248 



Canzonier, Walter J. 19 71. 



Measurement of the oxygen requirements of a large population of Mereenaria 

 mereenaria. Proc. Natl. Shellf. Assn. (1970) 61:2 (abstract). 



Oxygen consumption of a population of 100 clams was measured continuously in 

 a closed perfusion system. In a series of seven experiments consumption 

 ranged from 4.1-9.5 mg/clam/hr with a mean of 5.7. These values agree 

 closely with those obtained by others using individual clams (3.6-10 mg/clam/ 

 hr) . From observations of continuously monitored clam activity and pumping 

 observed in individuals, 65% oxygen saturation was the threshold below which 

 clams would be excessively inhibited. Using these values it is possible to 

 calculate minimum volumes of seawater required for operation of large-scale 

 aquarium systems (e .g. , depuration plants). Assuming a relatively high 

 activity level of 70%, values determined ranged from 220-280 litres (58-73 

 gal) per bushel (200 clams) per hour at 17 °C. - modified author's abstract - 

 D.L. 



249 



Canzonier, Walter J. 1971. 



Accumulation and elimination of coliphage S-13 by the hard clam, Mereenaria 

 mereenaria. Appl . Microbiol. 21(6): 1024-1031. 



Clams were exposed to low levels of S-13 (5 phage particles/mJl , max 7 par- 

 ticles/mS.) in running seawater for several days. Escherichia aoli uptake 

 and elimination also were monitored. Titers in clam tissues reached 2 to 

 more than 1,000 times levels of exposure. On exposure to virus-free running 

 water, clams polluted to relatively low levels (100 plaque- forming units/mS,) 

 eliminated most bacterial contaminants in 24 to 48 hr. Viral contaminants, 

 however, persisted for days to weeks, even under ideal conditions for clam 

 activity, provided that temp remained below inactivation threshold for virus. 

 Most accumulated virus appeared to be sequestered in digestive gland. Re- 

 tention of viral particles may occur even with low environmental levels of 

 virus. These are not easily dislodged, and their elimination is independent 

 of clam activity. Heavily contaminated clams eliminate most viral particles 

 rapidly, giving the impression of extremely effective depuration. Viruses 

 can persist in clams depurated to acceptable coliform levels. If small num- 

 bers of viral pathogens that remain in tissues are potentially infective, 

 their stability under conditions of depuration and handling is extremely 

 important. A monitoring system more critical than the coliform standard 

 now in use is needed. - J.L.M. 



250 



Captiva, Francis J. 1960. 



Equipment note no. 6. — Chain bridles and accumulators increase effectiveness 

 of "Fall River" clam dredges in deep water. Coram. Fish. Rev. 22(12) : 20-22. 



Exploratory fishing located hard clams (Venus sp.) offshore of N.C. but 

 several types of dredge were unsuccessful for commercial fishing because 

 bottom was soft mud, sea conditions were adverse, or water was too deep. 

 A 14-tooth Fall River dredge was modified to change the angle of attack and 

 allow greater control. To reduce tendency to skip, a length of chain was 

 inserted between chain bridle and towing warp. With this modification, 

 commercial-size catches of 6 bu clams/30 min drag were taken consistently, 

 whereas previous catches were only 1 to 2 bu/30 min. - J.L.M. 



251 



Carazzi, Davide. 1893. 



Revisione del genere Polydora Bosc e cenni su du specie che vivono sulle 

 ostriche. Mitth. Zool. Sta. Neaple 2(1-2): 4-45. 



According to Sewell Hopkins (in Baughman 1948) , Carazzi found Polydora 

 armata tunneling in shells of Venus at Naples. - J.L.M. 



68 



