34 U. S, BUREAU OF FISHERIES 



iiiaxinium fertility of the eggs, the necessary space requirements of 

 terrapins in captivity, winter requirements, and food and water 

 requirements. 



In the experiments on selective breeding several lots of terrapins 

 were selected Avhen quite young (usually at the age of 1 year) for 

 their large size and generally fine appearance. Other lots, represent- 

 ing the "' runts *" of the same brood or broods, were set aside for com- 

 parison. It is noteworthy that among these early selections of " fast 

 growers "' many have not continued the rapid growth, and in several 

 instances the " runts "' have overtaken the early fast growers. Dur- 

 ing the past year new selections have been made from among pre- 

 viously selected terrapins. The terrapins that were further selected 

 had attained sexual maturity. In these new selective breeding 

 experiments three of the very linest females were chosen from a 

 given lot and placed with a single male, which was selected with 

 equal care. Several of these small lots have been set aside, and it is 

 exijectecl that by a comparison of the olfspring from dift'erent males 

 it will be learned which male is the most desirable. A new and fur- 

 ther selection will then be made. It is hoped that in this way a 

 better, larger, and faster-growing terrapin may eventually be devel- 

 oped. 



Terrapins hibernate normally during the winter months, and in 

 an effort to produce more rapid growth experiments have been car- 

 ried on for a number of years in which young terrapin are kept in 

 hothouses during the first winter. Under these circumstances they 

 do not hibernate, but continue to feed and grow. 



Diseases are unknown among terrapins 2 years of age or more, 

 but many deaths usually occur among the younger individuals. 

 The deaths among the young up to the age of 1 year may amount to 

 one-third of the total number. This death rate has not differed 

 greatly among those placed in a hothouse for winter feeding and 

 the young that were permitted to hibernate. Advancement, however, 

 has been made in reducing the deaths among the winter-fed young. 

 The simple expedient of scalding the tanks in which the terrapin 

 are held with hot water once a week was employed during the past 

 winter. This treatment apparently was instrumental in reducing 

 the death rate below that of previous years, and it greatly reduced 

 the amount of work necessary to keep down growths of algse and 

 to keep the tanks clean. 



The necessity for daily feeding the young terrapins in the hot- 

 house, as had become the custom, was doubted. Therefore a part of 

 the terrapins were fed only once every other day. The terrapins fed 

 on alternate days gained in growth just as rapidly as those fed 

 every day. Feeding on alternate days was found to save food and 

 to lessen the work required for preparing the food for feeding, 

 and also in keeping the tanks clean. 



The diamond-back terrapin cultural work at Beaufort to date has 

 been carried on as experimental work with the view of determining 

 the practicability of growing terrapin in confinement. It has been 

 shown to the entire satisfaction of those who have conducted the ex- 

 periments that terrapin can be grown in confinement on a commercial 

 scale. The question of the practicability of hatching young in captiv- 

 ity, to be liberated for restocking the depleted natural grounds, has 

 presented itself as a secondary advantage to be gained from this 



