Status of research on Yangtze fish biology and fisheries

Abstract

The Yangtze is the largest river in China and the third largest river in the world. Being pregnant with plentiful fish resources, it is not only the representative of the areas with biological diversity, but also a cradle of freshwater fisheries in China. In the Yangtze, at present, the fishery resources are seriously depleted; the fishery yield by fishing is significantly reduced; significant changes have occurred on the structure of fish community, with decrease in migratory fish species, reduction in the quantity of the populations of rare, peculiar and economically important fish species and increase in the number of exotic fish species, and severe trend in fish stunting. Habitat fragmentation and shrinkage, resources overexploitation, water pollution and invasion of exotic species are the main causes for threatening fish stocks in the Yangtze River. Since 1950's, a lot of scientific researches have been conducted on biology of fishes from the Yangtze River and its fisheries to provide scientific basis for their protection. In recent years, measures such as closed spring, fish reserves, artificial enhancement & release, ecological rehabilitation, fishery management and international cooperation have played important roles. Nevertheless, researches on fishes from the Yangtze cannot adequately meet the demand for their protection. Especially, those in the aspects of population ecology of Yangtze fishes, species endangerment mechanism, ecological effects of large hydraulic projects and protection strategy are not deep enough. It is recommended that scientific researches should be conducted in comprehensive survey of Yangtze fish resources, fish endangerment mechanism, techniques in artificial enhancement and release of key species, risk assessment of exotic species, ecological rehabilitation of major fisheries functional zones, etc.

Life history traits and implications for conservation of rock carp Procypris rabaudi Tchang, an endemic fish in the upper Yangtze River, China

“…The Three Gorges Dam turned about 600 km of the mid-reaches of the Yangtze River into a reservoir, directly eliminating its major habitat in the impounded area [58]. In addition, a construction of another 14 hydroelectric stations on a section 2400 km below Shigu in the main channel of the upper Yangtze River is currently planned [59]. Additionally, a large number of dams on the upper-Yangtze tributaries have already been constructed, are under construction, or are planned in the future [59].…”

Effects of the length of inundation periods on investment in tuber biomass and sexual reproduction byVallisneria spinulosaS.Z. Yan Ramets

“…There is current concern about the reduction in diversity and biomass of submerged macrophytes in the Yangtze River floodplain (Fang et al, 2006). Widespread reductions in fish species richness, population size and fishery yields in many lakes have been blamed on declining water quality and flows (Fang et al, 2006;Cheng et al, 2009), but also on loss of submerged macrophyte beds, especially those of Vallisneria spp., which are highly prized and widely planted by fishermen (Fang et al, 2006;Cheng et al, 2009). Fish diversity and abundance are higher in submerged water plant beds compared with other habitats (Xie et al, 2000;Cheng et al, 2009), so planting of species such as Vallisneria has become important for lake restoration projects (Qiu et al, 2001).…”

“…Widespread reductions in fish species richness, population size and fishery yields in many lakes have been blamed on declining water quality and flows (Fang et al, 2006;Cheng et al, 2009), but also on loss of submerged macrophyte beds, especially those of Vallisneria spp., which are highly prized and widely planted by fishermen (Fang et al, 2006;Cheng et al, 2009). Fish diversity and abundance are higher in submerged water plant beds compared with other habitats (Xie et al, 2000;Cheng et al, 2009), so planting of species such as Vallisneria has become important for lake restoration projects (Qiu et al, 2001). Recent studies show a collapse of the tuberforming V. spinulosa beds in Shengjin Lake in the Yangtze River floodplain, which represent the food base for a guild of migratory waterbirds that have decreased dramatically in abundance as a consequence .…”

Long-term changes in fish assemblage following the impoundments of the Three Gorges Reservoir in Hejiang, a protected reach of the upper Yangtze River

“…Aquatic biodiversity has declined sharply around the world and correspondingly, a large number of species are considered to be already extinguished or endangered (Moyle, 1992;Fu et al, 2003;Chen et al, 2009). Dam construction is regarded as one of the most dramatic anthropogenic factors that affect freshwater ecosystems (Bunn and Arthington, 2002).…”