1592 



Ryther, John H. 197 5. 



Mariculture: How much protein and for whom? Oceanus, Winter 1975, 18(2): 

 10-22. 



This is a general discussion of the problems associated with mariculture. 

 The principal difficulty, according to the author, is hov; to cut the cost 

 of food, which accounts for 25-50% of total operating costs. There is hope 

 for success, but it has not yet been achieved in the United States. - J.L.M. 



1593 



Ryther, John H. 1976. 



Marine polyculture based upon natural food chains and recycled wastes. Irj 

 Marine Resources Development and Management. A Report on the Woods Hole 

 Oceanographic Institution Sea Grant Program for July 1975-June 1976. NOAA 

 Sea Grant 04-6-158-44016. Dean F. Bumpus (coordinator): 2-5. 



Emphasis was on phytoplankton-bivalve-seaweed culture. Control of phytoplankton 

 species that appeared was not possible. Phaeodactlyum tviaovnutum dominated 

 cultures most of the time. Temp is the single most important controlling 

 factor determining species. Mean ash-free dry weight yields ranged from 3 g/m / 

 day in winter to 9 g/m2/day in summer. Mevaenavia mevaenavia did not grow 

 significantly in 18 months, although some other bivalves grew well. - J.L.M. 



1594 



Ryther, John K. 1976. 



Marine polyculture based on natural food chains and recycled wastes. Woods 

 Hole Oceanogr. Inst., Woods Hole, Mass., Tech. Rept. WHOI-76-92. U.S. Dept. 

 Commerce, Natl. Tech. Inf. Serv. PB-261 939: 1-18. 



Concept of the system is to grow unicellular marine algae in mixtures of 

 seawater and effluent from a secondary sewage treatment plant. Algae grown 

 in continuous flow-through culture are fed to oysters, clams, scallops, or 

 mussels. Winter flounder and lobster are stocked 'as postlarvae or juveniles 

 to feed on feces and pseudofeces produced by bivalves, and on small 

 invertebrates supported by the wastes. Seaweeds provide a final polishing 

 stage, removing nutrients regenerated by excretion and metabolism of animals, 

 and remaining nutrients not initially removed from wastewater by phytoplankton. 

 In 1st year of operation shellfish culture raceways were stocked with large 

 numbers of juvenile or seed American oysters and hard clams (Meveenavia 

 mevaenavia) . These failed to grow significantly and most died during the 

 following 18 months. It was concluded that the phytoplankton, predominantly 

 Phaeodaatylum tviaovnutum, was inferior and unsuitable as food. The problem 

 was solved indirectly by using exotic bivalve species which did well in the 

 system. - J.L.M. 



1595 



Ryther, John H., and John E. Bardach. 1968. 



The status and potential of aquaculture , particularly invertebrate and algae 

 culture. Vol. 1, Pt. I. The status and potential of aquaculture, by John 

 H. Ryther and John E. Bardach. Pt. II. Invertebrate and algae culture, by 

 John H. Ryther. U.S. Dept. Commerce, Natl. Tech. Info. Serv., PB 177 767, 

 261 p. 



The report does not deal specifically with culture of Mevaenavia mevaenavia. 

 Part II, Chap. 1. Culture of the American oyster on Long Island, New York, 

 describes hatchery techniques for raising seed oysters, and mentions that in 

 the winter of 1966 10 million seed clams were produced experimentally in the 

 G. Vanderborgh and Son hatchery (now Long Island Oyster Farms Inc) . - J.L.M. 



443 



