Field Survey & Data Collection Flashcards

Which electrofishing technique is most effective for sampling large, deep rivers where boat access is possible?

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.

The Lincoln-Petersen mark-recapture estimator assumes which of the following?

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.

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:

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.

When using hydroacoustics (echo sounding) for fish surveys, target strength (TS) is primarily used to:

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.

Which water quality parameter is most critical to measure immediately upon collection because it changes rapidly after sampling?

Answer: Dissolved oxygen

Dissolved oxygen degasses or is consumed quickly, so it must be measured in situ or immediately after collection.

In a fyke net survey, the wings of the net are designed to:

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.

A biologist wants to determine age structure of a walleye population. Which hard part is most commonly used for age determination in this species?

Answer: Otoliths

Otoliths (ear stones) provide the most accurate annual ring counts for walleye and many other species.