Aquaculture Technology

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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.

Arctic charr and sea trout are kept here in illuminated net cages. The production method is based on feeding with plankton.

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
Submersible offshore netcage systemWELL-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!

Arctic charr and sea trout are kept here in illuminated net cages. The production method is based on feeding with plankton.

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.e
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 Flarvae 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:

More Reports in:
Fish Farming International, Northern Aquaculture, Hatchery Magazine, Aqua Revue, Aqua Noticias, Infofish International, Magazyn Przemyslu Rybnego, Fisch Magazin, Österreichs Fischerei, etc.


Electronic - Internet

FISH INFO SERVICE (06/26/1998)

Cage light is a bright idea
Illuminated submerged netcagesThe new UWG-Solar Cagesystem from Aquaculture Technology is the result of years of tests in sea and freshwater.
The system, which can be used in lagoons, sea-bays, fjords, lakes and large ponds, works by attracting plankton (mainly copepods and cladoceres) using a light source in the centre of fine-meshed submerged fish cages.
The net-cages (2 x 2 x 2m) are made from highly resistant monofile polyester fabric with 0.3-2.0 mm mesh, furnished with a large zippered entrance and space for the electric cable. The net cage is stretched, free of folds, onto a strong inox or aluminium frame.
An efficient Solar-Generator is also supplied so that the system can be run in remote sites, and with facilities for connections to an electric source, it can be equipped with an electric transformer to avoid high voltages and the risk of electrical accidents.
Depending on the zooplankton abundance, the fish-stocking density (from the hatchling stage to fingerling size of 5 cm) can reach 5.000 Ind./m3, and survival rates of more than 90% have been achieved with various marine and freshwater fish species.
The company says there is less operational effort needed, apart from periodic cleaning of the cages with a portable high pressure cleaner. The system runs free of any environmental contamination; plankton consumption is minimal and does not affect the natural stocks.

Luces para jaulas: una brillante idea
El nuevo UWG-Solar Cagesystem de Aquaculture Technology es el resultado de años de investigaciones en el mar y en agua dulce.
El sistema, que puede ser utilizado en lagunas, bahías, fiordos, lagos y grandes estanques, atrae el plancton (principalmente copepodos y claroceres), utilizando una fuente luminosa en el centro de las jaulas de pescado sumergidas.
Las jaulas (2 x 2 x 2m) están fabricadas a base de material de "monofile polyester" altamente resistente, con 0.3-2.0 mm de malla, equipadas con una gran cremallera en la entrada y espacio para el cable eléctrico. La red de la jaula es estirada, sin pliegos en un marco de inox o aluminio.
Asimismo, también se suministra un eficiente Generador Solar, por lo que el sistema puede ser dirigido en lugares remotos y con servicios para conexiones a una fuente eléctrica, éste puede ser equipado con un transformador eléctrico para evitar altos voltajes y riesgo de accidentes eléctricos.
Dependiendo de la abundancia de zooplancton, la densidad del "fish-stocking" (desde el estado de "hatchling" hasta "fuingerling" con un tamaño de 5 cm) puede alcanzar 5.000 Ind./m3, y con varias especies de pescado de agua dulce y salobre se han conseguido porcentajes de supervivencia de más del 90%.
La compañía ha declarado que se necesita menos esfuerzo operacional, sin contar una limpieza periódica de las jaulas con un limpiador portátil de alta presión. El sistema no supone ninguna contaminación para el medio ambiente.; el consumo de plancton es mínimo y no afecta a los stocks naturales.

FISH INFO SERVICE (07/04/2000)

New smoker from AquaTechUniversal system for smoking curing, steaming, cocking, backing and roasting etc.
has introduced a new, patented microprocessor controlled technology where all undesired smoke substances are removed but all durability and taste-giving matters are sustained. Besides smoking, with these indoor cabinets you can also cure, steam, cook, bake, roast etc. Larger systems (volume over 1000 litre) are also available.
These systems are completely different from traditional ones. They don’t need a smoke generator and burner. Instead of a generator, they use a tank with liquid smoke that is brought to a pressure of 3-5 bar. Using this patented technology, liquid smoke will be spread via a ventilation system over nozzles and re-circulated. During this process steam and gas is made, which generates an invisible smoke. This "smoke" is physically identical to conventional smoke, with all durability and taste-giving substances (carbonyls, acids and phenols), but has no tar and other undesired matters (Benzo-a-pyren).
The complete system is controlled by a microprocessor and easily allows for programming of temperature, moisture, time etc. It can also save up to 99 programs (with 20 steps each). The actual and required parameters, as well as alarms etc. can be viewed on a digital display. For a fully automated cleaning process (without aggressive cleaners or personnel) all equipment is placed in the cabinet and a program is started.

