Shrinking baseline: The growth in juvenile fisheries, with the Hong Kong grouper fishery as a case study

Abstract

Historic and current information on the grouper fishery from Hong Kong and adjacent waters reveals significant changes in species composition and fish sizes over the past 50 years in this important Asian centre for seafood consumption. Once dominant, large groupers are now rare and small species and sizes prevail in the present-day fishery. Juveniles comprise over 80% of marketed fish by number among the most commonly retailed groupers, and reproductive-sized fish are absent among larger species. Current fishery practices and the lack of management in Hong Kong and adjacent waters pose a significant threat to large species with limited geographic distribution such as Epinephelus akaara and Epinephelus bruneus, both now listed as threatened by the IUCN. The heavy reliance on juveniles, not only for groupers, but for an increasing diversity of desired fishes within Asia, potentially reduces stock spawning potential. The 'shrinking baseline' in terms of a progressive reduction in fish sizes being marketed in the region can seriously undermine fishery sustainability and recoverability of depleted fish stocks. Fishing pressure on groupers and other valuable food fishes within the Asia-Pacific is intensifying, the declining long-term trend of grouper landings in Hong Kong and the increasing focus on juveniles for immediate sale or for mariculture 'grow-out' signal a worrying direction for regional fisheries. Moreover, the common appearance of small groupers for sale will influence public perception regarding what are 'normal-sized' fish. Management attention is needed if these fisheries are to remain viable. © 2009 Blackwell Publishing Ltd.