Saturday, June 11, 2016

HOBAS aeration technology

Among the major shrimp farming countries in the world, India stands in 4th position in shrimp production. Sustainable shrimp production is possible with the use of best environmental management strategies. Pond based coastal aquaculture, particularly of shrimps gained considerable momentum in India due to rapid returns from both national and international markets. During the last decade, there has been a remarkable increase in annual shrimp production from 35500 (1990-91) to about 113,000 tonnes with an export value of 800 million US $. To maintain proper water conditions especially to increase the oxygen content of the water, the aerators are used to mix the air with water. Mix water with air either after the pump (e.g. Ejector base aeration) or with a propeller in open water (eg. Air O2, Paddle-wheels etc).

An innovative aeration technology developed in recent past by HOBAS water Engineering has many improved features The project was taken up under the aegis of Indo-Norwegian Institutional co- operation programme by the National Institute of Oceanography (NIO), Goa from India and RF- Roga land Research, Stavanger, Norwegian Institute for Water Research (NIVA) and HOBAS Tropical Aquaculture, Sola from Norway, to develop and demonstrate how the new technology could improve the water quality and in turn result in sustainable production under Indian conditions.

The HOBAS aeration technology mechanically mixes air and water in order to replace oxygen deficits, and flushes the excreted, potential toxic, carbon dioxide and ammonia. The pump also creates horizontal physical water current in the pond when sufficient numbers of aerators are employed and Implemented.

In order to know the capacity of HOBAS aeration technology a team of NIO scientists conducted various experiments for water quality, environment, bacteriology and production in commercial shrimp ponds along the Coastal Karnataka and observed the maintenance of optimum water quality conditions, particularly the dissolved oxygen, healthy bacterial counts and maintain sustainable shrimp growth, resulting in lower Food Conversion Ratio (FCR). This technology aids in improving conditions of pond for better utilization of nutrients if Best Management Practices (BMP’s) were followed. By implementing this technology due to optimal environmental conditions in the pond during the production cycle and the increased phytoplankton production due to re-suspension of available nutrients the yield may increase by about 20-25%.

The HOBAS aerator also showed a strong ability and high capacity in flushing the possible toxic gases such as Ammonia and Hydrogen Sulphide. This technology may be replaced or could be used in conjunction with the existing aeration technology for improvement in environmental conditions in the pond. Few more trials of HOBAS technology, particularly along the east coast of India to generate data under different environmental conditions with the}in nature leading to high mortality and involvement of stakeholders so that farmers gain confidence in this new technology is proposed. NIO would be providing R & D support to commercialize the HOBAS technology in India. Scientists from NIO - Dr. D. Chandramohan, Mr. R.A. Sreepada, Drs. P.A. Lokabharathi,S.G. Dalal, X.N. Verlecar, B.S. Ingole and a group of young project assistants were involved in evaluating this technology and developing other Best Management Practices (BMPs) for sustainable aquaculture for last 3 years.