Summary The authors reviewed the aquacultural history of Acipenseriformes in China, related the legal status and examined the current status of the cultured species or hybrids, origins of seedlings, quantities of production, geographic distribution in farming, and the sustainability for both restocking programmes and human consumption. The census shows that since 2000, the production of cultured sturgeons in China appears to have become the largest in the world. As of 2000, the rapid growth of sturgeon farming in China mainly for commercial purposes has shifted harvests in the Amur River from caviar production to the artificial culture of sturgeon seedlings. This dramatic development has also caused a series of extant and potential problems, including insufficient market availability and the impact of exotic sturgeons on indigenous sturgeon species. Annual preservation of sufficient higher‐age sturgeons should be a national priority in order to establish a sustainable sturgeon‐culture industry and to preserve a gene pool of critically endangered sturgeon species to prevent their extinction.

Eggs, gills, skin and intestinal tracts of fish harbour bacterial communities that are thought to impact fish health through their interaction with the tissues. In particular, the gastrointestinal (GI) tract possesses numerous microbes and is considered an infection route. During the infections caused by pathogenic bacteria, mucosal adhesion is a critical early phase and plays an important role in fish development. This review focused on knowledge regarding the adherence and colonization of microorganisms in fish GI tract mucus, including various methods such as in vivo, in vitro, and ex vivo, host specificity, lactic acid bacteria nonfish origin using the adherence of pathogenic bacteria, gnotobiotic approaches and molecular methods. However, probiotics might not be possible to truly colonize the digestive tract of fish. The term 'temporal colonization' might be a better phrase to use when discussing probiotic persistence and presence within the mucosal layer. Recent and promising results in this field were presented based on new perspectives and future research directions of the adherence and colonization of microorganisms in fish GI tracts.

Sonic tracking of 40 adult pre-spawning Chinese sturgeons (35 females, 5 males) was done during 8 spawning seasons (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004). Fish spent most of the time close to the dam (within 7 km). A yearly mean of 64% of the tracking locations of pre-spawners were in the small area of 1.08 km distance below the dam (cell I-B of the tracking grid system). These movements indicate fish continue to attempt to move farther upstream to pass the dam. Adults did not visit areas without major water spills or flow, i.e., the boat canal (the Sanjiang River), the spill gates, and 1# ship lock. Adults were not tracked in the fast current tail waters of the Erjiang power plant and rarely in the Yichang port, although their occurrence ranged from 4 km to 10 km downstream of the dam while also occuring in the channel. Pre-spawning Chinese sturgeon use the Yichang reach in a non-random manner while seeking certain habitats and avoiding others. Adults arrived on the "spawning ground" one day before spawning. Adults move quickly about the spawning ground. After spawning, females quickly moved downstream, whereas males remained for 12-21 days. During a spawning season, females moved less than males.

Aims: A study was conducted to compare the intestinal microbial compositions of two fish species with similar feeding strategy; paddlefish (Polyodon spathala) and bighead carp (Aristichthys nobilis) reared in the same pond. Methods and Results: Age-0 paddlefish and bighead carp with mean average body lengths of 43Á39 AE 2Á78 and 19Á33 AE 3Á68 cm, respectively, were reared with natural prey items in the same pond (20 m 2 ). After 30 days of rearing, the intestinal microbiota of the two fish species was assessed by pyrosequencing of 16S rRNA genes. Interestingly, deviations were observed in the microbial communities of the two fish species according to the alpha-and beta-diversity measurements and detrended correspondence analysis (DCA). Shannon diversity (P = 0Á015) and Pielou.evenness (P = 0Á035) revealed significant lower diversity of the intestinal microbiota of paddlefish. Moreover, different core intestinal microbiota was noticed in the two fish species. Proteobacteria (57Á3%), Firmicutes (11Á9%), Fusobacteria (8Á9%), Planctomycetes (7Á3%), Actinobacteria (6Á0%) and Verrucomicrobia (3Á2%) were detected in bighead carp, while the dominant phyla in paddlefish intestines were Bacteroidetes (37Á0%), Fusobacteria (35Á1%), Firmicutes (14Á8%) and Proteobacteria (12Á6%). Conclusions: Our results revealed that the intestinal microbiota differed between paddlefish and bighead carp reared in the same pond when fed similar nature food. The potential host factors, such as the genetic background, gut histology and physiology are assumed to be involved in the intestinal bacterial compositions. Significance and Impact of the Study: Considering the similar feeding strategy of paddlefish and bighead carp, this study presents basic knowledge for evaluation of the importance of host factors (genetic background and gut anatomy) on intestinal microbial composition.

The swimbladder of fishes is readily compressed by hydrostatic pressure with depth, causing changes in buoyancy. While modern fishes can regulate buoyancy by secreting gases from the blood into the swimbladder, primitive fishes, such as sturgeons, lack this secretion mechanism and rely entirely on air gulped at the surface to inflate the swimbladder. Therefore, sturgeons may experience changes in buoyancy that will affect their behavior at different depths. To test this prediction, we attached data loggers to seven free-ranging Chinese sturgeons Acipenser sinensis in the Yangtze River, China, to monitor their depth utilization, tailbeating activity, swim speed and body inclination. Two distinct, individualspecific, behavioral patterns were observed. Four fish swam at shallow depths (7-31 m), at speeds of 0.5-0.6 m s À1 , with ascending and descending movements of 1.0-2.4 m in amplitude. They beat their tails continuously, indicating that their buoyancy was close to neutral with their inflated swimbladders. In addition, their occasional visits to the surface suggest that they gulped air to inflate their swimbladders. The other three fish spent most of their time (88-94%) on the river bottom at a depth of 106-122 m with minimum activity. They occasionally swam upwards at speeds of 0.6-0.8 m s À1 with intense tailbeats before gliding back passively to the bottom, in a manner similar to fishes that lack a swimbladder. Their bladders were probably collapsed by hydrostatic pressure, resulting in negative buoyancy. We conclude that Chinese sturgeons behave according to their buoyancy, which varies with depth due to hydrostatic compression of the swimbladder.