Present status and risk for extinction of the Dabry's sturgeon (Acipenser dabryanus) in the Yangtze River watershed: a concern for intensified rehabilitation needs

摘要

Based on the restoration efforts related to Acipenser dabryanus, a fairly comprehensive knowledge has been gathered on the environmental variations within the upper Yangtze River ecosystem. This study aims to assess the potential options to rehabilitate the A. dabryanus population in its native river. This paper reviews the restoration efforts for A. dabryanus (from the start of the fishing ban, to the construction of nature reserve and programmes for controlled release of cultured fish) since the year of 2000. Based on the results some pathways were tentatively proposed linking human activities to the species conservation needs (including considerations on food supply/rearing habitat, migration, reproduction/spawning habitat and survival/recruitment). The analysis on variations of its native river ecosystem (including abiotic and biotic factors as well as direct effects of human activities) indicated that the major adverse factors threatening survival of this species involves river fragmentation (e. g. dam construction, waterway regulation) as well as sand/gravel extraction, intensive fishing and water pollution. To conserve or further to rehabilitate wild population of this species, damming in the upper Yangtze River and its tributaries and potential counter actions or adequate compensation measures need to be seriously considered at first.