* By Aquaculture Magazine Editorial Team
Aquaculture is expanding rapidly to meet the increasing global demand for fish while preserving natural stocks. However, challenges like disease outbreaks and environmental impact threaten sustainability. A promising solution is the polyculture of Genetically Improved Farmed Tilapia (GIFT) and Penaeus vannamei using Biofloc Technology. This method enhances water quality, optimizes resource utilization, and reduces pathogen pressure, creating a more sustainable and resilient aquaculture system; making aquaculture a viable solution for global food security
Aquaculture is a rapidly growing sector, contributing to global food security and livelihoods. India ranks second in aquaculture production with shrimp and fish farming playing vital role. However, challenges like protein loss, water pollution, and reliance on fishmeal demand sustainable solutions. Biofloc technology and polyculture offer ecoriendly alternatives.
Penaeus vannamei shrimp, known for high feed efficiency and disease resistance, thrive in polyculture with polyculture of Genetically Improved Farmed Tilapia (GIFT), a resilient omnivorous species. Their complementary feeding habits enhance resource utilization, improve water quality, and boost sustainability. Polyculture optimizes production by recycling nutrients, reducing costs, and creating a balanced ecosystem for aquaculture growth.
Fisheries and Aquaculture Scenario
Aquaculture is a rapidly growing sector that plays a crucial role in global food security. Despite advancements, hunger affects 811 million people, and 3 billion cannot afford a healthy diet. Aquaculture provides essential food and livelihoods to 820 million people worldwide. India ranks third in global fish production, contributing 8% of total production and second in aquaculture output.
In 2020, global aquaculture production reached 122.6 million tons, including fish, mollusks, and crustaceans. The consumption of aquatic foods has grown at an annual rate of 3% since 1961 to 2019, double the global population growth rate (1.6%) for the same period. Per capita consumption of aquatic animal foods grew by about 1.4% year, from 9.0 kg in 1961 to 20.2 kg in 2020.
Challenges in Aquaculture
Aquaculture is the culture of aquatic organisms. People have been involved in different forms of aquaculture for thousands of years. Today, the practice of aquaculture spans the globe. Many of the basic goals have not changed significantly in aquaculture: maximizing growth rate and minimizing production cost. A rapid growth rate minimizes the time to achieve a marketable size and decreases risk. Aquaculture faces challenges such as nutrient loss, water pollution, and dependency on fish meal and oil.
Only 24%-37% of nitrogen and 13%-28% of phosphorus in aquaculture feed are converted into biomass, while the rest is released as waste, affecting water quality and causing diseases. Frequent water exchange is required to maintain quality but contributes to environmental pollution. Additionally, the increasing demand for alternative protein and oil sources poses economic and environmental challenges.
Technological Solutions for Sustainable Aquaculture
To mitigate these issues, technologies such as biofloc, polyculture, raceway systems and lined pond culture system have been developed.
Biofioc technology (BFT)
Biofloc technology is a sustainable aquaculture method based on dense microbial communities that reduce toxic metabolites and convert waste into microbial biomass, which serves as food. This technology improves water quality, prevents diseases, and reduces feed costs. It is implemented by adjusting the carbon/nitrogen ratio and maintaining constant aeration.
Proper biofloc management prevents the accumulation of organic matter and maintains a balance between beneficial microorganisms. BFT has been successfully applied to species like tilapia and shrimp, enhancing feed conversion and reducing ammonia and nitrite toxicity.
Polyculture aquaculture
Polyculture is a traditional fish farming practice; where compatible species with different feeding habits were stocked in a single-pond for grow out practice to effectively increase production. Polyculture involves the simultaneous farming of compatible species with different feeding habits to optimize resource utilization and improve water quality.
In monoculture, excess nutrients accumulate, degrading water quality, whereas polyculture allows one species to consume the waste of another. The combination of tilapia and P. vannamei shrimp is particularly efficient: shrimp feed on detritus and organic waste, while tilapia filter phytoplankton, reducing the risk of nighttime hypoxia.
Additionally, shrimp bioturbation recycles nutrients and promotes phytoplankton production. Some authors affirmed that shrimp culture has severely affected the ecosystem and concluded that integrated aquaculture practices, such as polyculture, are good alternatives for reducing contamination (Table 1).
