U.S. Department of the Interior

U.S. Geological Survey

Data Series 239

Early Development of Four Cyprinids Native to the 

Yangtze River, China
Cover:  Selected early developmental stages of grass carp (Yi and others, 1988)
Early Development of Four Cyprinids 

Native to the Yangtze River, China

Edited by Duane C. Chapman

Chapter 1

Notes on the Translation and Use of “A Study of the Early 

Development of Grass Carp, Black Carp, Silver Carp, and 

Bighead Carp in the Yangtze River, China”

By Duane C. Chapman and Ning Wang

Chapter 2

A Study of the Early Development of Grass Carp, Black Carp, 

Silver Carp, and Bighead Carp in the Yangtze River, China

By Bolu Yi, Zhishen Liang, Zhitang Yu, Renduan Lin, and Mingjue He

Data Series 239

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2006

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Suggested citation:

Chapman, D.C., ed., 2006, Early development of four cyprinids native to the Yangtze River, China: U.S. Geological 

Survey Data Series 239, 51 p. 
Volume Contents

Chapter 1: Notes on the Translation and Use of “A Study of the Early Development of Grass

Carp, Black Carp, Silver Carp, and Bighead Carp in the Yangtze River, China”....................1

by Duane C. Chapman and Ning Wang

Chapter 2: A Study of the Early Development of Grass Carp, Black Carp, Silver Carp, and

Bighead Carp in the Yangtze River, China ................................................................................ 11

by Bolu Yi, Zhishen Liang, Zhitang Yu, Randuan Lin, and Mingjue He

Conversion Factors 

SI to Inch/Pound

Multiply By To obtain

Length

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

meter (m) 1.094 yard (yd) 

Area

square meter (m2) 0.0002471 acre 

square kilometer (km2) 247.1 acre

square centimeter (cm2) 0.001076 square foot (ft2)

square meter (m2) 10.76 square foot (ft2) 

square kilometer (km2) 0.3861 square mile (mi2)
Page intentionally blank 
Notes on the Translation and Use of 

“A Study of the Early Development of 

Grass Carp, Black Carp, Silver Carp, and 

Bighead Carp in the Yangtze River, China”

By Duane C. Chapman and Ning Wang

Chapter 1 of

Early Development of Four Cyprinids Native to the Yangtze River, 

China

Edited by Duane C. Chapman

Data Series 239-1

U.S. Department of the Interior

U.S. Geological Survey
Contents

Abstract...........................................................................................................................................................3

Introduction.....................................................................................................................................................3

Geographical and Historical Context .........................................................................................................3

Comments on the Translation and Use of the Document........................................................................5

Terms and conventions.................................................................................................................................5

Distinguishing Larvae of Grass, Black, Silver and Bighead Carps from other Riverine Species

of Central North America................................................................................................................6

Acknowledgements.......................................................................................................................................8

References Cited............................................................................................................................................8

Figures

1.  Map showing location of the Yangtze River in China .............................................................4

2.  Illustration showing grass carp larva, showing myomere number and difference in

carp larvae myomere count methods between China and North America .......................6

3–4. Photographs showing­—

3. Ventral view of grass carp at three different early developmental stages ........................7

4.  Melanophores on the preanal and postanal fin folds of bighead carp and silver carp ...8

Suggested citation: 

Chapman, D.C., and Wang, N., 2006, Notes on the translation and use of “a study of the early development of grass 

carp, black carp, silver carp, and bighead carp in the Yangtze River, China,” chap. 1 of Chapman, D.C., ed., Early development of four cyprinids native to the Yangtze River, China: U.S. Geological Survey, Data Series 239, p. 1–9.
Chapter 1

Notes on the Translation and Use of “A Study of the Early 

Development of Grass Carp, Black Carp, Silver Carp, and 

Bighead Carp in the Yangtze River, China”

By Duane C. Chapman and Ning Wang

Abstract

The document, “A Study of the Early Development of 

Grass Carp, Black Carp, Silver Carp, and Bighead Carp in the 

Yangtze River, China” (Chapter 2 of this volume), contains the 

most detailed description available of the early development 

of the subject fishes. This chapter is designed to place that 

translation into the appropriate context for the benefit of the 

North American scientist. We describe the historical context 

in which the data were collected. We also provide direction 

on the use of the translation, including a description of the 

Chinese morphometric conventions, which differ from those 

used by North American scientists. Lastly, we provide 

information on how the larvae of the subject fishes, which 

are now established in the Mississippi River Basin, may be 

differentiated from other fishes present in the basin.

Introduction

The document, “A Study of the Early Development of 

Grass Carp, Black Carp, Silver Carp, and Bighead Carp in the 

Yangtze River, China” (Yi and others, 1988a), provides the 

best existing comparative description of the early life stages 

of these fishes. Although the document was developed to 

address these fishes in their native range, we now require 

the ability to accurately identify these Asian fishes in North 

America. Non-native grass carp (Ctenopharyngodon idella), 

silver carp (Hypophthalmichthys molitrix), and bighead carp 

(H. nobilis) are established in the Mississippi River and its 

tributaries, including the Ohio, the Missouri, and the Illinois 

Rivers (Kolar and others, in press), and are considered 

invasive. The Mississippi Interstate Cooperative Resource 

Association (MICRA), a consortium of 28 state natural 

resource departments, considers bighead and silver carps 

the most important aquatic nuisance species in the basin. In 

addition, several black carp (Mylopharyngodon piceus) have 

been captured from the basin and this species may also be 

established in North America (Nico and others, 2005). 

A national plan for the management and control of these 

invasive carps (Wilson, 2006) indicates a need for further 

investigations into their life history requirements and 

chronology of development. Many of the studies will require 

the identification of the larvae and juveniles; this translation 

is designed to aid in those studies.

In this chapter we provide (1) the geographical and 

historical context of Yi and others (1988a), (2) comments on 

the translation of the document and its use by North American 

scientists, including explanations of the myomere and fin-ray 

numbering conventions used, which differ from North 

American conventions currently in place, and (3) some short 

notes that may be useful to scientists endeavoring to distinguish the early developmental stages of grass, black, silver, 

and bighead carps from those of other fishes resident in the 

Mississippi River Basin of North America.

Geographical and Historical Context

The Yangtze River (fig. 1), also known as the Changjiang 

River in China, is over 6,000 km long; it is the longest river 

in Asia and the third longest in the world. It drains a watershed of over 1,700,000 km2

. The headwaters are in eastern 

Tibet within the Dangla Mountains. The river flows through 

eastern Qinghai Province and turns southward towards Yunnan 

province, dropping in altitude from above 5,000 m to less than 

1,000 m. It reaches the basin of Sichuan at Yibin. The river 

then passes through the famous Three Gorges between the 

city of Chongqing and Hubei province. The Yangtze River 

continues through Jiangxi, Anhui, and Jiangsu provinces, 

terminating in the East China Sea at Shanghai. The “trunk 

stream” of the Yangtze River, as referred to in the translated 

document, consists of the 2,800-km portion of the Yangtze 

River below Yibin. The trunk stream consists of three main 

sections, the upper from Yibin to Yichang, the middle from 

Yichang to Hukou, and the lower from Hukou to Shanghai.

Grass, black, silver, and bighead carps are native to the 

Yangtze River and are thought to mainly exist in the middle 
and lower sections of the trunk stream and the associated lakes 

in the Yangtze Plain (Institute of Hydrobiology, 1973, 1976; Li 

and others, 1990), although the fishes sometimes occur farther 

upstream. This floodplain area contains thousands of lakes. 

Many of these lakes connect permanently or intermittently 

with the Yangtze River and are thought to be important, both 

as nurseries and as adult feeding grounds for grass, black, 

silver and bighead carps (Yi and others, 1966, 1988b; Institute 

of Hydrobiology, 1973, 1976). Most of the larval fishes used 

in the development of the document (Yi and others, 1988a) 

were collected from the Yangtze, but some came from the 

Han River, the largest tributary of the Yangtze, which enters at 

Wuhan.

In the late 1950s, the planned construction of the 

Gezhouba Dam and the Three Gorges Dam on the Yangtze 

River (fig. 1) evoked concerns that the change would negatively affect the populations of grass, black, silver and bighead 

carps. The four species are important commercially-harvested 

fishes in China (Zhong and others, 1965; Institute of Hydrobiology, 1973, 1976; Zhang and others, 1989; Li and others, 

1990), where they are known collectively as the “four famous 

domestic fishes.” Companion studies by Yi and others 

(1988a,b) and Yu and others (1988) were undertaken to 

determine if the construction of the dams might be detrimental 

to reproduction and recruitment of these four fishes by interfering with their migrations or spawning area. To make these 

determinations, the studies investigated the distribution of 

spawning areas in the 1,700-km section of the Yangtze River 

between Chongqing and Pengze. The research took place 

over several years during the 1960s (Yi and others, 1966; 

Yi and others, 1988b; Yu and others, 1988). Comparative 

identification studies were conducted to understand the four 

fishes’ early developmental stages and their spawning areas. 

The results were partially published in the 1960s (Yi and 

others, 1966) and 1970s (Institute of Hydrobiology, 1973, 

1976). The publication of the whole article was delayed until 

the late 1980s, with the intent of continually adding more 

information (Yi and others, 1988a).

The artificial spawning of grass, black, silver and bighead carps is now commonplace. If a study on comparative 

development of these fishes was to be performed now, 

certainly a researcher would use that technology to begin 

with embryos of known species. In the early 1960s, when this 

study was begun, artificial spawning had not yet been develYibin

Wan Xian Yichang

Huangshi

Hukou Chongqing Jianli

Wuhan

Shanghai

Three Gorges

Dam

Gezhouba

Dam

Jialing River

Hong

Lake

Dongting Lake

Poyang Lake

Tai Lake

Chao Lake

Hongze Lake

EAST

CHINA

SEA

Yuan River

Zi River

Xiang River

YANGTZE RIVER

YANGTZE RIVER Han River

Han River

Gan River

Huai River

Nanjing

Pemgze

Min River

Tuo River

Danjiangkou Reservoir

0 100 200 300 MILES

104°

34°

30°

26°

108° 112° 116° 120°

0 100 200 300 KILOMETERS

Base from U.S. Defense Mapping Agency digital data, 1993, 1:100,000,000

Asia North Albers Equal-Area Conic projection

Standard parallels 26°N and 34°N, central meridian 114°E

Horizontal coordinate information is referenced to the Geographic Coordinate Systems

World Geodetic Survey Datum of 1984 (GCS WGS 1984) 

\\Sps2dkslwr\home2\pubs\report_figs\10_0014chapman\yangtze_river1.ai

Index map

Enlarged area CHINA

Yangtze River

Figure 1. Location of the Yangtze River in China. The Yangtze River in China is over 6,000 km long and drains a watershed of 1,7000,000

km2. The trunk stream of the Yangtze consists of 2,800 km between Yibin and Shanghai. It is within the trunk stream where the research

of Yi and others (1988a) was conducted on the grass, black, silver, and bighead carp, mainly in the 1960s, in preparation for the building

of dams near Yichang. 

 Early Development of Four Cyprinids Native to the Yangtze River, China
oped. The embryos and larvae in this study were collected from 

the Yangtze River drift with no knowledge of their species until 

they had developed into identifiable juveniles. Before artificial spawning methods were developed, larvae of these carps 

had been commonly captured for use in pond aquaculture 

for over a thousand years (Institute of Hydrobiology, 1973). 

This had been done, however, without much knowledge of the 

species being transplanted until the fish grew to an identifiable 

size. Being unable to identify the embryos and larvae posed 

substantial difficulties to the researchers in this study. Also, the 

economics of the time and place precluded use of photographic 

microscopy. These difficulties were overcome by painstaking 

effort; thousands of embryos and larvae were collected and 

maintained alive in individual small dishes aboard a research 

vessel. The vessel and its scientific crew remained on the 

river day and night over the three-month spawning season 

for the several years of the study. It was necessary to keep 

the individual eggs and larvae alive as they were drawn and 

redrawn multiple times in great detail (see figures, Chapter 2, 

this volume), returning each individual to its specific container 

between sketchings.

This unique dataset and publication provides the scientific basis of current knowledge regarding the ontogeny 

of these four fishes. Therefore, we provide this translation 

to facilitate the identification and classification of early life 

stages of these species within the Mississippi River Basin.

Comments on the Translation and Use 

of the Document

The translated document is as close to a verbatim translation as possible, although we have included a few footnotes. 

The original document, which is an outstanding product of its 

time and place, includes certain information that may seem 

odd to North American scientists and may appear to be shortcomings or superfluous information. For example, information 

on the differences in color of eggs or color of different larval 

structures (i.e. “loquat-yellow” and “butter-yellow”) may be of 

little use to most scientists, especially if examining preserved 

specimens, which are not likely to retain most colors (Snyder, 

1983). Even if fish are observed alive, as they were for the 

translated document, the reader is cautioned that the color of 

fishes from the Yangtze River in the 1960s might not match 

that of the same species collected from other places and times. 

Although the water-hardened eggs of grass, black, silver, and 

bighead carps are generally larger than most species with 

drifting eggs in the Mississippi River basin, care should be 

exercised in the use of these sizes to distinguish between the 

four species, at least until those data are verified for their use 

in North America. There are many variables that can influence 

egg size, including the age and size of parental stock (Balon 

1984) and the ionic makeup of the water in which eggs are 

held (Kucera and others, 2002).

Another caution concerns the ages for the different stages 

recorded in the document. The temperature of the water in 

which the eggs and larvae were held could not be strictly controlled on the Chinese research vessel. Because development 

rates of larvae are highly dependent on temperature, the exact 

age of larvae collected in other studies might differ somewhat 

from ages listed for the different stages in the translated document. The ages in the translated document should be used as 

guidelines or as relative ages.

Most users will find the figures and tables, the information on myomere counts at the various stages, and the relative 

developmental stage of grass, black, silver and bighead carps to 

be the most useful portions of the translation. This information 

constitutes a great improvement over other documents currently 

available in English in terms of comparative morphology and 

identification of these fishes. Because individual stages are 

described in fine detail, the document also provides an excellent resource for those who wish to determine the relative ages 

of embryos and larvae of these fishes. Readers should note that 

the numbering of individual drawings within figures 1 through 

8 of the translated document is dependent on the stage of the 

embryo or young fish and is consistent across species. For 

example, drawing 32 in figure 5 of the translated document 

(referred to as fig. 5–32 in the text) is a depiction of the 

rudimentary-pectoral-fin stage of grass carp, and drawing 32 

in figure 6 of the translated document is the same developmental stage for black carp. Not all stages are depicted for all 

species, thus the numbering of the drawings within figures 

1 through 8 of the translated document is not always sequential. In contrast, note that the numbering of drawings in figure 

10 of the translated document do not refer to developmental 

stages and are numbered sequentially. We have maintained the 

structure of the original document in this matter.

Terms and Conventions

Melanophore types: The Chinese term “flower melanophore” is here interpreted to mean stellate melanophore. All 

other pigment spots are referred to as simply “melanophores.”

Myomere numbering: Since the 1960s, the convention 

for numbering myomeres has differed between China and 

North America. In North America, all myomeres transected by 

a vertical line from the point of interest (such as the posterior 

margin of the anus) are typically included in the count of 

myomeres anterior to that point (Siefer, 1969; Snyder, 1983; 

fig. 2). The translated document uses the Chinese convention 

whereby myomeres for which the ventral margin aligns above 

the posterior margin of the anus, and all anterior myomeres, 

are termed “preanal” myomeres (fig. 2). This results in a 

preanal myomere number that is generally one or two smaller, 

and a corresponding increase in the number of postanal myomeres than would be commonly interpreted with the North 

American convention.

Chapter 1 – Notes on the Translation and Use of Yi and others, 1988 
 The translated document also uses another myomere 

numbering convention with which North American readers 

may not be familiar. The convention breaks preanal myomeres into “predorsal” myomeres (those for which the dorsal 

margins align under or anterior to the origin of the dorsal fin 

or dorsal finfold) and “middle” myomeres (those between 

the predorsal and postanal myomeres). The convention is 

expressed as “8+22+13=43” for grass carp at the hatching 

stage (8 predorsal, 22 middle, and 13 postanal myomeres for a 

total of 43).

Lastly, there is generally some natural variation in myomere numbering of larval fishes of a given species; myomere 

counts are thus normally reported as a range. In the translated 

document a single modal value is given, but early in the text it 

is noted that myomere counts sometimes varied by one, more 

or less, than the given value. This equates closely to the ranges 

given elsewhere for myomere counts for these carps (Soin and 

Sukanhova, 1972).

Fin-ray numbering: The convention used in the translated document consists of a lower case Roman numeral 

and an Arabic numeral, separated by a comma. The Roman 

numeral indicates the number of un-branched rays in the fin, 

and the Arabic numeral indicates the number of branched rays. 

For example, “iii,8” would denote a fin with three un-branched 

rays and eight branched rays.

Scientific names: The translated document accurately 

reflects the original in terms of scientific names. The translated document uses Aristichthys as the generic name for bighead carp, which was the generally accepted name at that time. 

In western literature, bighead carp is now commonly grouped 

with silver carp under the genus Hypophthalmichthys (Kolar 

and others, in press) although the Aristichthys genus used 

in the translation is still sometimes used (Lovell and others, 

2006). Kolar and others (in press) provides an account of the 

history and controversy regarding the generic name of bighead 

carp. We also note that bighead carp and silver carp hybridize freely in the wild, and that the resulting hybrids are fertile 

(Kolar and others, in press). We regard this as a further indication that bighead carp should remain under the genus Hypophthalmichthys. Similarly, we retained the original use of the older 

specific name for grass carp (idellus rather than idella).

Figure 2.  Grass carp larva showing myomere number and difference in

carp larvae myomere count methods between China and North America. 

