1541 



Rhodes, Raymond J., Willis J. Keith, and V. G. Burrell, Jr. 1977. 



South Carolina's hydraulic escalator harvester fishery. Proc. Natl. Shellf. 

 Assn. 67: 122 (abstract). 



Nine hydraulic escalator clam dredges harvested 31,538 bags (250clams/bag) 

 of Mercenaria mercenaria from North and South Santee Rivers in the 1974-75 

 clamming season. In the 1975-76 season 25,948 bags were taken by 7 vessels 

 from North Santee Bay. Estimated mean hourly catches were 10.1, 10.8, and 

 19.8 bags/hr. in South Santee River, North Santee River, and North Santee Bay, 

 respectively. - J.L.M. 



1542 



Rhodes, Raymond J., Willis J. Keith, Peter J. Eldridge, and Victor G. Burrell, 

 Jr. 1977. 



An empirical evaluation of the Leslie-DeLury method applied to estimating hard 

 clam, Mercenaria mercenaria, abundance in the Santee River estuary. South 

 Carolina. Proc. Natl. Shellf. Assn. 67: 44-52. 



Estimates were made from catch and effort data for hydraulic escalator 

 harvesters, 1974-1976. Legal harvesting areas in South and North Santee 

 Rivers and North Santee Bay had estimated populations of 6.4 million, 

 5 million, and 10.7 million clams, respectively. Density of clams in preferred 

 harvesting areas varied from 18 to 24 clams/m 2 . The Leslie-DeLury method had 

 2 limitations. Effort estimates were not avail-able for specific locations, 

 and gear competition made abundance estimates questionable. - J.L.M. 



1543 



Rice, T. R., and J. P. Baptist. 1974. 



Ecoiogic effects of radioactive emissions from nuclear power plants. 

 Chap. 10 in Human and Ecoiogic Effects of Nuclear' Power Plants. Leonard 

 A. Sagan (ed.) . Charles C. Thomas, Publisher, Springfield, Illinois: 

 373-439. 



Price (1965) found that about 93,000 r killed 50% of the oysters (Crassostrea 

 virginica) in 34 days, and 50% of the clams (Mercenaria mercenaria) in 38.5 

 days. If LD-50s are calculated earlier or later than 30 days after irradia- 

 tion, the tolerances of the two species are not similar (White and Angelovic 

 1966) . Oysters have an LD-50 almost twice that of clams 20 days after 

 irradiation and only one-fourth that of clams 40 days after irradiation. 

 - J.L.M. 



1544 



Rice, Theodore R., and Rebecca J. Smith. 1958. 



Filtering rates of the hard clam (Venus mercenaria) determined with radio- 

 active phytoplankton. U.S. Fish Wildl. Serv. , Fish. Bull. 58(129): 73-82. 



Radioactive phosphorus was used to label four species of phytoplankton for 

 measuring filtering rates of hard clam. There was no relation between in- 

 itial concentration of Nannochloris and its rate of removal by an individual 

 clam. The ratio of water filtered per gram of meat was higher for small 

 clams than larger ones. Nannochloris and Chlorella were filtered at a lower 

 rate than the larger diatoms (2 Nitzschia species) . Intermediate populations 

 of diatoms (5-75 million/1) were filtered more rapidly than larger or smaller 

 populations. Filtering rate of clams in Nannochloris was higher when it was 

 in mixed suspensions of diatoms than in unialgal suspensions of Nannochloris , 

 but filtering of Nitzschia closterium was lower when it was mixed with 

 Chlorella than in unialgal suspensions of Nitzschia. Filtering rates are 

 higher for clams in natural phytoplankton than in unialgal green algae 

 suspensions, but lower in unialgal diatom suspension. Adding silt to algal 

 suspensions instantaneously lowered the filtering rate. - D.L. 



430 



