in this study have been previously documented (7). Gravid fish were collected 
from Bissel Cove, Narragansett Bay (R.I.) and trasported in aerated containers 
to holding tanks located at the Environmental Protection Agency Laboratory, 
Narragansett, R.I. Eggs were stripped from females onto nylon monofilament 
screens with a mesh size of 400jU, and fertilized by bathing them in the milt of 
two to three males (5). They were then suspended in egg hatching jars, 15 cm 
in diameter, modified from the original design of Buss (12) by the addition of a 
bottom center drain. 
After hatching, the fish were transferred to a 720 liter holding tank and ted 
live 3-day-old brine shrimp. Fish were periodically removed during the two 
month batch culture study for biochemical analyses. Fish used in both the 
preliminary and expanded diet evaluations were cultured for approximately 
two weeks. The jars used for hatching of the eggs, were also used as the culture 
vessels in the artificial diet studies. For the eight-diet expanded study each jar 
was stocked with 50, 23-day-old fish (individual mean weights, 8.90 mg) 
obtained from the batch culture population. Two replicates were run for each 
diet fed group. 
Diets and Feeding Procedures 
The wild plankton (Diet 1) were collected from a number of locations in the 
west passage of Narragansett Bay, R.I. and from local estuarine areas with a 
243ju mesh conical plankton net (Table 15-1). The plankton population was 
comprised of a mixture of copepods, primarily Acartia tonsa, and some 
invertebrate larvae (22). The plankton samples were transported to the 
laboratory in insulated containers and held at 20°C. 
The live brine shrimp nauplii (Diet 2) (San Francisco Bay Brand, USA) were 
incubated 12 to 24 hours in two liter separatory funnels containing filtered 
seawater (29.0 to 31.0 o/oo salinity, 20 to 22°C) and harvested after 72 hours. 
A starved group served as a control (Diet 3). The freeze-dried brine shrimp 
(Diet 4) was obtained by freezing the live brine shrimp to -38°C and then 
drying at 4jn/Hg pressure for 24 hours. 
Diets 5 through 9 were the artificial formulations. Tetra Marin (Diet 5) is a 
commercial flake diet used in aquarium fish applications and consists of 
unknown proportions of meals from fish, crab, mussel, lobster, beef heart, and 
brine shrimp. In addition, it is made up of such components as halibut liver, 
Calanus finmarchicus , kelp, oatflour, wheat germ, Agar-Agar , seaweed, and 
bone charcoal. The other four artificial diets were modified formulations 
originally prepared to suit the requirements of Atlantic salmon. The diets were 
prepared by the Tunison Laboratory of Fish Nutrition, U.S.F.W.S., Cortland, 
New York. The composition of these diets is given in Tables 15-2 and 15-3. 
216 
