As the lakes and ponds throughout the state are thawing after a long winter, anglers are itching to get out on the open water. So are the fisheries biologists for MDIF&W. Fisheries biologists are patrolling boat launches and lakes and interviewing anglers about the fishing and their catch. How many of each species did they catch? What were the lengths? What were the weights? Were the fish missing any fins? What do the fish have in their stomachs? Where on the lake did the angler fish? How long did the angler fish? No, they are not being nosy, trying to slow you down, or going to give away any secret honey hole. The information fisheries biologists gather from anglers in the spring will help them determine the health of the fishery on the lakes and ponds being surveyed. That information will then be used to make suggestions regarding management of that fishery, with the goal of keeping fish healthy and plentiful and angler’s lines tight.
MDIF&W stocks salmonids, brown trout, brook trout, landlocked salmon, rainbow trout, lake trout, and splake (lake trout/brook trout hybrid) in many water bodies throughout the state. As I touched on lightly in my last entry, MDIF&W grows and stocks a variety of strains of each of these species. Certain strains survive longer in some waters than others. Some strains provide higher catchability rates (this is the likelihood that the stocked fish will take a lure and be caught). Biologists ask the number of fish caught and how long the angler fished for to get an idea of catch rates and catchability of both wild fish and stocked fish. Catch rates are reported as how many fish are caught per hour of fishing.
Lengths and weights are important because it gives the biologists an idea of how healthy the fish and the fishery are. This may tie in with catchability rates. For example, if anglers were reporting lots of small, skinny fish caught, it may mean the population is too high, and there isn’t enough forage fish to allow for proper fish growth. If anglers are catching fish that are long, but not heavy, it may be because food is short and the fish are not putting on weight. The biologists would then look into the forage fish situation. If the fish being caught are short but fat, it may mean the fish have plenty of food, and even younger fish have plenty to eat.
Length and weight information paired with fin observation can also play a major role in providing information to fisheries biologists. In many waters where MDIF&W stocks fish where there is already a wild population, usually the stocked fish will have clipped fins, enabling biologists to easily determine which fish are stocked and which are wild. Biologists want to be sure that the stocked fish are growing well and that the strain of fish stocked is providing the best performance for that water. For example, a strain of brown trout may be stocked initially. After a few seasons of surveying anglers, the biologist may discover that the stocked trout are not growing well, or are not being caught. A different strain may then be stocked that grows better in that water, or provides a higher catch rate. Biologists also want to be sure that the quality of the wild fish is not adversely effected by the stocking of other fish, even fish of the same species.
Throughout the state spring fishing provides fun times, great fishing, and tasty meals, a perfect prelude to the long-awaited summer. Maine is lucky to have so much support from anglers, and in return, fisheries biologists are striving daily to ensure the bountiful aquatic resources Mainers treasure are thriving and ready to be caught by each generation in turn. Let’s hit the water. Tight lines!