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GB 21047-2007Red drum (English PDF)

眼斑拟石首鱼

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Issued by

State Administration for Market Regulation

Level / Type

National · Mandatory

Issue date

February 27, 2026

Implementation date

September 1, 2026

Scope

GB 21047-2007 is the English-translated version of 眼斑拟石首鱼.

GB 21047-2007 — The characteristics, growth and reproduction properties, cytogenetic properties, molecular genetic properties, and judgment rules are described, along with the corresponding detection methods.

This document applies to the germplasm identification and testing of the spotted totoaba.

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Document preview — GB 21047-2007

National Standard of the People's Republic of China

ICS: 65.150
Classification: B 51
Replacing: GB/T 21047-2007

Issued by: State Administration for Market Regulation

Foreword
1 Scope
4 Scientific name and classification
4.1 Scientific name
4.2 Classification
5 Main morphological and structural characteristics
5.1 External Form
5.2 Internal Structure
6 Growth and Reproduction Characteristics
6.1 Growth
6.2 Reproduction
7 Cytogenetic characteristics
7.1 Number of chromosomes
7.2 Karyotype
8 Molecular genetic characteristics
9 Detection Methods
9.1 Sampling
9.2 Main Morphological and Structural Characteristics
9.3 Growth and Reproduction Characteristics
9.4 Cytogenetic characteristics
9.5 Molecular genetic characteristics
10 Judgment Rules
Foreword

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 21047-2007 "Eye-spotted Sciaenia". Compared with GB/T 21047-2007, the only changes are structural adjustments and editing.

Aside from the sexual alterations, the main technical changes are as follows.

a) The "Category" has been changed (see 4.2, 3.2 in the 2007 edition);

b) The formula relating fork length (weight) to growth time and the measured values of body length and weight for different age groups have been removed (see section 5.2 of the 2007 edition);

c) The measurable and countable traits have been modified (see 5.1.2 and 5.1.3, and 4.1.2 and 4.1.3 in the 2007 edition);

d) The formula for the relationship between body length and weight has been modified (see 6.1, 5.3 in the 2007 edition);

e) The "age of sexual maturity" has been changed (see 6.2.1, 6.1 in the 2007 version);

f) "Sexual maturity and body length" has been removed (see 6.2 in the 2007 edition);

g) The term "smallest biological size" has been changed (see 6.2.2, 6.3 in the 2007 edition);

h) The "fertility rate" has been changed (see 6.2.5, 6.5 in the 2007 version);

i) The section on "Biochemical and Genetic Characteristics" (see Chapter 8 of the 2007 edition) and the corresponding detection methods (see 9.3 of the 2007 edition) have been removed;

j) A section on "Molecular Genetic Characteristics" and corresponding detection methods has been added (see Chapter 8 and Appendix A);

k) Added a detection method for "growth and reproductive characteristics" (see 9.3);

l) The "Judgment Rules" have been changed (see Chapter 10, Chapter 10 of the 2007 edition).

Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.

This document was proposed by the Ministry of Agriculture and Rural Affairs of the People's Republic of China.

This document is under the jurisdiction of the National Technical Committee on Fisheries Standardization (SAC/TC156).

1 Scope

The characteristics, growth and reproduction properties, cytogenetic properties, molecular genetic properties, and judgment rules are described, along with the corresponding detection methods.

This document applies to the germplasm identification and testing of the spotted totoaba.

4 Scientific name and classification

4.1 Scientific name

4.2 Classification

Phylum Chordata, Subphylum Vertebrata, Class Osteichthyes, Order Perciformes (Perciformes), family Sciaenidae, subfamily Sciaenopinae, genus Sciaenops.

5 Main morphological and structural characteristics

5.1 External Form

5.1.1 Appearance

The fish has a spindle-shaped, laterally compressed body with a slightly convex back and a medium-sized head. The mouth is subanterior or subinferior, with a relatively large mouth cleft and small, sharp, closely spaced teeth.

There are two pairs of nostrils; the first pair is short and tubular or round and smaller, while the second pair is oval and slightly larger. The eyes are positioned superiorly and laterally, with the posterior margin level with the end of the mouth, and are of medium size.

Size, located on both sides of the head. Positive tail, with one or more black spots at the base of the caudal peduncle or on the side of the body.

The appearance of the spotted totoaba is shown in Figure 1.

5.1.3 Countable traits

5.1.3.1 Fin-type

Dorsal fin. D. IX~X, I-21~26.

Pectoral fins. P.15~18.

Pelvic fin formula. V.I-5.

Anal fin fin formula. A.I~II-8~9.

Caudal fin formula. C.17.

5.1.3.2 Scale-like

7~10-A51

5.1.3.3 Number of gill rakers

There are 21 to 25 gill rakers on the outer side of the first gill arch on the left.

5.2 Internal Structure

5.2.1 Vertebrae

25 pieces.

5.2.2 Swim Bladder

It is long and bag-shaped, with a short angular tube protruding outward from both sides of the front part. The inner wall of the swim bladder is smooth and without septa, and it has one chamber.

