Aquaculture Environmental Capacity Research of Daiqu Fishery of Zhoushan: The Impact of Cage Culture on Sediment Quality

Impact of LaMmichthys crocea cage culture in Daiqu fishery （Zhoushan, Zhejiang Province） on the chemistry of the sediment was inves- tigated. Sediment samples, in different depths and from three stations at various distances from the cage, were collected, for analyzing total organic matter, total organic carbon, total nitrogen and phosphorus. The results showed a significant increase in all analyzed parameters in station 1, at 5 m from the cage. The difference between reference station （600 m from the cage） and station 2 at 95 m to the cage was insignificant, indicating lo- calized impact of cage farming to the vicinity of cage. The analyzed parameters in various depths did not show a significant difference. The values of analyzed parameters in the perimeter of the cage and their differences with reference stations showed small magnitude and localized impact on the chemistry of sediment. It might be because of deep water and moderate velocity of water current in this fjord. The magnitude of impact may dif- fer durina the summer when biomass and feedina rate would be at the maximum level.

Bio-ecological remediation of freshwater aquaculture environments:A systematic review and bibliometric analysis

Freshwater aquaculture plays an important role in the global aquaculture industry.The success of freshwater aquaculture relies on the integration of bio-ecological remediation technologies to ensure its sustainable development.This paper systematically reviews the global literatures on bio-ecological remediation of freshwater aquaculture environments from 1990 to 2021,and discusses in detail the research progress and status quo in this field using both bibliometric analysis and content analysis.Our results indicate that the number of publications per year has increased year by year,with a particularly rapid increase after 2015.Institutions and researchers from China and the USA publish the greatest number of papers and contribute the most to this field.By analyzing the research progress in this field,we also find that the protection and restoration of freshwater aquaculture environments has received attention since as early as 1990,such as the application of constructed wetlands and recirculating aquaculture systems.Recently,researchers have increasingly focused on the use of microbial communities in remediation.Furthermore,vanRijn,J's papers are of great value to the research in this field.In content analysis,the application of primary technologies,including plant selection,aquatic animals,microorganisms,and biological filtration and purification equipment,as well as ecological engineering technologies with combinations of various types of organisms,is described to improve the effectiveness and efficiency of remediation.The performance,advantages,disadvantages,or limitations and prospects of these technology applications are analyzed in detail.By comparison,ecological engineering is shown to be the best remediation technology,being most comprehensive,and well-established.Taken together,this paper composes and summarizes existing work in this field,and provides guidance for future research on the improvement of existing technologies and the development of new technologies,with the aim of enhancing remediation capability,improving ecological sustainability and ensuring economic viability.

Optimization of Fermentation and Product Collection Process of the Functional Bacteria for Bioremediation of Shrimp Culture Environment

In order to implement industrial production of selected functional bacteria for bioremediation of shrimp culture environment, the fermentation conditions of the three functional bacteria, which have high ability in degrading organic pollutants at the bottom of shrimp ponds, were studied. The results showed that the favorable fermentation medium （per L） was 25 g of peptone, 5 g of yeast extract, and 0.2 g of ferric phosphate, and the initial pH value of the medium was 8.0. The optimum fermentation time was 20 h. The optimum stirring way was stirring one hour after one hour. Iso-electric point sedimentation collecting method was the most efficient and economic method to collect the bacteria cells after fermentation, with the optimum sediment pH of 3.67, 4.02, and 3.40 for the strains Lt7222, Gy7018 and Lt7511,respectively. It was also indicated that the survival and reproducing ability of the bacterial cells were not affected by the sedimentation process.

Nutritional Conditions for Application of Bacillus in Intensive Aquaculture of Shrimp

With the rapid development of intensive shrimp aquaculture, breeding en- vironment has been damaged severely, and diseases occur frequently. In aquacul- ture, probiotics are generally used to improve the ecological environment and inhibit pathogenic microorganisms, thereby reducing the incidence of diseases.They have been more and more commonly used in the intensive aquaculture of shrimp, and require certain nutritional conditions and need to reach a certain number to produce a good performance. In this paper, the basic nutrition requirements of the common- ly-used probiotic Bacillus and its water quality-improving effect were investigated to provide theoretical guidance for production.

Integrated bioremediation techniques in a shrimp farming environment under controlled conditions

This study investigated the integrated bioremediation techniques for a shrimp culture system to reduce unconsumed feed and the contents of suspended solids（SS）, nutrients and organic pollutants using barracuda,clamworm, scallop, large algae and a biofilter. A multi-pool internal circulation system was designed to test the effectiveness of the techniques in the laboratory. The experimental result has shown that Argopecten irradians,Gracilaria lemaneiformis and the biofilter efficiently reduced the contents of SS, dissolved inorganic carbon（DIC）and dissolved organic carbon（DOC） in the breeding wastewater. The amount of unconsumed feed was significantly reduced by barracuda and clamworm, but there was an increase in the contents of SS, DIC and DOC in the water due to disturbance by the barracuda and clamworm. The capacity of macroalgae to extract inorganic nitrogen was insufficient. However, the balance of the nitrogen fixation rate of macroalgae and the biological exhaust nitrogen rate within the system should be fully considered. The use of the biofilter alone was not optimal for the remediation of organic matter in shrimp effluent so that auxiliary foam separation technology is needed to improve the ability of the system to remove macromolecules. This study provides a basis for the further development of remediation techniques to reduce the environmental impact of shrimp aquaculture.