Printed
    - Newspaper
    FISH INTERNATIONAL (Dezember 1995, 
	page
    54-57) 
    Farming Installations 
    Demand for fish is increasing worldwide but raw materials are becoming scarcer and
    scarcer. With respect to this, aquaculture is a young, innovative branch of industry with
    high growth rates and a secure outlook. The future of the aquaculture sector lies in the
    techniques developed to use water resources as saringly as possible and dispose of wast
    products in an environment-friendly manner, while at the same time keeping energy
    consumption at a minimum. 
      
    Aquaculture
    Technology is the name of an Austrian company which develops innovative
    technology for use within fish production, as well as offering various services in the
    field of water management, fish plant planning and management - for both fresh and
    salt-water species. 
    The one hundred per cent subsidiary "Satzfischzucht Hochleithner" runs
    three fish farming facilities for the production of fish for stocking purposes, mainly od
    species which are difficult to raise: Arctic char, sea trout, grayling, pike, pike-perch,
    burbot, sturgeon and others. These are exported to buyers in Germany, Italy, France and
    elsewhere. 
    Closed circuit installations: 
    Fish production within a closed circuit enables a high level of fish concentration within
    a given space, low proportional wage costs and high returns. The wastwater, which suffers
    organic contamination from products resulting from the fish's metabolism, is treated using
    biological and physical cleaning methods so that 90 per cent of it can be re-used.
    Selectice improvement of the water circulation and filter technology has enabled Aquaculture
    Technology to offer their customs an efficient, simple, low-cost system for
    fresh and salt water. To enable risk minimization, process stability and fish's general
    good health, the closed circuit installations are allways constructed in modules, with
    each module operating autonomously so that its water supply is seperate from that of other
    modules. The modules are are available as from an annual production capacity of two
    tonnes, equivalent to a fish stocks of 400 kilograms, and they consist of four round tanks
    with a diameter of two meters, one round tank with a diameter of four meters and the
    appropriate technology. Once the larger waste particles have been remove dusing an eddy
    flow scrubber, the wast-water from the tanks enters a biofilter. The carpet of bacteria
    necessary for the nitrification process is attached to the reactor packing; excess sludge
    is disloged by current. With 900 square meters per cubic metre of Siporax filter material,
    the Aquaculture Technology bioreactors have a
    large growth area so that relative small filtering units are sufficient. By blowing in air
    via a specially developed ventilation system, no pumps are required, say the company
    experts, a feature which leads to energy savings. 
    Circular current tanks: 
    The Austrian company's circular tanks are made of dark green or pale blue glass fibre
    reinforced polyester resin. The inner surface is absolute smoot. The special conical shape
    - inside heights 600 mm at the edge, 700 mm in the middle - and the tapered base with a
    funnel-shaped outlet in the middle means that the tank system practically cleans itself.
    The system is thus well-suited to keep sensitive ground species as well as raising
    juveniles. The drainage system consists of PVC pipes with a diameter of 70 millimeters and
    is fitted with a water-level regulator. It can be swivelled twice at an angle of 90
    degrees. The edge of the tank is reinforced, enabling the attachment of automatic feeding
    and other facilities. The three laminated feet can be adjusted in height so that the tank
    will always be stable, Its light weight - about 70 kilograms - means that it can be
    adjusted or transported at any time. Aquaculture Technology
    supplies the tank in two different sizes: with an inner diameter of two or four
    metre. A divided lid and various upright and ground sieves are available as acessories. 
    Injection aeration: 
    Aquaculture Technology's tried, tested and
    patented injector aerators are also suitable for large ponds. They are powered by a
    service-free underwater motor, designed for continous operation and 180 degrees rotatable
    with two different performance levels - 0.8 or 1.2 h.p. - and with 220 or 380 volts. The
    attached propeller generates a current which can be adjusted as required in any direction.
    Surface air is sucked in, atomized and distributed. The current aerates and propels the
    low-oxygen water, enabling maximum oxygen enrichment. Because decomposition porcesses on
    the pond bed usually lead to oxygen deficit, the system operates on an infinitely variable
    basisto a depth of 15 meters, bearing oxygen to the areas where it is needed. The
    introduction of exactly dosed pure oxygen is possible in submerged operation, too.
    Independent of the installation, depth and the resulting current, the bed can be cleaned
    of sediments, too. If the water is to be degassed or surface kept free of ice during the
    winter, the aerator should be positioned near the surface. All variations are possible. 
    Automatic feeders: 
    In cooperation with the Institute for Fish Research in Innsbruck, Aquaculture
    Technology designed a new automatic plankton feeder for the professionally
    controlled administration of frozen zooplankton. Zooplankton serves as initial feed for
    the production of high-value fish stocks of such species as Arctic char, salmon, grayling,
    sturgeon, cod, bass, gilt head bream, halibut and numerous others.The feeding technique is
    based on an electronic process, which "washes" the plankton layers off
    larger-sized frozen pieces of feed and distributes the rations evenly via a specially
    designed, self-cleaning system into the hatching tanks. The "washing" and
    defrosting of th eplankton layers is archieved by spraying of flooding, the remaining
    plankton is immediately re-fozen. The size of the plankton particles can be adjusted and
    controlled via a special sieve unit. In order to avoid the crushing of the defrosted
    plankton,distribution to the hatching tanks is carried out along water currents in pipes. 
     
