apparent in some of the fish. Emboli were also 

 apparent in all high saturation test specimens in 

 the pyloric caeca, intestines, eye, operculum, roof 

 of mouth, epithelium of dorsal fin, mesentery, and 

 gill arterioles. In two cases the bulbus arteriosis 

 was greatly distended, apparently by the presence 

 of an embolus. 



CONCLUSIONS 



Preliminary results indicated that adult men- 

 haden could be maintained, with care, for an 

 extended period of time. Results also showed that 

 gross symptoms of gas bubble disease could be 

 induced in menhaden at high levels of nitrogen 

 saturation. A probable threshold toxic effect for 

 adult menhaden exists between 115% and 120% 

 nitrogen saturation at 22°C. Further testing at other 

 temperatures will be necessary to define a relation- 

 ship between nitrogen saturation, toxicity and tem- 

 perature. We also intend to explore the tolerance 

 and recovery capabilities of menhaden to the effects 

 of intermittent exposure to supersaturation levels 

 of 120% to 130% nitrogen. 



ACKNOWLEDGMENTS 



This research project was funded by Boston 

 Edison Company, Boston, Massachusetts. The 

 authors gratefully acknowledge the technical advice 

 of Dr. Alan V. Nebeker of the Western Fish. Tox. 

 Lab., Corvallis, Oregon, the assistance of Captain 

 John Russo and the crew of the Agatha & Patricia 

 in collecting the fish, and the assistance of Captain 

 Rodney Swift and the Research Vessel Shrock. 



REFERENCES 



Hettler, William F. Personal communication. 



Marcello, R. A., Jr. and R. B. Fairbanks. 1974. Gas Bubble 

 Disease Mortality of Atlantic Menhaden, Brevoortia tyrannus, 

 at a Coastal Nuclear Power Plant. Presented at Gas Bubble 

 Disease Workshop, Richland, Washington. 



Nicholson, W. R. and ). R. Higham, Jr. 1966. Age and Size 

 Composition of the Menhaden Catch Along the Atlantic Coast 

 of the United States, 7962; With a Brief Review of the Com- 

 mercial Fishery. U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 

 (527), 24 pp. 



Reintjes, ). W. 1969. Synopsis of Biological Data on Atlantic 

 Menhaden, Brevoortia tyrannus. U.S. Fish. Wildl. Serv. Circ. 

 (320). 



84 Clay, Barker, Testaverde, Marcello, McLeod 



