Publications

Available population and diet data on double-crested cormorant (Phalacrocorax auritus) and smallmouth bass (Micropterus dolomieui) numbers, demographics, and exploitation rates were synthesized to examine the relationship between cormorant and smallmouth bass abundance in the U.S. waters of the eastern basin of Lake Ontario. It was found that after the number of cormorants nesting on...

Bottom substrates and overlying water at three sites where lake sturgeon were reported by others to spawn in the 160-km channel between lakes Huron and Erie were surveyed by boat just before or after the exact time of spawning in 2001 to determine the kinds of substrates present and differences in water quality at the sites. Substrates, examined and photographed using a high-resolution...

We used an angling study to examine catch per unit effort (CPUE), bait loss, and total landings by anglers fishing with natural bait on barbed and barbless hooks in a nearshore marine sport fishery located in the Gulf of Mexico near St. Petersburg, Florida. Anglers fished half the day with a barbed hook and half the day with a barbless hook. We also recorded anatomical hook placement...

This volume is the proceedings of the Seventh International Symposium on the Biology and Management of Coregonid Fishes (ISBMCF). As in all six preceding symposia, the seventh meeting of the ISBMCF provided an international forum for the scientific review and discussion of the various taxonomic, biological, ecological, and management issues that surround this important group of Holarctic...

The use of rubber-compound windows for fisheries acoustics must consider operating frequency and ambient water temperatures. Signal attenuation by the rubber becomes pronounced with increased frequency and decreased temperature. Based on our results, a 420 k Hz system could be expected to lose up to 3-4 dB in colder water through a 5.1-cm thick rubber diaphragm. At 120 k Hz, signal loss...

Classification methods used in machine learning (e.g., artificial neural networks, decision trees, and k-nearest neighbor clustering) are rarely used with population genetic data. We compare different nonparametric machine learning techniques with parametric likelihood estimations commonly employed in population genetics for purposes of assigning individuals to their population of origin...

One hundred slimy sculpins, Cottus cognatus (Cottidae), collected from Six Fathom Bank Lake Trout Refuge in Lake Huron in June 1995 were examined for parasites. A total of 17 parasite species (3 Digenea, 2 Monogenea, 3 Cestoda, 3 Nematoda, 2 Acanthocephala, 2 Ciliophora, 1 Microspora, and 1 Myxosporea) were found to infect sculpins. Tetracotyle sp. had the highest prevalence, mean...

A recent find of the groundwater-inhabiting copepod crustacean Diacyclops harryi extended the known range of this species far northwestward, to include northern Ohio and the drainage basin of the Laurentian Great Lakes. The species was previously collected in drainages of the Atlantic Slope from New York to North Carolina. Ostracodes tentatively identified as ?Nannocandona n. sp., and...

In fisheries, imprecise measurements in catch data from surveys add uncertainty to the results of fishery stock assessments. The USGS Great Lakes Science Center (GLSC) began to survey the fall fish community of Lake Michigan in 1962 with bottom trawls. The measurement error was evaluated at the level of individual tows for nine fish species collected in this survey by applying a...

Shortjaw cisco (Coregonus zenithicus) exhibit morphological variability across their geographic range in North America and could comprise more than one distinct morph or taxon. To investigate this, principal components analysis was applied to a data set that consisted of four variables from nine localities. All data were obtained from digital images of the specimens and the excised first...

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...

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...