Climate change and the migratory pattern for Norwegian spring-spawning herring-implications for management

Norwegian spring-spawning herring (Clupea harengus) is a migratory fish stock, and the migratory pattern has changed several times. There seems to be a connection between altering climatic conditions and the size of fish, year-class strength and the migratory pattern. The changing juridical status of the herring has caused problems and conflicts between the parties involved in the fishery. Investigating whether the change is due to over fishing or to environmental causes, or a combination of both, was one of the objectives of the analysis. Furthermore, we have looked at the processes involved in finding solutions to the problem of managing straddling stocks.