Factors Affecting the Hatching Success of Loggerhead Sea Turtle Eggs (Caretta caretta caretta)

Clutches of eggs wore collected from nesting loggerhead sea turtles (Caretta caretta caretta) on Merritt Island, Florida, during June - August 1977. Of these, 46 clutches were selected for experimentation to determine the extent to which certain factors affect hatching success. Twelve clutches were divided into subsamples which were incubated in sand maintained at 0, 25, 50, 75, and 100% moisture. Another twelve clutches were divided into subsamples and incubated in sand kept moist with the following percentages of seawater: 0 (distilled water), 25, 50, 75, and 100%; subsamples from four other clutches were subjected to the effects of one tidal inundation. Eggs from four of the clutches used in the moisture and salinity experiments were monitored for changes in size. Fifteen clutches were divided into subsamples which were kept in incubators maintained at 20, 24, 27, 30, 32, 35, and 38°C; subsamples from seven of these clutches were moved from unfavorable to optimal temperatures to study their ability to recover from stress. Three clutches were selected for an experiment to determine the effects of handling on hatching success; the following year, another five clutches were used for similar studies. Some of the hatchling turtles produced in this project were abnormal, and these were discussed in depth. From the experiments, it was determined that 25% moisture, 0-25% seawater, and 27°C produced the maximum percent hatch. The effects of handling on hatching success depended variably on the time and manner of handling. The optimum values indicated in the experiments closely approximated values for moisture, salinity, and temperature obtained from natural turtle nests on the beach.