Estimating productivity, technical and efficiency changes in the Western Pacific purse-seine fleets.

The purse-seine tuna fleet in the Western Pacific Ocean has undergone an accelerated expansion since the 1980s. The fishery is primarily managed using fishing effort limits. Constraining effort to ensure the biological health of the stock, while enhancing economic benefits generated by the fishery, is a major challenge faced by fisheries managers in this region. To maintain effort levels that achieve those objectives, there is a need to take into account technical and efficiency changes over time that influence the productivity of fleets. This study evaluates how the productivity of four of the region's purse-seine fleets has changed year on year between 1993 and 2010 using a robust bootstrapped Malmquist index approach. This index is separated into: technical change, which represents the change in productivity due to the introduction of new technology and efficiency change, the change in productivity resulting from a change in the level of efficiency in the use of inputs. The results show that half of the 56 purse-seine vessels examined displayed significant gains in productivity, which appeared to be driven primarily by technical change. The technical efficiency of fleets showed less marked changes, potentially due to the practical inability to maximize performance in the face of dramatic technological advances. [ABSTRACT FROM AUTHOR]