OP-ED: In-pond raceway system || Dhakatribune

A climate-smart aquaculture technology

In-pond raceway system or IPRS is a highly sophisticated innovative aquaculture technology, where optimal water chemistry is ensured by maintaining interrupted water flow and waste disposal management,

It eventually allows a suitable environment for super high density fish stocking.

Fishes are stocked in the channels or raceways installed in the pond.

Water chemistry, especially sufficient dissolved oxygen, is supplied round the clock.

In quest of climate change adaptation and growing concern on land and water resources scarcity, this is an environment friendly aquaculture technology that can help to ensure quality and safe seafood for human consumption.

Fish production from IPRS may vary 50-100 Ton/ha, even more depending on species types which is much higher than any other aquaculture systems.

Recent introduction of such an advanced technology in northwestern Chapainawabganj district can be considered as a golden milestone in aquaculture progress and mechanization in Bangladesh.

It also sounds that in near future Bangladesh can play a frontline role in global freshwater aquaculture.

IPRS was first invented in 2005 in Auburn university at Alabama in the USA by a research team headed by Professor Dr. Jesse Chappell and was first introduced in 2007 in a commercial catfish farm.

Thereafter during 2013-14 it was further adopted in China.

This super intensive aquaculture technology was extended in Vietnam, Mexico, India, Egypt and Pakistan in 2016, 2017, 2018, 2018 and 2019 respectively.

In the near future, IPRS technology is going to be introduced in Thailand, Cuba and some other countries of the globe.

Generally, in pond aquaculture fish production is 10-15 metric ton/ha, but with IPRS 50-100m.ton/ha, even more fish production is possible depending on different fish species.

Various types of fish species of different sizes can be cultivated at the same time in the same pond.

Principles of IPRS

Main principle of IPRS is to establish raceways/ channels in a big pond and maintain continuous water flow in those raceways.

Outer area of the raceways is also facilitated by continuous circular water flow.

At the same time, a mechanized feeding system and removal of all waste materials are also ensured.

Sufficient dissolved oxygen supply, continuous water exchange in the raceway and regular removal of pollutants make the system similar to a natural water stream.

Fishes feel convenient, swim freely as they are in their natural home. So they can be cultivated at super high density.

Salient feature of IPRS

Salient features of an IPRS are air-lift, bottom aeration, cells and waste collection arrangements that make this system unique ensuring optimal water chemistry that allows super high density stocking.

White water unit

This unit is the heart of IPRS located at the starting point of the race way.

Its main function is to circulate oxygenated water through the raceway.

In this unit a powerful air lift device or air blower is used that moves the water and passes through the raceway.

Thus water from outside continuously enters the raceway.

At the same time, it works for aeration.

As continuous water flow remains in the channels, fishes get a natural stream like environment so they enjoy spontaneous swimming and their health condition remains good.

Each air lift has a high power (2.2/2.5kw) blower.

With a highest 3kps pressure a blower can generate 230 cubic meter air flow.

There are more than 4 diffuser grids where tube aeration takes place.

In each cell air flow or water flow can be controlled individually thus oxygen supply in each cell is ensured.

This unit has a capacity to pass 15000-liter water per hour through a single cell or raceway that also helps to generate some plankton and beneficial bacteria.

Due to water current organic waste and other solids are accumulated in the waste channel or sludge unit located at the finishing line of the raceway.

Bottom aeration system

At the bottom of each cell there is a separate and independent aeration facility which is known as bottom aeration.

By this system along with horizontal aeration a vertical mixing also takes place that ensures booster aeration in the whole system which makes possible homogeneous water quality in all along the raceway.

High quality blower metal hose, PVC hose, bottom and aero tube aeration tubing are the parts of this system.

Waste collection system

This system acts as a toilet for the fishes where all waste is accumulating and mechanically removed.

This unit is also known as a sludge unit.

A cleaner made of stainless steel, hose and driving system are the main components of this system.

All waste derived from the raceway are accumulated in this unit and then periodically removed outside.

This waste can be used in agricultural crops as organic fertilizer.

Raceway/cell

These channels or cells made of concrete, permanently fixed at the bottom of the pond, are usually known as raceway.

Fish are stocked in these channels. Usually 3 raceways can be built in 2.0 ha pond area.

In Alabama, USA measurements of the raceways were 7.71m × 4.88m × 1.22m, in Egypt 12.0m × 3.0m ×1.5m, in Campeche, Mexico 5.0m × 25.0m × 1.2m and in Vietnam 25.0m × 5.0m × 2.0m. In our project this measurement is 25m× 5m× 2.5m.

Feeding system

To feed the fish demand or smart feeder is set at the outset of each raceway.

Feeding also can be done manually.

But auto feeding is better than manual feeding, as proper or homogeneous distribution of feed and proper hygiene only can be maintained by smart feeders.

Internet control system

Through the internet, control system implementation of all major activities including monitoring can be done.

Electricity system

Electricity is the lifeline of an IPRS.

It is a completely energy dependent technology.

As fishes are stocked in super high density so the total system can collapse if electricity fails even only for an hour.

So three layered energy supply security should be ensured.

In alternate electricity options oxygen supply is carried on so that emergency treatment can be done in case of diseases.

Because in this case water flow is stopped but oxygen supply remains uninterrupted.

As a result, if necessary medication is possible in treatment.

Besides these there are four powerful air lifts fixed at the four corners of the pond by which a gentle water flow is continued through the whole pond.

Some extra aerators are set up at suitable locations of the pond that supply continuous oxygen and remove noxious gases. 