In the Chinese method, the last preanal myomere (A) is directly dorsal

to the end of the anus (preanal myomere count 1-30; postanal myomere

count 31-45). In the North American method, the last preanal myomere

(B) is the most posterior myomere transected by a vertical line from the

posterior margin of the anus (preanal myomere count 1–32; postanal

myomere count 33–45) (Siefer, 1969; Snyder, 1983). Preanal myomere

counts in the translated document are thus one or two less than would

be interpreted with the North American convention, and the number of

postanal myomeres is correspondingly larger.

MYOMERES

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26

25 27

28

29

30

31

32

33

36

35

34 40

39

38

37 41

44

43

42

45

Anus

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26

25 27

28

29

30

31

32

33

36

35

34 40

39

38

37 41

43

42

A B

Anus

 Early Development of Four Cyprinids Native to the Yangtze River, China
Distinguishing Larvae of Grass, Black, 

Silver and Bighead Carps from other 

Riverine Species of Central North 

America

Before North American scientists can use the information 

contained in the translation to distinguish the different species 

and life history stages of these four fishes, it is necessary to 

distinguish the four species from other resident cypriniform 

species. As a part of our research on the Missouri River in 

2005, we have identified the larvae of thousands of grass, 

silver, and bighead carps, but not black carp. The four most 

useful characteristics we found include: 

(1) Myomere counts: Preanal counts of the four Asian 

carp species are greater than postanal counts. Using the North 

American convention, grass carp have 31–33 preanal and 

10–12 postanal myomeres and Hypophthalmichthys spp. have 

25–28 preanal myomeres and 12–14 postanal myomeres. 

Common carp (Cyprinus carpio) has a similar myomere count 

[(24–25) + (12–14) = (36–39)], but it has distinctive pigmentation that allows easy identification (Auer and others, 1982). 

Postanal myomere counts for grass, black, silver and bighead 

carps are 11 or greater (using the commonly used North 

American convention; 13 or greater using the method of Yi 

and others, 1988a), which eliminates similar-appearing catastomid fishes of the basin. Myomere counts, both preanal and 

postanal, do overlap with several other cyprinids of the basin.

(2) Overall egg and larvae size: The water-hardened eggs 

of grass, black, silver and bighead carps have a large perivitelline space and are larger in diameter than those of most other 

Mississippi River basin species with drifting eggs. The waterhardened egg diameters listed in Yi and others (1988a) for 

the four carps were usually between 4.9 to 6.0 mm in diameter. For comparison, the eggs of emerald shiner (Notropis 

atherinoides), another cyprinid commonly found in the 

drift, range between 3.0 to 3.3 mm (Auer and others, 1982). 

While we caution using small differences in egg size to differentiate between species of Asian carps without evaluating 

the efficacy, these large differences in egg size are sufficient to 

distinguish between Asian carps and native species likely to be 

found in the drift in the Mississippi River basin. At hatching, 

the four carps are around 6 mm in total length, compared to 

about 4 mm at hatching for emerald shiner (Auer and others, 

1982). The larvae of many native cyprinids are much smaller, 

relative to the state of development, than those of grass, black, 

silver, and bighead carps.

(3) Eye shape: The eyes of grass, black, silver and bighead carps are relatively large and more completely circular 

than many other native larvae shortly after hatching (Fuiman 

and others, 1983). The early larvae of many native cyprinids 

and catostomids have distinctly dorso-ventrally flattened eyes. 

Asian-carp eyes also tend to be positioned more anteriorly 

in the head relative to many cyprinid larvae. There are other 

cyprinids with large round eyes, notably in the Notropis and 

Pimephales genera, but the overall sizes of the larvae of these 

native fishes are much smaller than those of grass, black, 

silver, and bighead carps.

(4) Eye pigmentation: Prior to the complete pigmentation 

of the eye, there is a prominent dark spot on the inner ventral 

aspect of each eye in grass, black, silver, and bighead carps 

(fig. 3). Also described by Kryzhanovsky and others (1951; in 

Soin and Sukanhova, 1972), this useful diagnostic characteristic is easily visible from late embryonic stages until the eye 

is fully pigmented. At this time, we have not detected other 

species in our samples from the lower Missouri River and 

tributaries with a similar feature. In addition, a search of the 

literature on fishes of the Mississippi River basin has likewise 

not identified fish with a similar spot on the ventral portion of 

the eye.

Figure 3.  Ventral view of grass carp at three different early

developmental stages. The uppermost larva is at the hatching

stage, and the bottom larva is at the melanoid-eye stage. The

middle larva is intermediate to the others. Arrows indicate the

spots that are present on the ventral portion of the eyes of early

larvae of grass, black, silver, and bighead carps. The spots are

obscured as the eye becomes fully pigmented.

Chapter 1 – Notes on the Translation and Use of Yi and others, 1988 
(5) Pigmentation of the preanal and anal finfolds: Bighead and silver carps develop melanophores on the preanal 

and anal finfolds (fig. 4) around the one-chamber-gas-bladder 

or dorsal-fin-differentiation stage. The melanophores remain 

visible until squamation. Similar pigmentation is not found 

in North American cyprinids, or in grass carp or black carp, 

which makes this an excellent diagnostic characteristic. The 

pattern of these pigments is also useful in discriminating 

between bighead carp and silver carp. However, we found that 

the melanophores were often difficult to discern in preserved 

samples.

Acknowledgements

We thank Bolu Yi, Zhishen Liang, Zhitang Yu, and Renduan Lin for permission to translate and republish the original 

document and Bolu Yi for his review of the translation. We 

thank Keyi Yi for facilitating our communications with Bolu 

Yi. Additional appreciation is extended to Kerry Reeves for 

his valuable assistance with larval fish identification and for 

reviewing an early version of the translation. We thank Joe 

Deters and Jessica Counihan for their work in larval fish identification. We thank Darrel Snyder, Thomas Simon, and James 

Fairchild for providing reviews of this document.

Figure 4.  Melanophores (indicated by arrows) on the preanal and postanal finfolds of (A) bighead carp and (B) silver carp. 

A

B

References Cited

Auer, N.A., ed., 1982, Identification of larval fishes of the 

Great Lakes basin with emphasis on the Lake Michigan 

drainage: Ann Arbor, Mich., Great Lakes Fishery Commission, Special Publication, p. 82–83.

Balon, E.K., 1984, Patterns in the evolution of reproductive 

styles in fishes, in Potts, G.W., and Wootten, R.J., eds,. Fish 

reproduction, strategies and tactics: New York, Academic 

Press, p. 35–53.

Fuiman, L.A., Conner, J.V., Lathrop, B.F., Buynak, G.L., Snyder, D.E., and Loos, J.J., 1983, State of the art of identification for cyprinid fish larvae from eastern North America: 

Transactions of the American Fisheries Society, v. 112, p. 

319–332.

Institute of Hydrobiology, Chinese Academy of Science, 1973. 

Culture and Reproduction of Chinese freshwater fishes (2d 

ed.): Beijing, China, Science Press, 598 p. [In Chinese]

Institute of Hydrobiology, Chinese Academy of Science, 1976, 

Fishes in the Yangtze River: Beijing, China, Science Press, 

220 p. [In Chinese]

   Early Development of Four Cyprinids Native to the Yangtze River, China
Kolar, C.S., Chapman, D.C., Courtenay, W.R., Housel, C.M., 

Williams, J.D., and Jennings, D.P., in press, Asian carps 

of the Genus Hypophthalmichthys (Pisces, Cyprinidae), 

a biological synopsis and environmental risk assessment: 

Bethesda, Md., American Fisheries Society Special Publication.

Kryzhanovsky, C.G., Smirnov, A.I., Soin, S.G., 1951, Development of fish from the Amur River: Papers from the Amur 

River ichthyological expedition, 1945-1949, v. 2, p. 73–84. 

[In Russian]

Kucera, C.J., Faulk, C.K., and Holt, G.J., 2002, The effect of 

spawning salinity on eggs of spotted seatrout (Cynoscion 

nebulosus, Cuvier) from two bays with historically different 

salinity regimes: Journal of Experimental Marine Biology 

and Ecology, v. 272, p. 147–158.

Li, S., Lu, W., Zhou, B., Xu, M., and Ren, M., 1990, Current 

situation of fisheries resources of silver, bighead, and grass 

carp in the Yangtze River, Pearl River, and Heilongjiang 

River: Freshwater Fisheries, v. 6, p. 15–20. [In Chinese]

Lovell, J.M., Findlay, M.M., Nedwell, J.R., and Pegg, M.A., 

2006, The hearing abilities of the silver carp (Hypopthalmichthys molitrix) and bighead carp (Aristichthys nobilis): 

Comparative Biochemistry and Physiology, Part A—Molecular & Integrative Physiology, v. 143, p. 286–291.

Nico, L.G., Williams, J.D., and Jelks, H.L., 2005, Black 

carp—biological synopsis and risk assessment of an 

introduced fish: Bethesda, Md. American Fisheries Society 

Special Publication 31, 316 p.

Siefert, R.E., 1969, Characteristics for separation of white and 

black crappie larvae: Transactions of the American Fisheries Society, v. 98, p. 326–328.

Snyder, D.E., 1983, Fish eggs and larvae, in Nielson, L.A., and 

Johnson, D.L., eds., Fisheries techniques: Bethesda, Md., 

American Fisheries Society, p. 165–197.

Soin, S.G., and Sukhanova, A.I., 1972, Comparative morphological analysis of the development of the grass carp, the 

black carp, the silver carp and the bighead (Cyprinidae): 

Journal of Ichthyology, v. 12(1), p. 61–71.

Yi, B., Yu, Z., and Liang, Z., 1966, A comparative study of 

the embryonic development of grass carp, black carp, silver 

carp, big head carp and other fishes with drifting eggs in 

the Yangtze River, in Fisheries research committee of the 

western Pacific, 8th symposium, Beijing: Beijing, China, 

Science Press, p. 37–53. [In Chinese]

Yi, B., Liang, Z., Yu, Z., Lin, R., and He, M., 1988a, A 

comparative study of the early development of grass carp, 

black carp, silver carp and big head of the Yangtze River, in 

Yi, B., Yu, Z., and Liang, Z., eds., Gezhouba water control 

project and four famous fishes in Yangtze River: Wuhan, 

China, Hubei Science and Technology Press, p. 69–135. [In 

Chinese, English abstract].

Yi, B., Yu, Z., Liang, Z., Sujuan, S., Xu, Y., Chen, J., He, 

M., Liu, Y., Hu, Y., Deng, Z., Huang, S., Sun, J., Liu, R., 

and Xiang, Y., 1988b, The distribution, natural conditions, 

and breeding production of the spawning ground of four 

famous freshwater fishes on the main stream of the Yangtze 

River, in Yi, B., Yu, Z., and Liang, Z., eds., Gezhouba water 

control project and four famous fishes in the Yangtze River: 

Wuhan, China, Hubei Science and Technology Press, p. 

1–46. [In Chinese, English abstract].

Yu, Z., Deng, Z., Xu, Y., Cai, M., Zhao, Y., Liang, Z., Wang, 

N., and Zeng, X., 1988, The present situation of the 

spawning grounds of the four Chinese domestic fishes 

in the Changjiang (Yangtze River) after construction of 

the Gezhouba water control project, in Yi, B., Yu, Z., and 

Liang, Z., eds., Gezhouba water control project and four 

famous fishes in the Yangtze River: Wuhan, China, Hubei 

Science and Technology Press, p. 1–68. [In Chinese, English abstract]

Wilson, E., 2006, Draft management and control plan for 

Asian carps in the United States: FR Doc. E6–17794, v. 71, 

no. 205, Oct. 24.

Zhang, Y., Tang, Y., Ouyang, H., 1989, Chinese pond aquaculture: Beijing, China, Science Press, 673 p. [In Chinese]

Zhong, L., Li, Y., Zhang, S., Liu, J., Chen, F., 1965, Biology and artificial reproduction of the four famous Chinese 

fishes: Beijing, China, Science Press, 171 p. [In Chinese]

Chapter 1 – Notes on the Translation and Use of Yi and others, 1988   
10 Early Development of Four Cyprinids Native to the Yangtze River, China

Page intentionally blank
A Study of the Early Development of Grass 

Carp, Black Carp, Silver Carp, and Bighead 

Carp in the Yangtze River, China

By Bolu Yi, Zhishen Liang, Zhitang Yu, Renduan Lin, and Mingjue He

Translated by Duane C. Chapman and Ning Wang

Chapter 2 of

Early Development of Four Cyprinids Native to the Yangtze River, 

China

Edited by Duane C. Chapman

An identification guide translated from Chinese to English with approximately 200

original drawings. Original document published in Yi, B., Yu, Z., and Liang, Z., eds., 1988,

Gezhouba water control project and four famous fishes in Yangtze River, China: Wuhan,

China, Hubei Science and Technology Press, p. 69–135. 

Data Series 239­–2

U.S. Department of the Interior

U.S. Geological Survey
Contents

Abstract ........................................................................................................................................................15

Introduction ..................................................................................................................................................15

Materials and Methods ..............................................................................................................................16

Egg Characteristics .....................................................................................................................................17

Egg Size ................................................................................................................................................17

Egg Color..............................................................................................................................................17

Egg membrane transparency ...........................................................................................................18

Embryonic Development ............................................................................................................................18

Characteristics....................................................................................................................................18

Grass Carp ..................................................................................................................................18

Black Carp ..................................................................................................................................20

Silver Carp ..................................................................................................................................21

Bighead Carp .............................................................................................................................21

Comparison of the Embryological Development of Grass, Black, Silver, and

Bighead Carps .......................................................................................................................22

Post-hatch Development ...........................................................................................................................22

Characteristics....................................................................................................................................22

Grass Carp ..................................................................................................................................23

Black Carp ..................................................................................................................................24

Silver Carp ..................................................................................................................................26

Bighead Carp .............................................................................................................................27

Comparison of Post-hatch Development of Grass, Black, Silver, and Bighead Carps ...........29

Myomere Counts .......................................................................................................................29

Relative Postanal Length .........................................................................................................30

Caudal Vein ................................................................................................................................30

Pigmentation of the Dorsal Surface of the Head and Snout Shape .................................30

Deep Head Pigmentation .........................................................................................................30

Pigment Around the Base of the Rudimentary Pectoral Fin ..............................................31

Pigmentation of the Caudal Fin ...............................................................................................31

The Pigmentation of the Preanal and Anal Finfolds ............................................................31

Anal Fin Shape ...........................................................................................................................32

Discussion ....................................................................................................................................................32

References Cited .........................................................................................................................................32

Figures

1–4. Drawings showing the stages of embryonic development­—

1. (3–29). Grass carp ...................................................................................................................34

2. (2–29). Black carp ....................................................................................................................35

3. (4–29). Silver carp ....................................................................................................................36

4. (2–29). Bighead carp ...............................................................................................................37

5. Drawings showing the stages of post-hatch development of grass carp

(31–38) ..........................................................................................................................................38
Suggested citation: 

Yi, B., Liang, Z., Yu, Z., Lin, R., and He, M., 2006, A study of the early development of grass carp, black 

carp, silver carp, and bighead carp in the Yangtze River, China, chap. 2 of Chapman, D.C., ed., Early 

development of four cyprinids native to the Yangtze River, China: U.S. Geological Survey, Data Series 

239, p. 15–51.

6. Drawings showing the stages of post-hatch development of black carp

    (31–37) ..........................................................................................................................................41

    (38–43) ..........................................................................................................................................42

    (44–48) ..........................................................................................................................................43

7. Drawings showing the stages of post-hatch development of silver carp

(31–38) ..........................................................................................................................................44   

(40–45) ..........................................................................................................................................45   

(46–48)...........................................................................................................................................46

8. Drawings showing the stages of post-hatch development of bighead carp

    (31–37) ..........................................................................................................................................47

    (38–44) ..........................................................................................................................................48

    (45–48) ..........................................................................................................................................49

9.  Drawings showing the different patterns of melanophores of eight cyprinids ...............50

10.  Chart showing the primary diagnostic characteristics in the early development

of grass, black, silver, and bighead carps collected from the Yangtze River. ..................51

Tables

1.  The size-frequency distribution of the egg membranes of grass carp, black carp,

silver carp, and bighead carp collected from the Yangtze River between 1961 and

1964, and between 1976 and 1978 ...........................................................................................17

2.  Hues of the egg yolk of grass carp, black carp, silver carp, and bighead carp

collected from the Yangtze River in 1964, 1976, and 1977 ...................................................18

3.  Stages of embryonic development, hours of development at 18–24°C, and length of

embryos of grass carp, black carp, silver carp, and bighead carp collected from

the Yangtze River .......................................................................................................................19

4.  Myomere counts in three early development stages of grass carp, black carp,

silver carp, and bighead carp collected from the Yangtze River .......................................29

5.  Proportion of postanal length to total body length of yolk-sac larvae of grass carp,

black carp, silver carp, and bighead carp collected from the Yangtze River ..................30

6.  Melanophores of the dorsal surface of the head, and shape (as viewed dorsally) of

the anterior margin of the snouts of grass carp, black carp, silver carp, and

bighead carp at the gas-bladder-emergence stage ............................................................31

7.  Number of lateral-line scales at the squamation stage of grass carp larvae

originally collected from the Yangtze River and raised in containers with different

water volumes ............................................................................................................................32

    (40–44) ..........................................................................................................................................39

(45–48) ..........................................................................................................................................40
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Chapter 2

A Study of the Early Development of Grass Carp, Black 

Carp, Silver Carp, and Bighead Carp in the Yangtze River, 

China

(1935)5 and Chen and Lin (1935) briefly described the eggs 

and larvae of grass carp. Li and He (1937) partly described 

the early development of silver carp as part of their fish 

culture studies. Afterwards, there were no more studies on 

the early development until the 1950s. Liu (1954) described 

some characteristics of the embryological development of 

grass carp. A few years later other researchers observed and 

recorded the embryological development of grass, silver, and 

bighead carps (Ye, 1958; Yu, 19595; Institute of Experimental 

Biology, 1962; Yang, 1962; Yuan, 1962; Zhong, 1962; Chen, 

1963a,b; Shandong Institute of Freshwater Fisheries, 1963; 

Wu and Shi, 1964; Xie, 1964). Ye (1964) reported limited data 

on the embryological development of black carp. Outside of 

China, there were only a few reports on the early development 

of these four species in the early 50s (Verigin, 1950; Kryzhanovsky and others, 1951). However, in the above-mentioned 

studies, there was no detailed comparative description of the 

important characteristics of the four fishes and differences in 

their early development.

