275 
Larval development of the kishi velvet shrimp, 
Metapenaeopsis dales (Rathbun) 
(Decapoda: Penaeidae), reared in the laboratory 
Jung H. Choi 
Sung Y. Hong 
Department of Marine Biology 
Pukyong National University 
Pusan 608-737, Korea 
E-mail (for J H Choi): choijh@mail1.pknu ac.kr 
Abstract— The complete larva! devel- 
opment of Metapenaeopsis daiei (Rath- 
bun) is described from laboratory- 
reared larvae. The larvae were reared 
in a plastic container (20 L). Larvae 
from the first zoeal stage to the third 
zoeal stage were fed algae; larvae from 
the first mysis stage to the first postlar- 
val stage were fed newly hatched nau- 
plii of Artemia. The nauplii of M. daiei 
hatched about 20 hours after spawning. 
The larvae passed through six naupliar, 
three zoeal, and three mysis stages 
before the postlarval stage. About 15 
days (about 347 hours) were required 
from hatching to the first postlarval 
stage. Larval morphology of M. daiei 
is described and compared with those 
of other Metapenaeopsis spp. The first 
nauplius stage larva of M. daiei bears 
a chitinous conical protuberance on 
the mediodistal margin of the body. 
The third protozoeal stage larva has 
five dorsomedian abdominal spines on 
the abdomen. The morphological char- 
acters of the first postlarva are 43 
scaphognathite setae on the maxilla, 
three scaphocerite spines on the outer 
margin of antenna, and sternal plate 
spines: 2, 2, 0,1,1. 
Manuscript accepted 7 November 2000. 
Fish. Bull. 99:275-291 (2001). 
The kishi velvet shrimp, Metapenae- 
opsis daiei (Rathbun), inhabits coastal 
waters of Korea (Kim, 1977) and Japan 
(Kubo, 1949). Of the 26 penaeid genera 
comprising 215 species, the genus 
Metapenaeopsis is the largest with 76 
species (Perez Farfante and Kensley, 
1997). However, studies on the com- 
plete larval development oi Metapenae- 
opsis spp. are few. 
The mysis and postlarval stages of 
Metapenaeopsis mogiensis (Ratbun) and 
Metapenaeopsis andamanensis (Wood- 
Mason) and postlarval stages of Metap- 
enaeopsis barbata (De Haan) have been 
partially described by Paulinose (1988) 
from plankton samples. Jackson et al. 
(1989) reared Metapenaeopsis palmen- 
sis (Haswell) in the laboratory and de- 
scribed all the larval stages of the spe- 
cies except the naupliar stages. From 
previous works on Indo-west Pacific 
penaeid larvae, they also described the 
important morphological characters for 
identification. Chong and Sasekumar 
(1994) studied the larval development 
of Metapenaeopsis stridulans (Alcock) 
from the egg to the first postlarval stage 
reared in the laboratory and prepared 
descriptions of all the larval stages. 
Ronquillo and Saisho (1997) provided 
descriptions and illustrative figures of 
the complete larval development of M. 
barbata and compared the morphologi- 
cal characters of the larval stages with 
those of several penaeid species. 
The purpose of the present study is 
to describe the larval development of 
M. daiei from the egg to the postlarval 
stage and to compare its larval devel- 
opment with that of other known Meta- 
penaeopsis larvae. 
Materials and methods 
On 22 August 1996, gravid females of 
Metapenaeopsis daiei were caught by 
shrimp trawl in Oeyondo, Korea, and 
transported to the laboratory of the 
Taean Fish Hatchery, National Fisher- 
ies Research and Development Insti- 
tute, Korea (NFRDI). 
Each of them was kept in a 0.5 t 
container, containing filtered seawater 
(22.0°C; 32.2%o), until they spawned. 
On the night of 22 August 1996, a 
gravid female spawned, and the eggs 
hatched on the next day. The larvae 
were reared in a plastic 20-L contain- 
er. Half the total volume of rearing wa- 
ter was changed daily with fresh sea- 
water (24.0-26.0°C; 32.2-33.2%D. The 
larvae were fed with a mixture of algae 
( Chaetoceros calcitrans and Isochrysis 
galbana) from the first zoeal stage to 
the third zoeal stage and with newly 
hatched nauplii of Artemia from the 
first mysis stage to the first postlarval 
stage. 
For size measurement and morpho- 
logical observation, eggs were sampled 
from the bottom of the rearing tank im- 
mediately after having been spawned; 
the developmental processes of the eggs 
were observed every 10 minutes, the 
nauplii were sampled at four hour in- 
tervals after hatching, and subsequent 
larval stages were sampled at least 
twice a day. 
The following measurements were 
taken from preserved larvae by using 
an ocular micrometer: total length (TL), 
from the tip of the rostrum to the tip 
of the caudal end or telson; carapace 
length (CL), from the anterior margin of 
