KARLY STAGES OF PINK SHRIMP FROM FLORIDA WATERS 



323 



Figure 1. — Aquariums used in rearing experiments, showing plankton netting attached to collecting jar to catch larvae 



and eggs in runoff. 



mortality was high, insufficient larvae were ob- 

 tained to be certain of the number of nauplial 

 stages. 



Second Experiment 



In the second rearing experiment, April 8 to 

 17, 17 shrimp were brought to the laboratory and 

 divided among 3 aquariums. On the morning of 

 April 13, viable eggs and both newly hatched and 

 advanced nauplii were observed in the runoff from 

 one aquarium. This aquarium was drained and 

 the eggs and larvae collect-ed and placed in 16- 

 and 32-oimce jars as well as in a 5-gallon 

 aquarium, the bottom of which was covered with 

 sand and equipiied with a subsand filter. Indi- 

 vidual eggs were isolated in petri dishes in an 

 attempt to determine the number of molts under- 



gone by the nauplii and the inten-al between 

 molts. The developing eggs and nauplii were 

 observed continuously for 36 hours, in order to 

 preserve specimens of each developmental stage. 



Tlie eggs isolated in petri dishes failed to de- 

 velop past the first nauplius. Tlie larvae in the 

 5-gallon aquarium did not survive the molt into 

 the first protozoeal stage. Of the approximately 

 ■10 first pix>tozoea that did develop in the 16- and 

 32-ounce jars, only 1 larva passed through the 

 next molt. This high mortality in the first proto- 

 zoeal stage was probably due to a combination of 

 factors, one of which was tliat the larva must now 

 seek food for the first time, having been supplied 

 by its own yolk in the nauplial stages (Pesvrson, 

 1939; HudinagiL, 1942). During the experiment 

 a culture of Chlamydomonas sp. was fed to the 



