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Various gear types have been used to sample populations of channel catfish Ictalurus punctatus in lotic systems. However, these gears produce different population characteristics (i.e., recruitment, growth, and mortality). We compared the...
2008-02-01
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Three different electrofishing systems were compared to determine their relative efficiency with respect to species and numbers of fish collected. These results indicated that modifications or changes in electrofishing gear during a monitoring...
1983-07-01
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Accurate age information is critical to the biological understanding and management of most fish species, but particularly for species of concern, such as the pallid sturgeon Scaphirhynchus albus. The accuracy and precision of pallid sturgeon age...
2004-05-01
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During November 2002, 51 shovelnose sturgeon Scaphirhynchus platorynchus were sexed by ultrasound imaging using a portable ultrasonograph. We identified males with 96% accuracy (N = 25) and females with 80% accuracy (N = 25); one hermaphroditic...
2004-02-01
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For fish at high latitudes, short growing seasons should constrain size-at-age, although the converse often occurs. We used a dynamic state variable model to find energy allocation strategies to length, fat, and ovaries that maximize expected egg...
2003-08-01
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In northern Wisconsin lakes, the introduced crayfish Orconectes rusticus is replacing O. propinquus, a previous invader, and O. virilis, a native crayfish. Herein, we explore how fish predation and competition interact to drive this change in...
1994-03-01
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In small, hypereutrophic reservoirs (<100 ha; >100 mg total phosphorus/L), larval gizzard shad Dorosoma cepedianum and threadfin shad D. petenense (henceforth, shad) reach high densities in the limnetic zone, virtually eliminate zooplankton, and...
1998-11-01
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We evaluated the effects of stressor exposure and super-requirement levels of RRR-atocopheryl acetate (natural-source vitamin E [NSVE]) on production performance and nonspecific immunocompetency of juvenile sunshine bass (female white bass Morone...
2007-10-01
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Although oxygen frequently limits aquatic ecosystems, broad temporal-spatial oxygen dynamics in streams and consequences for aquatic life are poorly understood. In this perspective, we quantified dissolved oxygen (DO) concentrations (mg·L–1) in...
2007-12-01
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To determine how populations of shovelnose sturgeon Scaphirhynchus platorynchus are changing and may respond to poor environmental conditions, current commercial harvest of black-egg (sexually mature) females, and incidental mortality of males, we...
2009-03-01
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Most community-based models in ecology assume that all individuals within a species respond similarly to environmental conditions and thereby exert identical effects as consumers or prey. Rather, individuals differ among systems, with important...
2003-02-01
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To generate reliable age information for fishes, we must assess the robustness of techniques to environmental variation. We quantified daily ring deposition within the sagittal otoliths of known-age larval and juvenile redspotted sunfish Lepomis...
2004-02-01
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Winter temperatures may reduce energy costs for ectotherms. However, variable mid-temperate and low-latitude winters may interact with scaling of size, metabolism, and energy reserves to cause energy deficits and require trade-offs between...
2004-10-01
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Shovelnose sturgeon Scaphirhynchus platorynchus in the middle Mississippi River provide one of the last commercially viable sturgeon fisheries in the world, yet their maturation and reproduction have not been linked. During 2005 and 2006, we...
2009-06-01
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Within many ecological systems, relationships between controlling factors and associated response variables are complex. In many cases, the response should vary little when the controlling factor exerts strong effects. Conversely, when the effect...
1998-03-01
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The silver carp Hypophthalmichthys molitrix has spread throughout the Mississippi River drainage. During 2003, we determined its population status and potential impact in the middle Mississippi River (MMR), the conduit between the lower...
2005-11-01
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We evaluated the habitat use and movements of 50 adult bighead carp Hypophthalmichthys nobilis and 50 silver carp H. molitrix by means of ultrasonic telemetry during spring–summer 2004 and 2005 to gain insight into the conditions that facilitate...
2008-01-01
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Understanding how life histories influence reproductive success under uncertain conditions is necessary to predict population dynamics. For many organisms, protracted reproduction may increase expected offspring recruitment in variable...
2002-02-01
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Relationships between spawning fish (S) and surviving offspring (recruits, R) are typically assumed to be continuous and nonlinear. However, R may change abruptly with small changes in S if population-, community-, or ecosystem-scale processes...
2009-02-01
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