The Great Lakes - St.Lawrence Research Inventory

Based on recent evaluations of the Wisconsin fish bioenergetics models in the laboratory, some scientists have concluded that the models for all fish species contain a systematic bias in that the models underestimate food consumption at relatively high feeding rates. These scientists attributed this systematic bias to an error associated with the egestion, excretion, or specific dynamic action submodels within the bioenergetics model. Further, these scientists advocated that a correction factor be used in applying the bioenergetics model to fish in the field.

The sterile-male-release technique (SMRT) is a key alternative control strategy used to manage sea lampreys in the Great Lakes. To achieve sterilization, male sea lampreys are injected with the chemosterilant bisazir, which destroys genes essential for embryo development of offspring. While bisazir has proved to be an effective sterilant for male sea lampreys, there is the potential for problems to occur during the sterilization process that would prevent males from being sterilized.

Thiamine Deficiency Complex (TDC) results in low egg thiamine levels and reduced reproductive success of Great Lakes salmonines. TDC is caused by a diet composed of a high proportion of alewife, which contain thiaminase, and may be partially responsible for low levels of natural reproduction by lake trout in the Great Lakes. Recent research indicates that invasive dreissenid mussels from the Great Lakes have extremely high thiaminase activities.

Diet analyses are a tool commonly used by fisheries managers to determine feeding habits and food web interactions of aquatic organisms. Many different methods are used to identify and quantify diets of piscivores, but each method has unique advantages and disadvantages. There are several characteristic bony structures which can be used to identify partially digested fish, including otoliths, vertebrae, opercles, and cleithra.

The Acoustic User Group recently develop a standard operating procedure for collecting and processing acoustic data. The goal of this standardization was to make comparisons of acoustic fish densities across lakes directly comparable. Several approaches have emerged for apportioning acoustic densities to species using data of fish composition collected with trawls and other traditional fishing gear. Ideally, species-specific density and biomass estimates should also be directly comparable. It was with this goal that we developed our latest Science Transfer proposal.

RATIONALE: Although lampricides such as 3-trifluoromethyl-4- nitrophenol (TFM) and granular niclosamide have been used successfully for the control of sea lamprey in the Great Lakes region, their modes of toxic action are not completely understood. In addition, their effects on non-target fish species are not clear. Historically, toxicant effects on aquatic organisms have primarily been evaluated via lethality.

Hemimysis anomola is an invertebrate invader that was first reported in the Great Lakes basin in 2 6. Hemimysis are quickly spreading through the basin, becoming most abundant in nearshore areas where they are forecast to impact resident zooplankton (through competition & predation) and fishes (changed prey base) (H1: Hemimysis quickly become integrated into the Great Lakes food web).

Two novel control approaches have been proposed for the use of the sea lamprey migratory pheromone: 1) redistribution of migrants into areas where they are increasingly vulnerable to capture or destruction; 2) baiting traps to increase the efficiency of trapping operations.