Lake Michigan Fisheries News
November 30, 1999
TO: People interested in Great Lakes fisheries
FROM: Bill Horns, Great Lakes Fisheries Specialist
This is an update on some of the issues facing us on the Great Lakes. If you have questions or comments about the topics discussed here or any other issues related to Great Lakes fisheries, contact me by phone (608.266.8782), FAX (608.266.2244), or e-mail (william.horns@wisconsin.gov).
Big fish in Lake Michigan. Sport trolling turned around after a slow start and, fishing was good (in the north) to exceptional (in the south) in 1999. The fish, especially coho salmon, were unusually large. Catches of 8 to 10 pound cohos were common. A new state record coho (26 pounds 1.2) ounces was caught by John Gregory, fishing out of Milwaukee. This was a dramatic turn-around from the recent past. In the fall of 1998, for example, the average weight of mature two-year-old cohos returning to our weir on the Kewaunee River was only seven pounds. Growth in fish depends on two primary factors - food availability and water temperature. We can influence the food supply indirectly by limiting the numbers of predators we stock, but reproduction by alewives and other forage species will fluctuate widely, no matter what we do, and we cannot control the weather. So, expect the unexpected in 2000.
They keep on coming – the "fishhook water flea" is here. Recently Cercopagis pengoi, sometimes known as the fishhook water flea, made its way into Lake Michigan in ships ballast. Like the spiny water flea (Bythotrephes cederstoemi) this large zooplankton species eats smaller animals and may compete with young fish for food. The ecological impacts of this species are as yet unknown. Also like the spiny water flea, the fishhook water flea can become snagged on downrigger lines or fish nets, so you may see more of it in the future than you want to.
The following picture is available, along with others, at the Univ. of Windsor site. The largest of the fishhook water fleas shown here have body lengths slightly less than 1/16 inch and tailspines (cut off in this picture) almost 1/3 inch long.
Why can’t we stop this? The fishhook water flea is only the latest of a long series of exotic species (including round gobies and zebra mussels) to reach the Great Lakes in ships ballast. Why can’t we stop this? Much has been written on this topic. Although I am not an expert, I know a little about it. Background Ballast is water carried by ships to stabilize them when they are not fully loaded. It is held in chambers in the ship’s hull and is pumped in when cargo is unloaded and out when cargo is loaded. The translocation of organisms in ballast is a worldwide problem. It has been estimated that almost 800,000 tons of foreign ballast are legally discharged into the Great Lakes each year. Species transported to the Great Lakes in ballast water include everything from fish to bacteria, and can include pathogens. This problem has been the subject of extensive study, federal legislation, and a lot of hand wringing. The economic stakes are large, because of the economic importance of the shipping industry and because of the havoc that can be wreaked by exotic species. The Great Lakes shipping industry is well aware of and concerned about this problem. Studies of engineering fixes (including filters and biocides) are underway, but there are no cheap or easy solutions. An imperfect solution One method that has been employed to limit the damage is to require vessels to exchange ballast water at sea before entering the Great Lakes, thereby releasing some of the organisms that had been taken into the ballast compartments elsewhere and killing others that cannot live in salt water. This is an imperfect system, in large part because of ships referred to as NOBOBs. A NOBOB is a ship that enters the Great Lakes reporting "no ballast on board" because it contains no pumpable ballast in its tanks. Unfortunately the ballast compartments of NOBOBs are not empty. A Canadian study found that NOBOBs, although not carrying any pumpable ballast, carried an average of over 150 tons of residual water and sediment. Between 75% and 95% of vessels entering the Great Lakes are NOBOBs. Once in the Great Lakes, these vessels unload cargo and take on Great Lakes water as ballast, thereby diluting the slop already on board and making it available for discharge in other Great Lakes ports if the ship moves around the Great Lakes loading and unloading cargo. Can the discharge of organisms in ballast be prohibited by law? Currently, provisions of the National Pollutant Discharge Elimination System adopted under the Clean Water Act do not apply to ballast discharges. However, in response to a petition originated by the Pacific Environmental Advocacy Center (and signed by the Great Lakes Sportfishing Council, Great Lakes United, and the Chippewa-Ottawa Treaty Fishery Management Authority), the US Environmental Protection Agency is now reviewing the applicability of the Clean Water Act to this problem. A recent legal analysis prepared for the Michigan DEQ1 found that states may adopt legislation limiting the discharge of ballast into their waters, as long as they avoid specifying requirements for the design, construction, or equipment of commercial vessels. Wisconsin has adopted no such legislation and the Department of Natural Resources currently lacks legal authority to act in this area.
The Orienta Falls Dam is coming out. Most obstacles to removal of the Orienta Falls Dam from the Iron River (Lake Superior) have been resolved. The Department is now working with the dam’s owner, Northern States Power, and the US Fish and Wildlife Service to prepare for dam removal next year. The dam will be replaced by a low-head barrier that will prevent sea lamprey from colonizing the Iron River, and will prevent upstream fish passage until Iron River watershed management plans are developed.
Water quality in tributaries. The DNR is currently reviewing water quality rules with respect to the designated uses of surface waters. All Wisconsin surface waters are classified according to their use by fish and other aquatic life, and those "use designations" determine permit limits for industrial or municipal discharges. One of the options being considered is to upgrade some of the Great Lakes tributary streams that are currently classified as "warm water sport fish" to "cold water", to reflect their use by salmon and trout. The change might only be seasonal, reflecting the time of year when trout and salmon use the streams, but would have the effect of protecting those fish by limiting future discharges into the streams. An advisory committee which includes representatives of industries, municipalities, sport fishers, and environmentalists, as well as Department staff, has been meeting to discuss this issue. For more information on this contact Greg Searle (608/267-7644; greg.searle@wisconsin.gov) in the Department’s Bureau of Watershed Management.
USFWS cormorant plan. Cormorants are protected by the Migratory Bird Treaty Act, so management of that species is within the jurisdiction of the US Fish and Wildlife Service. Responding to concerns about the effects of the growing cormorant populations, the Service has announced that it will develop a comprehensive national cormorant management plan. The first step in that process will be the development by the Service of an Environmental Impact Statement (EIS) evaluating the species’ status, known and perceived impacts on other resources, and potential management strategies. If you would like to comment on the EIS, or obtain additional information, contact the Office of Migratory Bird Management, U.S. Fish and Wildlife Service, 4401 N. Fairfax Dr., Room 634, Arlington, VA 22203. Comments may also be submitted electronically to cormorant_eis@fws.gov. Public comments will be accepted until January 7, 2000.
Updated steelhead plan. Our new steelhead plan, "Lake Michigan Steelhead Fisheries Management Plan – 1999" is available electronically at http://dnr.wi.gov/fish/lakemich/index.htm(our Lake Michigan web site), or send me a note and I’ll mail you a copy.