PRELIMINARY CULTURE AND LIFE-CYCLE EXPERIMENTS WITH THE BENTHIC AMPHIPOD AMPELISCA-ABDITA

The tube-dwelling amphipod Ampelisca abdita Mills 1964 has been used e xtensively in acute sediment toxicity tests and has been shown to be a menable to chronic testing. Ampelisca abdita was held in the lab throu gh several generations when fed algal food in daily static renewals, a lthough culturing success was not consistent. Algal food consisted of one or more of the following: the flagellate Pseudoisochrysis paradoxa Sutton, and the diatoms Phaeodactylum tricornutum Bohlin and Chaetoce ros calcitrans (Paulsen) Tokano. Sensitivity of cultured animals to ca dmium chloride in 96-h seawater-only tests (LC50s 0.28-0.58 mg Cd/L) w as comparable to that of field-collected animals (LC50 0.20 mg Cd/L). A life-cycle test initiated with juveniles 8 to 10 d old resulted in p roduction of young or fertilized broods in only two of the 12 sample c ontainers in which young were expected. Amphipods were sexually mature at approximately 20 d of age at 25-degrees-C, and young were first pr oduced at 34 to 36 d. Short-term tests were used to quantify growth of this species in 10 to 14 d. Results from a variety of experiments ind icated that there are still one or more unresolved problems with the c ulture and chronic testing of Ampelisca abdita. Factors such as nutrit ion, flow rate, light, and temperature need to be examined further.