CFP Fish Population Dynamics & Stock Assessment Flashcards

Which length-frequency analysis technique separates overlapping age classes within a fish sample?

Answer: Bhattacharya method or ELEFAN

The Bhattacharya method and ELEFAN (Electronic LEngth Frequency ANalysis) decompose polymodal length-frequency distributions into component age classes.

In the von Bertalanffy growth function, what does the parameter K represent?

Answer: The curvature parameter indicating how fast the fish approaches its maximum size

The K parameter in the von Bertalanffy model describes the rate at which a fish's growth decelerates as it approaches its theoretical maximum size (L∞).

What is a 'cohort' in the context of fish population dynamics?

Answer: A group of fish born in the same year or season

A cohort (or year-class) is a group of fish originating from the same spawning event, typically defined by birth year.

Which federal act requires the US to end overfishing and rebuild overfished stocks by specific deadlines?

Answer: Magnuson-Stevens Fishery Conservation and Management Act

The Magnuson-Stevens Act mandates that US federal fishery management plans prevent overfishing and rebuild depleted stocks within specified time frames.

What does the term 'escapement' refer to in anadromous fish management?

Answer: The number of adult fish that return to spawn after surviving harvest

Escapement is the number of adult anadromous fish (such as salmon) allowed to pass through fisheries and reach spawning grounds.

What is the main advantage of using hydroacoustic surveys for stock assessment?

Answer: They allow non-destructive estimation of fish abundance and distribution over large areas

Hydroacoustic (echo sounder) surveys can rapidly estimate fish density and biomass across large water bodies without capturing or harming fish.