Since 1961, during studies of the potential effect of the 

Gezhouba Dam on the fisheries of the Yangtze River and 

determination of the spawning grounds of grass, black, silver, 

and bighead carps, we conducted thorough comparative studies on the early development of the four fishes. Identifying the 

developmental characteristics of these fishes was a prerequisite for identifying their spawning grounds. By knowing the 

common early developmental characteristics of the four fishes, 

it was possible to distinguish them from other co-occurring 

species with similar spawning habits and early life history. 

By determining various early development stages of the four 

fishes and the duration after fertilization, it was possible to 

locate the spawning grounds of these fishes. By determining 

the specific early development characteristics of each of the 

four species, it was possible to calculate the relative abundance 

of the four species, and the relative number of eggs/larvae 

produced between different spawning sites.

Most data were collected by the end of 1963 and a preliminary report was presented in the 8th Symposium of West 

Pacific Fisheries Research Committee (Yi and others, 1966). 

In that report, which was written based on partially complete 

data, the reproduction and early development characteristics 

5

 Translator’s note: Lin (1935) and Yu (1959) were not listed in the 

References section of the original document.

Bolu Yi1, Zhishen Liang2, Zhitang Yu3, Renduan Lin3,

and Mingjue He3

Abstract

The present paper describes the characteristics of 48 early 

developmental stages of the four famous domestic fishes in 

the Yangtze River in China—grass carp (Ctenopharyngodon 

idellus), black carp (Mylopharyngodon piceus), silver carp 

(Hypophthalmichthys molitrix), and bighead carp (Aristichthys 

nobilis). The paper compares the morphological similarities and differences among the four species with about 200 

original drawings. The results of this paper were mainly based 

on continuous observations of the early development of eggs 

and larvae of the four species collected from the upstream and 

middle sections of the Yangtze River trunk stream4 between 

1961 and 1963. In addition, some data and material collected 

during later studies of the four species in the Yangtze River 

and its tributary, the Han River, during spawning seasons 

between 1964 and 1966, between 1976 and 1978, and 1981 

were used to confirm and supplement the previous results.

Introduction

Grass carp (Ctenopharyngon idellus), black carp (Mylopharyngodon piceus), silver carp (Hypophthalmichthys

molitrix) and bighead carp (Aristichthys nobilis), known in 

China as “the four famous domestic fishes,” are the primary 

economically-important freshwater fish in China, especially 

in the Yangtze River system. There was no record of the 

early development of these four fishes before the 1930s. Lin 

1

 The College of Fisheries, Huazhong Agricultural University, Wuhan, 

430070, China

2

 Institute of Environment Protection, Guangzhou, 510620, China

3

 Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, 

China

4

 Translator’s note: definition of “trunk stream” in Chapman and Wang, this 

volume, chapter 1
of the four fishes were described, and also were compared 

with six other species which have similar spawning requirements and early life history. A few years later, the figures of 

early development of the four fishes were published in the 

book “Culture and Reproduction of Chinese Freshwater Fish” 

(Chapter 4, “Reproduction of Cultured Fish,” Institute of 

Hydrobiology, 1973) and in the book “Fishes of the Yangtze 

River” (Institute of Hydrobiology, 1976). This work from 

beginning to present lasted more than 20 years. Publication 

of the whole article has been delayed, but the intent was to 

continually add more information. For example, the study 

“Prediction of Timing of the Availability in Hatching of 

Larvae of the Four Fishes in the Yangtze River” was conducted between 1964 and 1968. During this study, eggs and 

larvae of the four fishes were collected, and the data and 

material were used to confirm and supplement our previous 

data. Some authors of the present paper participated in the 

study “The Juvenile Fish of Economical Importance of the 

Yangtze River” (1974 and 1975), the investigation “Fisheries 

Resources of the Han River” (1976–1978), and the study “The 

Present Situation on the Spawning Grounds of the Four Famous 

Domestic Fishes in the Yangtze River after Construction of the 

Gezhouba Water Control Project” (1981). Some results from 

these studies were also used to supplement current data and 

figures of early developmental stages of the four fishes.

The following people also participated in data collection 

and larvae culture for this research project: Sujuan Shan, 

Yungan Xu, Youliang Liu, Yizhi Hu, Jiangyi Sun, Jingxing 

Chen, Shangwu Huang, Zhonglin Deng, Henian Huang, Chungsheng Zhou, Yang Xiang, Zhigao Yang, Xiangjian Wei, and 

Ning Wang. We appreciate their efforts.

Materials and Methods

Eggs and larvae were mainly collected between 1961 

and 1963 in the trunk stream of the Yangtze River. During the 

entire reproduction season in 1961, the collection and observation of eggs and larvae were conducted at the Yichang spawning reach, which included a 35-km gorge section between 

the towns of Letianxi and Nanjinguan, located upstream of 

Yichang6, and the future site of the Gezhouba Dam (three km 

below Nanjinguan). In May and June of 1962, collections were 

performed in middle Yangtze River near the city of Huangshi 

and upper Yangtze River in Wuanxian County. In the first 

half of July 1961 and the first half of May 1962, our research 

vessel continually traveled back and forth between Wuhan 

and Yichang and between Wuhan and Hukou to collect eggs 

and larvae. We collected additional eggs and larvae between 

Huangshi and Hukou in 1963 and near Janli in 1964. Also, we 

6

 Translator’s note: For a map of locations, see Chapman and Wang, this 

volume, chapter 1.

collected eggs and larvae, observed their characteristics, and 

made additional illustrations of the early development stages 

in the Yangtze River in 1965, 1966, 1974, and 1981, and in the 

Han Riverin 1976 and 1978.

The data from the collections above represent the 

morphological characteristics of early development of fishes 

in the middle and upper sections of the trunk stream of the 

Yangtze River. No obviously different characteristics were 

found between various sections of the Yangtze River or its 

tributaries.

Three conditions had to be satisfied when observing the 

embryological development of fish eggs collected from the 

field: (1) The fertilized eggs must have been released from a 

female which had eggs of the right stage of development and 

the eggs must develop normally, (2) the early embryos of four 

fishes could be collected at the same time and same location, 

and (3) the eggs of the four species could be compared under 

the same conditions.

The eggs were collected quantitatively by using a 

D-frame net and a conical net. The D-frame opening had 

a radius of 0.5 m and opening area of 0.393 m2. The length 

of the cloth portion of the D-frame net was 2 m, followed by 

a box-shaped collection chamber. The conical net was used 

to collect eggs and larvae near the bottom of the river. The 

diameter of the opening of the conical net was 0.7 m. The 

opening area was 0.385 m2. The net could be lowered to near 

the bottom using a long rope. The eggs and larvae collected 

were observed and identified under a dissecting scope immediately after collection and illustrated at that time. They were 

then placed into Petri dishes for rearing so that they could be 

repeatedly observed and illustrated. For observation of hatched 

larvae, several drops of a 5 to 10 percent solution of urethane 

were added into the observation chamber to temporarily 

immobilize the fish. Additional water was added to prevent 

mortality as needed based on the temperature, the blood 

circulation rate of the larvae, and the time needed to finish the 

illustration.

Between 1961 and 1964, 1,192 fish were collected and 

observed. Of these, 578 were grass carp, 337 were black carp, 

199 were silver carp, and 78 were bighead carp. A total of 

2,608 eggs were used to confirm and supplement between 

1976 and 1978. Of that number, 977 were grass carp, 791 were 

black carp, 695 were silver carp, and 145 were bighead carp. 

From the 3,800 eggs randomly collected from the Yangtze 

River, the number of grass carp collected was highest (1,555), 

and the bighead carp the lowest. These data possibly indicate 

a rough ratio of populations of the four fish in the Yangtze 

River. The ratio of grass carp: black carp: silver carp: bighead 

carp was 7:5:4:1 (table 1).

From the collected eggs of the four species, about 50 

were used for drawing the pictures of the consecutive embryo 

stages. The eggs collected in April and May 1961 were held 

until hatching and then reared until November in order to 

identify the species. In the following two years, we repeated 

16  Early Development of Four Cyprinids Native to the Yangtze River, China
the observations and the illustrations of the developmental 

stages to fill remaining data gaps. Therefore, the 48 illustrated 

developmental stages of each species were first based on two 

or three organisms. Afterwards, more eggs and larvae were 

observed and used to perfect the illustrations and confirm that 

the illustrations were representative of the species. The shape 

and the size of the egg membrane of the four fishes were compared based on about 3,800 collected eggs.

Egg Characteristics

After mature eggs of the four species are released and 

fertilized, the vacuole is broken and fluid is released. Water 

enters the egg membrane, causing the egg to expand and creatTable 1.  The size-frequency distribution of the egg membranes

of grass carp, black carp, silver carp, and bighead carp collected

from the Yangtze River between 1961 and 1964, and between 1976

and 1978.

[mm, millimeters]

Diameter of 

egg membrane 

(mm)

Number of eggs

Grass 

carp

Black 

carp

Silver 

carp

Bighead 

carp Total

3.5-3.6 3 0 4 0 7

3.7-3.8 6 0 3 0 9

3.9-4.0 20 0 22 0 42

4.1-4.2 47 0 44 0 91

4.3-4.4 55 8 47 0 110

4.5-4.6 98 55 94 0 247

4.7-4.8 125 70 93 0 288

4.9-5.0 192 115 112 15 434

5.1-5.2 276 111 129 10 526

5.3-5.4 256 117 130 15 518

5.5-5.6 233 202 111 34 580

5.7-5.8 141 142 59 44 386

5.9-6.0 88 143 35 48 314

6.1-6.2 7 80 7 18 112

6.3-6.4 5 56 4 19 84

6.5-6.6 2 23 0 17 42

6.7-6.8 1 6 0 3 10

Total 1,555 1,128 894 223 3,800

Percentage 40.9 29.7 23.5 5.9 100

ing a space between the plasmolemma and the egg membrane. 

The eggs are slightly demersal and drift with the current. The 

eggs do not float; they will sink under still water conditions. 

These eggs may be called “drifting eggs.”7

Egg Size

There are more than 20 fishes with semi-buoyant drifting eggs in the Yangtze River. Of these, water-hardened eggs 

of the grass, black, silver, and bighead carp were the largest. 

The diameter of most egg membranes of the four species 

were between 4.9 to 6.0 mm after water-hardening (table 

1). However, the frequency of distribution of egg membrane 

sizes was different among the four species. The variation in 

grass carp egg diameters was largest. Among 1,555 grass carp 

eggs, the diameters were between 3.5 to 6.7 mm (range 3.2 

mm); most of the eggs (70.6 percent; n = 1,098) were between 

4.9 to 5.8 mm. There were no small eggs in black carp; the 

diameters were between 4.3 to 6.8 mm (range 2.5 mm) and 

most eggs (73.6 percent, n = 1128) were between 4.9 to 6.0 

mm. Eggs of silver carp were the smallest compared to the 

other three species, but the size range was large (3.5 to 6.4 

mm, range 2.9 mm); most of the eggs (74.8 percent, n = 894) 

were between 4.5 and 5.6 mm. The egg diameters of bighead 

carp were between 4.9 to 6.7 mm and the range was small (1.8 

mm); most of the eggs (73.1 percent, n = 223) were between 

5.5 to 6.4 mm. Among all four species, most of the eggs (72.6 

percent, n = 3,800) were between 4.9 and 6.0 mm in diameter. 

There were few eggs with diameters larger than 6.6 or less 

than 3.9 (0.68 percent).

From the frequency distribution of egg diameters of the 

four species, the egg size of bighead carp was the largest, then 

the black carp, then grass carp, then silver carp. The mean and 

standard deviation of the egg size were 5.82 ± 0.42, 5.51 ± 

0.51, 5.18 ± 0.48, 5.05 ± 0.52 for bighead, black, grass, and 

silver carps, respectively. On the other hand, we often found 

overlaps in the ranges of egg sizes for the four species, which 

caused difficulty in using egg size to identify the species. 

Based on frequency distribution, eggs with diameters between 

4.9 and 5.2 mm were most likely to be grass carp or silver 

carp, between 5.3 to 5.6 mm were likely to be grass, silver or 

black carp; between 5.7 and 6.2 mm were likely to be black or 

bighead carp. Eggs larger than 6.2 mm generally were black 

carp or bighead carp. Eggs with a diameter of less than 4.9 

mm were unlikely to be bighead carp; eggs less than 4.3 mm 

generally were grass or silver carp, but were unlikely to be 

black carp. When examining the eggs, one can use size along 

with other characteristics to make a decision as to the species.

7

 Translators’ note: The authors of the original document inserted the 

English words “drifting eggs” here. Eggs with these characteristics are often 

termed “semibuoyant” in North American literature.

Chapter 2 – Translation of Yi and Others, 1988 17
Egg Color

The yolk sac of the four species often exhibited different 

shades of yellow. The color range between dark yellow to light 

yellow can be described in four categories of loquat-yellow, 

apricot-yellow, butter-yellow, and cream-colored. The most 

easily distinguished colors were loquat-yellow8 and creamcolored. Apricot-yellow and butter-yellow were difficult to 

distinguish. The yolk sac of grass carp was relatively darker 

than the other three fish. Among the 379 grass carp eggs, 

63.6 percent were loquat-yellow and 23.2 percent apricotyellow. Most of the black carp (n = 263) were apricot-yellow 

(65.4 percent) and loquat-yellow (19.8 percent). The yolk sac 

of silver carp had a high degree of variance in color; however 

apricot-yellow was most prominent (49.5 percent; n = 186). 

Bighead carp had the lightest colored yolk sacs, with 61.5 

percent butter-yellow and 10 percent cream-colored (n = 83; 

table 2).

Egg membrane transparency

After water-hardening, there were substantial differences 

in the egg membrane transparency of the four species. The 

egg of the grass carp was obviously transparent to the unaided 

human eye. Egg membranes of silver and bighead carps were 

thicker than those of grass carp and were relatively transparent, although not quite as transparent as those of grass carp. 

The black carp egg membrane was relatively thick and slightly 

sticky; often small particles stuck to the surface, which made 

the egg membrane slightly opaque. The embryos of black carp 

could only be clearly distinguished only by using a dissecting 

microscope.

8

 Translator’s note: The names of the colors are not direct translations from 

the original document. These colors were suggested by the first author of the 

document (Bolu Yi) as appropriate color names for this translation.

Embryonic Development

Characteristics

The early development of grass, black, silver, and 

bighead carps had two primary periods, embryonic and posthatch. Before hatching, the embryos were observed in the 

dishes and the water was renewed a few times every day. The 

water temperature ranged from 18.0 to 24.2 oC. Under these 

conditions, the larvae of the four species hatched in about 11⁄2 

days (usually 33–34 hours). Similar to other cyprinids with 

drifting eggs, there were 30 embryonic development stages 

and the time between stages differed. The egg size changed 

between stages. From the two-cell stage to the heartbeat stage, 

the length of the embryo increased continually (table 3). The 

characteristics of various stages of embryonic development are 

described as follows:

Grass Carp

The youngest eggs collected were at the 4-cell stage 

(fig. 1–3). The color of divided cells was light yellow, while 

the yellow color of the yolk was darker. The cytoplasm was 

widely distributed. Cells divided vertically four times until the 

64-cell stage. From the 8-cell stage through the 32-cell stage 

(fig. 1–4 to 1–6), cells were large and arranged regularly; the 

cytoplasm diminished and streamed toward the animal pole. 

At the 64-cell stage (fig. 1–7), cells became smaller and were 

arranged irregularly; the cross-section width of the blastodisc 

was almost equal to that of the yolk. Cells divided horizontally 

between the 64-cell stage and the 128-cell stage (fig. 1–8). At 

the morula stage (fig. 1–9), the cells became smaller and cytoplasm continued to move toward the animal pole. At the earlyblastula stage (fig. 1–10), the blastodisc appeared mound-like. 

At the mid-blastula stage (fig. 1–11), the crowded cells 

expanded over the yolk and the blastodisc began flattening. 

At the late-blastula stage (fig. 1–12), the blastodisc flattened 

more, the whole egg looked round, and the cytoplasm disappeared. 

Table 2.  Hues of the egg yolk of grass carp, black carp, silver carp, and bighead carp collected from the Yangtze River in 1964, 1976,

and 1977.

Color Grass carp Black carp Silver carp Bighead carp

Number Percent Number Percent Number Percent Number Percent

Loquat-yellow 241 63.6 52 19.8 38 20.4 0 0

Apricot-yellow 88 23.2 172 65.4 92 49.5 25 30.1

Butter-yellow 18 4.8 11 4.2 42 22.6 51 61.5

Cream-colored 32 8.4 23 10.6 14 7.5 7 8.5

Total 379 258 186 83

18 Early Development of Four Cyprinids Native to the Yangtze River, China
Table 3.  Stages of embryonic development, hours of development at 18–24°C, and length of embryos of grass carp, black carp, silver

carp, and bighead carp collected from the Yangtze River.

