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Lake City, MN, United States

Sietman B.E.,00 Lafayette Road | Davis J.M.,801 South Oak Street | Hove M.C.,University of Minnesota
American Malacological Bulletin | Year: 2012

Diverse strategies have evolved in freshwater mussels to promote the transfer of their parasitic larvae to host fish. Among these, modification of the mantle as a host attracting lure has been well-documented in the Tribe Lampsilini, but only recently reported in the Tribe Quadrulini. Here we describe mantle modifications and glochidia release behaviors in five quadruline species, including members of the Quadrula quadrula (Rafinesque, 1820), Q. pustulosa (Lea, 1831), and Q. metanevra (Rafinesque, 1820) species groups. Displays were motionless and consisted of inflated mantle tissue surrounding the excurrent aperture. Gross display morphology was largely variable among species: Q. fragosa (Conrad, 1835) and Tritogonia verrucosa (Rafinesque, 1820) had relatively large, uniquely shaped displays; Cyclonaias tuberculata (Rafinesque, 1820) and Q. pustulosa had smaller, stomate-shaped displays; and Q. metanevra had a diminutive, polyp-like display. Cyclonaias tuberculata exhibited a bimodal host infection strategy where individuals had either a mantle display or released a gelatinous conglutinate. Quadrula pustulosa and Q. metanevra expelled glochidia in a forceful burst when their displays were touched. Quadruline mantle displays do not clearly mimic identifiable aquatic organisms suggesting they may represent non-specific food items to their fish hosts. Source

Hoxmeier R.J.H.,801 South Oak Street | Dieterman D.J.,801 South Oak Street | Miller L.M.,University of Minnesota
North American Journal of Fisheries Management | Year: 2015

Abstract: The Driftless Area in southeastern Minnesota is on the southwestern edge of the native range of Brook Trout Salvelinus fontinalis. It was assumed that native Brook Trout were extirpated from this region in the early 1900s due to degraded stream conditions and stockings of eastern-origin Brook Trout and European Brown Trout Salmo trutta. Our objectives were to examine Brook Trout populations in the region to determine their spatial and genetic distribution and quantify population characteristics. Information on presence or absence of Brook Trout was gathered by electrofishing 174 streams in southeastern Minnesota. Brook Trout were present in 68% of coldwater streams compared with only in 3% in the early 1970s. The increase is likely due to increasing stream discharge throughout the Driftless Area, enabling recolonization or successful establishment of stocked populations. Streams with higher base flow discharge also had higher abundance, larger size at maturity, and larger Brook Trout present. Genetic data on 74 populations were analyzed to characterize genetic variation within populations, assess genetic structure among populations, and determine possible origins. Numerous populations were not associated with known hatchery sources but were primarily composed of geographic groupings that could represent remnant lineages. Although population characteristics were similar among genetic origins, potentially remnant populations should be given conservation priority because they have proven their ability to sustain themselves in this region. Management actions that emphasize maintaining or increasing stream base flows throughout the region will likely enhance remnant Brook Trout populations in the Driftless Area. Received July 25, 2014; accepted March 17, 2015 © 2015, © American Fisheries Society. Source

Moore M.J.C.,801 South Oak Street | Langrehr H.A.,630 Fanta Reed Road | Angradi T.R.,U.S. Environmental Protection Agency
Ecological Indicators | Year: 2012

