1132 



Loosanoff, Victor L. , and Harry C. Davis. 1950. 



Conditioning V. meroenaria for spawning in winter and breeding its larvae 

 in the laboratory. Biol. Bull. 98(1): 60-65. 



Hard clam larvae were reared in the laboratory. Adult clams were removed 

 from 0.0 °C waters of Long Island Sound and placed in trays of running sea- 

 water 5.0-7.0°C. Water temperature was raised several degrees every few 

 days until it reached 20.0-22.0°C. Clams were now conditioned to spawn 

 and were induced to spawn by raising water temperature several more 

 degrees. Embryos were filtered and placed in jars where they were fed 

 mixed plankton cultures, primarily forms less than 5 u in size. 

 Morphology of the developing larvae was given. Most larvae reached 

 setting stage in 12 days, but some cultures at 24.0°C set in 10 days. - D.L. 



1133 



Loosanoff, V. L.,and H. C. Davis. 1951. 



Delaying spawning of lamellibranchs by low temperature. Sears Found., J. 

 Mar. Res. 10(2): 197-202. 



Venus meroenaria and several other bivalves can be spawned artificially in 

 winter by gradual increase in water temp to that at which they spawn in 

 summer. Conditioning for spawning in late fall and winter is possible only 

 after recovery from summer spawning, a stage that may not be reached until 

 the end of October by some bivalves. Adult hard clams from Long Island 

 Sound were transplanted to Boothbay Harbor, Me. , where the water is about 

 5 to 8°C cooler in summer. The transplant was made in May, and the clams 

 were brought back to Milford, Conn, in Sept of the same year. The clams 

 were ripe, with extremely thick gonads and were easily induced to spawn. 

 Another batch was brought back in October, with identical results. Clams 

 held in cool water through summer can be stimulated to spawn at any time 

 from fall to the following spring. - J.L.M. 



1134 



Loosanoff, V. L.,and H. C. Davis. 1953. 



Some observations on larvae of Venus mercenaria carried on at Milford during 

 the past year. 4th Ann. Conf. on Clam Research, Boothbay Harbor, Me. U.S. 

 Dept. Interior, Fish Wildl. Serv.: 7-8. 



Cultures of Chlorella sp. , Chromulina pleiades, Isoahrysis galbana, a species 

 of Chlamydomonas, and a blue-green alga, Porphyridium r -were fed to Venus 

 larvae. All but Porphyridium gave good growth to setting. Venus larvae 

 survived to setting even in concentrations of Chlorella as high as 500,000 

 cells/cc but died in 1 million Chlorella/ 'cc. Optimum concentration may be 

 about 250,000 cells/cc. - J.L.M. 



1135 



Loosanoff, Victor L., and Harry C. Davis. 1963. 



Rearing of bivalve mollusks. Adv. Mar. Biol. F. S. Russell (ed.) . Academic 

 Press, N.Y. 1: 1-136. 



Belding in 1912 could not raise hard clam larvae. He concluded that there was 

 no practical method for rearing to straight-hinge stage because the egg was 

 small and delicate. Wells in 1927 carried larvae to metamorphosis. At 

 Milford, Conn., of 21 species or hybrids, larvae of American oyster and hard 

 clam have been studied most intensively. The equipment is described and 

 figured in detail: storage tanks, pumps, piping, filters, and ultraviolet 

 light to eliminate undesirable organisms. To condition for out-of-season 

 spawning mollusks must be kept in running seawater at temp of 18-20°C or 

 higher. Warm seawater is also needed for rearing larvae and juveniles in 

 winter. The heat exchanger is described. Temp of about 24°C is optimal for 

 growth of algae which are best larval foods (e.g. Isoehrysis galbana) . 

 Gametes from mollusks placed directly in water of about 20°C are no less 



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