[mm, millimeter; hr:min, hour and minutes; –, no data]

Grass carp Black carp Silver carp Bighead carp

No. Stage Length Time Length Time Length Time Length Time

(mm) (hr:min) (mm) (hr:min) (mm) (hr:min) (mm) (hr:min)

1 1-cell _ _ _ _ _ _ _ _

2 2-cell _ _ 1.75 0:50 _ _ 1.85 0:55

3 4-cell 1.88 1:05 _ _ _ _ 1.90 1:03

4 8-cell 1.57 1:20 1.78 1:25 1.80 1:20 1.91 1:12

5 16-cell 1.88 1:40 1.80 1:45 1.90 1:45 1.93 1:24

6 32-cell 1.90 2:05 1.80 2:00 1.93 1:57 1.95 2:00

7 64-cell 1.88 2:45 1.88 2:15 1.93 2:30 1.97 2:20

8 128-cell 1.57 3:30 1.90 3:05 1.93 3:35 1.98 3:00

9 Morula 1.90 3:50 2.00 3:58 1.94 4:20 2.00 3:38

10 Early blastula 1.92 4:50 2.10 4:48 1.94 4:55 2.10 4:10

11 Mid-blastula 1.90 5:55 2.00 5:38 1.93 5:20 2.00 5:30

12 Late blastula 1.80 7:35 1.90 7:43 1.92 6:40 1.90 7:20

13 Early gastrula 1.80 8:55 1.80 9:38 1.92 8:40 1.85 8:10

14 Mid-gastrula 1.80 9:40 1.80 11:41 1.90 10:15 1.85 9:55

15 Late gastrula 1.80 10:30 1.80 12:35 1.90 12:50 1.90 11:20

16 Neurula 1.80 11:15 1.80 13:40 2.00 14:10 2.00 12:45

17 Blastopore closure 1.80 12:50 1.90 14:13 2.00 14:45 2.10 14:00

18 Somite appearance 1.82 13:20 2.00 15:21 2.10 15:20 2.10 14:50

19 Optic primordium 1.88 14:10 2.00 16:20 2.10 16:15 2.10 15:40

20 Optic vesicle 1.92 16:05 2.10 17:05 2.10 17:00 2.20 16:35

21 Olfactory placode 1.95 19:15 2.20 18:10 2.20 18:25 2.26 17:45

22 Tail bud 2.00 19:45 2.30 19:00 2.50 19:30 2.32 19:05

23 Otic capsule 2.40 20:30 2.50 19:50 2.60 20:45 2.56 19:35

24 Tail vesicle 2.71 21:20 2.70 21:20 2.80 22:00 3.00 22:00

25 Caudal fin 3.10 22:45 2.80 22:50 3.20 22:35 3.00 24:28

26 Lens formation 3.20 23:15 3.00 23:25 3.65 23:00 3.80 25:20

27 Muscular effect 3.30 23:50 3.50 24:15 3.90 24:25 4.40 26:25

28 Heart rudiment 4.00 27:32 4.00 28:10 4.10 28:20 5.20 28:40

29 Otolith appearance 4.80 31:30 4.70 31:48 4.30 30:00 5.80 32:30

30 Heart pulsation 5.50 33:35 5.80 34:35 5.40 34.15 6.30 33:00

Chapter 2 – Translation of Yi and Others, 1988 19
At the early-gastrula stage (fig. 1–13), the blastodisc began to 

invaginate, the germ ring formed, the dorsal lip appeared, 

and the blastoderm covered about one-half of the yolk. At the 

mid-gastrula stage (fig. 1–14), the germ ring and the enlarged 

region of the blastoderm thickened, the embryonic shield 

formed, the lower part of the yolk cell shrank, and the margin 

of the blastoderm covered about two-thirds of the yolk cell. 

At the late-gastrula stage (fig. 1–15), the embryonic shield 

developed, the rudiment of the embryo became evident, the 

blastoderm covered about four-fifths of the yolk, and the 

yolk was pear-shaped. At the neurula stage (fig. 1­­­­­–16), the 

blastoderm covered almost the whole yolk, leaving only the 

yolk plug uncovered, and the embryo thickened substantially. 

The blastopore-closure stage (fig. 1­–17) began one half-hour 

later and the embryo lengthened. At the somite-appearance 

stage (fig. 1–18), one to three pairs of somites appeared at the 

middle part of the embryo, the brain rudiment thickened, and 

the blastopore was still visible. At the optic-primordium stage 

(fig. 1–19), the optic primordium was a long oval shape, the 

lower edge appeared to have fine crenulations, the embryo 

embraced about five-sixths of the yolk, two to three oil 

droplets appeared on the yolk cell, and the somite number 

increased to four or five pairs. At the optic-vesicle stage 

(fig. 1–20), the optic primordium enlarged slightly and became 

more visible, the embryo encircled most of the yolk so that the 

head and tail were in close proximity, the somite number was 

six or seven pairs, and the notochord was clearly visible. At 

the olfactory-placode stage (fig. 1–21), the olfactory placode 

was barely visible above the optic vesicle and the somite 

number was nine pairs. At the tail-bud stage (fig. 1–22), the 

tail was more prominent, the brain rudiment differentiated 

substantially, and the somites numbered 10 to 15 pairs. At the 

otic-capsule stage (fig. 1–23), the otic capsule was clearly 

visible, the optic vesicle enlarged and became elliptical, the 

somites numbered 16 to 20 pairs, the yolk sac elongated, the 

distance between the head and tail increased, and an obvious 

bump appeared at the brain area. At the tail-vesicle stage 

(fig. 1–24), the tail extended outward, a vesicle appeared on 

the tail bud, the end of the yolk-sac showed sky-blue color, the 

somites numbered 21 or 22 pairs, the embryo elongated, and a 

constriction appeared in the posterior region of the yolk where 

the tail bud ended. At the caudal-fin stage (fig. 1–25), the 

embryo elongated further, the rudimentary caudal fin formed, 

the tail vesicle moved to the end of the tail, the eye was almost 

round, the yolk-sac looked like a kidney, and the somites numbered about 25 pairs. At the lens-formation stage (no figure), 

the eye lens formed, the otic vesicle appeared, and the somites 

numbered 26 pairs. The muscular-effect stage started about 

one-half hour later (fig. 1–27). The tail vesicle disappeared, 

the embryo was light yellow, the spontaneous myotomal 

constrictions produced a slight lashing motion, the brain developed further, the bump was more prominent, the embryo and 

the yolk continued elongating, the end of the yolk remained 

sky blue, and the myomeres numbered 27. At the heartrudiment stage (fig. 1–28), the embryo and the yolk elongated 

further, the caudal fin extended, the embryo lashed from side 

to side occasionally, the heart rudiment appeared between the 

head and the yolk, and the somites numbered 31 pairs. At the 

otolith-appearance stage (fig. 1–29), the embryo straightened 

but the head was still curved around the anterior yolk-sac. The 

embryo moved continuously, the yolk-sac was wider in the 

anterior than the posterior portion, the otoliths appeared, and 

the somites numbered 33 to 35 pairs. The heart-pulsation stage 

(no figure), was the last stage of embryonic development. 

The heart began to pulsate, the embryo rotated continuously, 

and the somites numbered 36 to 41 pairs, the egg membrane 

softened, and the embryo was ready to hatch.

Black Carp

The youngest eggs collected were at the 2-cell stage 

(fig. 2–2). The cell was dark yellow and the yolk was light 

yellow. The grey cytoplasm concentrated near the center of the 

yolk. Sometimes one or two cells divided earlier than others at 

the 8-cell stage (fig. 2–4). The cytoplasm diminished gradually 

at the 16-cell stage (fig. 2–5). At the 32- and 64-cell stages 

(fig. 2–6 and 2–7), the sizes of cells were different and cells at 

the periphery of the blastodisc were smaller. After a horizontal 

division, the 128-cell stage began (fig. 2–8). The blastodisc 

appeared mound-like and several oil droplets appeared on the 

yolk. At the morula stage (fig. 2–9), the blastodisc was highly 

raised above the yolk surface and the cross-sectional width 

of the blastodisc was obviously smaller than that of the yolk. 

At the early-blastula stage (fig. 2–10), the cells became still 

smaller and the cytoplasm almost disappeared. At the midblastula stage (fig. 2–11), the blastodisc began flattening and 

formed a half-sphere. At the late-blastula stage (fig. 2–12), the 

blastodisc gradually expanded over the yolk. At the early-gastrula stage (fig. 2–13), the germ ring appeared, the blastoderm 

covered about half of the yolk cell, and the whole egg was 

round. At the mid-gastrula stage (fig. 2–14), the dorsal lip and 

embryonic shield appeared and the margin of the blastoderm 

covered about two-thirds of the yolk cell. At the late-gastrula 

stage (fig. 2–15), the embryonic body was clearly visible, the 

head was slightly enlarged, the blastoderm covered about 5/6 

of the yolk, and the yolk cell was pear-shaped. At the neurula stage (fig. 2–16), the head part was clearly visible, the 

blastoderm covered almost the whole yolk cell leaving only 

the yolk plug uncovered, and the embryo thickened substantially. At the blastopore-closure stage (fig. 2–17), the embryo 

elongated and the front part of the head was slightly enlarged. 

At the somite-appearance stage (fig. 2–18), somites numbered 

one to five pairs: one pair appeared every 10 minutes or so. At 

the optic-primordium stage (fig. 2–19), the optic primordium 

was a long oval shape with a crenulated ventral margin. The 

un-encircled margin of the yolk was a straight line, and the 

somites numbered 6 to 10 pairs. At the optic-vesicle stage 

(fig. 2–20), a bump appeared obviously at the brain area, 

the somites numbered 11 to 12 pairs, and the notochord was 

clearly visible. At the olfactory-placode stage (fig. 2–21), the 

olfactory placode was barely visible above the optic vesicle 

and the somites numbered 13 to 14 pairs. At the tail-bud stage 

20 Early Development of Four Cyprinids Native to the Yangtze River, China
(fig. 2–22), the brain rudiment differentiated substantially, the 

eyes enlarged, and the somites numbered 15 to 16 pairs. At 

the otic-capsule stage (fig. 2–23), the otic capsule appeared, 

the tail bud extended outward further, the yolk between the 

head and tail began to invaginate, and the somites numbered 

17 to 18 pairs. At the tail-vesicle stage (fig. 2–24), the bump 

on the brain area was highly raised (a unique characteristic of 

black carp), a vesicle appeared on the tail bud, and the somites 

numbered 19 or 20 pairs. At the caudal-fin stage (fig. 2–25), 

the embryo and the yolk elongated, the yolk sac was kidneyshaped, the caudal fin formed, the tail vesicle moved to the 

end of the tail, and the somites numbered 21 to 23 pairs. At the 

lens-formation stage (no figure), the eye lens formed, the tail 

vesicle was still visible, and the somites numbered 24 pairs. 

At the muscular-effect stage (fig. 2–27), the tail vesicle 

disappeared, the olfactory vesicle formed, the eyes were 

round, the embryo lashed slightly, the yolk continued to 

elongate with an obvious constriction in the posterior portion 

of the yolk, the end of the yolk was grey-blue, and the somites 

numbered about 25 pairs. At the heart-rudiment stage (fig. 

2–28), the embryo elongated further, the caudal fin extended, 

the embryo lashed occasionally but was relatively inactive, the 

posterior portion of the yolk sac was narrow, the heart rudiment 

appeared between the head and the yolk, and the somites numbered 26 to 30 pairs. At the otolith-appearance stage (fig. 2–29), 

the embryo straightened and moved continuously, the yolk sac 

was wider in the anterior than the posterior portion, and the 

somites numbered 31 to 34 pairs. At the heart-pulsation stage 

(no figure), the heart began to pulsate, the embryo rotated 

continuously, the egg membrane softened, and the somites 

numbered 35 to 38 pairs. The embryo was ready to hatch.

Silver Carp

The youngest eggs collected were at the 8-cell stage (fig. 

3–4). The cells were orange and the yolk was light yellow. 

The grey cytoplasm was widely distributed in the yolk. At 

the 16- to 64-cells stages (fig. 3–5 to 3–7), the cytoplasm 

diminished gradually. At the 128-cell stage (fig. 3–8), the 

cell color lightened, and the cytoplasm almost disappeared. 

The blastodisc appeared mound-like and several oil droplets 

appeared on the yolk cell. At the morula stage (fig. 3–9), 

cells became smaller, the blastodisc was highly raised above 

the yolk, and the cytoplasm disappeared. At the early-blastula 

stage, the blastodisc formed a half-sphere. At the mid-blastula 

stage (fig. 3–12), the blastodisc began flattening. At the lateblastula stage, the blastodisc flattened more and gradually 

expanded over the yolk. At the early-gastrula stage (fig. 3–

13), the germ ring was visible, the blastoderm covered about 

one-third of the yolk cell, and the whole egg appeared round. 

At the mid-gastrula stage (fig. 3–14) the blastoderm covered 

about half of the yolk. At the late-gastrula stage (fig. 3–15), 

the embryo head enlarged, and the blastoderm covered about 

three-fourths of the yolk. At the neurula stage (no figure), 

the head part was clearly visible and the blastoderm covered 

almost the whole yolk, leaving only the yolk plug uncovered. 

At the blastopore-closure stage (fig. 3–17), the front part of 

the embryo head was square and the yolk was round. At the 

somite-appearance stage (fig. 3–18), somites numbered one to 

three pairs and the optic primordium was dimly visible. At the 

optic-primordium stage (fig. 3–19), the optic primordium was 

a long oval shape and clearly visible, the embryo embraced 

about three-fourths of the yolk, the un-encircled margin of the 

yolk was convex, and the somites numbered four to six pairs. 

At the optic-vesicle stage (fig. 3–20), the eyes enlarged and the 

somites numbered seven to nine pairs. At the olfactoryplacode stage (fig. 3–21), the olfactory placode was barely 

visible above the optic vesicle, the somite number was 10-13 

pairs, and the notochord was clearly visible. At the tail-bud 

stage (fig. 3–22), the eyes enlarged and were shaped like a 

watermelon seed, the brain rudiment differentiated slightly, 

the tail bud appeared, and the somites numbered 14 to 16 

pairs. At the otic-capsule stage (fig. 3–23), the tail bud was 

clearly visible, the otic capsule appeared, the yolk elongated, 

the portion of the yolk between the head and tail began 

invagination, and the somites numbered 17 to 19 pairs. At the 

tail-vesicle stage (fig. 3–24), the tail bud expanded outward 

further, the tail vesicle appeared, the bump on the brain area 

enlarged, the yolk elongated and became kidney-shaped, and 

the somites numbered 20 or 21 pairs. At the caudal-fin stage 

(fig. 3–25), the caudal fin expanded outward, the embryo and 

the yolk elongated, and the somites numbered 22 or 23 pairs. 

At the lens-formation stage (fig. 3–26), the eyes were round, 

the olfactory vesicle was clearly visible, the embryo 

elongated, the yolk invaginated further, and the somites 

numbered 24 or 25 pairs. At the muscular-effect stage (fig. 

3–27), the embryo continued elongating and lashed slightly, 

the tail vesicle disappeared, the bump on the brain area 

enlarged but was not highly raised, the end of the yolk was 

colorless, and the somites numbered about 26 to 28 pairs. 

At the heart-rudiment stage (no figure), the heart rudiment 

appeared, the embryo lashed occasionally, and the somites 

numbered 29 to 30 pairs. At the otolith-appearance stage (fig. 

3–29), the embryo elongated further, the embryo moved 

continuously, the otolith appeared, and the somites numbered 

31 to 35 pairs. At the heart-pulsation stage (no figure), the 

heart began to pulsate, the embryo rotated continuously, the 

egg membrane softened, and the somites numbered 36 or 37 

pairs. The embryo was ready to hatch.

Bighead Carp

At the 2-cell stage (fig. 4–2), the cytoplasm was widely 

distributed in the yolk. Cells divided vertically five times until 

the 64-cell stage (fig. 4–3 to 4–7); the cytoplasm diminished 

gradually. The cells were light yellow and the yolk was even 

lighter in color. The cross-section width of the animal pole 

was smaller than that of the yolk. After one horizontal celldivision, the 128-cell stage (no figure), started. At the morula 

stage (fig. 4–9), the blastodisc was highly raised above the 

yolk. At the early-blastula stage (fig. 4–10), the blastodisc 

remained high and the cells became smaller. At the midChapter 2 – Translation of Yi and Others, 1988 21
blastula stage (fig. 4–11), the blastodisc began flattening. At 

the late-blastula stage (fig. 4–12), the blastodisc gradually 

expanded over the yolk and the cytoplasm almost disappeared. 

At the early-gastrula stage (fig. 4–13), the whole egg looked 

round, the germ ring formed, the dorsal lip appeared, and the 

blastoderm covered about one-third of the yolk. At the midgastrula stage (fig. 4–14), the blastoderm covered about twothirds of the yolk, and the embryonic shield appeared. At the 

late-gastrula stage (fig. 4–15), the blastoderm covered about 

five-sixths of the yolk, and the rudimentary embryo was 

visible. At the neurula stage (fig. 4–16), the head part 

enlarged, and the blastoderm covered almost the whole yolk, 

leaving only the yolk plug uncovered. At the blastoporeclosure stage (no figure), the front part of the embryo head 

was slightly curved. At the somite-appearance stage (no 

figure), somites numbered one to three pairs, the head was 

round but the front margin of the head was flat. At the opticprimordium stage (fig. 4–19), the optic primordium was dimly 

visible and was a long oval shape with a slightly crenulated 

lower margin. The embryo embraced about three-fourths of 

the yolk. No oil droplets appeared on the yolk. The somites 

numbered four to six pairs. At the optic-vesicle stage (no figure), the eyes enlarged and the somites numbered seven to 10 

pairs. At the olfactory-placode stage (fig. 4–21), the eyes 

continued enlarging, the lower edge of the eye was still 

slightly crenulated, the olfactory placode appeared, the 

notochord was clearly visible, and the somites numbered 

11-14 pairs. At the tail-bud stage (fig. 4–22), the optic vesicle 

was large and clearly visible, the tail bud appeared, the yolk 

elongated, and the somites numbered 15 to 17 pairs. At the 

otic-capsule stage (no figure), the yolk between the head and 

tail began invagination, and the somites numbered 18 or 19 

pairs. At the tail-vesicle stage (fig. 4–24), the otic capsule was 

clearly visible, the tail bud expanded outward, the tail vesicle 

appeared, the embryo became thicker, the yolk elongated and 

looked like a kidney, and the somites numbered 20 or 21 pairs. 

