Rising temperatures, diminishing returns: lake temperature effects on the mass of larval fish caught within Kentucky Lake.

Academic Level at Time of Presentation

Junior

Major

Fisheries/ Aquatic Biology

2nd Student Academic Level at Time of Presentation

Graduate

List all Project Mentors & Advisor(s)

Dr. Michael Flinn

Presentation Format

Oral Presentation

Abstract/Description

Most fish species are poikilothermic and depend upon the environment to control their metabolic rate. Late winter and early spring can be a stressful time of year for larval fish because food resources are lower than that of summer and fish must partition energy reserves for survival. Higher temperatures cause fishes to allocate relatively more energy to metabolism (primarily respiration) compared to growth and development. An assessment of larval fish biomass over time shows that higher average temperature leads to a smaller average biomass of larval fish for that sampling season. Samples of the larval fish community were taken within the southern 30 km of Kentucky Lake from April to May of 2014, 2015, 2016, and 2017. Samples were collected using tandem larval pushnets (net=0.5m^2, mesh=1mm). Fish were enumerated in the lab and identified to family. The dry masses of Gizzard Shad, by far the most abundant family, were collected from various size classes (5-15 millimeters). Using a regression analysis, a model was created to estimate the average biomass of larval Gizzard Shad (a proxy for all larval fish). Lake temperature data was obtained form the Kentucky Long-Term Monitoring Program for the years that we have sampled for larval fishes. The average biomass of a larval Gizzard Shad on a warmer year was less than half that of the average biomass of a larval Gizzard Shad on a colder year. With climate change, more frequent warmer winters could negatively affect the recruitment of fishes into the Kentucky Lake system.

Spring Scholars Week 2018 Event

Watershed Research Institute Symposium

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Rising temperatures, diminishing returns: lake temperature effects on the mass of larval fish caught within Kentucky Lake.

Most fish species are poikilothermic and depend upon the environment to control their metabolic rate. Late winter and early spring can be a stressful time of year for larval fish because food resources are lower than that of summer and fish must partition energy reserves for survival. Higher temperatures cause fishes to allocate relatively more energy to metabolism (primarily respiration) compared to growth and development. An assessment of larval fish biomass over time shows that higher average temperature leads to a smaller average biomass of larval fish for that sampling season. Samples of the larval fish community were taken within the southern 30 km of Kentucky Lake from April to May of 2014, 2015, 2016, and 2017. Samples were collected using tandem larval pushnets (net=0.5m^2, mesh=1mm). Fish were enumerated in the lab and identified to family. The dry masses of Gizzard Shad, by far the most abundant family, were collected from various size classes (5-15 millimeters). Using a regression analysis, a model was created to estimate the average biomass of larval Gizzard Shad (a proxy for all larval fish). Lake temperature data was obtained form the Kentucky Long-Term Monitoring Program for the years that we have sampled for larval fishes. The average biomass of a larval Gizzard Shad on a warmer year was less than half that of the average biomass of a larval Gizzard Shad on a colder year. With climate change, more frequent warmer winters could negatively affect the recruitment of fishes into the Kentucky Lake system.