The surf clam has been overfished in a much shorter time, and it has been 

 suggested that the use of more "efficient" gear may be responsible. - J.L.M. 



2170 



McHugh, J. L. 19 81. 



Recent advances in hard clam mariculture. J. Shellf. Research 1(1): 

 (in press) . 



Failure to develop a- satisfactory method of hard clam aquaculture, despite 

 about 70 yrs of research, may be based on faulty premises. There is no 

 problem to raising Meroenavia mevoenavia to market size under artificial 

 conditions provided that adequate attention is given to care and cleanli- 

 ness. The only impediment is cost, which under present methods is too high 

 for economic gain. The flaw in thinking may be reliance on small numbers 

 of clams, thinking millions are sufficient when billions may be required to 

 smother predation. Another flaw may be lack of adequate enforcement. 

 Grounds must be patrolled constantly to keep out violators, and this means 

 adequate coverage 24 hrs a day, 7 days a week, and 365 days a year. It 

 also means adequate support in the courts, so that the penalty for being 

 caught is not worth the risk. Experimental management might be better. 

 One way would be to divide an area into three parts, keeping one open and 

 two closed, and rotating the closed areas each year. If enforced adequately 

 this would give adequate protection to seed, and the plan could be adjusted 

 according to local conditions as knowledge accumulates . - J.L.M. 



2171 



McReynolds, J. S. 1976. 



Hyperpolarizing photoreceptors in invertebrates. In Neural Principles in 

 Vision. F. Zettler and R. Weiler (eds.) , Springer-Verlag, New York: 

 394-409. 



In Mevoenavia mevoenavia an off discharge has been studied which resembles 

 in many ways that of the distal nerve fibers of Peoten, including the 

 ability to integrate the light stimulus over a long period of time (Wieder- 

 hold et al. 1973). As in Spisula no definite photoreceptor cell bodies 

 were found, but electron microscopy has revealed invaginated whorls of mem- 

 brane in the nerve fibers in the area to which light sensitivity is 

 restricted. Although no receptor potentials were recorded, it seems likely 

 that these cells would also show a hyperpolarizing receptor potential. 

 - J.L.M. 



2172 



Medcof, J. C. 1961. 



Effects of hydraulic escalator harvestors on undersized soft-shell clams. 

 Proc. Natl. Shellf. Assn. 50: 151-161. 



New material on Meroenaria meroenaria unlikely. Did not search beyond SUNY- 

 Stony Brook library. - J.L.M. 



2173 



Medcof, J. C, and R. A. Chandler. 1968. 



Exploring for uses of ocean quahogs : Obstacles and opportunities. Fish. 

 Res. Bd. Canada, Biol. Sta. , St. Andrews, N.B C Tech. Rept. 101. 



Meroenavia mevoenavia not mentioned. - J.L.M. 



2174 



Menzel, R. W. 1962. 



Experimental farming of hard clams, Meroenavia meroenavia, in Florida. 

 J. Fish. Res. Bd. Canada 7: 545-551. 



Incorrect reference. Could not locate. - J.L.M. 



604 