Raceway systems
The aquaculture term “raceway” is a highly generic name and implies little more than a water impoundment with water flowing through it. Raceways are continuous-flow water channels designed for intensive aquatic organism production. The water flow removes solids and dissolved waste, reducing effluent discharge.
This technology improves water quality and minimizes environmental pollution, making it a viable solution for intensive aquaculture. Raceway could potentially address the major challenges associated with the aquaculture effluent production.
Lined pond culture system
Earthen ponds are conventionally used for fish farming with some boundaries like continuous water seepage; complications with soilwater chemistry haven’t been understood with difficulties in determining the causes of physio chemical parameters related problems and organic load accretion.
Growth Performance and Water Quality in Biofloc
Hence, lining the ponds with High Density Polyethylene (HDPE) sheets has many advantages like reducing seepage, reducing pumping cost, complications due to soil-water interactions can be prevented and for undertaking advanced farming practices are more appropriate. The initial investment will be largely compensated by the huge advantages in terms of net profit. Lining materials should be long lasting and cost effective.
Biofloc systems enhance water quality by minimizing ammonia and nitrites, stabilizing pH, and reducing water exchange requirements. The adjusted carbon/nitrogen ratio in biofloc facilitates ammonia assimilation by heterotrophic bacteria. Research has shown that BFT improves feed efficiency and water quality in species like tilapia, shrimp, and carp.
Additionally, this technology reduces operational costs and environmental impact. BFT is one of such novel microbial biotechnologies that have been developed with an excellent ecofriendly technology not only for higher productivity but also for sustainable development (Table 1).
History and Status of Penaeus vannamei and GIF Tilapia
Penaeus vannamei is the most farmed shrimp species globally due to its adaptability and rapid growth. Its production reached 5.8 million tons in 2020, generating over USD 33 billion annually. It is widely cultivated in Latin America, China, India, and Southeast Asia.
GIF Tilapia is a selectively bred strain of Oreochromis niloticus developed by the World Fish Centre. This lineage has demonstrated an 85% improvement in growth rate after multiple generations of selection. In many countries, tilapia is co-farmed with shrimp in polyculture systems to enhance water quality and increase productivity.
Impact on Production and Water Quality
The use of biofloc and polyculture improves water quality by reducing organic waste and dissolved nutrients. Key parameters such as dissolved oxygen, pH, and alkalinity stabilize in these systems, reducing the need for water exchange. Additionally, microbial activity in biofloc degrades waste and enhances feed efficiency in fish and shrimp.
Growth and Digestive Enzymes in Biofloc
Biofloc systems stimulate digestive enzyme activity in farmers species, improving feed conversion and growth. Studies have shown that incorporating biofloc into diets enhances protease and amylase activity in tilapia and shrimp, optimizing digestibility and reducing reliance on fish meal,
Inmmunity and Microbiota in Biofloc
Consuming biofloc improves the immune response of shrimp and fish, increasing resistance to diseases. The bacterial diversity in these systems promotes the competitive exclusion of pathogens, creating a healthier pond environment. Studies have found that species such as Bacillus and Lactobacillus in biofloc contribute to protection against bacterial infections in aquaculture,
Conclusion
The combination of biofloc and polyculture represents a sustainable and profitable strategy for aquaculture. These technologies optimize resource use, reduce pollution, and improve feed efficiency. Their adoption can transform the aquaculture industry into a more environmentally friendly and economically viable model.
This informative version of the original article is sponsored by: REEF INDUSTRIES INC
This is a summarized version developed by the editorial team of Aquaculture Magazine based on the review article titled “POLYCULTURE OF GENETICALLY IMPROVED FARMED TILAPIA (GIF TILAPIA) AND PENAEUS VANNAMEI USING BIOFLOC TECHNOLOGY–A REVIEW)” developed by: JOSHNA, M., AHILAN, B., CHERYL A., RAVANESWARAN, K., CHIDAMBARAM, P., UMA, A., and RUBY, P. ─ Tamil Nadu Dr. J. Jayalalithaa Fisheries University. The original article, including tables and figures, was published on JULY, 2024, through INTERNATIONAL JOURNAL OF BIORESOURCE AND STRESS MANAGEMENT. The full version can be accessed online through this link: DOI: https://doi.org/10.23910/1.2024.5396
