Development And Application Of Several New Systems For Culture And Stock Enhancement In Typical Habitats Of Sea Areas

The deterioration of marine biological resources and their habitats in shallow water is becoming a serious problem, and few dedicated systems for the culture and stock enhancement of precious sea product, such as sea cucumber, Apostichopus japonicus, are developed. Based on the features of typical sea areas, such as pond, near-shore and off-shore, and behavioural characteristics of maricultural animals, several systems were developed, such as a new multilayer, plate-type system for the culture and stock enhancement of sea cucumbers in pond/cofferdam, a new artificial oyster-shell reef system for the culture and stock enhancement of sea cucumbers near shore, a new multilayer, combined-type system for the culture and stock enhancement of sea cucumbers off shore, and a new HAILONGⅠbottom mariculture system for the culture and stock enhancement of multi-species, and etc.. Moreover, the primary evaluations of these systems were also conducted. The study can contribute to the restoration of damaged maricultural areas, and can promote the application and spread of the new systems in coastal areas. The main results are as follows.1. The recent progress derived largely from engineering and facilities for maricuture and stock enhancement in shallow water was reviewed in this paper. The application status and future development of facilities and equipments for suspended culture, cage culture, bottom culture and pond/cofferdam culture were analyzed. And the key techniques of design, hydrodynamics, site selection, geograpHical layout, evaluation of artificial reef were also expounded. Furthermore, the application of artificial reefs in marine ranching and restoration of marine livings and their habitats were summarized.2. A new multilayer, plate-type system for the culture and stock enhancement of sea cucumbers in cofferdam was developed. To optimize and evaluate the system, four experimental designs were implemented using polyethylene corrugated sheets of various colors, interval spacing and shapes/styles. Results showed that a system equipped with black PE corrugated sheets attracted more animals than either blue, green, transparent or a selection of mixed sheets (five transparent sheets in the upper layer and six black sheets in the lower layer. The system with oblique-angled sheets attracted more animals than either a wavy or parallel arrangement, and the system with a 2-cm between sheets attracted more animals than spacings of 3, 4 or 5 cm. As expected, the upper layers of the systems attracted more animals than lower layers in most cases except for those with transparent and mixed oblique-angled sheets with a 3-cm spacing. Thus, a system with black, oblique-angled corrugated sheets and 2-cm spacing is recommended for A. japonicus culture and stock enhancement in cofferdams or ponds.3. A new artificial oyster-shell reef system for the culture and stock enhancement of sea cucumbers near shore was developed. From Mar 6th to Nov 26th, 2009, culture experiment of A. japonicus near Hongdao, Jiaozhou Bay was conducted. The average wet weights of sea cucumbers increased from (49.57±1.16) g ind^-1 to (79.87±1.46) g ind^-1. Densities of sea cucumbers in artificial oyster-shell reef zone on June 16th and Nov 26th,which are in the high mobility periods of sea cucumbers, are (21.5±1.0) ind m^-2 and (20.5±0.6) ind m^-2, and densities of sea cucumbers in artificial oyster-shell reef zone were significantly higher than that outside. The average distances from the farthest sea cucumbers to the edge of the nearest reefs were merely (86.3±4.6) cm, (85.7±2.8) cm and (8.2±3.5) cm on June 16th, Nov 26th and Apr 18th, which were significantly higher than that on the other observation days. Diatom communities on oyster shells are much similar to that in the stomachs of sea cucumbers in the reefs. The new system supplied concealment and food for sea cucumbers, and rather appealed to sea cucumbers. 4. A new matching device for manufacturing artificial oyster-shell reef system was developed. The device had the advantages of low cost and simple structure, which could also reduce the labor intensity and improve the productivity.5. A new multilayer, combined-type system for the culture and stock enhancement of sea cucumbers off shore was developed. After an acclimating period of more than one year in the sea area of Qiansandao, Rizhao, seasonal investigations were conducted. Gelidium amansii and Uiva pertusa are dominant species in algae communities on the new systems in spring, while Uiva pertusa and Dictyopteris divaricate in summer. In autumn there were only two species of algae, Gelidium amansii and Uiva pertusa, with low biomass. Water depth showed significant effect on algae species and biomass on the systems. More species and biomass of algae on the system were investigated in shallow water. The new systems should be laid in the sea areas within 10m depth. Sea cucumbers with average wet weight of 30g ind^-1 were sowed on the bottom of neighboring sea areas. After one and a half years, the average number of sea cucumbers, A. japonicus, in the new system was 5 ind, and the average density of sea cucumber within 5m around the system was 1.2 ind m^-2. The average wet weight of sea cucumbers was 90g ind^-1. The new systems showed beneficial effects on stock enhancement.6. A new HAILONGⅠbottom mariculture system for the culture and stock enhancement of multi-species, i.e. algae, scallop, sea cucumber, sea urchin and etc. were developed. Experiments in the sea area of Zhangzidao, Dalian were conducted. Different densities (10 ind m^-2,30 ind m^-2,50 ind m^-2)and the interactions of different densities and substrates showed no significant effect on the shell height of Japanese scallops Patinopecten yessoensis, while different substrates (sandy, semi-sandy, muddy) showed significant effect on that. Different densities, substrates and their interactions showed significant effect on the numbers of sea cucumbers, A. japonicus, in the new systems. There were more sea cucumbers in the system on sandy substrate than that on semi-sandy or muddy substrate. Different densities and substrates showed significant effect on the numbers of sea urchins in the new systems, and their interactions showed no significant effect on that. The relationship of the numbers of sea urchin in the systems on different substrates was muddy > semi-sandy > sandy. There was local seaweed bed in the new system on sandy substrate obviously.