The past few days I’ve had some time over the Christmas holiday to fish. Due to family and weather constraints I haven’t wanted to drive very far. The two local streams I have the opportunity to fish are smaller channels (20-40 feet wide at baseflow) and are primarily sand bed channels with some cobble, gravel, clay and sporadic boulders. There are ample downed trees and large woody debris and occasional trash from some of the runoff of the flashier storms we have had recently. The streams are in protected environmental areas with wide riparian zones and have good access and are highly pressured by area fishermen. I have had trips where I caught several fish and some where I’ve caught none. I’ve made a few observations over the years of fishing stocked streams and tried to gather lots of information from friends, books, blogs and YouTube videos. So these are the start of those observations:
Freshly stocked fish are used to a very regulated setting prior to being relocated to a stream. The trout are fed 3-5 times per day as they develop into adults. They are fed pellets made from fish meal with added nutrients and vitamins. After being removed from the fishery, they are transported in a tank on the back of the truck. The trips can be long and stressful on the fish. They are distributed by buckets or other containers to the stream sites. The fish are likely accustomed to people in the hatchery and are most likely protected from predators. The fish are used to being in crowded raceways with many other fish and typically have degraded or damaged fins from abrasions on the raceway or from contact with nearby fish.
I have subscribed to the Maryland Department of Natural Resources (DNR) fish stocking notification email list serve. The DNR provides daily updates and weekly summaries of stocking activities and general fishing information, statewide.
As I have had the opportunity to fish recently stocked trout, I have noticed there seem to be a few stages of the reactions of stocked trout over time. In the first few days (less than 5 days) after stocking, the trout have a tendency to densely stack up where the are dumped in the stream. They appear to congregate in larger pool areas and usually don’t hold in the faster riffle water. Fishing pressure is usually most intense in the first week after the stocking. Lots of people get the stocking notifications, and you’ll start to see familiar faces at the newly stocked locations in your area. In this early window the fish are transitioning from the pellet food to natural stream biota and seem to have little fear of people. I have found that egg patterns work very well during this time frame, as well as squirmy worms, mop flies, and brightly colored flies. Of the recently stocked fish I caught in 2019, roughly 75% were caught on these patterns.
I have also had success with wooly buggers in larger streams. Often the fish are out in the open and you can watch the strikes. They can hit abruptly or subtlety, so watching the fish is helpful in hook setting, particularly when they are gathered in slower pools. I have also observed that as the fish are tightly gathered, that competition between the fish can increase strikes on your flies. I’m not sure how sporting it is, but in this phase, I have found that by casting into a crowd with an egg, wooly bugger or attractor pattern (without a large indicator that may splash and scare the fish) and then slowing your drift in the group, the fish will have a tendency to get in a borderline frenzy to hit your fly. As it feels a little like shooting fish in a barrel, it takes a bit away from the satisfaction, but I have to admit it’s always fun to see the hit, set the hook, feel the rod bend and to land the fish.
After the first week has passed, the fish begin to spread out and become more wary of people, as many have been caught or hooked. You’ll see some fish that are scarred from hooks. Some will have scars that appear to be from herons and other birds of prey. The trout will begin to decipher drag and become line shy in clearer water. They will still hit attractor patterns, but will adapt to natural foods in the system. If there are significant storms, higher discharges and cloudy water can help them adjust by making it easier for the fish to move longer distances, by adding terrestrial food items and creating more macroinvertebrate drift in the system. Weaker or injured fish may die in this time frame and on occasion, you will see fish carcasses isolated through the stream reaches. There are fewer congregated pods, but there are still larger numbers of fish in the slower pools.
As you approach a month of a stocked fish being added to the stream system, it becomes harder for me to distinguish their behavior or fly selection from a native or wild fish. They are much more distributed, are easily spooked and take up better feeding and holding lies within the stream. They still can be determined as stocked fish with damaged fins and coloration differences, but they are becoming more acclimated. This is the time I generally have the most fun, as it is challenging to catch these fish, you need to work on your skills to manage your line and minimize drift and fly selection is more important.
Depending on the water quality and water levels, some of the stocked fish may leave the stream (such as to seek colder water in the warmer months), others may die from the stress or be harvested, and some can hold over, acclimating to the stream conditions. The fish that remain more than one season after being stocked are commonly referred to as “hold over” trout. These fish are unlikely to breed as the naturally reproducing trout waters are not typically stocked, but if conditions are right, they can hold over for several years and viable fisheries can remain due to the stocking efforts. With improved water quality mitigation efforts, catch and release practices, and improved stormwater management hopefully the biological communities can recover in time to support naturally reproducing trout populations.