555 



Epifanio, Charles E., Carla Mootz Logan, and Christine Turk. 1976. 



Culture of six species of bivalves in a recirculating seawater system. 

 Coll. Mar. Stud., Univ. Del., Newark and Lewes, Del. DEL-SG-1-76, 19 p. 



This abstract includes a digest only of the work with Mercenaria mercenaria 

 unless, for comparison, other information appeared to be merited. Experi- 

 mental animals were reared from eggs fertilized in the laboratory from 

 parents taken in local waters. The culture system was closed. No wild 

 phytoplankton was in the system, thus clams received only algae provided 

 experimentally. Water was purified periodically in waste treatment 

 apparatus, and tanks and shellfish were cleaned with jets of fresh water. 

 Shellfish were held above the bottom on plastic racks. Growth was measured 

 by shell height, but dry tissue weight was measured occasionally. Clams 

 had developed ripe gonads after one year's growth. Eight experimental 

 groups were fed 4 species of alga, singly or in some combination. Amount 

 fed was increased during the experiment. Phaeodactylum tricornutum alone 

 proved to be a very poor diet. Clams did not grow appreciably and all died 

 within 2 5 weeks. All other diets produced growth during a 4 6-week 

 experiment. Best growth was given by a mixture of equal numbers of 

 P. tricornutum, Carteria chuii , Isochrysis g alb an a, and Croomonas salina. 

 This fastest growing group was cultured for 110 weeks. Average shell 

 height was about 29 mm at end of experiment. In experiment 2 

 Thallassiosira pseudonana was substituted for P. tricornutum. Newly set 

 M. mercenaria were fed equal numbers of the four algal species in the same 

 quantities as before. Growth rate was double that in the first experiment. 

 In experiment #3 T. pseudonana alone supported growth equal to the 4-species 

 diet. In experiment 4 previous results with American oyster and hard clam 

 were compared with the same feeding experiments on other bivalves 

 (Crassostrea gigas, Tapes semidecussata, and Ostrea edulis). Results were 

 essentially the same. Annual growth rate of the fastest growing hard clams 

 in these experiments was nearly five times natural growth anywhere in the 

 geographic range of the species. - J.L.M. 



556 



Epifanio, Ch . E., C. Mootz Logan, and Ch. Turk. 1976 



Culture of six species of bivalves in a recirculating seawater system. 

 Proc. 10th Europ. Symp. Mar. Biol., Vol. 1: 97-108. 



Mercenaria mercenaria , fed diets of 4 algal species, Carteria chuii, 

 Croomonas salina, Isochrysis galbana, and Thallassiosira pseudonana, grew to 

 marketable size in 1 yr as compared to 3 to 5 yrs in the natural environ- 

 ment. Phaeodactylum tricornutum by itself was a poor diet. Hard clams did 

 not grow appreciably on this diet and all clams died within 25 weeks. T. 

 pseudonana was an excellent food. The recirculating culture system is 

 described. - J.L.M. 



557 



Epifanio, Charles E. , Richard Srna, and Gary Pruder. 1975. 



Mariculture of shellfish in controlled environments: a prognosis. 

 Aquaculture 5: 227-241. 



Husbandry of any species in a controlled environment depends on detailed 

 knowledge of biology of that species. Literature on hard clam is almost 

 as voluminous as that on American oyster. The authors reviewed literature 

 on food and feeding, oxygen requirements, production of CO2, nitrogenous 

 excreta, solid wastes, ammonia, nitrites and nitrates, pH, organic 

 compounds, salinity, and temperature, for American oyster and hard clam, 



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