6 Growth and Reproduction Characteristics

6.1 Growth

The relationship between body length and weight of the eye-spotted croaker (2.10cm~55.17cm) is shown in equation (1).

6.2 Reproduction

6.2.1 Age of sexual maturity

The female fish is 4 years old, and the male fish is 2 years old.

6.2.2 Smallest biological size

The male harpoon is 51.10cm long and weighs 2350.00g; the female harpoon is 59.80cm long and weighs 3430.00g.

6.2.3 Breeding season

Spawning season is generally from September to November, with spawning water temperatures ranging from 23°C to 28°C.

6.2.4 Spawning type

Batch-laying type.

6.2.5 Fecundity

Absolute fertility. 5.0 × 104 eggs to 3.5 × 106 eggs.

6.2.6 Properties of the egg

The eggs are buoyant, spherical, and 0.86 mm to 1.08 mm in diameter.

7 Cytogenetic characteristics

7.1 Number of chromosomes

Somatic cell chromosome number. 2n=48.

7.2 Karyotype

The karyotype formula is 2n=48t, and the number of arms NF=48.The chromosome karyotype is shown in Figure 2.

8 Molecular genetic characteristics

The base sequence of the mitochondrial COI gene fragment (652 bp).

CCTCTACCTA GTTTTCGGTG CATGAGCCGG AATAGTAGGC ACAGCCTTAA GCCTTCTAAT 60 CCGAGCAGAA CTAAGTCAGC CCGGTGCACT CCTCGGAGAT GACCAAATTT ATAACGTAAT 120 TGTTACGGCG CATGCCTTCG TTATAATTTT CTTTATAGTA ATGCCCATTA TGATTGGAGG 180 TTTCGGGAAC TGACTCGTAC CCTAATGAT TGGAGCCCCC GACATGGCAT TCCCCCGAAT 240 AAATAATATG AGCTTCTGGC TTCTTCCCCC ATCTTTCCTT CTTCTCCTTA CCTCCTCAGG 300 TGTAGAGGCA GGGGCCGGAA CAGGATGAAC AGTTTACCCT CCACTCGCCG GAAACCTTGC 360 ACACGCAGGA GCTTCCGTCG ACTTAGCCAT CTTTTCCCTC CACCTCGCGG GTGTTTCATC 420 AATTCTGGGG GCCATTAACT TTATCACAAC AATCATTAAC ATAAAACCCCCCGCTATTTC 480 CCAGTATCAG ACACCTTTTAT TTGTATGAGC TGTATTAATT ACAGCCGTTC TTCTACTTCT 540 ATCCCTCCCT GTCTTAGCTG CCGGCATTAC AATACTCCTG ACAGACCGCA ACCTCAATAC 600 AACCTTCTTC GACCCAGCAGGAGGGGGAGA CCCGATCCTC TACCAACATC TG 652 Intraspecific K2P (Kimura2-parameter) genetic distance should be less than 2%.

9 Detection Methods

9.1 Sampling

Perform in accordance with the provisions of GB/T 18654.2.

9.2 Main Morphological and Structural Characteristics

9.2.1 External Form

Perform according to the method in GB/T 18654.3.

9.2.2 Internal Structure

After dissecting the fish, visual observation and counting were performed.

9.3 Growth and Reproduction Characteristics

9.3.1 Growth

Body length and weight were measured according to GB/T 18654.3, and the relationship between body length and weight was performed according to GB/T 18654.4.

9.3.2 Age

The procedure was performed according to GB/T 18654.4, and the material being identified was otoliths.

9.3.3 Reproduction

9.3.3.1 Age of sexual maturity

Adult fish that have reached sexual maturity for the first time are examined under a microscope for their gonads. After determining their age according to the provisions of 9.3.2, sex chromosomes of female and male fish are obtained separately.

Mature age.

9.3.3.2 Smallest biological size

Take sexually mature fish and measure their minimum fork length and weight according to GB/T 18654.3.

9.3.3.3 Breeding season

It is determined by regularly observing the development of the gonads.

9.3.3.4 Gestational Value

The determination was performed according to the method of GB/T 18654.6.

9.4 Cytogenetic characteristics

Test according to the method of GB/T 18654.12.

9.5 Molecular genetic characteristics

Test according to the method in Appendix A.

10 Judgment Rules

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

10.2 When the following situations occur, it is necessary to add the requirements of other chapters for testing, and make a comprehensive judgment on the species based on the test results.

a) When Chapter 5 cannot be tested or accurately determined, or when a third party requests it, add testing to Chapter 7 or/and Chapter 8.

content;

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

c) During full-item testing.

GB/T 21047-2026. Eye-spotted Totodactylus ICS 65.150 CCSB 51 National Standards of the People's Republic of China Replaces GB/T 21047-2007 Eye-spotted Totodactylus Published on 2026-02-27 Implemented on 2026-09-01 State Administration for Market Regulation the State Administration for Standardization issued a statement.