THE MATURATION OF HYDROIDES DIANTHUS

¹ Environmental Sciences and Engineering Section, Research and Development Department, General Dynamics, Electric Boat Division, Groton, Connecticut, 06340

1. All microalgae used as food were satisfactory food for the worm. (a.) I. galbana and P. tricornutum were better food organisms than was Nannochloris sp. (b.) An algal mixture of I. galbana, D. inornata and P. tricornutum proved to be slightly better than the single food species P. tricornutum. (c.) No effect of feeding level was observed. An algal food concentration of 0.25 mg (dry weight) algae/worm/day appears satisfactory.

2. Artificial sea water did not inhibit maturation.

3. Gametogenesis was directly related to temperature up to 22° C, the higher the temperature the greater the number of sexually mature worms. The number of mature worms was not increased appreciably above 22° C.

4. Worms were mature in 12 days of conditioning, however, more worms indicated maturity in 25 days.

5. Low salinity (l5) affected worm survival and worm maturation.

6. A female worm expels an average of 30 thousand mature ova. The male worm releases about 62 million sperm. (a.) Sperm and ova production was decreased by high temperature (30° C) , and low salinity; ova production increased with time but sperm production decreased with time. (b.) Fecundity was greater in worms fed an algal mixture.