15. Which of the following statements is not true concerning water temperature of a pond?
A. Bass spawn only once a season and only when the water warms to
about 60 F.
B. Bluegill will first spawn when water temperatures reach 75 F.
C. Some herbicide labels discourage application when water
temperatures reach 75 F.
D. Water temperature should be measured at a depth of one foot.
16. Which of the following statements is not true concerning dissolved oxygen in pond water?
A. Pond fish require 4 ppm of oxygen
B. Normally pond water contains 20-30 ppm of oxygen
C. Oxygen depletion can be caused by decomposition of aquatic weeds.
17. Oxygen depletion in a pond can be caused by:
A. A pond turnover
B. Run-off waters rich in organic matter and nutrients
C. Large masses of decomposing aquatic plants
D. All of the above
18. The production of plankton is directly related to oxygen content of the water.
A. True
B. False
19. The density of plankton population determines the depth to which light will penetrate the water.
A. True
B. False
20. Most Ohio ponds need fertilizer added to increase the plankton population.
A. True
B. False
21. If light penetrates deeper than 18 inches, the pond has good fertility.
A. True
B. False
22. Pond fertility may be improved by:
A. Applying 80-100 pounds per surface acre of a balanced fertilizer like 12-12-
12.
B. Fertilizing twice during the season
C. Applying fertilizer only after August 15th
D. Applying fertilizer if light penetration is less than 12 inches
15. Correct Answer: B, OPM
Explanation: When the water temperature reaches 70 F, bluegill and redear nests will be seen in the shallow areas.
16. Correct Answer: B, OPM
Explanation: Normally pond water contains from 10 to 15 parts per million oxygen. Fish require about 4 parts per million.
17. Correct Answer: D, OPM
Explanation: A pond turnover, run-off waters rich in nutrients and organic matter and decomposition of large quantities of aquatic plants may cause oxygen depletion in a pond.
18. Correct Answer: B, OPM
Explanation: The production of plankton is directly related to the fertility of the water.
19. Correct Answer: A, OPM
Explanation: Plankton population determines the depth to which light will penetrate the water.
20. Correct Answer: B, OPM
Explanation: Most Ohio ponds do not need additional fertilizer. Fertility is usually added to a pond from nutrients in runoff within the watershed.
21. Correct Answer: B, OPM
Explanation: A plankton population that permits light to penetrate 15 to 18 inches deep is an indicator of good fertility. Deeper than 18 inches, the plankton should be encouraged to bloom by adding fertilizer.
22. Correct Answer: A, OPM
Explanation: Starting in late March or early April, apply 80 to 100 pounds of a balanced fertilizer like 10-10-10 or 12-12-12. Fertilization applications are generally needed every 2 to 4 weeks. Continue your program until mid-August. Do not apply fertilizer after August 15th. Excessive fertility may exist if light penetration is less than 12 inches.