Portions of the Upper Mississippi River are listed as impaired for aquatic life use under section 303(d) of the United States Clean Water Act by the State of Minnesota's Pollution Control Agency and Wisconsin's Department of Natural Resources for exceeding turbidity and eutrophication standards. To help regulatory agencies address Clean Water Act requirements, we developed a submersed macrophyte index (SMI) for the Upper Mississippi River. Aquatic macrophytes are a critical driver of the ecology of the Upper Mississippi River. Because they are rooted, they integrate the effects of long and short term physical and chemical disturbance. Fifty-four submersed macrophyte-based attributes were evaluated for inclusion in the index by testing their range, responsiveness to a published multimetric stressor gradient, scope of impairment among least impaired samples, and redundancy. Four attributes were ultimately selected as metrics for the SMI including (1) percent frequency of occurrence, (2) 95th percentile of maximum depth of submersed macrophyte occurrence, (3) total rake score, a measurement of abundance quantified by the proportion of rake tines filled by aquatic macrophytes, and (4) 95th percentile of submersed species richness. The SMI separated least and most impaired samples. Using the validation dataset, the stressor gradient explained 36% of the variation in the SMI. There was a significant downriver increase in SMI scores mostly due to the effect of Lake Pepin, in the middle of Pool 4 of the Upper Mississippi River, which serves as a settling basin for transported suspended solids, increasing water clarity and improving conditions for submersed macrophyte growth in areas downstream of the lake. Proximity to a navigation dam also affected SMI scores, which consistently decreased from the sample immediately above a dam to the sample immediately below. The individual metrics within the SMI appear to be driven by two principal forces: light penetration and hydrologic conditions created by navigation dams. The correspondingly low SMI scores where listed impairments occur substantiate the use of our SMI to detect such impairments. A significant relationship between the stressor gradient and our SMI further confirms our index's ability to detect anthropogenic stresses on the Upper Mississippi River. Our index is the first developed in North America using aquatic macrophytes for assessing large river ecosystem condition. © 2011 Elsevier Ltd. Source

Meerbeek J.R.,801 South Oak Street | Hoxmeier R.J.H.,801 South Oak Street
North American Journal of Fisheries Management | Year: 2011

We evaluated the effect of length and depth of capture of saugers Sander canadensis on winter hooking mortality below Lock and Dam 3 of the Mississippi River (i.e., Pool 4) by catching saugers using the most common recreational fishing gear in these fisheries (jig and plastic, jig and minnow, and jigging spoons) and holding the fish for 72 h in a net-pen. Sauger winter hooking mortality was 26.4% and increased with depth of capture. Thirty-three percent (56 of 172) of the saugers caught at depths of 9 to 24 m died, compared with only 2% (1 of 41) of those caught at depths of 9 m or less. There was no relationship between fish length and mortality; however, fish caught at depths of 12 m or less were significantly larger. We applied our hooking mortality estimates (26.4%) to a concurrent creel census and estimated that 2,500-2,900 kg of saugers were lost each year to winter hooking mortality. The percentage of total angling mortality (harvest and hooking) resulting from catch and release each winter was 30.5% (2,515 kg/8,256 kg) in 2005-2006 and 33.0% (2,812 kg/8,529 kg) in 2006-2007. Based on the historical abundance and annual mortality estimates available for Pool 4 saugers, winter hooking mortality did not substantially reduce the population. However, anglers may reduce winter catch-and-release hooking mortality by fishing in shallower water (<9 m). © American Fisheries Society 2011. Source

Hoxmeier R.J.H.,801 South Oak Street | Dieterman D.J.,801 South Oak Street
Biological Invasions | Year: 2016

Although laboratory studies have provided evidence for negative interactions between brook trout and brown trout, it is unknown how these interactions affect larger scale demographics in a natural setting. We tested the effects of invasive brown trout on brook trout demographics by removing brown trout from a sympatric population using a before–after control-impact study design. The study was conducted across a large stream network for a period of 6 years. Abundance of brook trout increased after brown trout removal primarily as a result of increased recruitment and immigration. Size structure also shifted towards larger individuals as a result of increased growth rates and a decrease in emigration of larger trout. Size at maturity and body condition did not change after brown trout removal. Adult brook trout survival increased during the post-treatment period in both the treatment and control reach. A decrease in flood intensity during the post-treatment time period may have led to increased survival. Adult survival may not be the best metric to use when assessing interactions between trout species, especially when the subordinate species has suitable areas to emigrate. © 2016 Springer International Publishing Switzerland Source

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