23. If the fish population is out of balance, correct the problem by use of the following method:
A. Regulate bass harvest
B. Encourage bluegill fishing and not putting them back
C. Seine the pond or use fish traps
D. Use a fish toxicant (rotenone)
E. All of the above
24. When a pond is overpopulated with stunted fish, neither bass nor forage fish (bluegills) will reproduce.
A. True
B. False
25. A small flock of ducks or geese is recommended to keep swimming ponds weed free.
A. True
B. False
26. Leeches in Ohio ponds are blood suckers and must be controlled in swimming ponds.
A. True
B. False
27. Swimmers itch is controlled by eliminating snails with copper sulfate.
A. True
B. False
28. Muskrats may burrow into pond banks or dams. They may be controlled by:
A. Trapping in season
B. Removing cattails
C. Using repellents
D. All of the above
29. To control an over-population of forage fish, a partial treatment of rotenone may be applied by putting down a line of this chemical 10 to 15 feet out from the bank.
A. True
B. False
30. What is the best prevention of weed-related fish kills?
A. Kill all free floating weed and algae
B. Allow large areas of living pond weeds
C. Practice a good aquatic weed control program
D. Never use weed control chemicals
23. Correct Answer: E, OPM
Explanation: Several methods may be used to correct an out-of-balance problem. The first is to regulate harvest, Enforcement of a minimum length limit on bass harvested of 12 to 14 inches may help. You may even want to ban all bass harvest for a season. Encouraging forage fish harvest, with all bluegills and redears caught being kept, also may help.
Larger seines (at least 20 x 4 feet with 0.5 inch mesh) also may be used to reduce forage fish populations. Fish traps can be used to accomplish the same thing as seining. When seining or fish traps are not practical as population reduction methods, the forage fish population may be reduced using a fish toxicant. Rotenone, long used as an insecticide, can be used.
24. Correct Answer: True, OPM
Explanation: When a pond is overpopulated with stunted forage fish and neither bass nor forage are reproducing, removal of part of the fish population will seldom solve the problem. Complete elimination of all fish and subsequent restocking is recommended.
25. Correct Answer: False, OPM
Explanation: Waterfowl provide viewing pleasure and their feeding habits may help to control some weed problems; however, they also can create problems. Coliform bacteria thrive in water enriched with waterfowl droppings, especially when the ducks and geese use the pond year-round. For ponds used for swimming, maintenance of more than one pair of domestic ducks or geese per surface acre of water is discouraged.
26. Correct Answer: False, OPM
Explanation: Leeches present in Ohio ponds are usually small (less than 1 inch long), colorless and opaque. They are not blood suckers, but feed on decomposing organic matter in the pond. They attach themselves to swimmers, fish and the legs and feet of ducks and other water birds. Although harmless, leeches can be very frightening and thus detract from the recreational uses of a pond.
27. Correct Answer: True, OPM
Explanation: Although not common in Ohio ponds, this problem is occasionally reported. Swimmer's itch is caused by a free-swimming parasite that burrows into and irritates the skin of humans. The parasite develops in certain birds and snails before it becomes freeswimming. Elimination of swimmer's itch means controlling the snails. Snails can be eliminated by applying copper sulfate at the rate of 4 parts per million (ppm), or 10.8 pounds per acre-foot of water. Caution: At this rate any fish present in the pond may also be killed.
28. Correct Answer: D, OPM
Explanation: Muskrats in ponds usually dig a burrow into the bank as a den. Such burrows may present problems, especially if dug into the dam of a pond. Since muskrats are furbearers and are protected by wildlife laws, the recommended method of control is to trap them heavily during the legal trapping season. Also, large areas of cattails and other aquatic plants will encourage muskrat activity. Get rid of this vegetation, particularly near the dam, if you expect to reduce muskrat populations. Repellents may be used to drive muskrats from an embankment.
29. Correct Answer: A, OPM
Explanation: Apply a line of the rotenone under the surface following the shoreline of the pond 10 to 15 feet out from the bank. The rotenone will settle downward and mix with the water on each side of the line of application. Most of the fish between the line of rotenone and the bank will be killed, while those outside the line are likely to move away. If weather conditions are right and care is taken with this method, only small fish will be killed.
30. Correct Answer: C, ILL
Explanation: An algal bloom or a heavy infestation of weeds can cause a significant drain on the oxygen content of the water. The best way to prevent a fish kill is to control the vegetation before one can occur.