5. Fisheries Science
Assessment Techniques — Quiz
Test your understanding of assessment techniques with 5 practice questions.
Practice Questions
Question 1
Which principle underlies the swept‐area method in demersal trawl surveys for estimating fish density?
Question 2
A research vessel tows a bottom trawl at 3 knots for 2 hours with a door spread of 20 m. What is the swept area in km²? Show calculation.
Question 3
In fisheries acoustic surveys, target strength (TS) in dB is related to fish length L (cm) by $TS=20\log_{10}L-72$. If TS=−40 dB, what is L? Show calculation.
Question 4
What unit is the Nautical Area Scattering Coefficient (NASC) expressed in, and what does it represent?
Question 5
Which is a primary advantage of multi‐frequency echosounders over single‐frequency systems in fisheries surveys?