Thermal ecology of subadult and adult muskellunge in a thermally enriched reservoir

Abstract

The movement of adult muskellunge, Esox masquinongy Mitchill, has been investigated in a variety of systems, but temperature selection by muskellunge has not been examined where well-oxygenated waters were available over a range of temperatures for much of the year. Thirty subadult and adult muskellunge tagged internally with temperature-sensing radio tags were tracked from their realised thermal niche (mean AE 1 SD) was 22.3°C AE 1.8; the realised thermal niche was affected by fish size (smaller fish selected slightly warmer temperatures) but not sex. An electric generating steam plant discharging warm water resumed operation in January 2011, and most (86%) tagged fish occupied the plume where temperatures were %10°C warmer than ambient water temperatures. No mortalities were observed 15 days later when plant operations ceased. Their affinity for the heated plume prompted concerns that muskellunge will be too easily exploited when the plant operates during winter. K E Y W O R D S :Esox masquinongy, temperature selection, thermal ecology, thermal niche.

Seasonal Movement Patterns and Summertime Use of Thermal Refuge Areas by Muskellunge in the Nontidal Potomac River, Maryland

“…Observations of Muskellunge concentrating near creek mouths, springs, seeps, and upwellings during summer months have been evident since the establishment of this population (J.E.M., personal observation). Throughout this study, tagged Muskellunge sought out the cooler water available during summer months as main-stem river temperatures approached 23°C, which is supported by similar findings from reservoir studies (Beck and Brooks 2003;Cole and Bettoli 2014). The results of this study suggest that Muskellunge rely heavily on TRAs when water temperatures exceed 27.0°C (>90% occupancy).…”

“…The use of radiotelemetry in understanding seasonal movement patterns is critical to identify and protect spawning locations (Crossman 1990;Younk et al 1996;Jennings et al 2011;Morrison and Warren 2015), determine habitat types and preferences (Brenden et al 2006), and identify seasonal vulnerabilities to angling (Cole and Bettoli 2014). Multiple radiotelemetry studies have investigated Muskellunge behaviors (i.e., seasonal movements and habitat preferences, spawning behavior and homing) in riverine environments (Minor and Crossman 1978;Younk et al 1996;Brenden et al 2006), but limited work has been done on populations in the southern part of the Muskellunge's range.…”

“…Beck and Brooks (2003) observed adult Muskellunge selecting deeper, cooler water when surface temperatures reached 25°C, despite lower dissolved oxygen (DO) concentrations (<3.0 mg/L) during summer months in a southern Illinois reservoir. In a Tennessee reservoir, Cole and Bettoli (2014) reported a thermal range for adult Muskellunge of 22.3°C and concluded that fish never occupied water temperatures greater than 27.5°C and rarely occupied water warmer than 25°C, despite the sufficient availability of DO.…”

Muskellunge Survival, Interbasin Movement, and Emigration in a Simple and a Complex Interconnected Glacial Lake

“…Muskellunge may move upstream or downstream in response to environmental cues (Miles 1978; Kerr and Jones 2017) or in relation to prey abundance, water temperatures, dissolved oxygen, and precipitation (Dombeck 1979; Henley 1981; Landsman et al 2011; Wolter et al 2013; Cole and Bettoli 2014). Among these factors, increases in water levels due to periods of excessive rainfall have been directly linked to Muskellunge emigration.…”

Understanding factors regulating Muskellunge and Walleye reservoir populations using radio telemetry

“…) but quantifying natural mortality is of major importance for Midwestern reservoirs, as systems on the southern edge of their range reach temperatures beyond the optimum of the species (Wagner and Wahl 2007;Cole and Bettoli 2014) and could lead to increased stress during angling events ) and mortality . However, knowledge is limited regarding factors related to Muskellunge natural mortality rates, as well as the relative influence of escapement versus mortality on adult Muskellunge populations.…”