Research Document 1997/57
Examining the risk of a stock status classification system for east and southeast Newfoundland herring stocks
By W.G. Warren
Abstract
Wheeler and Winters (1996) presented a stock-specific model that relates recruitment of east and southeast Newfoundland herring to mature biomass and the overwintering/prespawning temperature and salinity. They also presented a stock status classification system which, perforce, uses solely the mature biomass, which might be reasonably projected. A potential problem with this system is the considerable variation about the recruitment-biomass relationship, of which much can be attributed to temperature and salinity. The risk, i.e. the probability of having the system select an inappropriate exploitation rate (f), is evaluated through the recruitment model and estimates of the distributions of salinity and temperature. Since temperature exhibits significant serial correlation, the temperature distribution is that of the temperature projected one year in advance form the current temperature. The method has been validated by its application to the existing to the existing time series of the four Newfoundland stocks and behaves within the bounds of expectation. Finally, it is used to project future recruitment for the four stocks at exploitation rates suggested by the classification system.
Accessibility Notice
This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.
- Date modified: