Intensive shrimp aquaculture has been associated with environmental challenges such as water pollution and habitat degradation. However, an innovative approach known as Integrated Multi-Trophic Aquaculture (IMTA) offers a sustainable solution by combining the cultivation of different aquatic organisms in a synergistic manner.
A study published in Algal Research by scientists from the ICAR-Central Institute of Fisheries Education and the ICAR-Indian Agricultural Research Institute explored the potential of co-cultivating shrimp (Penaeus vannamei) with the seaweed Gracilaria foliifera. This co-culture strategy aimed to optimize shrimp production while mitigating environmental impacts. The researchers also examined the shrimp’s physiological responses in the IMTA system, including stress, serum profiles, and histological alterations.
The Promise of Integrated Multi-Trophic Aquaculture (IMTA)
IMTA is a promising approach to sustainable aquaculture, involving the cultivation of multiple species in a single system. By combining fed species like shrimp with unfed species such as seaweeds, IMTA can significantly reduce environmental impacts while enhancing overall productivity.
Seaweed: A Natural Solution
Seaweeds, a diverse group of marine algae, play a crucial role in IMTA systems. These marine plants efficiently absorb excess nutrients from the water, such as nitrogen and phosphorus, often released during shrimp farming operations. By removing these nutrients, seaweeds help improve water quality and reduce the risk of harmful algal blooms.
The Potential of Gracilaria
One particular species of seaweed, Gracilaria, has emerged as a promising candidate for IMTA systems. Gracilaria is known for its rapid growth rate, high biomass yield, and tolerance to a wide range of environmental conditions. Additionally, it has several commercial applications, including food, feed, and biofuel production.
The Study
The researchers conducted a series of experiments to evaluate the potential of seaweed-shrimp co-culture. Initially, they examined locally available seaweeds along the Maharashtra coast and selected Gracilaria foliifera for further study.
The seaweed was co-cultivated with Pacific white shrimp (Litopenaeus vannamei) in a zero-water exchange system to assess production performance and physiological responses.
Key Findings
Enhanced Nutrient Removal
G. foliifera demonstrated exceptional nutrient absorption efficiency, significantly reducing levels of ammonia, phosphate, nitrite, and nitrate in the water. The seaweed removed up to 64% of total ammonia nitrogen, 99.87% of phosphate, 32% of nitrite, and 13% of nitrate from shrimp wastewater.
The optimal population density for G. foliifera was determined to be 1–3.5 gL⁻¹ based on nutrient absorption efficiency.
Improved Shrimp Growth and Health
Co-cultivated shrimp exhibited higher growth rates, better feed conversion ratios, and lower stress levels compared to those reared in monoculture systems.
The researchers found that co-cultivating P. vannamei at 20 nos. m⁻² followed by 60 nos. m⁻² with G. foliifera at 3.5 gL⁻¹ yielded the highest average weight gain, specific growth rate, and production while improving water quality. The co-culture system also resulted in lower stress enzyme levels, reduced serum glucose and cholesterol, and normal histological observations in the hepatopancreas compared to monoculture.
Implications for the Shrimp Industry
The study’s findings highlight the potential of seaweed-shrimp co-culture for sustainable aquaculture. By carefully selecting compatible species and optimizing cultivation conditions, it is possible to create efficient, environmentally friendly aquaculture systems. Further research is needed to explore the economic viability and scalability of this approach, as well as to identify additional seaweed species with high nutrient removal potential and biomass production.
Adopting innovative practices such as seaweed-shrimp co-culture can ensure the long-term sustainability of aquaculture, meet the growing global demand for seafood, and protect marine ecosystems.
Conclusion
This study demonstrates the potential of co-cultivating seaweed with shrimp to address the challenges of intensive shrimp farming and promote sustainable aquaculture practices. The co-culture system not only improves water quality and reduces shrimp stress but also provides a valuable nutritional resource and helps mitigate coastal pollution.
The findings suggest that co-cultivating P. vannamei at 60 nos. m⁻² with G. foliifera at 1–3.5 gL⁻¹ is a superior approach that can be sustainably implemented without compromising productivity and physiological responses.
As the world continues to tackle sustainable aquaculture challenges, the potential of seaweed-shrimp co-culture offers a promising solution aligned with the United Nations Sustainable Development Goals.
Contact
Madhuri S. Pathak
Aquaculture Division, ICAR-Central Institute of Fisheries Education
Andheri (W), Mumbai 400 061, Maharashtra, India
Email: madhuri@cife.edu.in
Reference
Harini, G., Pathak, M. S., Munilkumar, S., Sukhdhane, K. S., Chanu, T. I., Balange, A. K., & Jeena, K. (2024). Unlocking synergies: Enhancing bioremediation, growth, and physiological responses of Penaeus vannamei co-cultured with seaweed. Algal Research, 103816. https://doi.org/10.1016/j.algal.2024.103816
