CFP Water Quality & Management 2

Question 1

Which form of nitrogen is most directly toxic to fish at elevated concentrations?

Accepted Answer

Un-ionized ammonia (NH3)

Answer

Un-ionized ammonia (NH3) is the primary toxic form because it readily crosses gill membranes, unlike the ionized ammonium form.

Question 2

A fisheries manager measures a total alkalinity of 15 mg/L CaCO3 in a pond. This value indicates the water is:

Accepted Answer

Poorly buffered and susceptible to pH crashes

Answer

Total alkalinity below 20 mg/L CaCO3 is considered poorly buffered, making the system vulnerable to rapid pH fluctuations.

Question 3

During a fish kill investigation, you find DO = 0 mg/L at dawn and water temperature = 28°C. The most likely cause is:

Accepted Answer

Overnight algal and bacterial respiration depleting oxygen

Answer

Dense algal blooms and microbial respiration consume dissolved oxygen throughout the night, commonly causing pre-dawn DO crashes in warm, eutrophic systems.

Question 4

What is the primary function of a constructed wetland used as a fish farm effluent treatment system?

Accepted Answer

Removing suspended solids, nutrients, and BOD through biological and physical processes

Answer

Constructed wetlands use substrate filtration, plant uptake, and microbial activity to reduce suspended solids, nitrogen, phosphorus, and oxygen demand in effluent.

Question 5

Which chemical is most commonly applied to raise pond pH and total alkalinity in acidic aquaculture ponds?

Accepted Answer

Agricultural limestone (CaCO3)

Answer

Agricultural limestone (calcium carbonate) dissolves slowly to neutralize acidity and raise both pH and total alkalinity in pond waters.

(CFP) Certified Fisheries Professional Practice Test

(CFP) Certified Fisheries Professional Practice Test

CFP Water Quality & Management 2