Pond Boss Magazine: How Important is an Electrofishing Survey?

When you’ve set the hook on a monster Largemouth bass in your own lake, there’s no feeling like it. With rod bowed, your reel’s drag set to give just enough, the sound of your line singing through the eyes as the unseen beast heads deep, is something you’ll never forget as you do battle with underwater royalty in your waters. You’ve developed this almost innate ability to bring this fish topside, which runs parallel to the way you’ve learned to manage your precious waters. It’s a learning process that becomes instinctive, and you need to be ready when that big bite happens.

Managing a fishery of this caliber, however, depends much less on instinct and more on data. Data can be collected multiple ways, including visual observations, creel data, and electrofishing data. Both observations and creel data are critical and inexpensive, as they usually only require sweat equity; conversely, electrofishing is a process that requires specialized equipment and the help of an experienced fisheries biologist. As a result, electrofishing is a budget item that needs to be considered and prioritized amongst the various other fisheries management improvements required to establish or maintain your fishery.

A challenge some people face is determining when to electrofish versus when to invest that money into tangible improvements. The answer to this question will vary depending on your goals and budget, as well as your ability to implement known improvements using sweat equity. In other words, are catch records and observations enough to steer your fishery where you want it to go?

Electrofishing is a widely accepted sampling technique that allows biologists to safely collect and record data on freshwater fish, and then release those fish unharmed. Observations made, along with data collected, helps reduce assumptions, allowing for a greater chance of the fishery’s management plan succeeding. In other words, electrofishing paints a broader picture of your fishery, as it’s not as biased as angling data.

The frequency which a fishery is sampled may vary, depending how often anglers are there, and that reflects in the amount and type of data collected. With electrofishing surveys, the type of data collected and the depth of data analysis performed by the biologist provides an underwater snapshot of the fishery in its current state. Data collected includes the different fish species, length, and weight. In some cases, age, genetics, tag numbers, and other specific data is valuable as well. Most of the time during electrofishing, the biologist also gets a good idea of other important factors via visual observations of the water, fish distribution, and the fishery’s habitat. Once data is collected, it can be analyzed a variety of ways to interpret where the fisheries management strategies are succeeding, where they are lacking, and where they are most vulnerable to failing. Some common types of analysis include looking at growth rates compared to age, relative weights (Wr), Catch Per Unit Effort (CPUE), Proportional Size Distribution (PSD), length frequency histograms by species, length at age, etc. Each type of analysis is subjective, but collectively they can provide valuable insight regarding the needs of the fishery based on the set goals. The more frequently a waterbody is electrofished, the faster the needs of the fishery can be identified and addressed. Managed well, electrofishing gives a lake owner the benefit of being proactive, rather than reactive.

Having high quality data available makes fisheries management a more successful endeavor. Be aware, the cost to collect data can cut into the available budget to implement the necessary improvements identified by the data. Therefore, the frequency at which waterbodies are assessed should tie back to the speed at which the improvements identified during the previous electrofishing study are implemented. If it takes two years to properly implement what was learned, you should typically dedicate more resources to making the needed improvements during those two years rather than spending critical dollars to electrofish one year later to simply re-identify things you already knew needed to occur. That’s a delicate way to say if budgets are limited, be smart with those dollars. I remember a kid in college who saved to buy a Jaguar, but didn’t have gas money to drive it.

A real-world example of this would be a fishery that requires a large amount of fish habitat improvement teamed with harvesting a large number of intermediate size bass. Prior to sampling the fishery again, money should be used for these two improvements. In this process, you run the risk of the bass population’s size structure changing based on harvest strategies. Therefore, it is best to try and complete the fish cover and habitat improvements as quickly as possible. In this example, habitat improvement is Job One. If habitat improvements take three or four years and bass harvest is neglected, there’s less need to electrofish sooner, because you’ll find the same thing you saw in the last survey. As a rule of thumb, the improvements identified in an electrofishing report to a low budget project should be carried out within one or two years of being identified, as the success of the fishery will be adversely impacted until the improvements are implemented. For you old timers, you’ll remember that famous motivational speaker, Zig Ziglar, who said, “If you keep doing what you’ve been doing, you’ll keep getting what you’ve been getting.”

Conversely, someone with a great deal of resources (more money) and lofty goals, should typically electrofish twice per year to ensure that everything is on track and to assist in harvesting fish as needed. For someone in this position, there are typically few reasons to justify making assumptions for twelve months before checking the fishery. Sampling the fishery twice per year allows a pond or lake owner to stay proactive versus reactive, while also creating a platform to better learn from the strategies employed. This helps ensure potential problems are caught before they negatively impact the forage base and well before the issues have a large impact on predator growth. Once issues have impacted predator fish growth, that growth is lost. Lost growth will have a cumulative effect on the bass population’s success, resulting in bass growth falling short in comparison to their growth potential under a lifetime of ideal growing conditions.

Electrofishing assessments aimed at collecting high quality data are best conducted in the spring and fall months. Both seasons are a suitable choice and there are unique benefits to each time of year. Depending on geography and goals, there are scenarios when sampling in the summer or winter are good options as well, even though data collected tends to be lower in quality. Some biologists are comfortable forcing a waterbody’s initial assessment, especially for owners who have a great deal of resources. Even though the data may be sub-par, off season electrofishing can provide insight regarding why a fishery is struggling. As a result, improvements to fish habitat, fish harvesting, fish feeding, fertilizing, fish stocking, and other parameters can be implemented, allowing the fishery to begin improving immediately. Knowing when you should force an electrofishing study and when to be patient is an insight that often requires the expertise of a fisheries biologist.

To get the most out of electrofishing, it is best to ride on the boat during the sampling process. Talk with your biologist to ensure they allow guests on their boat, as it is not always feasible. The enjoyment experienced when netting fish and talking with a biologist about the visual observations made will greatly aid in the process of justifying the financial commitment to both electrofishing, as well as the improvements identified from the information collected. The more informed you are about your fishery, the more likely your fishery will succeed. In this process of improving your fishery, make sure you are working with a biologist who cares as much as you do about the success of your fishery.

David Beasley is a Fisheries Biologist and the Director of Fisheries at SOLitude Lake Management, an environmental firm providing sustainable lake, pond, wetland and fisheries management services. Learn more at www.solitudelakemanagement.com.