The bio-economically optimal stock size of the alien invasive red king crab in the Barents Sea, representing a commercial value as well as a threat to the ecosystem and its services, is explored assuming linear as well as non-linear relationships between crab stock size and ecosystem damage. The results show that the management goal of harvesting the crab at maximum sustainable yield cannot be reconciled with the overall objective of the Barents Sea management plan of securing ecosystem structure. The importance of identifying the correct damage relationship is demonstrated by large differences in optimal stock sizes and altered sensitivity of the models to input parameters. The analysis also shows the importance of knowing the carrying capacity of the crab stock, as well as the carrying capacity of the natural ecosystem with respect to the crab.

JEL Classification Codes: Q2, Q5