A Bioenergetic Analysis of Factors Limiting Brown Trout Growth in an Ozark Tailwater River

Abstract

We examined prey utilization and energy consumption by brown trout, Salmo trutta, in a cold tailwater (Little Red River, Arkansas, USA; LRR) having low biodiversity and low availability of fish as prey. Stomach content analysis and age estimation were performed on thirty brown trout (10 each of three size classes for a total of 710 trout) collected monthly from an upstream and downstream site over a 1-year period. Diet diversity was low at both sites, as 80% and 70% of all prey consumed by upstream and downstream brown trout, respectively, were isopods. Piscivory ( < 0.5% of individuals sampled) and consumption of terrestrial invertebrates were rare. There was no relation between diet diversity and trout age, and a very small ontogenetic shift in brown trout diet. Second, we investigated brown trout growth rates relative to prey consumption and temperature. Temperatures and availability of prey were less than required for maximal trout growth. However, prey availability limited trout growth directly, but sub-optimal temperatures probably buffered the effect of this reduced energy consumption by reducing metabolic energy expenditures. Brown trout growth was 54.8-57.0% of the maximum predicted by a bioenergetics model. Instantaneous growth rates for age 1 and adult brown trout were slightly higher for those downstream (0.195) versus those upstream (0.152). Although isopods are abundant within this tailwater to serve as a forage base, the displacement of native fish fauna and subsequent lack of establishment of cold-tolerant forage fish species due to the thermal regime of hypolimnetic release from Greers Ferry Reservoir probably serves as a major barrier to brown trout growth.

Exploring the relative influence of biotic interactions and environmental conditions on the abundance and distribution of exotic brown trout (Salmo trutta) in a high mountain stream

“…experimentally at colder, high-elevation sites where they do not occur naturally, brown trout grew faster as compared with low-elevation sites (this study; McHugh & Budy 2005). Further, although direct comparisons are difficult to find, growth rates of wild brown trout in the Logan River generally exceeded rates documented in other published studies from other countries (Greenberg & Dahl 1998;Lobon-Cervia & Rincon 1998;Johnson et al 2006; but see Jensen et al 2006). In temperate streams like the Logan River, temperatures are within the range suitable for growth over a limited time period from spring through early autumn (May-September), and most of the annual fish growth occurs over this time period (this study; Lobon-Cervia & Rincon 1998).…”

“…In addition, growth rates of wild brown trout at colder, higher‐elevation sites were similar to rates observed at low‐elevation warmer sites; however, when reared experimentally at colder, high‐elevation sites where they do not occur naturally, brown trout grew faster as compared with low‐elevation sites (this study; McHugh & Budy 2005). Further, although direct comparisons are difficult to find, growth rates of wild brown trout in the Logan River generally exceeded rates documented in other published studies from other countries (Greenberg & Dahl 1998;Lobon‐Cervia & Rincon 1998; Johnson et al. 2006; but see Jensen et al.…”

Density Dynamics of a Threatened Species of Darter at Spatial and Temporal Scales

“…Numerous studies have examined downstream faunal changes following stream impoundment (e.g., Johnson and Harp 2004, Johnson et al 2006a, Shaver et al 1997. Less frequently studied are upstream faunal effects from impoundment (Erman 1973, Herbert and Gelwick 2003, Winston et al 1991.…”

Quantifying the effect of semi‐natural riparian cover on stream temperatures: implications for salmonid habitat management

“…It directly affects feeding rates and growth efficiencies as well as invertebrate prey production (Johnson et al . ). In general, uptake and costs have been found to be exponential functions of temperature (Broekhusien et al .…”

“…Temperature is considered a key abiotic factor affecting salmonid growth and maintenance (Preall & Ringler 1989;Lobon-Cervia & Rincon 1998;Railsback & Rose 1999). It directly affects feeding rates and growth efficiencies as well as invertebrate prey production (Johnson et al 2006). In general, uptake and costs have been found to be exponential functions of temperature (Broekhusien et al 1994).…”