At the caudal-fin stage (no figure), the caudal fin expanded 

outward, and the somites numbered 22 or 23 pairs. At the lensformation stage (fig. 4–26), the olfactory vesicle was clearly 

visible, the lens formed, the embryo and the yolk elongated, 

a bump on the brain area was slightly raised, the tail vesicle 

disappeared, and the somites numbered 24 pairs. At the muscular-effect stage (no figure), the embryo lashed slightly, the 

end of the yolk was light grey-blue, and the somites numbered 

about 25 to 27 pairs. At the heart-rudiment stage (no figure), 

the embryo lashed occasionally, the somites numbered 28 

to 29 pairs. At the otolith-appearance stage (fig. 4–29), the 

otolith appeared, the embryo elongated further, the tail was 

relative long and often moved to one side, the embryo rotated 

occasionally. While the anterior half of the yolk-sac was oval 

and wide, the posterior half was narrow. The somites 

numbered 30 to 32 pairs. At the heart-pulsation stage (no 

figure), the heart began to pulsate, the embryo rotated 

continuously, and the somites numbered 33 or 35 pairs. 

The embryo was ready to hatch.

Comparison of the Embryological Development 

of Grass, Black, Silver, and Bighead Carps

Although the reproductive habits among the four 

species are similar and the general characteristics of eggs 

and embryological development are also similar, speciesspecific differences in morphology and time of organ 

differentiation could be found by careful observation of the 

various stages. Through comprehensive observation, some 

diagnostic characteristics of eggs were distinguished among 

species.

Before the blastula stage, there was no obvious difference 

between the developing eggs of the four species. At the 

blastula stage, when the blastoderm margin covered one-half 

to two-thirds of the yolk surface, the form of the yolk was 

different among species. The upper part of the covered yolk 

of grass carp had a greater diameter than that of the lower part 

(fig. 1–14); in black carp, the upper part of the covered yolk was 

the same size as the lower part (fig. 2–14); in silver carp, the 

entire yolk had a round shape (fig. 3–14); and in bighead carp, 

the yolk was relatively wide (fig. 4–14). At the blastoporeclosure stage, when the embryo began to form, the head of grass 

carp was smoothly curved (fig 1–17). The black carp head was 

somewhat wider in the vertical aspect and the anterior margin 

was straight (fig. 2–17). The silver carp head was square 

(fig. 3–17). These characteristics were obvious.

At the somite-appearance stage, the optic rudiment of the 

silver carp appeared (fig. 3–18), while that of the bighead carp 

did not appear until the olfactory-placode stage (fig. 4–21). 

From the optic- rudiment stage to the otic-capsule stage, there 

were oil droplets on the yolk of the grass carp (fig. 1–19 to 

1–23). The black carp also had these oil droplets until the 

otolith-appearance stage (fig. 2–20 to 2–29). There were no 

oil droplets on the yolk sac of silver and bighead carps. At 

that time, the embryo lengthened and embraced the yolk. The 

shape of the un-encircled margin of the yolk was different 

between species. The un-encircled margin of the yolk was 

short and slightly convex in grass carp (fig. 1–19 to 1–21); 

nearly straight in black carp (fig. 2–19 to 2–21); more 

convex in silver carp than in grass carp, (fig. 3–19 to 3–21); 

and gradually changing from convex to straight in bighead 

carp (fig. 4–19 to 4–21).

From the otic-capsule stage to the heart-pulsation stage, 

the head of the embryo gradually developed a bump (fig. 

10A). The bump on black carp was largest (fig. 10A2), 

followed by the grass carp (fig. 10A1). The bump on silver 

and bighead carps was not obvious (fig. 10A3, 4); especially 

the bighead carp which only had a small wave shape.

At the otolith-appearance stage, the yolk sac lengthened 

with the development of the embryo, and the anterior portion 

was wider than the posterior portion. However, there were 

differences among species. The anterior one-third of the yolk 

sac of grass carp was round, and the remainder was narrow 

and straight (fig. 1–29). In black carp (fig. 2–29), the yolk sac 

gradually narrowed toward the vent. In silver carp (fig. 3–29), 

the front two-thirds of the yolk sac was wide and the posterior 

22 Early Development of Four Cyprinids Native to the Yangtze River, China
one-third was narrow with an obvious concavity between these 

two parts. In bighead carp (fig. 4–29), the front half of yolk 

sac was extremely large and the posterior half was very narrow 

with a deep constriction between the two halves.

Post-hatch Development

Characteristics

There were 18 stages between hatching and the 

juvenile stage when the lateral line scales were complete. 

During these stages, the fish underwent the change from 

endogenous to exogenous nutrition. During post-hatch 

development, the various organs gradually differentiated 

and became identifiable. There were many characteristics 

that were similar between the four species, but there were 

certain obvious differences.

Grass Carp

(1) Hatching stage (fig. 5–31): Total length was 6.0 mm 

at 37 hours post-fertilization. The tail length was 24 percent of 

the total length. The body was transparent and the heart was 

at the top of the anterior edge of the yolk sac. The posterior 

aorta, the main vein, the caudal vein, and myomere blood 

vessels were differentiated. The blood color was apricotyellow. The yolk sac was a lengthened teardrop shape with a 

bright-blue color on the posterior end. Below the eye, there 

was a triangular black spot. The eye diameter was 0.35 mm. 

The myomere numbering was 8+22+13=43. The larvae 

remained on their side at the bottom of the container most of 

the time, but occasionally they darted to the surface.

(2) Rudimentary-pectoral-fin stage (fig. 5–32): Total 

length was 6.8 mm at 47 hours post-fertilization. The 

rudimentary pectoral fin was crescent-shaped and located 

below myomeres two or three. The heart moved slightly 

ventrally and was located anterior to the middle of the yolk 

sac. The Cuvierian duct appeared. The caudal vein was large 

and wide. The black spot below the eye became oval. The 

heartbeat was 182 times per minute (at 26.8 oC). The larva 

swam actively.

(3) Gill-arch stage (fig. 5–33): Total length was 7.0 mm at 

51 hours post-fertilization. The body color was butter-yellow. 

The tail length was 27 percent of total length. Ventral to the 

otic capsule and posterior to the eye, four gill arches appeared. 

The head extended straight out from the body. The indentation 

of the mouth appeared. The pectoral fin enlarged. The blood 

vessels were clearly evident. The caudal vein expanded and 

was apricot-yellow. The diameter of the eye was about 0.40 

mm and the myomere numbering was 8+22+14=44.

(4) Xanthic-eye stage (fig. 5–34): Total length was 7.2 

mm at 62 hours post-fertilization. Yellow pigmentation of the 

eye appeared. The caudal vein was thick and the color was 

loquat-yellow. The mouth was slightly open. The rudiments 

of the gill filaments appeared. The myomere numbering was 

8+22+15=45. Viewed dorsally, there were clear embryonic 

hairs9 on the sides of the embryo.

(5) Gill-filament stage (fig. 5–35): Total length was 7.5 

mm at 73 hours post-fertilization. The gill filaments were clear 

and the operculum appeared. The blue color of the posterior 

end of the yolk sac disappeared. The caudal vein and the 

Cuvierian duct narrowed.

(6) Melanoid-eye stage (fig. 5–36): Total length was 7.7 

mm at 83 hours post-fertilization. Black pigment appeared in 

the eye at the top front and later extended all the way around. 

The black spot below the eye disappeared. The operculum 

was clearly evident. The rudimentary cleithrum appeared. The 

yolk sac became narrow and elongated. Two or three stellate 

melanophores appeared on the anterior portion of the yolk sac. 

There were four or five stellate melanophores at the ventral 

edge of the myomeres in front of the vent. The caudal vein 

became thinner. The diameter of the eye was 0.42 mm.

(7) Gas-bladder-emergence stage (fig. 5–37): Total 

length was 8.13 mm at 98 hours post-fertilization. Tail length 

was about 30 percent of total length. The gas bladder began 

to appear. The yolk sac continued to elongate. The gut was 

continuous, the mouth moved forward, and the gill filaments 

grew longer. The otic capsule enlarged to almost the diameter 

of the eye. The pectoral fins extended; near the insertion of the 

fin there was one stellate melanophore. From the dorsal view, 

the anterior margin of the head was flattened and there were 

eight stellate melanophores. From the dorsal surface of the 

gas bladder, there were two lines of pigment between the gut 

and myomeres. The pigment lines extended to the caudal end 

of the vertebral column. (With the naked eye, one black line 

was visible. Fish caught at this stage directly from the river 

were less pigmented than those raised in the lab.) The body 

was lemon-yellow and the eye was orange-yellow with a blue 

tint on the edge. The caudal vein was intense orange-yellow. 

Myomere numbering was 9+21+15=45. Some embryonic hairs 

were still visible.

(8) One-chamber-gas-bladder stage (fig. 5–38): Total 

length was 8.55 mm at 139 hours post-fertilization. The inside 

of the gut appeared wavy, gut folds appeared, and feeding 

began. The yolk sac was mostly gone, as this was the period of 

mixed endogenous and exogenous nutrition. The mouth was 

terminal. The nares moved to the dorsal surface of the head. 

The body was lemon-yellow, covered by many melanophores; 

on the body side, there were four lines of pigment and another 

one along the gut. Many stellate melanophores were visible 

in the dorsal view of the head. The stellate melanophore on 

the pectoral fin enlarged. Many melanophores were grouped 

together inside the deep posterior portion of the head. From 

the dorsal view these melanophores appeared vase-shaped 

(fig. 9a). There were a few melanophores below the caudal 

end of the notochord. (The larvae caught from the river at this 

stage had a lighter body color. Except for the melanophores on 

the dorsal body and the pectoral fin, the melanophores on the 

9

 Translator’s note: Assumed to be neuromast cupulae.

Chapter 2 – Translation of Yi and Others, 1988 23
other parts of the body were not obvious.) The caudal vein was 

orange-yellow. At this time the fish could swim normally.

(9) Yolk-absorption stage (no figure): Total length was 

8.62 mm at 167 hours post-fertilization. The yolk sac was 

exhausted. The gut folds were more developed. The fish 

began to feed on plankton. The anterior margin of the head 

was flattened. The pigment on the body side and dorsal head 

surface increased, but the deep pigment inside the head did not 

change. The stellate melanophores on the pectoral fin numbered 

two or three. There were two or three stellate melanophores on 

the lower caudal finfold.

(10) Dorsal-fin-differentiation stage (fig. 5–40): Total 

length was 8.7 mm at 190 hours post-fertilization. The dorsal 

margin of the anterior part of the dorsal finfold had a sigmoid 

shape. The melanophores on the pectoral fins formed an arch 

shape. There were stellate melanophores and some small 

melanophores on the lower part of the caudal fin; with the 

naked eye these together appeared as a gray spot. Myomere 

numbering was 10+20+15=45.

(11) Notochord-tip-lifting stage (fig. 5–41): Total length 

was 9.20 mm at 215 hours post-fertilization. The anterior 

portion of the dorsal finfold had a pronounced triangular form, 

which was the rudimentary dorsal fin. The end of the vertebral 

column curved upward. The caudal finfold began to differentiate; the edge was crenulated. There were 12 initial rays in the 

caudal fin. The anal finfold began to differentiate. The caudal 

vein was still visible and was loquat-yellow. The pigment 

on the surface of the head between the eyes increased. Also, 

pigment appeared on the maxillary. The anterior margin of 

the dorsal finfold moved backward. Myomere numbering was 

11+19+15=45. The operculum enlarged and covered the entire 

gill chamber.

(12) Two-chamber-gas-bladder stage (fig. 5–42): Total 

length was 10.16 mm at 253 hours post-fertilization. The 

anterior gas bladder appeared and formed a ball shape. The 

posterior gas bladder moved backward, lengthened, and 

tapered towards the rear. On the rudimentary dorsal fin and 

anal fin, there were six or seven initial rays and several stellate 

melanophores. The caudal fin continued to differentiate; 

16 rays were apparent. The vertebrae were clearly visible. 

Myomere numbering was 12+18+15=45.

(13) Pelvic-fin-bud stage (fig. 5–43): Total length was 

10.68 mm at 302 hours post-fertilization. The tail length was 

about 31.5 percent of total length. The pelvic fin bud appeared 

in the midpart of the preanal finfold. The rudimentary 

dorsal fin grew larger; the numbers of rays and melanophores 

increased. The dorsal finfold shrank. The numbers of rays 

and melanophores on the anal finfold increased. The caudal 

fin was forked; between the rays there were melanophores. 

The mandible and maxillary were developed. The mouth was 

terminal. The anterior gas bladder enlarged and became oval. 

The pattern of the deep pigment in the head changed. Below 

the end of the urostyle, there was a large and obvious stellate 

melanophore. Myomere numbering was 13+17+15=45.

(14) Dorsal-fin-formation stage: At the beginning of this 

stage (fig. 5–44a), total length was ll.8 mm at 15 days postfertilization. The dorsal fin was separate from the dorsal 

finfold (ray numbering = ii, 7). The anal fin extended and the 

number of rays increased. The pelvic fin bud enlarged. At 

the end of the dorsal-fin-formation stage (fig. 5–44b), total 

length was 12.5 mm at 18 days post-fertilization. The dorsal 

fin was thoroughly formed (ray numbering = iii, 7). The anal 

fin enlarged (ray numbering = ii, 8). The dorsal finfold and 

anal finfold shrank to the caudal peduncle. The pelvic fin 

enlarged; three or four rays appeared. The ribs and vertebral 

processes began to appear. The myomeres further developed 

from a single chevron shape to chevrons both above and below 

the lateral line. Myomere numbering was 14+16+15=45. The 

operculum became thicker.

(15) Anal-fin-formation stage (fig. 5–45): Total length 

was 14.9 mm at 21 days post-fertilization. The anal fin was 

formed (ray numbering = iii, 8). The anal finfold continued to 

shrink. The caudal fin was thoroughly developed. The pelvic 

fin lengthened and the preanal finfold shrank.

(16) Pelvic-fin-formation stage (fig.5–46): Total length 

was 16.2 mm at 24 days post-fertilization. The pelvic fin 

formed. The preanal finfold remained only in a narrow strip. 

The pectoral fin continued to develop; the stellate melanophores on the base of the fin reduced. The whole body was 

pigmented.

(17) Squamation stage (fig. 5–47). Total length was 

between 21 to 32 mm at 44 to 58 days post-fertilization. The 

morphology was similar to that of an adult fish; very little 

remained of the preanal finfold. Lateral line scales and several 

rows of scales above and below it developed from the front 

to the back. The growth of scales depended on environmental 

conditions (table 7).10

(18) Juvenile stage (fig. 5–48): Total length was about 35 

mm. This stage lasted from 63 to 92 days post-fertilization. 

Squamation was complete. The lateral line scales numbered 

39. Other than the larger eyes, the fish resembled an adult fish.

Black Carp

(1) Hatching stage (fig. 6–31): Total length was 6.7 mm 

at hatching, which occurred at 43 hours post-fertilization. The 

tail length was 26.5 percent of the total length. The anterior 

part of the yolk sac was large and wide, and the posterior part 

of the yolk sac was long and thin, becoming a lengthened teardrop shape. The posterior end of the yolk sac had a slightly 

blue color. The heart was at the bottom of the anterior edge 

of the yolk sac. The caudal vein was not clear. The embryo 

color was apricot-yellow. The head was angled downward. 

The diameter of the eye was 0.37 mm. At the lower edge of 

the eye there was a black spot. The myomere numbering was 

7+19+14=40. The larvae rested on their side on the bottom of 

the container, occasionally darting to the surface.

10 Translator’s note: tables 4, 5, and 6 are first referenced later in the original document than this reference to table 7. Table 7 is again referenced, and 

discussed in more detail, later in the document.

24  Early Development of Four Cyprinids Native to the Yangtze River, China
(2) Rudimentary-pectoral-fin stage (fig. 6–32): Total 

length was 7.0 mm at 48 hours post-fertilization. The tail 

length was 27.5 percent of the total length. The embryo was 

butter-yellow. The rudimentary pectoral fin was crescentshaped and located below myomeres two to three. The heart 

moved slightly ventrally, and was now located anterior to the 

middle of the anterior edge of the yolk sac. The Cuvierian 

ducts were clear. The heartbeat was 154 times per minute at 

26.8 oC or 200 times per minute at 27.7 oC. The bottom edge 

of caudal vein was crenulated and tapered posteriorly along 

the anal finfold, the end curving upward into the tenth postanal myomere. The eye diameter was 0.41 mm. The myomere 

numbering was 8+18+14=40. The larvae rested on their side 

on the bottom of the container, but occasionally darted to the 

surface.

(3) Gill-arch stage (fig. 6–33): Total length was 7.38 mm 

at 56 hours post-fertilization. The tail length was about 30 

percent of total length. Four gill arches appeared. The caudal 

vein margin was wavy and very clear. The anterior portion 

of the yolk sac shrank slightly. The myomere numbering was 

8+18+15=41.

(4) Xanthic-eye stage (fig. 6–34): Total length was 7.5 

mm at 70 hours post-fertilization. The yellow pigmentation 

of the eye appeared. The head extended straightly; the mouth 

opened and began slight movements. The rudiments of the gill 

filaments appeared. The rudimentary pectoral fin expanded to 

a semi-circular shape. The larvae rested on their side on the 

bottom of the container and were not active.

 (5) Gill-filament stage (fig. 6–35): Total length was 

7.66 mm at 79 hours post-fertilization. The gill filaments 

appeared. The head grew straight out from the body. The yolk 

sac became a lengthened tear-drop shape. The otic capsule 

enlarged and was about one-half the eye size. The larvae were 

still not active, but occasionally swam without vertical orientation.

(6) Melanoid-eye stage (fig. 6–36): Total length was 8.0 

mm at 89 hours post-fertilization. The black spot at the lower 

edge of the eye disappeared. Black pigments gradually appeared 

around the edge of the eye and often displayed gold-yellow or 

blue colors. The lower jaw shook continuously and the pectoral 

fins quivered. The otic capsule continued to enlarge. The gill 

filaments became evident. The larvae laid on their side or 

swam unbalanced, occasionally swimming normally.

