Tribes/USFWS cooperate on larval lamprey capture
By Bill Mattes, GLIFWC Great Lakes Biologist
Keweenaw Bay, Mich.—On March 15th 2012, staff from GLIFWC, Keweenaw Bay Indian Community (KBIC), and US Fish and Wildlife Service Sea Lamprey Control Program (SLCP) met on the banks of Namebini-ziibiins (the Little Carp River). It was here that GLIFWC's Great Lakes Section expanded its cooperative work with KBIC and SLCP to trap bimiizii (sea lampreys) in the 1842 Treaty ceded area.
Two mini-fyke net traps were set facing upstream in the river to capture larval and transformed lampreys as they migrated out on flows created by the spring snow melt (see inset picture).
Larval lampreys live in streams and sometimes migrate out of streams into near-shore areas of the Great Lakes. Larval lampreys burrow into soft sediments found in streams and near-shore areas of the lake. It is here that larval lampreys filter feed on algae and decaying matter that drift past their hiding places until they are ready to transform into their next life phase.
Larval lampreys can live in these areas for up to six years before they transform from filter feeders to parasites.
Once larval lampreys reach an average length of six inches long, they undergo a transformation which changes their mouth from that of a filter feeder to that of a parasite. The newly transformed lampreys leave their burrows, find a fish, then attach to them and feed off the fish's body fluids. After eighteen months feeding in this way, each lamprey will have grown from six inches long to 15-20 inches long, at which time they mature, migrate up streams, spawn, and die.
GLIFWC in cooperation with KBIC and SLCP set the mini-fyke nets in the Little Carp River to remove larval lampreys and newly transformed lampreys. The larval lampreys were removed before exiting the stream to settle into near-shore areas of the lake and transformed lampreys before they exit the stream and begin feeding on fish. It is beneficial to remove the larval lampreys because near shore, or lentic, areas of the lake are more difficult and more expensive to treat than streams.
As for the transformed lampreys, each one removed is unable to grow to adulthood. Transformed lampreys that leave the stream must find a fish quickly or die of starvation, no longer being able to filter feed. Each lamprey that makes it from the transformed stage to adulthood kills an estimated 20 pounds of fish in Gichigami (Lake Superior).
Asian carp: Threat to the Great Lakes
Odanah, Wis.—To date Asian carp, which could negatively impact native fish populations, have not established a population in the Great Lakes. Three Asian Carp were captured between 1999 and 2000 in Lake Erie and one was captured five miles from Lake Michigan in 2010. While their origin and route of entry is unknown, no others have been captured following intensive sampling.
Asian carp refers to four recently introduced carps; silver, bighead, black, and grass. Three other carps native to Asia have been here for years; common carp, goldfish, and crucian carp.
It is the silver carp that is famous for jumping into boats. In many U.S. waterways, silver carp are widespread and abundant.
Bighead carp are found in the wild, but most are raised in ponds as a commercial food-fish and sold in local fish markets as well as exported abroad.
Grass and black carp also have commercial applications; they are used in commercial ponds as a bio-control to keep unwanted plants and mussels at low numbers.
Carp found outside of fish farm ponds have been introduced as a result of both stocking and escape from ponds during floods.
There is much concern over Asian carp invading the Great Lakes through the Chicago Area Waterway System
(CAWS) which connects Lake Michigan with the Mississippi river system, where the carp are found in abundance.
The impact of Asian carp should they enter the Great Lakes is unknown but here is what we do know:
Bighead and silver carps feed low on the food chain, similar to Gichigami's cisco and whitefish. Therefore, they are low in contaminants such as mercury. Also, like the native cisco and whitefish, they contain heart healthy omega 3 fatty oils.
In comparison to the favorite food fishes of most tribal members, such as walleye and whitefish, bighead and silver carps are very bony fish; having a similar bone structure to northern pike and muskellunge.
Silver carp are prone to propelling themselves into the air when a boat motor comes near which has led to boaters and water skiers being struck and injured by flying fish.
The concern people have over bighead and silver carp is that they will compete with larval native fish in the Great Lakes. Their feeding may drive down the number of young predatory fish and disrupt the food chain by competing with and/or eating native larval prey fish. Carp photos courtesy of www.ttp://www.allfishingbuy.com/Fish-Species/.
For the most current information on what is being done to prevent and control the spread of Asian carp in the United States visit http://www.asiancarp.us/ .