feasibility of hatching, rearing and breeding a laboratory population of the 
shrimp for use as experimental animals. Of primary consideration in this study 
was the development of flow-through culture systems for the various life 
stages. Static designs represent poor simulations of field conditions and may 
impose unnecessary stresses on the animals (8). A secondary concern was to 
determine suitable diets for the juvenile and adult grass shrimp; Broad (1) 
found brine shrimp, Artemia salina , nauplii to be a very satisfactory larval 
food. Success for the project must be measured in terms of growth, survival, 
and population reproduction. 
The advantages of using lab-reared organisms are countered by several 
anomalous characteristics of organisms maintained in the lab. Morphological 
changes, as compared to field animals, have been noted by Paul Yevich 
(Environmental Research Lab, Narragansett, R.I.; personal communication) in 
many marine animals. However, the increased control of age, nutrition, and 
prior exposure to environmental variables would appear to outweigh slight 
changes in morphology and behavior. 
The grass shrimp, Palaemonetes vulgaris (Say), was selected for these studies 
for several reasons: the shrimp is a common estaurine species available to 
researchers along the Atlantic and Gulf of Mexico coasts (9); the animal is 
relatively easy to rear in the laboratory; and the life cycle can be greatly 
compressed in the lab (4). 
EXPERIMENTAL 
Several ovigerous grass shrimp were collected by dip net on 14 July 1976 in 
the Pettaquamscut River estuary adjacent to Narragansett Bay, Rhode Island. 
Mid-summer salinities at the collection site range from 25-30o/oo depending 
on the tidal cycle; water temperature was 21.5°C. 
Egg-bearing females were isolated in six C (1.6 U.S. gal.) tubs^ at 21.0- 
23.5°C and oceanic salinities (29 T4.5o/oo). Photoperiod was maintained at 
ambient levels of LI4:DIO. Water was changed daily and aerated gently. 
Shrimp were offered food during this holding period but rarely fed. 
Larvae hatched after 1 to 17 days of holding and were immediately pipetted 
into the flow-through system shown in Figure 14-1. About 200 larvae were 
held in this two £ system for 21 days, by which time all shrimp had reached the 
late larval stages. Developing larvae were fed excess quantities of newly hatched 
and one-day old brine shrimp nauplii, Artemia salina (San Francisco Bay 
Brand). 
1 Rubbermaid Commercial Products, Inc., Winchester, VA. 
207 
