Quzhou, Zhejiang province, has introduced a quality grading and evaluation system for Qingshui fish, giving consumers clearer criteria for selecting locally raised fish and supporting upgrades in aquaculture.

Qingshui fish are grass carp raised in extremely high-quality waters in Quzhou.

The system divides Qingshui fish into three grades: premium, superior, and first grade. The grade is based on flavor and nutrition, including geosmin, 2-methylisoborneol, crude protein, crude fat, DHA, EPA, and amino acids.

Applicants must have no record of excessive fishery drug residues over the previous year. Samples in which geosmin, a major contributor to earthy or muddy odors in fish, is detected are excluded from the grading process.

Fresh flesh of Qingshui fish. [Photo/Sanqu App]

This year, 32 aquaculture operators applied for the evaluation, and 30 completed sample submissions. The applicants recorded a 100 percent compliance rate in fishery drug residue testing. Of the submitted samples, three were rated premium, eight superior, and seven first grade.

The evaluation results apply only to the batches tested and do not represent all products from an operator.

The city will establish a dynamic list of qualified operators, conduct regular quality testing, and improve product traceability.