Challenges for Diadromous Fishes in a Dynamic Global Environment

<em>Abstract</em>.-The five species of shads (Clupeidae: <em>Tenualosa</em>) that form the basis of important fisheries in the estuaries and coastal waters of tropical Asia are subject to a variety of management regimes in the countries of the region. The most widespread species, hilsa <em>T. ilisha</em>, is managed differently in Bangladesh, India, Burma, Pakistan, and Kuwait. The fishery for Reeves shad <em>T. reevesii </em>along the south China coast and far up the Yangtze, Pearl, and Qiantang rivers has collapsed and the species is being cultured, while Laotian shad <em>T. thibaudeaui</em>, in the lower and middle Mekong system, was a component of co-managed multispecies fisheries, but is now almost extinct. The fishery for toli <em>T. toli </em>in the estuaries and coastal areas of Sarawak (Malaysian Borneo) is now successfully co-managed, while fisheries for Terubuk (also known as longtail shad) <em>T. macrura</em>, in the coastal waters of Sumatra are currently unmanaged. The degree to which agencies in the various countries have been successful in managing shad fisheries for sustainability is analyzed in relation to the socioeconomic and governance environments in which they operate. The key to the future of tropical shad fisheries may be determined by the extent to which fishery management plans can be integrated into overall coastal or river basin management plans and is discussed in relation to population pressures and widespread environmental changes, as well as biopolitical and social linkages that could facilitate actions leading to concrete measures to re-establish migration pathways for the fish.