Basic Survey – data is collected to determine fish species composition, relative abundance, and size structure.
Comprehensive Survey – in addition to the data collected in the Basic Survey, scale samples are also collected to determine growth rates of fish, and a “mark-recapture” population estimate is performed to determine the abundance of individual species present. Data collected will provide information on the reproductive success of fish species present as well.
Electrofishing is a common and safe technique to sample populations of fish in lakes and ponds. As the name implies, electrofishing uses electricity to sample fish populations. By using an onboard generator, an electrofishing boat produces electrical currents between positive and negative electrodes that hang partially submerged in the water. When fish encounter this mild electrical field, an involuntary muscular response called taxis causes fish to swim towards the electrodes where they become temporarily stunned. Once stunned, the fish are dip-netted by the boat crew and placed in a tank for processing. Since this stunned state only lasts a few seconds, fish can be sampled and return to the water body unharmed. Also, since fish are not confined in a small net, there is often less stress to the fish.
Data collected during electrofishing surveys can be used to determine:
• length at age (growth rate)
• length frequency
• proportional stock density
• growth trends
• age composition (relative year class strength)
• catch curves
• mortality rate
• length - weight relationship
• condition factor data
• population estimates
Not all fish species can be adequately sampled in traditional fyke-net surveys. Some game fish species, such as largemouth bass, are difficult to adequately sample in fyke-nets due to their natural behaviors. Electrofishing is a preferred method to sample these “harder to sample species”.
Electrofishing surveys typically take place in spring or fall of the year (an exact date can be scheduled) and can occur during the day or night. Commonly, electrofishing surveys occur at night. Largemouth bass, northern pike, walleye and other game fish species are more active at night, feeding in shallow depths of water.
Data analysis and report preparation will be completed within six months of the survey. Survey costs vary depending on the extent of the parameters measured and the size of the water body. Electrofishing surveys provide valuable information about your fish community. Combined with fyke-netting surveys, electrofishing can provide a comprehensive assessment of your fishery. Call today for pricing of a electrofishing survey that is customized to your needs.