CFP Field Survey & Data Collection 2 — Questions and Answers
Question 1: Which electrofishing technique is most effective for sampling large, deep rivers where boat access is possible?
- Backpack electrofishing
- Boom electrofishing from a boat (Correct answer)
- Tote-barge electrofishing
- Shore-based electrofishing
Correct answer: Boom electrofishing from a boat
Boom electrofishing from a boat is the standard method for sampling large rivers, projecting electrodes ahead of the vessel.
Question 2: The Lincoln-Petersen mark-recapture estimator assumes which of the following?
- The population is open to immigration and emigration
- All individuals have an equal probability of capture (Correct answer)
- Marked individuals suffer higher mortality than unmarked ones
- Sampling occurs over multiple seasons
Correct answer: All individuals have an equal probability of capture
Equal probability of capture for all individuals is a core assumption of the Lincoln-Petersen estimator.
Question 3: A fisheries biologist records total length (TL) and weight for each fish in a sample. The primary purpose of calculating a condition factor (K) is to:
- Estimate population size
- Assess the relative well-being and nutritional status of fish (Correct answer)
- Determine the species composition of the catch
- Measure habitat quality through a surrogate index
Correct answer: Assess the relative well-being and nutritional status of fish
Condition factor K reflects how well a fish is nourished relative to its length, indicating overall health.
Question 4: When using hydroacoustics (echo sounding) for fish surveys, target strength (TS) is primarily used to:
- Estimate water depth
- Convert acoustic backscatter to fish size or species estimates (Correct answer)
- Measure dissolved oxygen at depth
- Calibrate the electrofishing output voltage
Correct answer: Convert acoustic backscatter to fish size or species estimates
Target strength relates the acoustic echo intensity to fish size, enabling density and biomass estimation.
Question 5: Which water quality parameter is most critical to measure immediately upon collection because it changes rapidly after sampling?
- Total dissolved solids
- Dissolved oxygen (Correct answer)
- Total hardness
- Nitrate concentration
Correct answer: Dissolved oxygen
Dissolved oxygen degasses or is consumed quickly, so it must be measured in situ or immediately after collection.
Question 6: In a fyke net survey, the wings of the net are designed to:
- Filter fine sediment from the catch
- Guide fish into the trap through the throat (Correct answer)
- Weigh the net on the substrate
- Measure current velocity at the site
Correct answer: Guide fish into the trap through the throat
Wings act as fish fences that intercept and direct fish movement toward the throat of the fyke net.
Question 7: A biologist wants to determine age structure of a walleye population. Which hard part is most commonly used for age determination in this species?
- Vertebrae
- Dorsal spines
- Otoliths (Correct answer)
- Scales
Correct answer: Otoliths
Otoliths (ear stones) provide the most accurate annual ring counts for walleye and many other species.
CFP Field Survey & Data Collection 2
Which electrofishing technique is most effective for sampling large, deep rivers where boat access is possible?