Green development is not an optional choice, but an obligatory task.
The newly revised Fisheries Law came into force on May 1, 2026. Establishing green development as a fundamental principle, the legislation sets the directional tone for aquaculture policies in the years ahead. Among all provisions, the clear regulatory requirements for aquaculture effluent treatment attract the greatest attention from fish farmers.
Legal Red Lines: Key Provisions You Must Know
Article 27 of the new Fisheries Law stipulates clearly: Anyone engaged in aquaculture shall protect the ecological environment of water areas and tidal flats, scientifically determine breeding density and scale, apply feed and veterinary drugs rationally, and ensure discharged aquaculture effluent complies with pollutant discharge standards, so as to avoid water pollution and ecological damage to water areas and tidal flats.
Article 80 lays out punitive measures: Those who use prohibited feed, feed additives, veterinary drugs or other toxic and harmful substances in aquaculture, transportation or sales; construct or expand sewage outlets within aquatic germplasm resource reserves; or cause ecological damage to fishery waters or fishery pollution incidents shall be penalized in accordance with relevant laws and administrative regulations on agricultural product quality safety, food safety and ecological environmental protection.
Three-Tier Effluent Control Framework with Escalating Standards
China has built a three-tier effluent governance system covering national, provincial and municipal authorities with increasingly stringent technical requirements：
National Level：
The Technical Guidelines for Formulating Local Discharge Standards of Water Pollutants from Aquaculture Industry, issued by the Ministry of Ecology and Environment, took effect on March 1, 2023. It guides provincial administrative regions to formulate differentiated local pollutant discharge standards tailored to regional conditions.
Provincial Level：
All provinces, autonomous regions and municipalities directly under the Central Government formulate targeted standards pursuant to the Water Pollution Prevention and Control Law and Measures for the Administration of Ecological Environment Standards. Provincial governments shall formulate local ecological environment quality standards, ecological risk control standards and pollutant discharge standards, and submit them to the competent ecological and environmental authority under the State Council for filing.
Municipal Level：
Prefecture-level cities enact local regulations or administrative measures to refine implementation rules for provincial standards, translating technical specifications into actionable management measures.
Five Mandatory Control Indicators, with Local Governments Allowed to Impose Extra Limits
The Technical Guidelines specifies five mandatory basic monitoring indicators for aquaculture effluent: suspended solids, pH value, chemical oxygen demand, total phosphorus and total nitrogen. Beyond these five core metrics, local authorities may add supplementary control items including 5-day biochemical oxygen demand (BOD5), ammonia nitrogen (for freshwater discharge), inorganic nitrogen (for seawater discharge), active phosphate (for seawater discharge), color and odor, heavy metals, antibiotics, and other indicators required for regional water quality improvement.
In short, standards will grow more detailed and supervision will grow tighter over time.
Prior to the implementation of the revised Fisheries Law, local effluent discharge standards only served as quantitative benchmarks lacking superior legal support. After the law took effect, local standards carry legal binding force and will be enforced rigorously.
For aquaculture farmers, legal and sustainable green farming is no longer an elective extra, but a mandatory requirement critical to survival and long-term growth.
Varying Difficulty Levels of Pollutant Treatment
Based on practical aquaculture experience, the technical difficulty of treating each indicator ranks from highest to lowest as follows:
😱Most challenging: Total Nitrogen (TN)
Excessive TN mainly originates from feed protein and aquatic metabolic waste, with overshoots potentially reaching 10 times the standard limit. Natural plant absorption and volatilization exert negligible reduction effects, making TN treatment extremely difficult. The core solution lies in regulating the carbon-nitrogen ratio and removing nitrogen via aerobic nitrification and anaerobic denitrification processes — the top priority of effluent treatment systems.
😥Moderate difficulty: Total Phosphorus (TP)
TP primarily comes from phosphorus-containing feed ingredients and aquatic metabolites, with relatively mild standard violations. Sedimentation, flocculation and aquatic plant absorption can readily bring TP within compliance limits.
😐Conventional indicators: Suspended Solids, COD, pH
Suspended solids: Easily controlled through sedimentation, filtration and regular sludge dredging.
COD: Effectively eliminated via aeration, aquatic vegetation and microbial decomposition.
pH: Naturally maintained within acceptable ranges in standard aquaculture water, requiring minimal additional treatment.
Practical Solution: "Three Ponds and Two Dams" Model plus Systematic Management
Promoted nationwide by the National Fisheries Technology Extension Center, the green aquaculture model of "Three Ponds and Two Dams" adopts a sequential treatment flow: sedimentation pond → filter dam → aeration pond → filter dam → ecological purification pond. Multi-stage physical sedimentation, filtration interception and biological purification work in tandem to ensure compliant effluent discharge. The treatment facilities occupy approximately 10% of the total aquaculture area.
Complementary supporting measures for farmers in addition to the building of treatment facilities:
✅ Adopt low-phosphorus, low-protein, high-digestibility aquafeed
✅ Implement precise, rational feeding to reduce residual feed
✅ Conduct regular sludge dredging and limit organic fertilization input
✅ Deploy filter-feeding fish and cultivate submerged aquatic plants
Rough cost estimates: Constructing the Three Ponds and Two Dams system for effluent treatment increases farming costs by RMB 300–400 per mu per year in core breeding zones subject to strict standards, equivalent to an extra production cost of RMB 0.1–0.3 per jin of market-ready aquatic products.
Green Transition: First Movers Reap the Rewards
The revised Fisheries Law is not a shackle restricting the industry, but a banner signaling a pivotal shift toward balanced development of product quality and ecological protection. While effluent governance raises short-term operating costs, it serves as a profound upgrade to strengthen core competitiveness.
This explains why Tongwei persists in sourcing high-quality fishmeal and developing low-phosphorus, low-protein, high-absorption green feed with precise formula design, even amid drastic price hikes of raw materials including fishmeal and soybean meal. This commitment not only maximizes farmers’ economic returns, but also embodies a long-term promise: stable raw material supply guarantees consistent feed quality, and eco-friendly practices safeguard shared clear waters and blue skies.
The future of aquaculture belongs to forward-thinking practitioners who pursue harmonious coexistence with the ecological environment.