Park et al.: Larval development of Pandalopsis dispor 



119 



1999 by using a small shrimp 

 trawl fished at depths of about 

 40 m near Gabriola Island in 

 the vicinity of the Pacific Bio- 

 logical Station, Nanaimo, Brit- 

 ish Columbia (latitude 49°13', 

 longitude 123°55'). Water tem- 

 perature at the collection site 

 was around 9°C, and salinity 

 was 29.0 < ?c The females were 

 each kept in a 20-L jar with 

 seawater. The larvae hatched 

 on 1 April 1999. Hundreds of 

 larvae hatched from one female. 

 Of these, one hundred newly 

 hatched larvae were transferred 

 into individual 250-mL jars. To 

 obtain samples for drawing and 

 descriptions, a total of 150 larvae 

 from the female were reared in a 

 20-L jar. Newly hatched Artemia 

 nauplii were used to feed the 

 larvae. We used filtered natu- 

 ral seawater from 40 m depth 

 without adjusting the water 

 temperature or salinity. Water 

 temperature during the rearing 

 experiments ranged from 8.7°C 

 to 12.2°C (mean 10.5°C). Salin- 

 ity during the rearing experi- 

 ments ranged from 26.0%c to 

 31.0% f (mean 28.9%o). The water 

 in each jar was changed daily. 



All drawings were made with 

 a drawing tube attached to a mi- 

 croscope. Carapace length (CD 

 was measured with an ocular 

 micrometer from the posterior 

 edge of the orbital arch to the 

 middorsal posterior edge of the 

 carapace. The anatomical terms 

 used in this paper are from 

 Pike and Williamson ( 1969) and 

 Haynes (1985). 



Measurement bars represent 1 mm. 

 Figure 1 



Results 



In the complete larval development of Pandalopsis dispar 

 there are five zoeal stages. In addition, there is one post- 

 larval stage. The duration of each larval stage and the 

 survival rate of P. dispar are shown in Table 1. 



Larval description 

 First stage 



Carapace (Fig. 1A) Carapace length (CL), 1.6 mm (SD: 

 0.06 mm, n=89); with concave lateral margin; rostrum long. 

 well developed and directed forward and upward; weak 



