730 



Gunter, G., B. S. Ballard, and A. Venkataramaiah. 1973. 



Salinity problems of organisms in coastal areas subject to the effect of 

 engineering works. U.S. Army Engineer Waterways Experiment Station, 

 Vicksburg, Miss., Contract Rept. H-73-3, x+176 p. 



The report contains a summary of the influence of salinity on marine 

 invertebrates, and sections on specific invertebrate and vertebrate groups, 

 including Mollusca. Mercenaria mercenaria is not cited specifically, but 

 the principles and mechanisms discussed are pertinent. - J.L.M. 



731 



Gurski, Edwin, and Albert F. Eble. 1973. 



Studies of the blood cells of the hard clam, Mercenaria mercenaria. Bull. 

 N.J. Acad. Sci. 18(1): 20 (abstract). 



Large and small amoebocytes of Mercenaria mercenaria varied in phagocytic 

 activity: small amoebocytes engulfed yeast cells faster and accumulated more 

 yeast cells per amoebocyte. Rate of phagocytosis increased with yeast 

 concentration. Phagocytic activity was reduced when a coverslip was applied. 

 Total blood counts at 20°C and 25% were 2 , 400, 055=x, 738,155-s. Blood cell 

 counts did not vary significantly between 15° and 24°C. Amoebocytes in 

 counting chambers invariably gathered in irregular clusters of 20 to 50 cells. 

 Within 8 to 10 min all clusters dispersed. At 4°C clumping did not occur. 

 - J.L.M. 



732 



Gusey, William F. 1976. 



The fish and wildlife resources of the Middle Atlantic Bight. Environmental 

 Affairs, Shell Oil Co., Houston, Texas, 2nd printing, revised. Clams and 

 quahogs: 513-529. 



Range of Mercenaria mercenaria: Gulf of St. Lawrence to Gulf of Mexico; 

 M. campechiensis : north to New Jersey. Hard clam supports the 2nd most 

 valuable mollusk fishery in the Middle Atlantic Bight. Brief notes on 

 natural history are included. Mercenaria can tolerate high levels of 

 pollution and can survive low oxygen. Thus, large beds may be found in 

 polluted areas where competitors, natural predators, and man pose little 

 threat. Charts show distribution of hard clam state by state from N.C. to 

 Mass. Commercial landings 1951 to 1974 are given in a table and graphically. 

 Brief comments are included on condition of stocks and management of the 

 harvest. (Abstracter's note: discussion of hard clam, life discussions of 

 all fisheries, reflect lack of personal experience with details. Conclusions 

 should be accepted with caution. The charts are of dubious value.) - J.L.M. 



733 



Gustafson, Alton H. 1955. 



Protecting Venus sets from green crabs by fencing. 5th Conf . on Clam 

 Research, 4 p. 



Green crab, Carcinides maenas , is a serious predator of Mercenaria mercenaria 

 up to one inch long. A hard clam seed bed of about 5 acres was found above 

 mean low water level in Brickyard Cove, Me. in 1953. Density was 200 to 

 1,500 clams/ft^ ranging from 2 to 15 mm long (mean 10 mm). Green crab 

 predation had begun and was spreading. The cove is long and narrow. A fence 

 was built across the cove at the narrowest point. One-inch mesh chicken wire 

 2 ft wide was fastened to wooden stakes; one section was 1/4-inch mesh 

 hardware cloth. A few inches of the wire extended into the substrate. A 

 wooden flange was nailed to the top of the stakes to prevent crabs from 

 climbing over. Crabs were caught with baited traps inside and outside the 

 fence. The catch outside was about 3 times the inside catch. It was 

 concluded that the fence prevented a considerable number of crabs from 

 reaching the seedbed. It was difficult to maintain a tight fence, and 

 breaches were made during storms. A better designed and sturdier fence, with 

 closer supervision, could be effective. Total cost of materials was about 

 $75. - J.L.M. 



205 



