Managing uncertainty in fi shing and processing of an integrated fishery

Abstract

This paper considers uncertainties in fishing trawler scheduling and production planning in a quota-based integrated commercial fishery. A commercial fishery faces uncertainty mainly from variation in catch rate, which may be due to weather, and other environmental factors. The firm attempts to manage this uncertainty through planning co-ordination of fishing trawler scheduling, catch quota, processing and labour allocation, and inventory control. Schedules must necessarily be determined over some finite planning time horizon, and the trawler schedule itself introduces man-made variability, which in turn induces inventory in the processing plant. This induced inventory must be managed, and is complicated by the inability to plan beyond the current planning time horizon. A simple constraint is introduced requiring beginning inventory to equal ending inventory of the planning period. This enables management to calculate a profit-maximizing safety stock that counter-acts the  man-made variability due to the trawler scheduling. It is found that the variability of catch rate had virtually no efiects on the profitability. Numerical results for several planning time horizon models are presented, based on data for a major New Zealand fishery.

Key words: Integer programming, trawler scheduling, fish processing, safety stock.