Fish Population Analysis

The Lake Ecology and Water Quality Laboratory here at the Bella Vista Property Owners Association have mirrored techniques developed by the Kentucky Department of Fish and Wildlife to assess the overall status of fish populations in Bella Vista lakes.  The goal of these techniques is to give an overall look at the health and structure of fish populations.  This data is useful for our biologists, but it can also help anglers better understand our lakes and help them make decisions about where to focus their efforts.  For example, some lakes might be better for harvesting many eating size fish, while other lakes might be better for trophy fish.

Understanding the Analysis

The goal of these techniques is to give an overall look at the health and structure of fish populations. Currently the analysis focuses on largemouth bass (aka LMB). The data for the analysis is collected for each lake during spring electrofishing surveys and represent the number of fish collected in one hour of electrofishing. The analysis covers fish growth, the ability for the population to sustain itself (i.e. recruitment), and overall population structure as it pertains to fish size (i.e. how many and how big fish are).

The parameters listed below are rated for each lake for each year of data based on the following table. The score of each parameter can range from 1 to 4 (1 = Poor, 2 = Fair, 3 = Good, 4 = Excellent). For example, if 25 bass sized 12-14.9 inches are collected per hour, it would receive a 2 or a FAIR rating.

  • Length at Age 3 (Growth)
  • Number of Age 1 Bass (Recruitment)
  • Number of Bass 12.0 to 14.9 Inches (Population Structure)
  • Number of Bass 15 inches and Longer (Population Structure)
  • Number of Bass 20 inches and Longer (Population Structure)
Largemouth Bass Analysis Parameter Ratings

The scores of each parameter are added together to give an overall rating for the bass population in each lake for each year.  The overall rating for each lake ranges from poor to excellent based on the table below. For example, if a lake had an average length 11.2 for age 3 fish, 50 age 1 fish, 30 12-15 inch bass, 10 15+ inch bass, and 2 20+ inch bass, it would have scores of 3 (Good), 3 (Good), 2 (Fair), 2 (Fair), and 3 (Good) with the sum of those three parameter scores being 13, giving an overall rating of “Good”.

Largemouth Bass Analysis Chart

The overall rating and the rating for each parameter can be tracked across years to inform biologists and anglers about long term trends in populations.

Windsor LMB chart

Reading the Graphs

Graphs dealing with size class and the overall ratings

At the top of each graph is a title indicating which lake and species the graph is showing data for. The x-axis or bottom horizontal axis shows the years for which we have data.  The y-axis or left-hand vertical axis shows the values of the data. For length at age 3 this will be inches. For the remaining parameters this will be the number of fish gathered in one hour of electrofishing. For the overall rating, this will be the sum of the ratings of the individual parameters for each year. A red horizontal line through the data points indicates the average of those data points. Finally, the background of the graph will be colored and labeled with the rating level.

Reading the Graphs infographic

About The Author of this Study

Chris Fuller

Chris Fuller, M.S.

Lake Ecology and Water Quality Manager

  • Native of Central Arkansas.
  • With the Bella Vista POA since 2015.
  • In the field of aquatic ecology since 2009.
  • Holds B.S. and M.S. in Biology from University of Central Arkansas.
  • Started career as an aquatic insect technician during B.S.