576 U. S. BUREAU OF FISHERIES 



TERRAPIN CULTURE 



Experiments in diamond-back terrapin culture, carried on at the 

 biolo(;ical station at Beaufort, N. C, under the direction of Dr. 

 Samuel F. Hildebrand, progressed very satisfactorily. 



Ego; production from the entire brood stock was hijjjh and a fair 

 rate of fertility prevailed. The hatch for the season of 1930 con- 

 sisted of 7,054 young. The entire hatch of the season was placed in 

 the brooder house and a large series of experiments pertaining to 

 feeding and other treatment is being conducted. 



Experiments with the 1929 brood again showed that salt water 

 is a better medium for the young in the brooder house than fresh 

 water, for the death rate was considerably lower and the grow^th 

 rate slightly higher among the animals kept in salt water than those 

 in fresh w^ater, although the last-mentioned difference may have been 

 due to the greater loss in fresh water among the smaller and weaker 

 animals. Among the various foods and CGmbinations of foods used, 

 a mixture of fresh fish and oysters gave the best results when rate of 

 survival and growth are both taken into consideration. Liver, beef, 

 and vegetables did not give satisfactory results. 



No epidemics occurred among the young animals, although " sores," 

 a disease of unknown origin and for which no cure has been found, 

 again were present. Among 7,782 young of the 1929 brood placed in 

 the brooder house, 3.4 per cent died Oif this cause. " Soft-shell," a 

 condition correlated with a failure to feed and resulting in a generally 

 emaciated condition, caused 10.7 per cent of deaths, and all other 

 causes resulted in 3.6 per cent of deaths. The total number of deaths, 

 prior to liberation of the brood of 1929, or during about the first 

 8 or 9 months of life, therefore, was 17.9 per cent, Avhich is regarded 

 as a rather low death rate. 



The surviving animals, exclusive of 200, Avhich were retained for 

 further experimentation, were turned over to the North Carolina 

 Department of Conservation and Development for liberation in suit- 

 able areas. The animals had attained a length on the median line 

 of the plastron of about II/3 inches (32.4 millimeters) w^iich repre- 

 sents a growth of slightly more than 14 i^^ch (5.4 millimeters) since 

 hatching. Many of the animals, however, were II/2 inches and over 

 in length, the average being reduced by numerous " runts " which 

 always have been present during the course of this work. The aver- 

 age rate of growth shown is not the best obtainable with our present 

 state of knowledge, because certain foods used, although showing 

 unsatisfactory results, were continued throughout the season in order 

 to emphasize the results. 



Practical results from the liberation of young terrapins are be- 

 coming more and more evident in the commercial catches from the 

 frequent occurrence of terrapins which bear the marks made a-, the 

 laboratory on a marginal plate upon liberation. 



BAT SCALLOP 



At Beaufort, N. C, Dr. J. S. Outsell has been conducting investi- 

 gations as to the commercially important bay scallop, which nation- 

 ally is about equal to the soft clam in commercial vahie. The facts 

 learned offer a basis for wise conservation or for active development 

 through scallop culture. 



