Output Substitution in Multi-Species Trawl Fisheries: Implications for Quota Setting
Phoebe Koundouri, Trond Bjorndal, Sean Pascoe
Multi-output fishery,Multi-output distance function,Elasticities of substitution,
Climate Change and Sustainable Development
In most multi-species fisheries managed through output controls, total allowable catches (TACs) are set primarily on the basis of biological considerations, usually on a species by species basis. An implicit assumption of management is that fishers are able to adjust their product mix in line with these quotas. If this is not the case, then over-quota catch occurs, leading to either illegal landings or discards. In either case, the effectiveness of the TAC in conserving the resource is reduced. In this paper we show that in the case of multi-species fisheries that exhibit jointness in production, setting TACs on an individual species’ basis is inappropriate. In particular, we quantify technical interactions through the estimation of a multi-output distance function for the UK North Sea beam and otter trawl fisheries, and find that in most cases, the potential of substitutability between the main and alternative species is relatively small. We argue that failure to quantify and integrate these technical interactions in the construction of management instruments for fisheries regulation, may result in increased discarding, illegal fishing and potentially lower than expected future yields.