Research has found a strong correlation between sport fishing and electrofishing data in largemouth bass populations, when Proportional Stock Density (PSD), Relative Stock Density (RSD), and relative weight values were compared. There was a weaker correlation between sport fishing and electrofishing data for sunfish populations when values for PSD, RSD, and relative weights were compared. The fishing method described below for largemouth bass was used in that study. The method described for sunfish should increase the strength of that correlation.
The objective of these fishing methods is to catch fish that represent the proportion of different sizes
present in the pond. To collect data for largemouth bass and sunfish, follow the directions below:
Largemouth Bass Sampling
1. Use artificial lures in three length categories: 1- to 2-inch, 2- to 4-inch, and 4- to 8-inch. The combination of these lure lengths allows you to target all sizes of bass in the pond.
2. Fish each lure for 30-minute intervals until you have caught 20 largemouth bass 8 inches or longer
3. Be sure to fish all three lures an equal amount of time before you stop fishing.
4. Fish all areas of the pond. The fish caught in each 30-minute interval should be kept alive until the end of the interval and then weighed and measured. If you are returning them to the pond, clip their fins (one pelvic or pectoral fin) so you can be sure not to count them again in the analysis. Be aware that, in muddy ponds (secchi disk values 12 inches or less), this fishing method may overestimate the proportion of large fish in the population.
Sunfish Sampling
1. Use 1 or 2 segments of a Berkley Power Wiggler or some other small lure on a #8 hook, #1 split shot, and light line.
2. Fish each bait type for 30-minute intervals until you collect 100 sunfish.
3. Fish each lure an equal amount of time.
4. Fish all areas of the pond. With these fishing methods, you can use the data you collect to calculate population structure indices for largemouth bass and sunfish in ponds. However, this method is not a substitute for having an experienced biologist sample your pond and make management recommendations.
Interpret the results once you have collected assessment data for your pond. It is absolutely necessary to interpret the data collected in order to make informed lake management decisions. Interpretations are based on the species composition and sizes for both bass and bluegill populations.