“Balanced Harvesting” has been suggested as a possible strategy to meet the objectives of the Ecosystem Approach to Fisheries, ensuring a high sustainable yield while maintaining ecosystem structure and function.
Balanced Harvesting proposes a moderate fishing mortality in proportion to productivity spread across the widest possible range of species, stocks, and sizes in an ecosystem producing a sustainable and overall non-selective harvest.
Could fishing according to the Balanced Harvesting approach give gains over well-implemented traditional fisheries management in the Norwegian and Barents Seas?
The Norwegian and Barents Seas have been subjected to moderate fishing pressure on commercial species, and elements of an ecosystem based approach to management for many years, but not the fishing pattern proposed by Balanced Harvesting.
In a recent study, Nansen Legacy PhD student Ina Nilsen and co-workers used an Atlantis ecosystem model of the Nordic and Barents Seas to investigate the effects of applying a Balanced Harvesting regime to a region with existing successful fisheries management. This work is the first to study the effects of Balanced Harvesting in the Norwegian and Barents Seas.
The results from the Atlantis ecosystem model showed that implementing a Balanced Harvesting regime in the Norwegian and Barents Seas would only produce marginal increases in total yields of currently commercially exploited stocks, likely because the Norwegian fisheries are already mostly well-managed. However, expanding the fishery to include species that are not commercially exploited today did produce higher yields, especially on lower trophic levels.
The study also shows that Norwegian fisheries are well-monitored and managed, and already score relatively high in terms of a balanced fishing pattern, with fishing levels on most species close to their respective maximum sustainable yields, which suggests that there are only limited gains for implementing a Balanced Harvesting regime on the current commercial stocks.
[Title picture (c) Christian Morel / christianmorel.net]