Technicians and experts in ASAKUA are experienced figures thanks to the international projects realized in past and recent years. Some of our realized projects in regard with the assemblage of HDPE cages have been done in countries ranging from Azerbaijan, Russian Federation, Tunisia, Bulgaria, Iran, and Kyrgyzstan.

ASAKUA today is looking for new challenges and new projects in offshore installation systems. We are looking for sharing our experiences and expertise with our clients. ASAKUA fish farming cage products are ready to assemble in site by our experienced technicians. We have unique bracket design and installation techniques.

*Stocking volume calculated for optimum depth and site parameters.

*Stocking volume calculated for optimum depth and site parameters.

CAGE CULTURE

The standard approach to cage culture is to float cages at the surface of the water, with the cage bottoms kept above the substrate. Each individual cage can be fitted with floats, or floating platforms, from which the cages are hung, can be constructed. Popular float materials are Styrofoam, cork, and plastic. Cages can also be elevated above the bottom of the substrate from poles driven into the substrate, although this approach is suitable only in relatively shallow water.

Each cage needs to be provided with a top, to keep the animals from jumping out. Tops may be solid or constructed of the same type of mesh that wraps the sides and bottom of the cages. The water quality in cages can be very high if the cage site is properly selected. Cages placed in currents constantly receive water exchanges that help maintain good water quality, unless the incoming water is not of high quality. If several cages are placed in a string within a current, the most upstream cage will have the best water quality. As the water passes through each cage, the amount of dissolved oxygen will be reduced, the concentration of ammonia will increase, and fecal wastes will build up in a downstream direction. Ultimately, the water quality may be degraded to the point that growth in downstream cages is reduced. Stress associated with degraded water quality can be a precursor to diseases and even directly cause mortality. Proper separation of cages to allow maintenance of water quality is important. The appropriate number of cages in pods or strings needs to be determined for each water body. Those numbers will vary as a function of prevailing currents, tidal or stream flows, stocking densities, temperature, the level of dissolved oxygen, and the species being reared. Animals are much more densely crowded in cages than in open ponds. As a result, there have been instances of fighting; scraping of the integument on cage sides, leading to scale loss and skin lesions; and increased levels of cannibalism and disease associated with close confinement. In theory, it is easy to treat diseases in cages. One method involves fitting a plastic bag around a cage containing diseased fish and placing therapeutants in the water. Placement of such bags around cages is, however, much more easily described than actually put into practice. Even if such a bag can be put in place, it cannot remain there long before water-quality deterioration will exacerbate the situation. Removing fish from cages to apply dip or bath treatments may not be difficult, but is an additional source of stress. If efficacious medications can be provided in feed, they can be administered quite easily to caged fish.

Biofouling of cages can be a problem in freshwater, though it tends to be a more significant source of trouble in the marine environment. Algae, bryozoans, and a few types of freshwater clams andmussels (e.g., zebramussels) can cause significant problems in freshwater, while a wide variety of organisms, notably barnacles and bryozoans, foul cages in the marine environment. The situation can become so severe that the flow of water through cages becomes severely restricted or even stopped. As the fouling problem increases, the water quality will be negatively impacted. Frequent cleaning may be required to keep the mesh of the cage walls open.

SPECIES CULTURED IN CAGES

Nearly any aquatic animal can, at least theoretically, be reared in cages. Because cages are generally fairly small, species that are marketed at a large size. Small commercial marine cages suspended from floating walkways in Malaysia. as tuna, are not good candidates for cages, but can be reared, as are salmon, in net pens. Cages have been used to rear channel catfish in reservoirs, including cooling reservoirs and the discharge canals associated with power plants. Tilapia are reared in very large net pens in the Philippines and are also reared in cages in various countries. Cage culture in lakes and reservoirs is often permitted in developing countries.