Hallo everyone ! At this time, we live in the age of globalization or can also be called the era of modernization. Modernization covers many fields, for exaample in science and technology. At the ime of such modernization now, humans rely heavily on technology. This makes the technology becomes the basic needs of everyone. From the elderly to young people, experts to any layman use technology in various aspects of his life. The aquaculture sector also do technology development, it is RAS ( Recirculating Aquaculture System ) and we had discuss about it ! Here is all about our discussion of RAS, happy reading !
Various innovations continue to be developed by the Government of Indonesia to promote the aquaculture sector alongside the same sectors at the international level. Most recently, innovations have been made for the Recirculating Aquaculture System (RAS) technology system. In developed countries such as Norway, such technology is commonly used. The Director General of Aquaculture Fisheries (DJPB) of the Ministry of Maritime Affairs and Fisheries (KKP) Slamet Soebjakto in Jakarta recently explained that the modern technology that has been successfully developed, is a fruit of hard work from the team of Freshwater Aquaculture (BPBAT) Tatelu, Minahasa, North Sulawesi.
Recirculation aquaculture systems (RAS) represent a new and unique way to farm fish. Instead of the traditional method of growing fish outdoors in open ponds and raceways this system rears fish at high densities, in indoor tanks with a “controlled” environment. Recirculating systems filter and clean the water for recycling back through fish culture tanks. New water is added to the tanks only to make up for splash out and evaporation and for that used to flush out waste materials. In contrast, many raceway systems used to grow trout are termed “open” or “flow through” systems because all the water makes only one pass through the tank and then is discarded. The steps in RAS include solids removal, ammonia removal, Co2 removal and oxygenation.
Fish grown in RAS must be supplied with all the conditions necessary to remain healthy and grow. They need a continuous supply of clean water at a temperature and dissolved oxygen content that is optimum for growth. A filtering (biofilter) system is necessary to purify the water and remove or detoxify harmful waste products and uneaten feed. The fish must be fed a nutritionally-complete feed on a daily basis to encourage fast growth and high survival. RAS are currently being used to grow catfish, striped bass, tilapia, crawfish, blue crabs, oysters, mussels, and aquarium pets.
Combining plants and fish in a RAS is referred to as aquaponics. In this type of system ammonia produced by the fish is not only converted to nitrate but is also removed by the plants from the water. In an aquaponics system fish effectively fertilize the plants, this creates a closed looped system where very little waste is generated and inputs are minimized. Aquaponics provides the advantage of being able to harvest and sell multiple crops.
Home aquaria and inland commercial aquariums are a form of RAS where the water quality is very carefully controlled and the stocking density of fish is relatively low. In these systems the goal is to display the fish rather than producing food. However, biofilters and other forms of water treatment are still used to reduce the need to exchange water and to maintain water clarity. Just like in traditional RAS water must be removed periodically to prevent nitrate and other toxic chemicals from building up in the system. Coastal aquariums often have high rates of water exchange and are typically not operated as a RAS due to their proximity to a large body of clean water.
The functional parts of a RAS include a: (1) growing tank, (2) sump of particulate removal device, (3) biofilter, (4) oxygen injection with U-tube aeration and, (5) water circulation pump. Depending on the water temperature and fish species selected, a water heating system may be necessary. Ozone and ultraviolet sterilization also may be advantageous to reduce organic and bacteria loads.
These include a method to maximize production on a limited supply of water and land, nearly complete environmental control to maximize fish growth year-round, the flexibility to locate production facilities near large markets, complete and convenient harvesting, and quick and effective disease control. RAS can be of various sizes ranging from large-scale production systems (over 1 million pounds per year) to intermediate-sized systems (500,000 pounds per year), to small systems (50,000 pounds per year). They can be used as grow-out systems to produce food fish or as hatcheries to produce eggs and fingerling sport fish for stocking and ornamental fish for home aquariums.