    FISH FARMER (July/August 2000, 
	page
    49-50) 
    Submersible has automatic
    underwater feeder 
     WELL-KNOWN for its pontoon cage
    systems, Aquaculture Technology, based in Kitzbühel, Austria offers a wide range
    of stock management, fishlarval rearing and production equipment. One of its most recent
    developments is an ingenious submersible netcage for offshore locations. The nine-sided
    structur, with an axial diameter of ~20 m, has service platforms, passage walkways with
    railings and removable hand-ropes. It houses ballast tanks and compressed air cylinders,
    permanent buoyancy compartments, balancing tanks and compensation tanks of residual
    buoyancy tio allow for discharge of changing loads. Hot galvanized coating provides an
    expected service life of more than 20 years. It is reliable, practically excluding
    restoration and repair, report the company. Automatic underwater feed distribution is a
    feature of the system, designed to store and distribute measured quantities of feed over
    periods of 7-30 days. It consist of a cylindrical-conic watertight hopper of 3,000 litre
    capacity - holding 2 tons of feed on average - and an automatic feed distributor with a
    volumetric type dosage. The feeder houses selenoid vaklves, a system controller and
    batteries. Construction is of corrosion-proofed steel (6-8 mm thickness) and non-ferrous
    metals. To submerge and surface the cage it is equipped with ballast compartments filled
    by gravity via drain holes equipped with valves operated by remote-control pneumatic
    drive. Water in the ballast compartments is displaced by compressed air from th eservice
    boat compressor. The process of raising and lowering is supervised by the depth sensor,
    which has a display located either in the service boat or on-shore via a water acoustic
    communication channel. Flexible pipelines and electricity cables come from the signal buoy
    to the cage to supply compressed air and power. The net chamber, with a volume of 1,000 to
    2,000 cu. m is located in the steel structure on guy ropes running up and down from the
    platform. Waste removal is organised with a tray device, liftes to the surface by means of
    winches. It is possible to position the cage system in a depth range of 4-40 m, and when
    floating, the makers say it will withstand waves up to 6 m and conditions up to Force 6.
    Submerged, it can take weather up Force 9 and waves of 8-9 m. Aquaculture
    Technology say the cage structure is produced to the "Rules for
    Building and Classing Underwater Vehicles, Systems and Hyperbaric Facilities". It
    will have the certificate of the official "Maritime Register of Shipping". 
     
    ARAB WORLD AGRIBUSINESS (August 2006, 
	page 11) 
    Aquaculture technology, fish
    farming & equipment - quality for reasonable prices! 
      
    Aquaculture
    Technology is the name of an Austrian based company which develops
    and exports innovative technology for use within fish production, as well as offering
    various services and consulting in the field of water management, fish farm planning and
    management - for both fresh- and salt-water species. AquaTech offers an approved range of products for:
    breeding (hatching jars, vertical incubators, breeding troughs), holding (filter systems,
    water conditioners, holding basins) feeding (solar, clockwork, pendulum feeders), aerating
    (injectors, blowers, diffusers) controlling (meters, scales, pumps), catching (nets,
    traps, electro-fishers), transporting (sorters, lifts, tanks), processing (scaling,
    skinning, filleting machines) and others (pontoons, motors, boats) and much more (books,
    feeds, hormones). To view the huge range of products, the best would be to visit the
    extensive website at www.aqua-tech.eu The one hundred per cent subsidiary "Satzfischzucht
    Hochleithner" runs three fish farming facilities for the production of fish maily for
    stocking purposes, of species which are usually difficult to raise, like: Arctic charr
    (Salvelinus alpinus), Lake trout (Salmo trutta lacustris), Grayling (Thymallus thymallus),
    Pike (Esox lucius), Pike-perch (Sander lucioperca), Catfish (Silurus glanis), Burbot (Lota
    lota), Sturgeons (Acipenser baerii, Acipenser gueldenstaedtii, Huso huso etc.), and other
    species. These are exported as eggs, larvae, fry or fingerlings to buyers mainly in Europe but also elsewhere around the world. 
     
