Publications

After nearly 30 years of recolonization and expansion across North America, the double-crested cormorant (Phalacrocorax auritus) occupies the role of a perceived and, in some situations, realized threat to fish stocks and other resources. However, population data necessary to plan, defend, and implement management of this species are few. Our purpose was to gain insight into the relative

Recent aquatic Hemiptera collections have yielded 15 new state records distributed among four midwestern States. These records include two species of water boatmen (Palmacorixa gillettei and Sigara mathesoni) new for Indiana, four water boatmen species (Cenocorixa utahensis, Corisella inscripta, Hesperocorixa laevigata, S. decorata), including one genus (Cenocorixa) new for Michigan...

The Grand Calumet River lies in an area of great ecological diversity, a result of the convergence of three biomes during glaciation. Over thousands of years the region and the river have changed ecologically due to ice retreat, lake level declines, settlement and industrialization. Settlement and industrialization have greatly accelerated the rate of change, and the Grand Calumet River...

Conservation of skeletal structure and unique body ratios in fishes facilitated the development of truss analysis as a taxonomic tool to separate physically-similar species. The methodology is predicated on the measurement of across-body distances from a sequential series of connected polygons. Changes in body shape or condition among members of the same species can be quantified with...

The immunotoxicity of chemical combinations commonly encountered by the lake trout (Salvelinus namaycush) immune system was the focus of this study. It was hypothesised that combinations of an environmental contaminant (mercuric chloride or Aroclor 1254) and an immunomodulatory agent (bacterial endotoxin or cortisol) might interact to produce a greater toxicity than that of the...

Omul, Coregonus autumnalis, are a commercially important coregonine fish from Lake Baikal, Siberia, Russia. In Lake Baikal, three morphotypes recognized by fishery experts occupy different zones in the lake: they are referred to as "littoral," "pelagic," and "benthic". Expressed character divergence was supported by whole-body morphometric analysis, but it is not known whether discrete...

We analyzed buoyancy in two deepwater ciscoes, Coregonus hoyi and C. kiyi, and in C. artedi, their putative ancestor, and also analyzed how variations in fish weight, water content, and lipid content affected buoyancy. Buoyancy was significantly different among the three species (p 0.0001). Estimates of percent buoyancy (neutral buoyancy = 0.0%) were: kiyi, 3.8%; hoyi, 4.7%; and artedi...

We describe a safe and effective apparatus for washing and reducing the volume of benthic samples collected by grab samplers aboard ship. The sample is transferred directly from the dredge to the apparatus and then washed with water pumped through pipes in the apparatus and from onboard hoses. Wastewater and materials smaller than 0.541 mm in diameter are washed overboard. Larger...

Benthic copepods (Copepoda: Harpacticoida) in the nearshore sediments of southern Lake Michigan appear to be dominated by two new invasive species. We report the first occurrence in North America of Schizopera borutzkyi Montschenko, a native to the Danube River delta, and Heteropsyllus nr. nunni, likely a new species that is morphologically similar to the marine species Heteropsyllus...

In 1976, the Wisconsin Department of Natural Resources established a refuge for a nearly depleted population of lake trout (Salvelinus namaycush) at Gull Island Shoal, Lake Superior. The refuge was intended to reduce fishing mortality by protecting adult lake trout. We examined the growth dynamics of these lake trout during the period of recovery by comparing estimates of ndividual...

The Great Lakes Science Center has conducted lake-wide bottom trawl surveys of the fish community in Lake Michigan each fall since 1973. These systematic surveys are performed at depths of 9 to 110 m at each of seven index sites around Lake Michigan. Zebra mussel (Dreissena polymorpha) populations have expanded to all survey locations and at a level to sufficiently contribute to the...

Fishes were assessed in Guffin, Chaumount, and Black River bays in northeastern Lake Ontario with a 7.9-m (headrope) bottom trawl during late September and early October, 1978 to 1997. Fish density declined in the early 1990s with sharp declines in abundance of spottail shiner (Notropis hudsonius), trout-perch (Percopsis omiscomaycus), and johnny darter (Etheostoma nigrum) occurring in...