Cultured species and production capacity

In IPRS of Auburn University, USA channel catfish (Ictalurus punctatus), blue catfish (Ictalurus furcatus), nile tilapia (Oreochromis niloticus) striped bass (Morone saxatilis) rainbow trout (Oncorhynchus mykiss) etc. were stocked.

They produced catfish up to 200kg/m³.

In some channels they stocked tilapia as co-species with catfish.

Tilapia consumes periphyton and unused food for catfish.

In 2008 they produced 20.58 metric ton/ha catfish plus tilapia 2.61Mton/ha.

Survival rate was 83.7%.

At present this technology has passed several generations and meanwhile it’s capability also has improved many folds.

In Mexico 57kg/m³ tilapia was produced in IPRS where survival rate was 86%.

In this way it was found that 69Mton/ha fish was produced where in normal pond only 30-35Mton/ha can be obtained.

So the capability of IPRS technology is promising.

In 2013 42 metric ton grass carp was produced in 3 channels in an IPRS established in 2.1ha pond in Jiangsu province, China which is much more than regular pond production.

Climate of Bangladesh including its soil and water quality is favorable for aquaculture so IPRS technology can open a new horizon in the aquaculture industry in Bangladesh.

IPRS technology in Bangladesh

Bangladesh is one of the leading countries in the world aquaculture industry.

Although in the past couple of decades significant development in aquaculture technology has taken place in different parts of the globe, Bangladesh is lagging far behind in this case.

Lack of progressive thoughtful entrepreneurs and hesitation of investment of financial institutions are the main bottlenecks behind it.

On the other hand, adverse impact of climate change, ever increasing population growth and such various causes, land and water scarcity gradually becoming worse, those also impact on our aquaculture industry.

In this hard time an advanced aquaculture farm Nawab Matshya Khamar located at Chapainawabganj district of northwest Bangladesh has come forward to receive this technology.

Having 42 ponds of 40ha this aquaculture farm obtained the National Fish Medal (silver) in 2018.

With the help of Chinese technology, a 13 channel IPRS has been installed in an 8.0ha pond.

A pilot phase has launched in July 2020. Due to Covid-19 pandemic equipments and machineries for IPRS from China were not received in time and the project implementation was delayed for at least 4 months.

Area of each channel is 22m × 5m × 2.5m.

The channels occupy 2.5% of the total project area.

This is the first in Bangladesh and largest IPRS in south Asia.

We have stocked Rui, Catla, Common Carp, Grass Carp, Pangas, Tilapia, and Pabda species of fish.

On the basis of trial specific fish species, depending on market demand will be stocked in future.

From the very beginning the Department of Fisheries (DoF) is providing technical and specialist expert support for this project.

DoF also assists in appointing technical manpower and providing training to improve their skill for the project.

They provide regular water quality monitoring and fish health management. DoF also helps for financing in this project.

The Department of Fisheries affirms to extend its all support to implement such a high tech aquaculture project in any area of the country.

Introduction of such an advanced technology in northwestern Chapainawabganj district can be considered as a golden milestone in aquaculture progress and mechanization in Bangladesh.

We have advanced one step forward in good aquaculture practice (GAP) which is an accreditation for our aquaculture industry.

We hope that in the near future many aquaculture entrepreneurs will come forward and implement IPRS technology.

Local and international consumers will have safe and pure Bangladeshi fish cuisine.

It also sounds that in near future Bangladesh can play a frontline role globally.

Advantages

·        Due to continuous water flow a stream like current exists in the whole pond. Fish always swims and remains healthy.

·        High productivity. Depending on species 50-200kg/m³ fish can be produced.

·        Better food conversion ratio FCR (1.1-1.3) can be achieved.

·        100% fish can be harvested with minimal water waste.

·        Water can be recycled thus optimum use of water can be ensured.

·        At the same time different types of fish species can be cultured in different channels. Stocking and harvesting can be done any time or staggered stocking and harvesting are possible that helps in marketing.

·        Minimal aqua medicine is needed so produced fishes are human heath friendly

·        Fish health management is comparatively easier

·        Around 70% of released nutrient through fish excreta can be removed from the system

·        Sustainable and environment friendly technology

·        Fish can be harvested quickly and mechanically with minimum labor

·        No off flavor, produced fishes taste and smell good

·        A climate smart technology in response to adaptation due to climate change impacts

Challenges

·        Primary investment is comparatively high that usually can’t be afforded by the fish farmers.

·        Knowledge based technology so full time expert consultation and skilled manpower is a prerequisite.

·        Energy dependent management. So if the power supply is interrupted even for a few minutes’ critical conditions can arise. Emergency and alternate electricity options must be facilitated. Without electricity back-up IPRS cannot be operated.

·        Seepage and evaporation can lower water depth and additional water may be required.

Conclusion

In case of high density aquaculture fish farmers face some general problems.

These are ammonia toxicity, large volume of water, water pollution, and disease.

Fish dwell in water, they feed in water and leave its excreta in the same water.

Hundreds of species of plankton, periphyton, nekton and neuston grow in that water. Also grow unicellular and multicellular microbes and parasites.

So in case of high density stocking to maintain ecological balance becomes the biggest challenge to a fish farmer.

IPRS technology can address these problems.

So considering climate change adaptation especially in a country like Bangladesh where land and water scarcity are always remaining in utmost consideration, climate smart IPRS technology can augment our aquaculture development meaningfully.

With the latest knowledge and technology may our farm become enlightened and quality producers, as well as kick poverty and unemployment to the museum at the corner of the city.

May this "Made in Bangladesh" product of ours spread all over the globe.

IPRS technology can open a new horizon in aquaculture development of Bangladesh 

The author is district fisheries officer at Chapainawabganj. He can be reached at amisan72@yahoo.com

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