    HATCHERY INTERNATIONAL (July/August 2017, 
	page 28) 
	
	First out-of-season reproduction of beluga sturgeon 
	The Beluga sturgeon (Huso 
	huso Linnaeus, 1758) has a decreasing 
	population trend and is classified as critically endangered in the Black- 
	and Azov seas, and regionally extinct in the Adriatic Sea. It is extirpated 
	from the upper parts of almost all the European spawning rivers (e.g. Danube, 
	Dniester, Dnieper, Don, Kuban, Terek and Volga) mainly because of 
	overfishing and dams that block migration routes. 
	Depleted fishery 
	Official commercial landings (mainly Russian) 
	have decreased dramatically during recent decades, from >520 t/a in the 
	early 1990’s to <3 t/a at the beginning of the 2010’s. Huso 
	huso is the largest freshwater fish in the 
	world, and is a valuable candidate for aquaculture as it has the fastest 
	growth within the family, and its caviar commands the highest price. 
	Martin Hochleithner (owner of AquaTech, in 
	Kitzbuehel, Austria) started farming sturgeon in the mid 1980s, first with 
	bester (a hybrid of Huso 
	huso and sterlet, Acipenser 
	ruthenus), and later with pure-bred 
	sterlet, Siberian sturgeon (A. baerii), Russian 
	sturgeon (A. gueldenstaedtii), and 
	Adriatic sturgeon (A. naccarii). 
	Early days 
	In the early 1990s a large number of fertilized H. 
	huso eggs from the Pontic Danube stock was 
	hatched and cultured in Austria. These F1 larvae were fed with 
	live zooplankton (Daphnia) 
	and choppped live oligochaetes (Tubifex) 
	for the first weeks. After a month, the fry were weaned onto crumbled 
	dry-food, mixed with moist feed for a few weeks, then stocked into 5m Ø 
	circular tanks for five years, until a heavy bacterial infection occurred. 
	Thereafter the fish were stocked into small earthen ponds (100-2000 m2), 
	for an additional five years. Under a cooperation contract with Stefano 
	Marturano (manager of Azienda Agricola Pisani Dossi in Cisliano, Italy) part 
	of the 10-year-old sub-adult stock was transferred to Italy (the rest 
	remained in Austria), in order to divide the risk for these highly valuable 
	broodstock specimens. There the fish are kept in circular tanks (6m Ø) 
	supplied with ground-water (at about 12-18 °C), and are fed ad libitum with 
	pelleted dry-food. 
	Slow to mature Under these culture 
	conditions, the first males matured at nine years of age, but females did 
	not mature before the age of 18. The first maturing females were found in 
	the over-ripe stage VI in spring. Later it was discovered that beluga 
	broodfish in culture conditions get ready for reproduction (stage V) in 
	northern Italy in autumn (October-December), rather than in spring 
	(March-May) like wild stocks under natural conditions. Out-of-season 
	reproduction is reported here for the first time. 
	Full circle beluga 
	Full circle cultivation of beluga was reached at 
	the end of last year, where a new generation (F2) of H. 
	huso was successfully produced in 
	captivity. The hatched larvae have been split (50:50) and sent to two 
	different farms (in Italy and Austria), where they are stocked in different 
	tanks (large rectangular and small square), and supplied with water at 
	different temperatures (13-14 and 17-18 °C), and fed with different diets (frozen 
	chironomids and live zooplankton), and finally weaned onto crumbled 
	dry-food. The survival 
	rates after two months were almost identical, but growth was significantly 
	faster in the warmer water. A small number of these out-of-season offspring 
	were supplied for a restocking project in the Italian Po River and another 
	larger number for farming activities in the European Union. Breeding 
	beluga sturgeon in captivity is still far from being routine, but the 
	outlook is promising. The main problems have been solved, and the minor 
	troubles identified, so regular reproduction can be expected henceforward. 
	However, cannibalistic behaviour by the larvae remains an important issue to 
	solve. 
	For more information contact Martin Hochleithner by email at: aquatech@a1.net 
	More Reports in: 
    Fish Farming International, Northern Aquaculture, Hatchery Magazine, Aqua Revue, Aqua
    Noticias, Infofish International, Magazyn Przemyslu Rybnego, Fisch Magazin, Österreichs
    Fischerei, etc.  |