GB/T 20556-2026Swimming crab (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents". Drafting. This document replaces GB/T 20556-2006 "Portunus trituberculatus". Compared with GB/T 20556-2006, the main differences are structural adjustments and editorial changes. Aside from the modifications, the main technical changes are as follows:

a) The "classification status" has been changed (see 4.2,

3.2 in the.2006 edition);

b) The section on "Distribution and Ecological Habits" (see Chapter 4 of the.2006 edition) has been removed;

c) The external morphology description has been changed (see 5.1,.2006 edition 5.1);

d) The measurable characteristics have been modified (see 5.3,.2006 version 5.3), and corresponding detection methods have been added (see 8.1.3);

e) The wording for "growth" has been changed (see 6.1,.2006 edition 6.1);

f) The content regarding egg production has been removed, and the range for the number of eggs carried has been expanded (see 6.2.3,

6.2.4 in the.2006 edition);

g) Breeding water temperature has been removed (see

6.2.5 in the.2006 edition);

h) The section on "Biochemical and Genetic Characteristics" (see Chapter 7 of the.2006 edition) and the corresponding detection methods (see

9.2 of the.2006 edition) have been deleted;

1 Scope

GB/T 20556-2026 is the Chinese national standard covering the Chinese swimming crab as a farmed and traded product - the size and weight grades, the shell condition and fullness, the vigour of a live animal and the freshness criteria. It replaces GB/T 20556-2006 and has been in force since 1 September 2026. It was issued on 27 February 2026 and has been in force since 1 September 2026, replacing GB/T 20556-2006. The document is under the responsibility of the Ministry of Agriculture and Rural Affairs. This page is published from the official record of the 2026 edition; the clause text of a standard this recent is not yet in circulation, and the figures, limits and tables it contains are those of the document itself, delivered in full with the English translation.

The study describes the structural characteristics, growth and reproduction features, molecular genetic characteristics, and judgment rules, and outlines the corresponding detection methods. This document applies to the germplasm identification and testing of the swimming crab (Portunus trituberculatus).

5 Main morphological and structural characteristics

5.1 External Form The cephalothorax is fusiform with three wart-like projections; the dorsal surface is mostly tea-green, yellowish-brown, or purplish-red, while the ventral surface is grayish-white; the anterior lateral margin is oblique. Arched, longer than the posterior lateral margin; the cephalothorax has nine serrated teeth on each of the two anterior lateral margins, with the ninth serration being particularly long and large; the chelipeds are well-developed, with the meristem prismatic in shape, internally... The margins have blunt teeth; the dorsal surface of the chelipeds is purple with grayish-white spots; the first three pairs of walking legs are blue with purple dactyls; the fourth pair of walking legs has flattened and broad metacarpals and dactyls. Thin; flat abdomen, male crabs have a triangular or bell-shaped navel, while female crabs have a semi-circular or semi-elliptical navel. The external morphology of the three-spined swimming crab is shown in Figure 1.

6 Growth and Reproduction Characteristics

6.1 Growth The process involves a series of molts, resulting in intermittent growth. After molting, the animal's weight and size increase significantly within a short period.

9 Judgment Rules

9.1 When the test results meet the requirements of Chapter 5, the species can be identified.

9.2 When the following situations occur, additional testing requirements from other chapters should be added, and a comprehensive determination of the species should be made based on the test results.

a) If Chapter 5 cannot be detected or accurately determined, add the content from Chapter 7;

b) When a third party requests testing of all or part of Chapter 6;

c) During full-item testing. GB/T 20556-2026. Portunus trituberculatus ICS

51 National Standards of the People's Republic of China Replaces GB/T 20556-2006 swimming crab Published on 2026-02-

27 Implemented on 2026-09-

01 State Administration for Market Regulation The State Administration for Standardization issued a statement.