(7) Gas-bladder-emergence stage (fig. 6–37): Total 

length was 8.14 mm at 109 hours post-fertilization. The gas 

bladder began to appear. The gut was now continuous. The 

otic capsule enlarged almost to the size of the eye. Pectoral 

fins started to move at this stage. The mouth occupied a more 

forward position. The yolk sac shrank to a baseball-bat shape. 

From the dorsal view, the snout was curved with the central 

portion prominent. Along the dorsal surface of the gas bladder 

and the gut, there was a pigment line that extended to the 

caudal vein (with the naked eye, one black line was visible; 

darker than that of grass carp). There was a large black stellate 

melanophore below the tail myomeres on the caudal finfold. 

The caudal vein was clear and orange-yellow. Myomere 

numbering was 9+17+15=41. Head and body sides had 

embryonic hair. The larva swam normally, maintaining 

vertical orientation.

(8) One-chamber-gas-bladder stage (fig. 6–38): Total 

length was 8.55 mm at 140 hours post-fertilization. The inside 

of the gut appeared wavy because of the development of the 

gut folds. Feeding began. The yolk sac remained only as a 

small strip. The dorsal margin of the body was slightly arched 

at the beginning of the dorsal finfold. Initial rays appeared on 

the caudal finfold. From the dorsal view of the melanophores 

inside the head, there were two short pigment lines near otic 

capsule and two large stellate melanophores above the base 

of pectoral fin, which formed two “ \ / ” shapes (fig. 9b). On 

the surface of the head there was no pigment, while the sides 

of the body were covered by a few melanophores. There were 

also a few melanophores at and below the urostyle.

(9) Yolk-absorption stage (fig. 6–39): Total length was 

9.35 mm at 174 hours post-fertilization. The tail length was 

32 percent of the total length. The yolk was exhausted. At 

the junction of the lower lobe of the caudal finfold and the 

caudal vein, there was a lemon-yellow lymph node. Initial 

rays appeared in the ventral half of the caudal finfold. The 

gas bladder enlarged; the anterior margin was rounded and 

the posterior part was more pointed. There were some melanophores on the dorsal surface of the head, but no pigment 

between the eyes. There was a faint pigment line on the upper 

body side. Some small melanophores appeared at the posterior 

end of the vertebral column. The pigments inside the head 

and on the lower part of the caudal finfold were the same as in 

the one-chamber-gas-bladder stage (the melanophores of the 

larvae caught directly from the river looked like small dots). 

The mouth was terminal; there were a few melanophores on 

the upper jaw. The operculum completely covered the gills. 

Myomere numbering was 10+16+15=41.

(10) Dorsal-fin-differentiation stage (fig. 6–40): Total 

length was 10.0 mm at 197 hours post-fertilization. The dorsal 

margin of the anterior part of the dorsal finfold had a sigmoid 

shape. Nine initial rays appeared in the caudal finfold with 

melanophores between the rays. The pectoral fins enlarged; 

there was no pigment on the base of pectoral fins. The otic 

capsule became triangular. There were two pigment lines 

on the upper body side. The melanophores on the upper jaw 

increased. The stellate melanophore on the low part of the 

caudal fin was more obvious.

(11) Notochord-tip-lifting stage (fig. 6–41): Total length 

was 10.7 mm at 226 hours post-fertilization. The anterior 

portion of the dorsal finfold had a pronounced triangular form. 

The caudal finfold began to differentiate; the margin of the 

fin was crenulated. There were 12 rays in the caudal fin. The 

vertebrae were partially formed. On the dorsal surface of the 

head, there were few or no melanophores between the eyes. 

Some individuals had a small melanophore on the base of the 

pectoral fin. Myomere numbering was 10+16+15=41.

(12) Two-chamber-gas-bladder stage (fig. 6–42): Total 

length was 11.3 mm at 285 hours post-fertilization. The anterior gas bladder chamber appeared, forming a yellow, slightly 

transparent ball. As time progressed, more and more melanoChapter 2 – Translation of Yi and Others, 1988 25
phores covered the upper part of the gas bladder, which was 

often grayish silver in color. The dorsal fin began to separate 

from the dorsal finfold, and had seven initial rays and a large 

stellate melanophore. The vertebrae differentiated. Myomere 

numbering was 11+15+15=41 and the myomeres further 

developed from a single chevron to a double chevron shape.

(13) Pelvic-fin-bud stage (fig. 6–43): Total length was 

12.0 mm at 324 hours post-fertilization. The pelvic fin bud 

appeared in the mid-part of the preanal finfold. The melanophores inside the head changed shape from that shown in fig. 

10, D, 18 to that in fig. 10, D, 22. The caudal fin began differentiation. The dorsal and anal fins extended. The gas bladder 

enlarged. Embryonic hairs disappeared.

(14) Dorsal-fin-formation stage: Total length ranged 

between 13.0 to 14.4 mm at 15 to 18 days post-fertilization. 

At the beginning of this stage (fig. 6–44a), the dorsal fin was 

separate from the dorsal finfold (dorsal fin ray numbering = 

ii, 7). The caudal fin had 18 rays. The pectoral fin was curved 

convexly. The pelvic fin bud enlarged slightly; rays began 

appearing. At the end of the dorsal-fin-formation stage (fig. 

6–44b), the dorsal fin formed completely (ray numbering = iii, 

7). The anal fin enlarged rapidly (ray numbering = ii, 8). The 

dorsal finfold and anal finfold began to disappear. The caudal 

fin was forked deeply. The pelvic fin enlarged; rays were 

obvious. The stellate melanophore below the urostyle was 

very obvious. There were few melanophores on the body. The 

operculum became thicker. The ribs and vertebral processes 

began to appear.

(15) Anal-fin-formation stage (fig. 6–45): Total length 

was 14.9 mm at 22 days post-fertilization. The anal fin was 

formed completely (ray numbering = iii, 8). Rays appeared in 

the pectoral fin. The pelvic fin lengthened and the preanal finfold shrank. There were no or few melanophores between the 

eyes on the dorsal surface of the head. The snout and mouth 

became even more pointed.

(16) Pelvic-fin-formation stage (fig. 6–46): Total length 

was 16.1 mm at 25 days post-fertilization. The pelvic fin 

formed and had eight rays. The preanal finfold shrank further. 

Rays in the pectoral fin were obvious. Several of the anterior 

rays became branched and extended on the anal fin. The gas 

bladders enlarged.

(17) Squamation stage (no figure): Total length was 

between 20 to 27 mm. This stage lasted from 35 to 60 days 

post-fertilization. For the larvae raised in a container, the 

number of scales increased with increasing body length. 

When total lengths of the fish were 20, 21, 23, and 27 mm, the 

numbers of lateral line scales were 2, 4, 9, and 13 respectively 

(observed in 1961 in Yichang).

(18) Juvenile stage (fig. 6–48; 69 days old): Total length 

was about 35.5 mm. The juvenile stage lasted 60 to 83 days 

post-fertilization. Squamation was complete. All fins developed completely. Other than the larger eyes, the juvenile 

resembled an adult fish. The lateral line scales numbered 43. 

The large stellate melanophore below the urostyle was still 

obvious. The anal fin was relatively large; branched rays are 

long.

Silver Carp

(1) Hatching stage (fig. 7–31): Total length was 6.1 mm 

at 38 hours post-fertilization. Tail length was 28.5 percent 

of the total length. Unlike grass and black carps, the head of 

silver carp did not curve and extend downwards, and instead 

extended obliquely forward from the body. The yolk sac was 

light in color and slightly transparent. The anterior portion of 

yolk sac was large and oval; the posterior portion was a narrow and lengthened tear-drop shape. Body was butter-yellow. 

The heart was at the top of the anterior edge of the yolk sac. 

The caudal vein was not very obvious. The otic capsule was 

relatively small. The eye diameter was 0.37 mm. A black spot 

appeared at the lower edge of the eye about 10 minutes after 

hatching. The myomere numbering was 6+19+14=39. Larvae 

usually rested on their side on the bottom of the container, but 

occasionally they swam actively.

(2) Rudimentary-pectoral-fin stage (fig. 7–32): Total 

length was 6.3 mm at 48 hours post-fertilization. The tail 

length was 29.5 percent of total length. The head extended 

straight out from the body. The rudimentary pectoral fin was 

located below myomeres two to three. The heart moved to the 

anterior edge of the yolk sac. Cuvierian ducts were located 

on the anterior tip of yolk sac. The myomere numbering was 

7+18+14=39. The larvae still usually rested on the bottom but 

occasionally swam.

(3) Gill-arch-stage (fig. 7–33): Total length was 6.83 mm 

at 53 hours post-fertilization. The tail length was about 31 

percent of total length. Four gill arches appeared. Cuvierian 

ducts were now located on the front side of yolk sac. The 

yolk sac shrank and became a lengthened tear-drop shape. 

The eye diameter was 0.4 mm. The myomere numbering was 

7+18+15=40.

(4) Xanthic-eye-stage (fig. 7–34): Total length was 

7.2 mm at 63 hours post-fertilization. Tail length was about 

32 percent of total length. Yellow pigmentation of the eye 

appeared; it was apricot-yellow. There was a small black spot 

on the front edge of the eyes. Blood vessels between 

myomeres were obvious. The indentation of the mouth 

appeared. The myomere numbering was 8+17+15=40. The 

larvae still laid on the bottom and occasionally swam.

(5) Gill-filament stage (fig. 7–35): Total length was 7.55 

mm at 74 hours post-fertilization. The tail length was about 

33percent of total length. The gill filaments extended. The 

head and body straightened. Melanophores on the front edge 

of eyes increased. The mouth was open. The lower jaw began 

movement.

(6) Melanoid-eye stage (fig. 7–36): Total length was 8.0 

mm at 92 hours post-fertilization. Melanophores extended all 

the way around the eye. The otic capsule enlarged and was 

about 1⁄2 of the eye diameter. The rudimentary pectoral fin base 

appeared. The mouth moved forward and was located below 

the front margin of the eye.

(7) Gas-bladder-emergence stage (fig. 7–37): Total length 

is 8.24 mm at 106 hours post-fertilization. Tail length was 

about 34 percent of total length. The gas bladder began to 

26  Early Development of Four Cyprinids Native to the Yangtze River, China
appear. There were melanophores on the gas bladder. The gut 

was now continuous. The mouth continued to move forward. 

The otic capsule enlarged to a size slightly smaller than that 

of the eye. The yolk sac remained only as a narrow strip. On 

the front tip of the yolk sac there were several stellate melanophores. From the dorsal view, the tip of the snout was round 

and there were several stellate melanophores on the surface 

of the head and between the eyes. There was a faint line of 

pigment along the upper edge of myomeres. On the posterior 

part of the fish body there was a short pigment line along the 

lower edge of myomeres. The body was butter-yellow. The 

caudal vein was apricot-yellow. Larvae were able to swim 

normally.

(8) One-chamber-gas-bladder stage (fig. 7–38): Total 

length was 8.5 mm at 146 hours post-fertilization. The gas 

bladder appeared and was oval or olive shape. The maxillary 

differentiated. The mouth was terminal. Feeding began. The 

inside of the gut appeared wavy due to the development of 

the gut folds. Very little yolk sac remained. The pectoral fin 

enlarged and covered the front third of the gas bladder. The 

otic capsule continued to enlarge, and was triangular and 

equal in size to the eye. Dorsal and anal finfolds began to 

separate from the caudal finfold. The body was covered by 

many melanophores. Pigment density increased on the dorsal 

surface of the head and between the eyes. From the dorsal 

view, two pigment lines appeared between the otic capsule and 

the cleithrum and formed a U shape (fig. 9c). There were four 

lines of pigment on the body side. Seven or eight melanophores 

of various sizes were visible on the preanal finfold. Around the 

posterior end of the notochord in the caudal finfold there was a 

group of melanophores that appeared as two large black points 

when viewed with the naked eye. There were also a few small 

melanophores on the anterior part of the anal finfold. The 

myomere numbering was 8+16+16=40.

(9) Yolk-absorption stage (no figure): Total length was 

8.7 mm at 168 hours post-fertilization. The yolk sac was 

exhausted. Pigment was distributed as in the previous stage, but 

melanophores were darker and denser. Myomere numbering 

was 9+15+16=40.

(10) Dorsal-fin-differentiation stage (fig. 7–40): Total 

length was 9.0 mm at 212 hours post-fertilization. The dorsal 

margin of the anterior part of the dorsal finfold had a sigmoid 

shape. There were a few small melanophores on the dorsal 

finfold. The posterior tip of the notochord curved slightly 

upward. The large stellate melanophores on the preanal finfold 

increased. There were also one or two stellate melanophores 

on the anal finfold. The two groups of melanophores on the 

caudal fin were even darker.

(11) Notochord-tip-lifting stage (fig. 7–41): Total length 

was 9.4 mm at 240 hours post-fertilization. Tail length was 

about 36 percent of total length. The end of the notochord 

curved upward obviously. The anterior portion of the dorsal 

finfold continued to differentiate and melanophores increased. 

The posterior margin of the caudal finfold was crenulated; 

there were eight initial rays in the caudal fin. The two groups 

of melanophores on the caudal finfold dispersed and three 

stellate melanophores were visible above and below the 

notochord tip. The operculum completely covered the gills. 

Melanophores on the anal finfold increased and extended to 

the entire finfold. Two small stellate melanophores appeared 

on the base of the pectoral fin. Myomere numbering was 

9+15+16=40.

(12) Two-chamber-gas-bladder stage (fig. 7–42): Total 

length was 10.32 mm at 279 hours post-fertilization. The 

anterior gas bladder appeared, forming a ball. The mouth 

was terminal and angled upward. Five rays were now visible 

in the dorsal fin. The posterior margin of the caudal fin was 

crenulated. There were 11 or 12 initial rays in the caudal fin 

with melanophores between the rays. The vertebral column 

was developing. Six rays appeared in the anal fin. Melanophores on the dorsal surface of the head increased. Below 

the tip of the notochord in the caudal fin there were two 

groups of small melanophores. Myomere numbering was 

10+14+16=40.

(13) Pelvic-fin-bud stage (fig. 7–43): Total length was 

11.2 mm at 312 hours post-fertilization. The pelvic fin bud 

appeared near the mid-part of the preanal finfold. The caudal 

fin was forked with 16 rays. The rudimentary dorsal fin grew 

larger with nine initial rays. The dorsal finfold shrank. The 

anal fin differentiated obviously with seven initial rays. The 

myomeres further developed from a single chevron to a double 

chevron. Body height increased obviously. The vertebral 

column was fully formed.

(14) Dorsal-fin-formation stage (fig. 7–44): Total length 

was 14.1 mm at 19 days post-fertilization. The dorsal fin was 

separate from the dorsal finfold (ray numbering = ii, 7). The 

anal fin extended obviously but had not yet separated from 

the anal finfold (anal fin ray numbering = ii, 12). The caudal 

fin was deeply forked, and had 16 branched rays and three 

unbranched rays both in the upper and lower portions of the 

fin. The pelvic fin bud extended. Initial rays start to appear 

in the pectoral fin. Melanophores on the preanal finfold were 

even darker and their branches shrank in size. Myomere 

numbering was 11+13+16=40. The ribs and large dorsal and 

ventral vertebral processes appeared on the vertebrae.

(15) Anal-fin-formation stage (fig. 7–45): Total length 

was 15.7 mm at 22 days post-fertilization. The anal fin (ray 

numbering iii, 12) was separated from the anal finfold. The 

dorsal fin had iii, 7 rays. The pelvic fin lengthened and 

extended beyond the preanal finfold. The preanal finfold was 

still large; on the posterior two-thirds there were many 

melanophores.

(16) Pelvic-fin-formation stage (fig. 7–46): Total length 

was 17.0 mm at 25 days post-fertilization. The pectoral fin 

formed (ray numbering = i, 8). The preanal finfold shrank 

slightly. The pelvic fin formed completely. The mouth opening 

was large, terminal, and strongly upturned. The upper side of 

the body was more pigmented than in previous stages.

(17) Squamation stage (fig. 7–47; 40–d old). Total length 

was about 20.0 mm. The squamation stage lasted from 34 to 

55 days post-fertilization. Scales at the anterior end of the 

body appeared first and scale development progressed towards 

Chapter 2 – Translation of Yi and Others, 1988 27
the rear of the body. There were 50 lateral line scales. The end 

of the pectoral fin did not reach the base of the pelvic fin. The 

preanal finfold gradually shrank.

(18) Juvenile stage (fig. 7–48): Total length was about 

34 mm. The stage lasted from 60 to 90 days post-fertilization. 

The fish resembled adult fish. The lateral line scales developed 

completely and numbered 101. The preanal finfold remained 

only as a narrow strip, on which there were some melanophores. The preanal finfold eventually developed into the full 

keel.

Bighead Carp

(1) Hatching stage (fig. 8–31): Total length was 7.0 mm 

at 39 hours post-fertilization. The body was large compared 

to the other three species. The tail length was relatively long 

and about 32 percent of the total length. The head extended 

straight forward from the body. The anterior half of yolk 

sac was large and oval; the posterior half was a narrow and 

lengthened tear-drop shape. The heart was at the top of the 

anterior edge of the yolk sac. Eye diameter was 0.39 mm. A 

black spot appeared below the eye. Caudal vein was large and 

flat. Myomere numbering was 6+17+15=38.

(2) Rudimentary-pectoral-fin stage (fig. 8–32): Total 

length was 7.1 mm at 49 hours post-fertilization. The 

rudimentary pectoral fin was located below myomeres two 

to three. The caudal vein was wide and long. The Cuvierian 

ducts appeared on the anterior tip of yolk sac. Blood color 

was apricot-yellow. Body color was butter-yellow and head 

color was lighter.

