231 



Cabelli, Victor J., and W. Paul Heffernan. 196 8. 



Seasonal factors relevant to fecal coliform levels in Mercenaria mercenaria. 

 Proc. Natl. Shellf. Assn. 58: 1 (abstract). 



Where water temp falls below 10°C for considerable periods very few coliform 

 organisms can be recovered from Mercenaria mercenaria even in heavily 

 polluted waters. This could be because low temp has a greater effect on 

 uptake as compared with elimination, or that organisms die within the clam. 

 Experiments were described which demonstrated a more marked inhibition of 

 uptake as compared to elimination of E. coli at temps of 10°C and lower, 

 and turbidities greater than 10 Jackson turbidity units. Seasonal changes 

 also were found to affect uptake and elimination of coliform organisms by 

 hard clam. - from authors' abstract - J.L.M. 



232 



Cabelli, V. J., and W. P. Heffernan. 1970. 



Accumulation of Escherichia coli by the northern quahaug. Appl. Microbiol. 

 19(2): 239-244. 



Concentration of coliform bacteria in Mercenaria mercenaria is a function of 

 coliform content of surrounding water. In time an equilibrium level is 

 reached at which intake and removal are equal. Digestive gland concentrates 

 Escherichia coli by more than an order of magnitude over that of the 

 surrounding water. Siphons contain more than ambient concentration. Gills, 

 mantle, and shell liquor contain very low residues. - J.L.M. 



233 



Cabelli, Victor J., and W. Paul Heffernan. 1971. 



Seasonal factors relevant to coliform levels in the northern quahaug. 

 Proc. Natl. Shellf. Assn. 61: 95-101. 



Few coliform organisms can be recovered from northern quahaug, Mercenaria 

 mercenaria , when water temperature falls below 10°C for considerable periods 

 of time, even though they are growing in heavily polluted waters. This 

 could be due to a more marked effect of low temperatures on microbial uptake 

 as contrasted to elimination, resulting in a gradual decrease in coliform 

 levels in the animals. A second possibility is death of the organisms within 

 the animal. The effect of seasonal changes on presence of fecal coliforms in 

 animals from a polluted area is documented. The greater inhibitory action by 

 temperatures of 10°C and lower and by turbidities above 10 Jackson Turbidity 

 Units on uptake as compared to elimination of Escherichia coli by quahaug is 

 demonstrated. Data on effect of temperature and turbidity changes on 

 experimental uptake and elimination of E. coli by the animal are presented. 

 Possible bases for these differences are discussed. - authors' abstract - 

 D.L. 



234 



Cahn, A. R. 1951. 



Clam culture in Japan. U.S. Dept. Interior, Fish Wildl. Serv. , Fish. Leafl. 

 399, 103 p. 



Mercenaria (Venus) mercenaria is not included. However, the paper contains 

 much useful information on life histories, ecology, reproduction, predators, 

 culture methods, harvesting of wild crops, toxic effects of many clam 

 species. Species and fishing gears are illustrated. Tables of production 

 since 1909 are included. - J.L.M. 



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