REPORT OF THE COMMISSIONER OF FISHERIES. 37 
PROGRESS OF DIAMOND-BACK TERRAPIN CULTURE. 
The success which has previously been attained in the experiments 
in terrapin culture has been continued in the past year in even more 
marked degree. It is timely to summarize some of the more impor- 
tant results at the Beaufort laboratory. 
(1) Perhaps*the most interesting development of the year is the 
fact that the three oldest broods of terrapin that were hatched in the 
experimental pounds and grown in captivity have produced eggs. 
The two oldest broods, one of which had been winter-fed during the 
first season while the other had been permitted to hibernate, began 
laying in 1915 and the eggs hatched successfully. The terrapin of 
the hatch of 1911 laid eggs in 1916, before the close of the fiscal year. 
These significant inferences a be made: (a) That terrapin born 
and reared in confinement develop in a normal way and will repro- 
duce their kind; (6) that the reproductive cycle may be completed 
in six years, even though the terrapin hibernate as in nature; (c) that 
by preventing hibernation and forcing growth through the first winter 
by feeding in a heated house the maturity as well as the growth of the 
terrapin may be advanced by one year, so that a new generation is 
started in five years rather than in six. 
(2) The adult breeding stock of terrapin has from year to year 
steadily increased in productivity, and there is ground for belief that 
the adult breeders have not yet reached the maximum capacity for 
reproduction. The following figures show the number of young pro- 
duced by adult breeders during each of the past four years and also 
the average number per female yielded by the original stock of 
breeders: ; 
Average 
Reena of | number per 
x young from} female of 
Year. alladult | original 
breeders. | breeding 
stock. 
2S Spo TUNTsLe PURSES ITE S RS aRN ay odes geen G ho Rie FOS OLR RGR PEW GT 1,326 12. 81 
COE oo TL SEIS SOAR CR Tea i TAN Ss Ce 1, 506 14. 52 
Pee een tee ee eA UA, ARAYA RACONSE C59! FRET ACN SET SCTEIUE Se 1, 690 15. 23 
Matern VER Orca ty Ihe Erle crys). de beUnpsh fe peeMauctumencle aadd 4b Wipes ab ee 2,128 21. 43 
Those terrapin which have been longest in captivity produced in 
1915 an average of 21.43 young for each female. 
(3) The value of winter feeding during the first season is well 
- established by the increased rate of growth, the shortening of the time 
required to attain reproductive maturity, and the very low rate of 
mortality. The death rate has never been so low as during the winter 
of 1915-16. Among 700 terrapin fed on fresh food the loss was about 
6% per cent, while among those fed on salted food the loss was about 
8; per cent. The death rate in hibernating stock was 13 per cent. 
The cost of food for winter feeding at Beaufort varies trom 3 to 15 
cents per 1,000 young terrapin per day, according as salt fish, fresh 
fish, or oysters are used. Assuming 10 cents as an average daily 
expenditure per 1,000 terrapin, the cost of food for 1 terrapin for a 
period of 5 months in the first winter would be 14 cents. 