(3) Gill-arch stage (fig. 8–33): Total length was 7.5 mm 

at 59 hours post-fertilization. The tail length was 33 percent 

of total length. Four gill arches appeared. The head extended 

straight out from the body. The indentation of the mouth 

appeared. The caudal vein and Cuvierian ducts were obvious. 

The yolk sac shrank and the anterior portion narrowed. 

Myomere numbering was 7+16+15=38.

(4) Xanthic-eye stage (fig. 8–34): Total length was 7.8 

mm at 65 hours post-fertilization. Yellow pigmentation of 

the eye appeared. The mouth was open and could move. The 

lower edge of the caudal vein was crenulated.

(5) Gill-filament stage (fig. 8–35): Total length was 8.1 

mm at 76 hours post-fertilization. The body was relatively 

thick. The tail length was about 34.5 percent of total length. 

The eye diameter was 0.42 mm. The gill filaments appeared. 

The otic capsule and rudimentary pectoral fin enlarged. The 

blood systems were obvious.

(6) Melanoid-eye stage (fig. 8–36): Total length was 8.3 

mm at 98 hours post-fertilization. The eye diameter was 0.44 

mm. Melanophores appeared around the eye. The caudal vein 

was wide, long, and dark yellow. Myomere numbering was 

8+15+16=39. Normal swimming began.

(7) Gas-bladder-emergence stage (fig. 8–37): Total length 

was 9.2 mm at 111 hours post-fertilization. Tail length was 

about 36 percent of total length (the largest percentage among 

the four fishes). The snout was blunt. The initial gas bladder 

appeared. The gill filaments extended. The gut was continuous. 

The caudal vein was narrowing slightly but still visible. The otic 

capsule enlarged. From the dorsal view there were some stellate 

melanophores between the posterior edge of eyes and otic 

capsule (fig. 9d). There were separate faint pigment lines 

along the upper body side and vertebral column. There was 

also a distinct pigment line along the ventral edge of 

myomeres starting from the dorsal margin of the initial gas 

bladder. There were several large stellate melanophores 

in the region of the heart and top front yolk sac. Myomere 

numbering was 8+15+16=39. The larvae swam normally.

(8) One-chamber-gas-bladder stage (fig. 8–38): Total 

length was 9.4 mm at 135 hours post-fertilization. The gas 

bladder appeared and was oval. The inside of the gut appeared 

wavy (gut folds appeared). The yolk sac shrank and became a 

curved strip. The size of the otic capsule was equal to the eye 

size. The upper jaw formed. Pigment density increased on the 

dorsal surface of the head but there was no pigment between 

eyes (fig. 9d). There were four incomplete pigment lines on 

the body side. Some melanophores appeared on the anterior 

portion of the yolk sac. Two or three stellate melanophores 

appeared on the anal finfold. The melanophores on the lower 

part of the caudal finfold linked as a curve line. From the 

dorsal view, two pigment lines appeared between the otic 

capsule and cleithrum and form a “) (” shape (fig. 9d). The 

preanal finfold extended forward to below the posterior margin 

of the gas bladder. The myomere numbering was 9+14+16=39.

 (9) Dorsal-fin-differentiation stage (fig. 8–3911): Total 

length was 9.7 mm 166 hours post-fertilization. Tail length 

was about 37 percent of total length. The dorsal margin of the 

anterior part of the dorsal finfold had a sigmoid shape. A 

narrow strip of yolk sac still remained. There were four 

pigment lines; three of them along the upper body side. The 

notochord and the ventral edge of myomeres are relatively 

obvious. One short line on the anal finfold became slightly 

curved. Melanophores on the lower part of the caudal fin did 

not change.

(10) Yolk-absorption stage (fig. 8–40): Total length was 

10.0 mm at 202 hours post-fertilization. The yolk sac was 

exhausted. The dorsal fin further differentiated. There were 

some melanophores on the dorsal fin. The posterior margin 

of the caudal finfold began to become crenulated. The melanophores on the lower part of the caudal fin dispersed. Nine 

initial rays appeared in the caudal fin. The preanal finfold 

enlarged. Six or seven small stellate melanophores appeared 

on the posterior portion of the preanal finfold. The size and 

number of stellate melanophores on the anal finfold increased. 

The anal finfold extended to the edge of lower part of the 

caudal fin. A few larvae had one or two stellate melanophores 

on the base of the pectoral fin. Myomere numbering was 

10+13+16=39.

11 Translator’s note: In bighead carp only, the dorsal-fin-differentiation 

stage is listed as stage 39 and the yolk-absorption stages as stage 40. In the 

other three species, these are reversed. Although there is no discussion of this 

reversal in the original document, it does not appear to be an error, judging 

from the illustrations. 

28 Early Development of Four Cyprinids Native to the Yangtze River, China
(11) Notochord-tip-lifting stage (fig. 8–41): Total length 

was 10.8 mm at 216 hours post-fertilization. The dorsal fin 

further differentiated and had three initial rays. The posterior 

margin of the caudal finfold became crenulated. The caudal 

finfold had 14 initial rays. Eight initial rays appear in the anal 

fin, which was differentiating. The end of the the notochord 

curves upward. The mouth was terminal and angled upward. 

Melanophores appeared between the eyes on the dorsal surface 

of the head. Melanophores on the posterior portion of the preanal finfold increased. There were one or two stellate 

melanophores on the base of the pectoral fin. Myomere 

numbering was 11+12+16=39.

(12) Two-chamber-gas-bladder stage (fig. 8–42): Total 

length was 11.0 mm at 275 hours post-fertilization. The 

anterior gas bladder appeared, forming a sphere. The 

differentiating dorsal fin had five initial rays. The posterior 

edge of the caudal fin became crenulated with three curves. 

There were 12 or 13 initial rays in the caudal fin. Rays 

started to appear in the pectoral fin. The vertebrae formed.

(13) Pelvic-fin-bud stage (no figure): Total length was 

12.5 mm at 339 hours post-fertilization. The pelvic fin bud 

appeared. The dorsal fin lengthened, but was still connected 

with the dorsal finfold. The dorsal fin had eight rays. The 

caudal fin was forked with 16 rays. The anal fin had 10 initial 

rays. The pigment distribution was the same as in the twochamber-gas-bladder stage. Myomeres further developed from 

a single chevron to a double chevron shape. Myomere 

numbering was 11+12+17=40.

(14) Dorsal-fin-formation stage (fig. 8–44): Total length 

was 14.8 mm at 19 days post-fertilization. The dorsal fin was 

separate from the dorsal finfold (ray numbering = iii, 7). The 

caudal fin also formed and had 16 branched rays and three 

unbranched rays both in the upper and lower portions of the 

fin. The anal fin began to separate from the anal finfold (ray 

numbering = iii, 12). The preanal finfold increased in size; the 

melanophores on the fold increased and enlarged. The pelvic 

fin bud extended. The pectoral fin enlarged and rays began to 

appear. Ribs and vertebral processes appeared on the vertebrae.

(15) Anal-fin-formation stage (fig. 8–45): Total length 

was 17.3 mm at 23 days post-fertilization. The anal fin formed 

(ray numbering = iii,13). The preanal finfold was short and 

deep. The pelvic fin bud was still small and had not extended 

beyond the fold.

(16) Pelvic-fin-formation stage (fig. 8–46): Total length 

was 19.0 mm at 27 days post-fertilization. The pelvic fin 

formed (ray numbering = i,8). The preanal finfold was short 

and deep; there were still many melanophores on the fold. 

Rays on the pectoral fin were forming. The mouth opening 

was large, terminal, and strongly upturned. The head was 

relatively large, the length being over one-quarter of the total 

body length.

(17) Squamation stage (fig. 8–47; 45–d old). Total length 

was 24.5 mm. This stage lasted from 35 to 57 days postfertilization. Lateral line scales and scales on the body sides 

formed, but there were no scales on the dorsal and ventral 

parts. The preanal finfold shrank. There were many melanophores on the preanal finfold between the base of the pelvic 

fin and vent. The pectoral fin was fully formed and the distal 

end of the fin extended to the anterior margin of the preanal 

finfold.

(18) Juvenile stage (fig. 8–48): Total length was about 

36 mm at about 70 days post- fertilization. Squamation was 

complete. The anal fin enlarged. The preanal finfold shrank 

further, later becoming the keel. The distal end of the pectoral 

fin extended over the anterior margin of the preanal finfold. 

The fish resembled an adult fish.

Comparison of Post-hatch Development of 

Grass, Black, Silver, and Bighead Carps

The grass, black, silver, and bighead carps are taxonomically 

related and their reproductive habits are similar. However, each 

species had some distinguishing characteristics; some of these 

were obvious and some subtle. The differences were more 

obvious when the species could be directly compared. Although 

the organ morphology was similar, there were differences in 

1) morphometrics, 2) the position of body structures, and 

3) the timing of development of the different structures. By 

comparison and identification of these subtle differences, the 

Table 4.  Myomere counts in three early development stages of grass carp, black carp, silver carp, and bighead carp collected from

the Yangtze River.

Species

Hatching stage Gas-bladder-emergence stage 2-chamber-gas-bladder stage

Preanal

Postanal Total

Preanal

Postanal Total

Preanal

Postanal Pre Total -

dorsal Middle Predorsal Middle Predorsal Middle

Grass carp 81 22 13 43 9 21 15 45 12 18 15 45

Black carp 7 19 14 40 9 17 15 41 11 15 15 41

Silver carp 6 19 14 39 8 17 15 40 10 15 15 40

Bighead carp 6 17 15 38 8 15 16 39 11 12 16 39

1

 See Chapter 1 for a description of the myomere numbering conventions used in this table.

Chapter 2 – Translation of Yi and Others, 1988 29
larvae could be identified to species. From hatching to the 

one-chamber-gas-bladder stage, the morphology of the larva 

was more complicated compared to that of the embryonic 

stages. There were more characteristics to compare. From the 

yolk-absorption stage to squamation, the organs of the larvae 

differentiated. During this period it was easier to identify 

the differences between the species. Sometimes diagnostic 

characters were subtle or consisted of subtle differences 

that caused difficulty in determining species. Under these 

conditions, it was necessary to make determinations using 

multiple characteristics to identify the fish.

Myomere Counts

The myomere counts of the four fishes were close, but 

slightly different (table 4). The total grass carp myomere 

number was three or four more than that of black carp; black 

carp had one more myomere than silver carp, and silver carp 

had one more than bighead carp. During the hatching period, 

grass, black, silver, and bighead carps had 43, 40, 39, and 38 

myomeres, respectively. Larvae often had one more or less 

myomere. By the gas-bladder-emergence stage, the number 

of myomeres increased to 45, 41, 40, or 39 for the four fishes, 

respectively. The total number of preanal myomeres (predorsal 

and central combined) were 30, 26, 25, and 23 for the grass, 

black, silver, and bighead carps, respectively. Grass carp 

had the most and bighead carp the least, and the number did 

not change during later development. However, because the 

anterior margin of the dorsal fin gradually moved backward, 

the number of predorsal myomeres increased gradually, and 

central myomere counts reduced correspondingly. The number 

of postanal myomeres increased from 13, 14, 14, 15 to 15, 15, 

15, 16 between hatching- and gas-bladder-emergence stages of 

the four species, respectively. In contrast to the situation with 

predorsal myomeres, the grass carp had the fewest postanal 

myomeres and the bighead had the most. The increase in 

the total number of myomeres during development resulted 

from an increase in postanal myomeres. The quickest method 

of identification of larvae was the central myomere count. 

However, black and silver carps were the same in this respect. 

In this case, one can refer to the predorsal myomere count, 

which differed between the two species, or use other obvious 

characteristics.

Relative Postanal Length

From the hatching stage to the gas-bladder-emergence 

stage, the relation between postanal length and total length 

was obviously different among the four species (table 5). 

Postanal to total length ratio was largest in the bighead carp, 

then silver carp, then black carp, then grass carp. The data in 

table 5 shows that postanal length grew most rapidly at the 

rudimentary-pectoral-fin stage.

Caudal Vein

(fig. 10B, 5-8)

The caudal vein was located along the base of the 

postanal finfold. It was the most diagnostic morphological 

characteristic of the larval circulatory system over the period 

from the rudimentary-pectoral-fin stage to the gasbladderemergence stage. There were different characteristics of the 

caudal vein between the four species. The caudal vein of grass 

carp was the most obvious because it was bigger and the blood 

was loquat-yellow. With the naked eye the caudal vein looked 

like a thin red line. The caudal vein of the black carp was not 

straight, but wavy with little blood in the vein. The color was 

first apricot-yellow and then changed to lemon-yellow over 

time. The caudal vein of silver carp was shorter, narrower, and 

butter-yellow or apricot-yellow. In the bighead carp, the caudal 

vein was long and wide. The under edge of the caudal vein 

was not very straight, and often was apricot-yellow.

Pigmentation of the Dorsal Surface of the Head

and Snout Shape

(fig. 10C, 9-16; table 6)

At the gas-bladder-emergence stage, the larva could 

orient itself and swim normally. It was possible to observe the 

pigment distribution on the dorsal surface of the head, as well 

as the snout shape to identify the species (table 6). After the 

pelvic-fin bud-stage, the head pigmentation did not change, 

except there was some development of pigment on the dorsal 

surface of the head of the black carp, and between the eyes of 

the bighead carp.

Table 5.  Proportion in percent of postanal length to total body length of yolk-sac larvae of grass carp, black carp, silver carp, and

bighead carp collected from the Yangtze River.

Stages Grass carp Black carp Silver carp Bighead carp

Hatching 23.0-25.0 25.5-27.0 28.0-29.0 30.0-32.0

Rudimentary pectoral fin 26.0-29.0 27.5-31.0 29.5-33.5 32.5-35.0

Gas bladder emergence 29.5-30.5 30.5-31.5 33.5-34.5 35.5-36.5

One-chamber gas bladder 30.0-31.0 31.5-32.5 34.0-35.0 36.0-37.0

30 Early Development of Four Cyprinids Native to the Yangtze River, China
Deep Head Pigmentation

(fig. 9a-h and fig. 10D, 17-24)

During the developmental stages from the one-chamber 

gas bladder to the two-chamber gas bladder, there were large 

interconnected patterns of stellate melanophores close to the 

otic capsule and gill arch in the inner part of the head, and 

anterior and dorsal to the pectoral fin base. Viewed dorsally 

through the transparent top of the head, these pigments made 

patterns that were diagnostic to species. The pigment pattern 

of grass carp resembled a short, wide, flower vase (fig. 9a). 

The pigment pattern of black carp resembled two “\ /“ shapes 

(fig. 9b). The pigment pattern of silver carp was U-shaped (fig. 

9c). The pigment pattern of bighead carp formed two roughly 

parallel lines (fig. 9d). These patterns were obvious when 

observing the swimming larvae in a dish of shallow water.

There are some other cyprinid fishes with drifting eggs, 

which also had different pigment patterns within their heads 

(fig. 9e–h). Some of them were similar to grass carp, black 

carp, silver carp, or bighead carp; however, differences were 

visible with close observation. For example, the pigment 

pattern of Rhinogobio typus resembled inverted parenthesis 

over a “\ /” shape (fig. 9e). The pigment pattern of Parabramis 

pekinensis also resembled two stacked “\ /” shapes, but was 

smaller than those of black carp (fig. 9f). The pigment pattern of 

Ochetobius elongatus resembled inverted parenthesis over two 

large stellate melanophores (fig. 9g). The pigment pattern of 

Elopichthys bambusa was a short “ \ /" anterior to two parallel 

lines (fig. 9h). Generally, the pigment patterns of these other 

cyprinids could be easily discriminated from those of grass 

carp, black carp, silver carp, or bighead carp. Also, the general 

shape, color, and size of the other cyprinids were quite different from the four famous domestic fishes. At the later developmental stages of the four species, after about the pelvic-fin-bud 

stage, the pigment patterns changed and become more similar 

to each other. This made identification using these parameters 

more difficult.

Pigment Around the Base of the Rudimentary

Pectoral Fin

(fig. 10E, 25-36).

The presence, absence, or abundance of stellate melanophores on the base of the rudimentary pectoral fin of larvae 

and juvenile also could be used as a characteristic to identify 

the species. At the gas-bladder-emergence stage, only the 

grass carp had one or two melanophores on the pectoral fin. 

The other three species had none (fig. 10E, 25-28). From the 

one-chamber-gas-bladder stage to the dorsal-fin-differentiation 

stage, the number of stellate melanophores on the rudimentary 

pectoral fin of grass carp increased to two or three (fig. 10E, 

29). At this same stage, the rudimentary pectoral fin of bighead carp had one stellate melanophore, and black and silver 

carps had none (fig. 10E, 30-32). After the notochord-tiplifting stage, all four fishes had stellate melanophores on the 

base of the rudimentary pectoral fin, but the number was 

different: the grass carp had three or four, the black carp had 

one, the silver carp had two, and the bighead carp had one or 

two (fig. 10E, 33-36).

Pigmentation of the Caudal Fin

(fig. 10F, 37-40)

From the one-chamber-gas-bladder stage to the dorsalfin-differentiation stage, the pigment on the caudal fin of the 

four species had different characteristics. Some of them could 

be seen by the naked eye and proved to be a rapid and efficient 

way to identify the species. There was a small grouping of 

melanophores on the anterior ventral portion of the caudal fin 

of the grass carp. With the naked eye, this grouping appeared 

as a large black point. Similar to grass carp, silver carp also 

had the black point on the anterior ventral portion of the caudal fin, but silver carp had another black point on the dorsal 

portion of the caudal fin (two points visible by the naked 

eye). Black carp had a very obvious single large dark stellate 

melanophore on the anterior ventral portion of the caudal fin. 

Bighead carp had some melanophores on the ventral portion 

of the caudal fin, which connected in a curved line.

The Pigmentation of the Preanal and Anal

Finfolds

(fig. 10G, 41-48).

