NOAA PROFESSIONAL PAPER 11 



than clams at a level of 2. 1 ml/1 . The higher rate of oxygen 

 consumption at a lower oxygen tension probably signals 

 metabolic stress. Several researchers have reported higher 

 metabolic activity in other bivalves under reduced oxygen 

 conditions (Bayne 1971 in Mytilus edulis; Taylor 1976 in 

 Arctica islandica; and Deaton and Mangum 1976 in Noetia 

 ponderosa). Any further interpretation of oxygen con- 

 sumption rates reported here must await future studies. 

 These ideally should include hourly rate studies to deter- 

 mine diurnal patterns of oxygen consumption rates for 

 both normal clams and clams held in low D.O. water. 



Although S. solidissima is able to tolerate low oxygen 

 conditions at or above 1.4 ml/1 for extended periods of 

 time, the survival of a population depends on a variety of 

 other environmental factors during an oxygen depletion 

 episode. Future studies should concentrate on synergistic 

 effects of low D.O. and other toxicants. Such studies are 

 particularly important in the New York-New Jersey area 

 where portions of the coastal and offshore waters receive 

 continual doses of municipal and industrial wastes that 

 lead to these stresses. 



SUMMARY 



Under laboratory conditions, the surf clam survived low 

 levels of D.O. for extended periods of time. Levels below 

 1.4 ml/1 were nearly always fatal. No deaths were recorded 

 after 8 weeks at 2.1 ml/I D.O., and clams placed in water 

 at 0.7 ml/I after previous exposure to 2.1 ml/1 survived for 

 8 weeks, indicating that a gradual shift to anaerobic path- 

 ways is possibly advantageous. Flowing water exposures 



permitted better survival than did static water systems. 

 Metabolic studies indicated that animals held under low 

 oxygen conditions consumed oxygen at higher rates than 

 normal. 



REFERENCES 



Bayne, B. L , 1971. Ventilation, the heart beat and oxygen uptake by 

 Mytilus edulis L. in declining oxygen tension. Comp. Biochem. Phys- 

 iol. 40A: 1065-1085. 



Davis, J. C, 1975. Minimal dissolved oxygen requirements of aquatic 

 life with emphasis on Canadian species: a review, J. Fish. Res Board 

 Can 32:229-5-2332. 



Deaton. L. E.. and Mangum, C. P., 1976. The function of hemoglobin 

 in the arcid clam Noelia ponderosa — II. Oxygen uptake and storage. 

 Comp. Biochem. Physiol. 53(A): 181-186. 



Hammen, C. S., 1969. Metabolism of the oyster. Crassosirea virginica. 

 Amer. Zool. 9:309-318. 



Hochachka, P. W.. and Mustafa, T.. 1972. Invertebrate facultative an- 

 aerobiosis. Science 178:1056-1060. 



Rhodes, E. W., Calabrese, A., Cable, W. D., and Landers, W S.. 1975. 

 The development of methods of rearing the coot clam. Mulinia 

 lateralis, and three species of coastal bivalves in the laboratory, in 

 W. L. Smith and M. H. Chanley (eds.) Culture of Marine Inverte- 

 brate Animals. Plenum Press, New York. N.Y., pp. 273-281. 



Rossi, S. S., and Reish. D. J., 1976. Studies on the Mytilus edulis com- 

 munity in Alamitos Bay, California, VI. Regulation of anaerobiosis 

 by dissolved oxygen concentration. Veliger 18:357-360. 



Taylor, A. C, 1976. Burrowing behavior and anaerobiosis in the bivalve 

 Arctica islandica (L). J. Mar. Biol. Assoc. U.K. 56:95-109. 



Theede, H., Ponat, A., Hiroki, K.. and Schlieper, C, 1969. Studies on 

 the resistance of marine bottom invertebrates to oxygen deficiency 

 and hydrogen sulfide. Mar. Biol. 2:325-337. 



Vernberg, F. J., 1972. Dissolved gasses: Animals, in O. Kinne (ed.). 

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