Trophy Bass Telemetry
FWRI biologists try to crack the riddle of Kingsley Lake
- FWC has made trophy Largemouth Bass management a priority in FWC’s Black Bass Management Plan.
- The TrophyCatch program helps biologists collect data on hard to study trophy-size largemouth bass.
- Kingsley Lake is home to a disproportionate number of trophy bass documented in the program.
- Biologists theorize the deep cooler waters of Kingsley provide a summer refuge for bass, slowing metabolism and reducing stress.
- Researchers are currently conducting a study tracking these large bass while logging water temperatures and depth.
Trophy-size fish are a critical component of Florida’s world-renowned bass fisheries. Big Florida bass are part of the identity of our freshwater fisheries and the chance to catch one draws anglers from near and far. To underscore their importance the Florida Fish and Wildlife Conservation Commission (FWC) has made trophy Largemouth Bass management a priority in FWC’s Black Bass Management Plan (BBMP) and launched TrophyCatch, Florida’s trophy bass conservation program. TrophyCatch serves as both an angler recognition program and a crowd-sourced data collection mechanism for trophy bass in Florida. These fish are relatively rare and infrequently collected by the FWC.
As data grew biologists noticed that Kingsley Lake was home to a disproportionate number of trophy bass documented in the program and four of the top five heaviest bass documented in TrophyCatch have come from this old, north-Florida lake. This led researchers to the question—what is going on at Kingsley Lake?
Big bass aside, Kingsley Lake stands out among typical Florida lakes due to its depth. Previous reports indicated depths up to nearly 80 feet, which were confirmed with our sonar (82 feet max depth). Interestingly, upwards of 300 acres of the interior of the lake, is ≥40 feet deep. This provides stark contrast to most Florida lakes, where “deep” is around 10–15 feet.
One theory as to why Kingsley Lake grows such big bass is that its depth provides cool sanctuary for bass during Florida’s warmest months. Water density changes with temperature, with warmer water floating on top of cooler water. Often this results in layering (thermal stratification) of water in lakes in summer. Because bass are cold-blooded, they are always the same temperature as their surrounding water, and their metabolism is governed largely by temperature. Florida bass thrive in warm waters, but summer temperatures put their metabolism in high gear, where they burn through calories, somewhat reducing the energy available for packing on body mass. Having access to deeper, cooler water in lakes like Kingsley might allow bass to maintain metabolic rates closer to optimum during summer. It may also reduce their natural mortality rate by reducing some of the stress that bass endure after spawning, as water temps quickly rise. Possibly, Kingsley bass enjoy a combination of both of these factors. Biologists do know that some bass in Kingsley Lake have reached an absurdly old age for bass in Florida with researchers recently ageing two bass that died of natural causes that were a few months shy of 16 years of age. This gives some credence to the thought that Kingsley bass attain such large sizes, simply by living much longer than the average bass in Florida.
To find out what is going on biologists designed a temperature and depth selection study. They implanted 10 bass with acoustic telemetry tags equipped with depth and temperature sensors. The tags continuously emit ultra-sonic signals that contain the depth and temperature measurements for where the bass is located. Researchers hear and decode the tag signals with underwater receivers that temporarily store these data. They also made a detailed bathymetric map of Kingsley Lake and have temperature loggers deployed across a range of depths. Later biologists can compare the depths and water temperatures used by our tagged bass with the depths and water temperatures available to them in the lake. Researchers also designed the receiver array to provide 100% coverage of the lake, meaning they should continuously hear the fish for the duration of the project as long as they remain in the lake. Study bass were tagged during December 2015–January 2016, and the operational life of the tags is about 24 months. The study is expected to last at least those two years.
In the end biologists hope to better understand the conditions that drive exceptional trophy-bass fisheries, like Kingsley Lake. If they are able to identify critical depth or temperature preferences of bass at Kingsley Lake, they could use that knowledge to identify other lakes in Florida that have similar characteristics with the possibility of implementing fisheries management actions such as stocking, boat ramp access and construction, or fish attractor construction at these lakes.