During and after the one-chamber-gas-bladder stage, 

some stellate melanophores appeared on the preanal and anal 

finfolds of silver and bighead carps, but the grass and black 

carps did not have them. This was an important and stable 

characteristic to identify the species. The melanophores of 

silver and bighead carps had different characteristics. The 

melanophores of the silver carp were distributed on the 

posterior two-thirds of the preanal finfold at the one-chambergas-bladder stage. The stellate melanophores were large and 

Species Melanophores distribution Shape of the 

snout

Grass carp Melanophores on dorsal surface of 

head, some between eyes

Flat

Black carp No melanophores on dorsal surface 

of head 

Arc

Silver carp Melanophores on dorsal surface of 

head, some between eyes

Obtuse

Bighead carp Melanophores on dorsal surface of 

head, but none between eyes

Obtuse

Table 6.  Melanophores of the dorsal surface of the head, and

shape (as viewed dorsally) of the anterior margin of the snouts of

grass carp, black carp, silver carp, and bighead carp at the gasbladder-emergence stage.

Chapter 2 – Translation of Yi and Others, 1988 31
had many branches. However, the stellate melanophores of 

bighead carp appeared at the dorsal-fin-differentiation stage 

and they were few in number. The abundance of melanophores 

increased gradually in the anterior direction on the preanal 

finfold; melanophores were distributed over the posterior half 

of the preanal finfold. The stellate melanophores were small 

and darkly pigmented. Until the appearance of scales, when the 

preanal finfold was mostly reduced, the melanophores of silver 

carp were still more abundant than those of bighead carp. In 

contrast, the melanophores of the anal finfolds of bighead carp 

appeared at the one-chamber-gas-bladder stage, and gradually 

formed a dark wavy line. Melanophores on the anal finfold of 

silver carp appeared later at the dorsal-fin-differentiation stage. 

The number of melanophores were few and the color light.

Anal Fin Shape

(fig. 10H, 49–52)

By the juvenile stage, the scales and fins were similar 

in shape to the adult fishes. The shape of the anal fin differed 

between species. The base of the grass and black carps’ anal 

fins were shorter than that of silver and bighead carps. The 

first two or three rays of the black carp anal fin were long, 

so that the posterior margin of the anal fin was somewhat 

pointed. By comparison, the anal fin of the grass carp was 

more rounded. The base of the silver carp anal fin was long, 

and the base of the bighead carp anal fin was longer yet.

Discussion

The spawning grounds of grass, black, silver, and bighead 

carps were widely distributed in the upper- and middle-streams 

of the Yangtze River and its main tributaries. At each spawning 

ground or some spawning areas, “pure” early-stage eggs of the 

four fish could generally be collected at the same time. After 

they developed and grew, hybrids were never found. This may 

have contributed to the different fertilization process and time 

sequence between fish species (Wang and Xu, 1980), which 

becomes a natural block of hybridization.

Overall, the morphology and structure of the four fishes 

were very similar during the early development. It was not 

easy to instantly identify the difference among the four species. 

These four cyprinid fishes, which have similar reproduction 

habits, have similar ontogeny. However, by observing individual 

structures closely, we found many obvious characteristics that 

were useful in species determination.

During the early development, grass and black carps 

showed differences from silver and bighead carps, such as 

presence or absence of melanophores on preanal and anal 

finfolds, and the relative length of the tail section. In addition, 

each species had unique characteristics, such as distribution 

and shapes of melanophores, which are clearly apparent at 

certain stages.

During the post-embryonic development, the growth and 

organ differentiation of larvae and juveniles were occasionally 

found to overlap (Yi and others, 1966). In addition, as mentioned before, the larvae and juveniles held under laboratory 

conditions grew slower than those living in the wild. However, 

the organ differentiations of yolk-sac larvae held in the laboratory did not progress at a slower rate. Their body color was 

generally darker than those in nature, probably due to different 

backgrounds and light intensities. The darker colors resulted 

from more melanophores and more highly-branched stellate 

melanophores. By contrast, larvae collected from rivers had 

few melanophores; their melanophores generally were not 

stellate, resulting in a light body color.

At the post-yolk-sac, larval, and juvenile periods, the 

laboratory-reared fish not only grew slower, their structures 

formed more slowly. For example, at the squamation stage, the 

larvae of the four species raised in the laboratory were one and 

half months old and had reached a total length ranging from 

20.0 to 24.5 mm; however, scales generally had not covered 

the whole body. In nature, it generally takes only three weeks 

for the fish to reach that body length and grow out all scales. 

An obvious difference between the laboratory and natural 

conditions is the water volume. There are relatively constant 

temperatures and dissolved oxygen, rich nutrition, and minerals in the natural water bodies providing much more favorable 

conditions than the water in the laboratory containers. Even in 

the laboratory under similar conditions, the different container 

sizes used to raise the larvae may also have led to different 

results. Table 7 shows the differences in the number of lateral 

line scales of the same size of grass carp larvae raised in different sizes of containers at the squamation stage. Obviously, 

a large container with more water volume provides more 

calcium, which supports scale formation and growth. Calcium 

can be absorbed by the fish through the body surface, mouth, 

and gill (Simkiss, 1974), especially during larval fish period.

Table 7.  Number of lateral-line scales at the squamation stage of grass carp larvae originally collected from the Yangtze River

and raised in containers with different water volumes.

Container size Total length of larvae (millimeters)

(Liter) 21 22 23 24 25 26 27 28 29 30 31 32

34 30 34 34 35 35 35 35 36 36 37 38 39

 18.5 5 10 15 18 20 23 25 27 30 33 35 38

32 Early Development of Four Cyprinids Native to the Yangtze River, China
References Cited

Chen, Chungshou, and Shuyan Lin, 1935, Chinese larval 

fishes. Fisheries Report of Zhejiang Fisheries Experimental 

Station, 1(4). [In Chinese]

Chen, Zhenran, 1963a, Morphological characteristics of larval 

and juvenile grass carp Chinese Journal of Zoology, v. 1, p. 

23–29. ]In Chinese]

Chen, Zhenran, 1963b, Morphological characteristics of early 

development of silver carp. Journal of Wuhan University 

(natural science edition), v. 2, p. 48–64. [In Chinese]

Institute of Experimental Biology, Chinese Academy of 

Science, 1962. Embryonic development of silver Carp. In 

Institute of Experimental Biology (ed.), Study on Artificial 

Reproduction of Cultured Fishes. 125–136. [In Chinese]

Institute of Hydrobiology, Chinese Academy of Science, 1973. 

Reproduction of cultured fishes in Fishes. In Institute of 

Hydrobiology (ed.), Culture and Reproduction of Chinese 

Freshwater Fishes (second edition). Science Press, Beijing. 

96-107. [In Chinese]

Institute of Hydrobiology, Chinese Academy of Science, 1976. 

Fishes in the Yangtze River. Science Press, Beijing. 220 pp. 

[In Chinese]

Kryzhanovsky, C.G. A.I. Smirnov, S. G. Soin. 1951. Development of fish from the Amur River. Papers from the Amur 

River Ichthyological expedition, 1945–1949. Vol II: 73–84. 

[In Russian]

Li, Pu, 1959. Embryonic developmental stages of crucian carp 

and goldfish. Acta Zoologica Sinica, 11(2):145–157. [In 

Chinese]

Li, Xiangyuan and Xiazhong He, 1937. Study of silver carp 

and the experiment of their artificial fertilization and hatch. 

Quaternary Publication of Fish Culture, 1(3–4):1–21. 

Guangxi Fish Culture Experimental Station. [In Chinese]

Liu, Jiankang, 1954. Egg fertilization and hatch of Chinese 

freshwater fish. Biology Bulletin, 1954 (1):11–16. [In 

Chinese]

Rugh, R., 1962. Experimental Embryology. Burgess Publishing Company, Minnesota, USA.

Shangdong Freshwater Fisheries Institute, 1963. Embryonic 

development of grass carp. [In Chinese]

Simkiss, K., 1974. Calcium metabolism of fish in relation to 

aging. In T. Bagenal (ed.): Aging of Fish, Unwin Bros Ltd, 

London, 1–12.

Verigin, B.V. 1950. Biological characteristics of age and 

growth of silver carp (H. m Val.) Papers from the Amur 

River Ichthyological expedition, 1945–1949. Vol I: 303–

318. [In Russian]

Wang, Changxie, 1959. Species identification of larval fish 

in the middle stream of the Yangtze River. Acta Hydrobiologica Sinica, 3:315–344. (In Chinese)

Wang, Youlan and Guojiang Xu, 1980. Cytology study on egg 

cell fertilization of silver carp. Acta Hydrobiologica Sinica, 

7(2):189–194. [In Chinese]

Wu, Hongtu and Youqi Shi, 1964. Embryonic development 

of bighead carp (Aristichthys nobilis). Journal of Harbin 

Normal University (natural science edition), 2:115–126. [In 

Chinese]

Xie, Yuhao, 1964. Post-hatch development of larval bighead 

carp and silver carp. Scientific Report of Liaoning Fisheries 

Research Institute. [In Chinese]

Yang, Yijuan, 1962. Preliminary observation of embryonic and 

post-hatch development of bighead carp. Journal of Jimei 

Fisheries College, 2:18–26. [In Chinese]

Luanzuo, 1958. Preliminary study on morphology of larval 

fish. Bulletin of Biology, 7:7–13. [In Chinese]

Ye, Luanzuo, 1964. Preliminary study on post-hatching 

development of black carp. Journal of Fisheries of China, 

1:39–60. [In Chinese]

Yi, Bolu, Zhitang Yu and Zhishen Liang, 1966. A comparative study of the embryonic development of grass carp, 

black carp, silver carp, big head carp and other fishes with 

drifting eggs in the Yangtze River. 8th Symposium, Fisheries Research Committee of the Western Pacific, Beijing. 

Science Press, Beijing: 37–53. [In Chinese]

Yuan, Chuanbi, 1962. The method of distinguishing species 

differences among larvae of black carp, grass carp, silver 

carp, and bighead carp. Journal of Nanjing University (natural science edition), 1:75–90. [In Chinese]

Zhong, Lin, 1962. Growth and artificial reproduction of silver 

carp. 8th Symposium, Fisheries Research Committee of the 

Western Pacific, Beijing. Science Press, Beijing: 54–66. [In 

Chinese]

Chapter 2 – Translation of Yi and Others, 1988 33
 Figure 1 (3–29).  The stages of embryonic development of grass carp: (3) 4-cell, (4) 8-cell, (5) 16-cell,

(6) 32-cell, (7) 64-cell, (8) 128-cell, (9) morula, (10) early blastula, (11) mid-blastula , (12) late blastula,

(13) early gastrula, (14) mid-gastrula, (15) late gastrula, (16) neurula, (17) blastopore closure, (18)

somite appearance, (19) optic primordium, (20) optic vesicle, (21) olfactory placode, (22) tail bud, (23)

otic capsule, (24) tail vesicle, (25) caudal fin, (27) muscular effect, (28) heart rudiment, and (29) otolith

appearance.

28

29

34  Early Development of Four Cyprinids Native to the Yangtze River, China
Figure 2 (2–29).  The stages of embryonic development of black carp: (2) 2-cell, (3) 4-cell, (4) 8-cell,

(5) 16-cell, (6) 32-cell, (7) 64-cell, (8) 128-cell, (9) morula, (10) early blastula, (11) mid-blastula, (12) late

blastula, (13) early gastrula, (14) mid-gastrula, (15) late gastrula, (16) neurula, (17) blastopore closure,

(18) somite appearance, (19) optic primordium, (20) optic vesicle, (21) olfactory placode, (22) tail bud,

(23) otic capsule, (24) tail vesicle, (25) caudal fin, (27) muscular effect, (28) heart rudiment, and (29)

appearance of otolith.

Chapter 2 – Translation of Yi and Others, 1988 35
Figure 3 (4–29).  The stages of embryonic development of silver carp: (4) 8-cell, (5) 16-cell, (6) 32-cell, (7)

64-cell, (8) 128-cell, (9) morula, (12) late blastula, (13) early gastrula, (14) mid-gastrula, (15) late gastrula, (17)

blastopore closure, (18) somite appearance, (19) optic primordium, (20) optic vesicle, (21) olfactory placode,

(22) tail bud, (23) otic capsule, (24) tail vesicle, (26) lens formation, (27) muscular effect, and (29) otolith

appearance.

36  Early Development of Four Cyprinids Native to the Yangtze River, China
Figure 4 (2–29).  The stages of embryonic development of bighead carp: (2) 2-cell, (3) 4-cell, (4) 8-cell, (5) 16-

cell, (6) 32-cell, (7) 64-cell, (9) morula, (10) early blastula, (11) mid-blastula, (12) late blastula, (13) early gastrula,

(14) mid-gastrula, (15) late gastrula, (16) neurula, (19) optic primordium, (21) olfactory placode, (22) tail bud, (24)

tail vesicle, (26) lens formation, and (29) otolith appearance.

29

Chapter 2 – Translation of Yi and Others, 1988 37
Figure 5 (31–38).  The stages of post-hatch development of grass carp: (31) hatching, (32) rudimentary

pectoral fin, (33) gill arch, (34) xanthic eye, (35) gill filaments, (36) melanoid eye, (37) gas bladder emergence,

and (38) one-chamber gas bladder.

38 Early Development of Four Cyprinids Native to the Yangtze River, China
Figure 5 (40–44).  The stages of post-hatch development of grass carp: (40) dorsal fin differentiation, (41)

notochord tip lifting, (42) two-chamber gas bladder, (43) pelvic fin bud, (44a) early dorsal fin formation, and (44b)

late dorsal fin formation.

Chapter 2 – Translation of Yi and Others, 1988 39
Figure 5 (45–48).  The stages of post-hatch development of grass carp: (45) anal fin formation, (46) pelvic fin

formation, (47) squamation, and (48) juvenile stage.

40 Early Development of Four Cyprinids Native to the Yangtze River, China
Figure 6 (31–37).  The stages of post-hatch development of black carp: (31) hatching, (32)

rudimentary pectoral fin, (33) gill arch, (34) xanthic eye, (35) gill filaments, (36) melanoid eye,

and (37) gas-bladder emergence.

Chapter 2 – Translation of Yi and Others, 1988 41
Figure 6 (38–43).  The stages of post-hatch development of black carp: (38) one-chamber gas bladder, (39)

yolk absorption, (40) dorsal fin differentiation, (41) notochord tip lifting, (42) two-chamber gas bladder, and

(43) pelvic fin bud.

42 Early Development of Four Cyprinids Native to the Yangtze River, China
Figure 6 (44–48).  The stages of post-hatch development of black carp: (44) dorsal fin formation, (45) anal fin

formation, (46) pelvic fin formation, and (48) juvenile stage.

Chapter 2 – Translation of Yi and Others, 1988 43
Figure 7 (31–38).  The stages of post-hatch development of silver carp: (31) hatching, (32)

rudimentary pectoral fin, (33) gill arch, (34) xanthic eye, (35) gill filaments, (36) melanoid eye, (37)

gas bladder emergence, and (38) one-chamber gas bladder.

44  Early Development of Four Cyprinids Native to the Yangtze River, China
Figure 7 (40–45).  The stages of post-hatch development of silver carp: (40) dorsal fin differentiation,

(41) notochord tip lifting, (42) two-chamber gas bladder, (43) pelvic fin bud, (44) dorsal fin formation, and

(45) anal fin formation.

Chapter 2 – Translation of Yi and Others, 1988 45
Figure 7 (46–48).  The stages of post-hatch development of silver carp: (46) pelvic fin formation, (47)

squamation, and (48) juvenile stage.

46  Early Development of Four Cyprinids Native to the Yangtze River, China
Figure 8 (31–37).  The stages of post-hatch development of bighead carp: (31) hatching, (32) rudimentary

pectoral fin, (33) gill arch, (34) xanthic eye, (35) gill filaments, (36) melanoid eye, and (37) gas-bladder emergence.

Chapter 2 – Translation of Yi and Others, 1988 47
Figure 8 (38–44).  The stages of post-hatch development of bighead carp: (38) one-chamber gas

bladder, (39) dorsal fin differentiation, (40) yolk absorption, (41) notochord tip lifting, (42) twochamber gas bladder, and (44) dorsal fin formation.

48 Early Development of Four Cyprinids Native to the Yangtze River, China
Figure 8 (45–48).  The stages of post-hatch development of bighead carp: (45) anal fin formation, (46) pelvic fin

formation, (47) squamation, and (48) juvenile stage.

Chapter 2 – Translation of Yi and Others, 1988 49
Figure 9.  Different patterns of melanophores of the heads of grass carp (a), black carp (b), silver

carp (c), bighead carp (d), Rhinogobio typus (e), Parabramis pekinensis (f), Ochetobius elongatus 

(g), and Elopichthys bambusa (h) at the one-chamber-gas-bladder stage.

50 Early Development of Four Cyprinids Native to the Yangtze River, China
Comparative 

character

Stage Grass carp Black carp Silver carp Bighead carp

A. Protrusion on 

the head

Otic capsule to heart 

pulsation

B. Caudal vein Hatching to gill 

filaments

C. Snout shape 

and 

pigmentation 

of the dorsal 

surface of the 

head

Gas bladder emergence 

to yolk absorption

Differentiation of 

dorsal fin to juvenile

D. Deep head pigment 

pattern

One-chamber gas bladder to two-chamber 

gas bladder

Pelvic fin bud to 

squamation

E. Pigment around 

the rudimentary 

pectoral fins

Gas bladder 

emergence

One-chamber gas bladder to differentiation 

of dorsal fin

Notochord tip lifting to 

anal fin formation

F. Pigment on 

caudal fin

One-chamber gas bladder to differentiation 

of dorsal fin

G. Pigmentation 

of the preanal 

and anal fin 

folds

One-chamber gas bladder to two-chamber 

gas bladder

Pelvic fin bud to 

squamation

H. Anal fin shape Anal fin formation to 

juvenile

Figure 10.  Primary diagnostic characteristics in the early development of grass, black, silver, and bighead carps collected from the

Yangtze River.

Chapter 2 – Translation of Yi and Others, 1988 51