Managing Populations and Habitat

It seems like everyone likes to go fishing! Boys, girls, moms, dads and even grandparents like to fish. Fisheries managers are responsible for maintaining healthy and productive fish populations. But with so many anglers, this is not an easy job. More and more fisheries managers are starting to become "people managers" too!
What is good fishing to one person, may not be good fishing to another. Some anglers don't care what they catch as long as they catch something. Other anglers are only interested in a certain species of fish. Some want to catch lots of fish while others want big fish. Still others don't care if they catch anything as long as they get to relax in the beautiful outdoors.

Managing Fish Populations
A fishery manager must first consider the habitat in order to manage fish. As you have learned already, fish require the right water temperature, oxygen level, food source and cover. If you stocked a trout in warm water, you would be wasting the fish because it would not survive for very long. Likewise, if you put pike in a lake without vegetation, they wouldn't do very well either.
Most fish will spawn naturally and produce their own young. In these cases, a fishery manager does not have to stock fish every year. The fish replenish the waters on their own. A manager will then manage the fishery by improving the habitat, regulating the catch, and trying to balance the populations of fish species sharing the aquatic environment.

Hatcheries And Fish Stocking
Federal and provincial hatcheries raise many kinds of fish for stocking. Most hatcheries raise freshwater fish, but saltwater fish such as striped bass, red drum, salmon, snook, and sea trout are now being raised successfully. Fry, the smallest fish stocked, are the least costly to raise, but many of them die after release. Adult fish survive better but cost more to raise.

Raising and stocking fish, however, is costly and sometimes not necessary. Why stock trout in a lake if the yellow perch fishing is great? Why risk upsetting the balance in a great bass lake by stocking northern pike? Fisheries managers realize that each lake or river has its own unique combination of fish present. This assortment of fish represents the "carrying capacity" of that aquatic system. Smart anglers know that if they sample different waters, they will discover a wide variety of fish. They also know that all of them are fun to catch and just about all of them are great to eat!
Certain fish populations, including sunfish, perch and bullheads, would benefit by more people fishing for them. Many anglers don't even know all these fish are out there waiting to be caught! Without enough angling pressure, panfish may overpopulate a lake or pond, resulting in lots of very small fish. This phenomenon, called "stunting" can be helped by anglers who take some of these panfish home to eat. More and more anglers are also discovering that these panfish can be the most delicious fish to eat!

Managing Habitat
There are many ways to protect habitat for fish populations. Aquatic plants are important for fish in most waters. They provide oxygen, attract food, and offer protection. However, too many plants are harmful and can "choke" a lake. Aquatic plants are hard to control. To manage weed growth, cutting, poisoning, uprooting excess plant growth and introducing fish that eat vegetation have all been tried. One of the best controls is limiting the plant food that enters the water in the form of sewage, fertilizers, or farm waste.

Building "artificial reefs" to attract and provide a home for both freshwater and saltwater fish is another way fisheries managers improve some fisheries. Such artificial habitat provides cover, safety, and food for fish. Artificial reefs can be as simple as sinking a weighted Christmas tree in a lake or as complex as sinking an old ship offshore in the ocean. Reefs are important because they provide an area for the bottom of the food chain to develop. The algae and plankton that develop there are a source of food for bait fish and for game fish. Also, many fish are attracted because the reefs provide them with cover. If you haven't guessed by now, reefs are good places for you to fish! However, always check with management authorities before attempting to put something in the water to attract fish. You may need a permit to place structures in a lake or stream.

Working to improve water quality by reducing the amount of pollution entering the water is one of the best methods of improving fish habitat. Government agencies make most of the efforts to improve habitat, but fishing clubs, scout troops, businesses, and local community groups supervised by government fisheries people have helped on local projects too. Building small dams to raise the level of a pool of water, placing rocks or logs on banks to reduce soil erosion, organizing a stream clean-up effort, and building small reefs are projects that can be done in your area.