How are fish and shellfish graded?

Fish and shellfish are graded based on various criteria, including size, appearance, freshness, and texture. The grading systems often involve visual inspections, where factors like color, odor, and the presence of defects are evaluated. For fish, categories like U.S. Grade A, B, or C may be used, while shellfish may be graded based on meat yield and quality. These grades help consumers and retailers make informed choices about quality and safety.