Nueva ahumadora de AquaTech
ha introducido un nuevo microprocesador patentado de tecnología controlada, en el que todas las sustancias de humo no deseadas son eliminadas, pero todas las materias que le otorgan gusto y durabilidad se mantienen. Aparte del ahumado, ésta máquina también puede curar, preparar al vapor, cocinar, asar, etc. Los sistemas de superior tamaño (con un volumen superior a los 1000 l) también estan disponibles.
Estos sistemas son completamente diferentes a los tradicionales, en cuanto a que no necesitan un generador o quemador de humo, debido a que en lugar de un generador, un tanque con humo líquido es preparado a una presión de 3-5 bares. Con esta tecnología patentada, el humo líquido es esparcido a través de un sistema de ventilación en toberas y reciclado. Durante este proceso se realiza una fase de humo y gas, la cual genera un humo invisible. Este "humo" es físicamente idéntico al humo tradicional, con toda la durabilidad y sustancias para el sabor, pero no cuenta con "tarphase" y otras materias no deseadas (Benzo-a-pyren).
El sistema completo es controlado mediante un microprocesador y permite una fácil programación de las temperaturas, la humedad, el tiempo, etc., y cuenta con hasta 99 programas (con 20 pasos cada uno). Los parámetros y las alarmas son mostrados en un display digital. Para el proceso de limpieza automática (sin tener que disponer de agresivos limpiadores o personal), todo el equipo es introducido en la máquina y se comienza el programa.

FISH INFO SERVICE (07/23/2001)

Electric Fishing Devices with Direct- or Impulse-Current
Electric Fishing DeviceSafe and powerful electric fishing devices are already being used worldwide with successful results. In various and sometimes problematic areas of use, a wide range of devices was developed which will match nearly any requirements.
All devices are built to VDE-regulations and are TÜV-tested. The electric building corresponds to security class II. Therefore, all power delivering parts are double isolated and guarantee the best possible security for persons. A "Totmannswitch" (in Germany required) guarantees for additional security, so that all outlets of the device are without electric current if dangerous situations arise. The permanent excited generator and the high quality magnet materials guarantee a continous and reliable power. Each device will be tested mechanically and electrically completely and delivered with user manual.
Direct current creates usually a better anodic reaction as impuls current would do. But at extreme conductivities or for electric barriers with direct current, soon the borders are reached. As a result, powerful combinated (Direct-/Impulse-Current) devices were created, where the impulse frequency and volts can be adjusted (via motor turns or switch). The back carry units are compact lightweight systems with high outgoing power. Impulse devices are a little larger and have a little more weight than direct current devices.
AquaTech delivers net-, battery-, petrol-driven backcarry- or stand-devices with direct- and/or impulse current with an outgoing power of 250-11.000 Watt (5-160 kw/impuls at 25-100 Impulse/sec.), and a current of 300-960 Volt with a weight of 10-135 kg and for a conductivity of 50-10.000 µS.


Smoking equipment
Aquaculture Technology (AquaTech) markets all sorts of equipment to breed and process fish. From breeding to scaling machines, filleting machines, several kinds of smokers and vacuum packers, the company market almost everything one needs to operating a fish breeding and processing operation.
Courtesy of AquaTechCourtesy of AquaTechIn direct relation to current delivery, AquaTech offers a multipurpose equipment to smoke fish, sausage, meat, poultry in the same oven. (Pictures of said equipment - closed and opened)
Up to 300 kg of fish or 200 kg of meat per batch can be smoked and the process takes up to 60 minutes to be completed. Further, the equipment is fuel versatile. It can be powered either by propane-gas or fuel-wood and delivered with both built in. It can operate cold-smoking or hot-smoking processes.
AquaTech proposes in its catalogue an alternative to the above described equipment. It is electricity powered and can handle the same quantities of raw materials - meat or fish as the previous system. It features electric smokers with double wall isolation (50 mm), pipe connection, heating coils and thermostat (50-250 °C), switches, and drip-pan etc.
For the purpose of this delivery we will consider the dual powered (propane-gas and fuel-wood) equipment to estimate investment and operating costs for a small scale smoking operations under the following conditions:

Operating conditions
Alternate batch of 300 kg of tilapia and catfish cold-smoked during 60 processing-minutes; 20 minutes interval to load one batch after the finished batch in a dual (wood and propane gas) powered AquaTech equipment (RS-300). Which means 6 (six) cycles per 8-hour working day to handling (300 kg x 6) = 1,800 kg per day of fresh tilapia and catfish. Considering the combined weight loss during brinning and the smoking process to be in average fifteen percent for both species of processed fish (tilapia and catfish), the final daily processed production would be: 1,530 kg. The following table summarizes operating costs:

Operating Inputs & Costs


Daily (8 hours)

Monthly (24 days)


Yearly costs (US$)

Tilapia (kg)





Catfish (kg)





Brinning (lt)





Gas (kg)*





Remark*: Propane-gas' consumption for AquaTech's RS-300 smoking equipment is approximately 1.92 kg per hour. The daily smoking process of 1,800 kg of fresh fish (per batch of 300 kg per 60 minutes' smoking cycle) would be consuming 1.92 x 6 = 11.52 kg of propane-gas per day. 25 kg of propane gas container cost around US$ 12 (in Benin).

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