Fish stock assessment reports
Stock assessments involve using statistical and mathematical methods to make quantitative statements about the status of fished populations and predictions about how they are likely to respond to alternative management choices. There is often considerable uncertainty in the population parameter estimates used in the assessment models, particularly for parameters such as growth rates, natural mortality rates, fishing mortality rates and spawning stock-recruitment relationships.
Assumptions often have to be made in order to model fished populations. For example, assumptions may be made about:
- the size or age at which a species becomes vulnerable to capture
- survival rates of discarded fish
- fishermen's responses to alternative management measures.
Stock assessments also rely on a series of data gathered over time. These series are usually incomplete, which complicates the reconstruction of the history of the fishery.