Achieving Maximum Sustainable Yield in mixed fisheries. A management approach for the North Sea demersal fisheries

Achieving single species objectives in complex and dynamic fisheries targeting multiple species (mixed fisheries) is challenging as achieving the objective for one species may mean missing the objective for another. This particularly applies to the concept of Maximum Sustainable Yield (MSY) in mixed fisheries in the North Sea, where the diversity of species and fisheries induce numerous biological and technical interactions. These interactions are though increasingly well understood and quantified for the most important stocks, allowing for new approaches to emerge. Recent paths towards operationalising MSY at the regional scale have suggested the expansion of the concept into a desirable area of “Pretty Good Yield”, materialised by a range around FMSY that would allow for more flexibility in management targets. This paper investigates the potential of FMSY ranges to combine long-term single-stock targets with flexible short-term mixed-fisheries management requirements, applied to the main North Sea demersal stocks. It is shown that sustained fishing at the upper bound of the range may not be appropriate when technical interactions occur. An objective method is suggested that minimises the risk of mixed-fisheries imbalance, using advantageously the flexibility of the ranges to address explicitly the trade-offs between the most and least productive stocks.JRC.D.2-Water and Marine Resource