Cason & Associates, LLC

Accredited lake management professionals, providing professional resources for managing, building and restoring lakes, ponds, rivers and wetlands.

Serving Wisconsin, Upper Peninsula of Michigan and Northwestern Illinois.

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Fyke Net Surveys, Fish Scale Aging


The goal of this survey is to offer the lake association and the DNR data to best manage the lakes fishery.  There are multiple options for surveys ranging from very simple to comprehensive.  Each survey type can provide valuable data.  However, the association will have to evaluate its goals for the survey when choosing the right one.  Too much data is never a problem, but as a survey gets more thorough it takes more time and is more expensive.  On the other hand if we don’t collect enough data your project may be cheap, but you won’t get the information necessary to achieve your goals.

All fish will be captured in a net called a fyke net. A fyke net works like a large minnow trap and allows the majority of the fish to be released unharmed.  This allows for recapture of fish that can aide in a population estimate.  Nets will be lifted once per day with the number of days depending on the survey type.  Fish surveys are an event that usually attracts large interest on the lake, and there may be opportunity for volunteer help and viewing.

The survey types are listed below with descriptions.

Types of Fish Surveys

Simple Informative Survey

This option entails one fyke net lift and the final report will contain the type of fish caught, how many of each species, and how long the average fish in each species was.  This type of survey gives you an idea of what your fishery looks like but would not give any age, growth, population, or weight data.

Simple Spring Marked Recapture Survey

This option would involve 3-5 fyke net lifts.  Fish caught in the first net lift would be marked, weighed and measured.   Subsequent recapture of fish would allow for a population estimate.  Since this would take place in early spring it would target mainly walleye, musky, and some panfish.  We would expect to catch some of every species but the number can be highly variable.  This survey would be a good choice if you want to look into management for only walleye, musky and panfish.

Spring/Fall Marked Recapture Survey

This survey would involve 3-5 fyke net lifts in early spring and 3-5 net lifts in fall.  All fish would be measured and weighed and their numbers will be recorded.  Fish would be marked and recaptured for a population estimate during both seasons.   Fish captured during both seasons would give a broader species spectrum.   Bass and panfish would be more susceptible to being caught in the fyke nets in fall.  This is a great option for gathering data on the majority of your game fish.  This survey also gets you the most accurate population estimates.  Population estimates are required for an argument to change bag limits for any species.

Comprehensive Survey

The comprehensive survey includes everything listed above, but also incorporates fish aging.  One or two aging structures (scale and/or fin spine) will be taken from each fish during the survey.  During the winter, aging structures from each species will be processed and aged to give an accurate idea of the age structure of fish in your body of water.  Aging can also be incorporated in the other surveys for an additional charge. This type of survey provides the best information for making management decisions.  Age of fish can help to calculate growth rate and estimate mortality.  Without growth rates, it is unlikely there would be an argument to change a size limit.

Fish Scale Aging: Addition to Other Surveys

This is the amount that would be added to any survey to obtain age information on the fish that were captured. Click here for information on how to collect scale samples.