in Prince Edward Island and New Brunswick were not significant. There appeared 

 to be no threat to the clam stocks, although the possibility of reproductive 

 damage at some level of contamination should not be dismissed. No threat to 

 human health from consumption of clams was recognized. - J.L.M. 



1709 



Sprague, Victor. 19 70. 



Some protozoan parasites and hyperparasites in marine bivalve molluscs. In 



A Symposium on Diseases of Fishes and Shellfishes. Stanislas F. Snieszko (ed.). 



Am. Fish. Soc, Washington, D.C. Spec. Pub. 5: 511-526. 



Nematopsis veneriis has been found in gills of Venus fasoiata in France. 

 N. ostrearum has been found in Venus ziczac in North America. Unidentified 

 haplosporidian ciliates of the Order Thigmotrichida have been found in 

 Mercenaria . - J.L.M. 



1710 



Srna, R. F., and A. Baggaley. 1976. 



Rate of excretion of ammonia by the hard clam Mercenaria mercenavia and the 

 American oyster Crassostrea virginica. Mar. Biol. 36(3): 251-258. 



The 2 bivalve species were maintained in identical laboratory environments 

 and fed the same diet for one month prior to measuring ammonia excretion. 

 Juveniles and adults were measured. M. mercenaria excreted more ammonia per 

 gram body weight, and data for Mercenaria were more scattered. Neither temp 

 fluctuation nor decomposition of organic nitrogen in test water accounted for 

 the scatter. Behavioral differences between the 2 species may explain the 

 differences. - modified authors' abstract - J.L.M. 



1711 



Srna, Richard F., Anne Baggaley, and Walter Page. 1976. 



Physical-chemical methods for the control of algal species and composition 

 in algal culturing facilities. Proc . 7th Annual Meeting World Marie. Soc., 

 Univ. Delaware Sea Grant DEL-SG-8-76, iii + 28 p. 



Mercenaria mercenaria requires certain species of algae in adequate amounts 

 for satisfactory growth. Thallassiosira pseudonana is suitable, but when 

 contaminated with Phaeodactylum tricornutum growth is unsatisfactory. In 

 fact .'.'. mercenaria, when fed P. tricornutum alone, does not survive. Three 

 methods were tried to provide optimum food conditions, ultrasonic waves, 

 manipulation of nutrient concentrations, and continuous seeding to compensate 

 for slow growth of one alga over another. A two-loop algal culturing process 

 was the result. One loop consists of a seed culture utilizing a small per- 

 centage of influent water and a larger mass algae culture. The mass algae 

 loop is inoculated continuously with new seed so that desirable species 

 outcompete undesirable species. Water entering the seed loop is purified 

 by ultrasonic treatment so that undesirable species may be eliminated from 

 the seed cultures. - J.L.M. 



1712 



Srna, Richard F., Charles Epifanio, Michael Hartman, Gary Pruder, and Ann 

 Stubbs. 19 73. 



The use of ion specific electrodes for chemical monitoring of marine systems. 

 Part I. The ammonia electrode as a sensitive water quality indicator probe 

 for recirculating mariculture systems. DEL-SG-14-73 , June 1973, work 

 sponsored by NOAA, Office of Sea Grant under grant no. 2-35223. 



The ammonia (Orion 95-10 ammonia ion specific) electrode was tested and 

 characterized for use in monitoring water quality and biological activity in 

 a closed cycle system. Its precision and ease of use make it possible to 

 monitor the ammonia level in a system. - M.C. 



473 



