CFP Field Survey & Data Collection 3

Question 1

A biologist uses a stratified random sampling design for a lake survey. The primary advantage over simple random sampling is:

Accepted Answer

It reduces variance within strata and improves precision for subgroups

Answer

Stratified sampling reduces overall variance by grouping similar units together, improving estimates for each stratum.

Question 2

When sampling benthic macroinvertebrates in a riffle habitat, the Surber sampler is preferred because it:

Accepted Answer

Samples a defined area while a net captures dislodged organisms downstream

Answer

The Surber sampler frames a fixed area and catches organisms dislodged from that substrate with a downstream net.

Question 3

Catch-per-unit-effort (CPUE) data are most useful when:

Accepted Answer

Gear efficiency remains constant across surveys

Answer

CPUE is a valid index of abundance only when catchability (gear efficiency) is consistent across time and space.

Question 4

A trawl survey is being conducted in a large reservoir. At minimum, how should tow locations be selected to ensure representative sampling?

Accepted Answer

Randomly or systematically across available habitat types

Answer

Random or systematic placement across habitats ensures unbiased coverage and representative CPUE estimates.

Question 5

Which of the following is a major limitation of using scales for aging fish compared to otoliths?

Accepted Answer

Scale annuli may be reabsorbed or false rings may form, reducing accuracy

Answer

Scale resorption during periods of stress and false check formation can cause underestimation of age.

(CFP) Certified Fisheries Professional Practice Test