcoma in the fish that were sampled.

Lymphosarcoma is described as an infectious disease of probable viral origin. The disease has been recognized for over 100 years and has been documented in many locations in North America. It is more lethal in Muskellunge than in Northern Pike, which is a cause for concern because Lake Champlain’s native muskellunge population is already in jeopardy.    

The disease starts as small malignant tumors just below the fish’s skin and may develop into tumors as large as an orange. The color of the tumor can be whitish-gray, red or pink. The tumors are very soft and upon maturity can rupture and appear as dead tissue. Tumors can also spread internally into the fish’s organs.

Lymphosarcoma can transfer from fish to fish through contact during spawning activity in the spring. Tumor prevalence and development are believed to be highest in late winter and spring and lowest during the summer months. This may suggest that colder water may play a role in tumor development.

Jones is uncertain if the disease has been present in Lake Champlain for some time, or if it may have been introduced through transfer of fish from other waters. “Un-authorized transfer of fish can be very damaging to Vermont’s fisheries through species competition and potential transfer of disease,” said Jones.

He reminds people that it is illegal to transfer most fish species, including northern pike, from one body of water to another in Vermont.

The disease is not known to infect humans but the Vermont Fish & Wildlife Department recommends infected fish not be consumed.

Jones says he will continue to monitor Esocid lymphosarcoma in Lake Champlain and encourages anglers to report this condition as well as other unusual conditions to him at Fish & Wildlife’s office in Waterbury. His phone number is (802) 241-3708 and his email is tomj@fwd.anr.state.vt.us.
                    

Here are some pictures of pike with this problem.

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