Written by Industry Expert David Beasley, Fisheries Biologist
Electrofishing... sounds hard on the fish doesn’t it? Surprisingly most fish species find the process to be simple with minimal stress. The process requires a power source which is usually a generator. That power is then converted to Direct Current (DC) and regulated to keep power levels minimal rather than just putting as much electricity into the water as possible. Generators produce Alternating Current (AC) but the power is transformed into Direct Current (DC) is because DC is easier on the fish. It is important to point out that many parts of the electrofishing process have been developed to make the process safe for the fish. Once fish enter the field of electricity produced by the boat they are temporarily stunned and collected using a net. This controlled location where electricity is stunning fish is in front of the boat in an area usually 8-10 feet wide by 8-10 feet long and around 6 feet deep. Once the fish have been netted they are then placed in a live well on the boat where they await data collection. Data collection usually consists of recording the fish species, length and weight of each fish captured. Once the needed data is collected the fish are released back into the water.
Depending on the goals of the study the fish can be aged as well. Aging fish is nearly identical to aging a tree. Like a tree fish are always producing layers of growth. The two primary ways to age fish are to use either using scales from the fish or removing the otolith (inner ear bone). During times of slow growth, such as winter, these layers of growth are closer together forming a dark line. In the summer when fish are growing more quickly, these layers of growth spread out resulting in a lighter area. This allows biologists to determine how may winters and summers a fish has lived. The most amazing part of this is that you can actually determine how many inches the fish grew each year of its life using some basic math. This fish growth knowledge can be very important to understanding the water bodies history and current condition.
Management implications that result from the electrofishing process are tailored to the goals of the client. One benefit to electrofishing aside from collecting fish data is having a biologist examine the water body to understand why it is in its current state. Knowing that the fish population is out of balance is one thing, but understanding how to fix the problem and make necessary improvements to keep the fishery from reverting back to its old ways is equally important. The frequency in which a water body has an electrofishing study completed is directly related to the goals of the water body. Those who want a balanced, healthy fishery should consider a 3-5 year rotation between studies whereas those who want a trophy fishery or want to make big improvements in a relatively short period of time will require electrofishing every year if possible.
Contact the experts at 888-480-LAKE (5253) for all of your lake, pond and fisheries management needs.
David Beasley is a Lead Fisheries Biologist with SOLitude Lake Management. Since 1998, SOLitude Lake Management has been committed to providing full service lake and pond management services that improve water quality, preserve natural resources, and reduce our environmental footprint. Services are available throughout the Eastern United States. Fisheries management consulting and aquatic products are available nationwide. Learn more about SOLitude Lake Management and purchase products at www.solitudelakemanagement.com.