All About Electrofishing

You may have heard of fly-fishing or spearfishing, but electrofishing? Electrofishing is a common way of fishing that is used by fisheries biologists. They use electrofishing to sample the fish populations in freshwater. Electrofishing means just what it sounds like – using electricity to catch fish.

Why Electrofishing Is Used

The biologists shock the fish, making them easier to catch without harming the fish with hooks. Stunned fish can then be easily scooped up in a net and placed in a temporary holding tank where they can revive and be observed for data collection. Biologists use the method of electrofishing to determine:

  • Abundance
  • Density
  • Species Composition
  • Age distribution
  • Presence of invasive species

The different types of pulses depend on the size and nature of the catch. For electrofishing to be effective, it must be adjusted for technical, logistical, biological, and environmental factors that could influence the outcome. The stronger the electric field and pulse, the bigger the fish that will be able to be caught.

How Electrofishing Works

There are three types of electrofishers.

Backpack electrofishers use gas or battery power to create the electrical current. These work by employing a transformer to pulse the current before it’s delivered into the water. They also have safety features like speakers that make sounds when the unit is operating, quick-release straps, and tilt-switches if the backpack is tilted more than 45 degrees.

Boat electrofishing is when the boat itself is a cathode with the anodes mounted on the bow. The boat makes the fish swim towards the bow and are caught with a dip net.

Another method available but not prevalent is by illegally diverting electricity from overhead electric lines. This is dangerous and can cause electrocution.

Safe Practices

  1. Fish will not be affected by electrical fields if the waters are turbid.
  2. Only electrofish with backpacks in waters that are knee deep to prevent any drowning.
  3. The more skilled a team, the more fish that will be caught that are not harmed.

Benefits of Electrofishing

One of the main benefits of electrofishing is that the method can capture a large and diverse sample of fish in a relatively short period of time. By using information from this sample, we can collect data about the number of species and the conditions in a body of water. This information can then be used to craft a strategy for managing the fishery. The strategy may include tactics such as harvest restrictions, fish stocking, water quality improvement, feeding, fertilization, and fisheries habitat management.

Electrofishing is a reliable method for collecting target fish species. It aids in determining the size and composition of the fish population with minimal impact. Additionally, electrofishing as a sampling method is generally much less damaging than other methods that trap or entangle fish and can injure or kill them. Electrofishing also does not harm a female fish’s eggs. In fact, the Florida Fish and Wildlife Conservation Commission (FWC) uses this method to collect females of breeding at the state hatcheries.

Effectiveness of Electrofishing

Biologists use electrofishing to inspect fish for the presence of parasites or sores and to identify any issues in the fish population that might otherwise go unnoticed. It can also expose any invasive species that could cause harm to the native fish population or be an impediment to the long-term goals of the fishery. In some cases, invasive species are removed to manage a lake or pond effectively.

Limitations of Electrofishing

The effectiveness of electrofishing is influenced by numerous biological, logistical, and environmental factors. Fish size, water visibility, level of stunning, and crew experience are all factors that can have an impact on catches. In addition, fish that live in deep areas or the pond bottom, including most catfish, often don’t float up in time and recover before they can be netted.

Fish at the edge of the electrical field are often not completely stunned and may escape capture. Since not all fish can be collected, electrofishing provides a sample of the lake or pond’s population. It is important to note that electrofishing is only effective in freshwater; saltwater is too conductive to operate the unit. The electricity goes around the fish instead of through it, making the method ineffective.

Controversy behind Electrofishing

Although electrofishing is used by many government agencies, it is illegal to use it as a fishing method in public waters in Florida, and many other states. The only exception to this law is if you are electrofishing on your own lake.

Some contend that electrofishing harms nontargeted marine life. However, others contend that it causes less environmental damage and harm to the fish since they can be released once studied.

Because this method uses high-voltage electric fields in the presence of water, it is a potentially hazardous activity for the operator and surrounding personnel. Safety and operational guidelines should be observed, and electrofishing certification is recommended.

Electrofishing in Florida Lakes

Biologists use electrofishing as part of the FWC’s long-term monitoring program. Each fall, they sample 25 locations within a lake. Every fish is counted, measured, and identified. The number and types of fish found can say a lot about the lake or pond’s fish community, such as:

  • Do the bigger fish have enough prey to eat?
  • Are there not enough big fish for anglers to catch?
  • Are there too many small fish?
  • Is the fish population made up of just a few species, or is it balanced?
  • Are there any invasive, non-native species, and are they influencing the fish population?

Since 2006, FWC biologists have collected samples from about 39 lakes using electrofishing. During that time, they have recorded 119 different species of fish with an average of 21 fish species found in any given body of water. Species that are seen every year are considered typical species by biologists. The most common ones are bluegill and largemouth bass. These species are found in almost every system every year. These two species and threadfin shad, an important prey fish, make up approximately 50 percent of the total fish collected be electrofishing in Florida lakes.

Lakes and ponds change constantly year over year, and regular assessments make it possible to consistently implement the best management practices and make necessary adaptations to the plan when needed. We can assess the wildlife in your waterbody and help you make the best decisions for the growth and enhancement of your lake or pond.