293 



Casey, James F. 1978. 



DNR continues hard clam repletion program. Comm. Fish. News, Md. Dept. 

 Nat. Resour . 11 (1) : 3. 



In 1977 Maryland planted 1,232,000 hard clams in coastal bays, mostly (70%) 

 on existing beds in Chincoteague Bay, which included small amounts in 

 recreational clamming areas near Assateague Island. The remaining 30% were 

 scattered throughout Isle of Wight and Assawoman Bays in shallow and deep 

 waters. The cost was given as $15,776,000. (Abstracter's note: cost was 

 corrected in the March issue, vol. 11, no. 3, to $15,776.) Sizes and 

 sources of clams were not given. The project will monitor clam populations, 

 growth, and predation. - J.L.M. 



294 



Castagna, Michael. 1970. 



Field experiments testing the use of aggregate covers to protect juvenile 

 clams. Proc. Natl. Shellf. Assn. (1969) 60: 2 (abstract). 



Juvenile clams ranging in height from 0.6 to over 20 mm were placed in a 

 series of field experiments to test aggregates as protective covers. The 

 aggregates used were crushed rock (2-3 cm crushed gabbra) , pea gravel (1-3 

 cm stream gravels), crushed oyster shell, or whole oyster shell. The survival 

 rate was compared to unprotected areas. Survival of over 80% was accomplished in 

 protected plots, while survival in control plots was usually between 15 and 35%. 

 Crabs were the major predators of juvenile clams in the test area. - D.L. 



295 



Castagna, Mike. 1972. 



Economic potential of clam operation and economic survey of scallop 

 operation. Va. Inst. Mar. Sci., prelim, rept. (unpub.), 16 p. 



This is a detailed listing of all costs relating to a clam operation in 

 Virginia. The species is not named, but presumably it is MeTaenavia 

 mevcenavia. Certain assumptions must be made if the figures are to be 

 accepted. Seawater must be of suitable quality. Planting area also must 

 have suitable seawater and physical properties adequate for growth. This 

 requires a test brood and salinity samples in certain periods when water is 

 suspect. Bottom sampling should be done to find out if wild clams are in the 

 area and if there is sufficient diversity of age groups to show growth rates. 

 Clam production was based on figures from Jan to June 1972. The 40 percent 

 survival figure used for each step is lower than average. If this method is 

 used in a pretested area, assuming no unseen disaster strikes during the 

 first 10 years when loans are paid off, it appears that growing clams has 

 some potential. - J.L.M. 



296 



Castagna, Michael. 1978. 



Need and use of low technology aquaculture. Rept. Conf . on Marine Resources 

 of the Coastal Plains States, 8-9 Dec 1977, Williamsburg, Va. Coastal Plains 

 Center for Marine Devel . Serv.: 59-60. 



The trend in culture of bivalve mollusks has been toward more technical and 

 sophisticated methods, which may be too costly for profit. A bivalve culture 

 system usually consists of 7 units: 1) a conditioning or holding unit for 

 ripening or holding spawning stocks - this can be eliminated and the spawning 

 season increased by bringing spawners in from other areas; 2) a spawning unit - 

 a simple water bath is adequate; 3) a larval culture unit - use filtered cen- 

 trifuged seawater warmed in a greenhouse and control temp with fans; 4) a 

 postlarval culture unit - use ambient seawater with minimum filtering, no 

 food added, and no temp control; 5) juvenile nursery unit . - do in the field, 

 with protection as necessary; 6) a finishing unit - may require thinning, 

 or planting of rafted clams on natural bottom - some harvesting may be pos- 

 sible at this stage; and 7) an algal food culture unit - this is where 

 greatest savings are possible by using selectively filtered or centrifuged 



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