جستجوی مقالات مرتبط با کلیدواژه « hatching success » در نشریات گروه « علوم پایه »

Hawksbill turtle is a species which endangered and much researchs was not done on condition of this species in Kish Island which is one of main places for nesting. This study was performed for reproductive characteristics Hawksbill turtles of kish Island in 2010-2011. Biological and reproductive characteristics of female turtules and embryos were measured the obtained results contain average weight of turtle 40. 143kg،straight carapace length 65cm،straight carapace width 50. 619cm and the average total of eggs 92. 5±2. 862، number of normal eggs 74. 5±2. 178، number of abnormal eggs 17. 3±1. 548، diameter of eggs 37. 927±0. 19، weight of eggs 30. 793±0. 47، the average straight carapace length 38. 746±0. 18 mm، straight carapace width 30. 792±0. 15 mm and weight 12. 416 ±0. 19gr، percent hatching success 84. 76، incubation period 67 days. The highest correlation between weight and straight carapace length for embryo obtained with correlation coefficient r =0. 858. Results of study showed that there is no significant difference between reproductive characteristics of Hawksbill turtles of Iranian Persian Gulf Islands and countries of Persian Gulf and Oman sea، but size of egg in Persian Gulf region is bigger than other parts of world because of smaller size of female turtle and average lower number of eggs. Percent of hatching success is lower than the other parts of world mainly because of oil pollution.

Nest site location in reptiles is an important stage of their life cycle because environmental factors influence embryo survivorship, incubation quality and sex ratio. For studying effective factors on nest site location in the hawksbill turtle, we measured temperature, moisture, beach slope, particle size of sand and vegetation related to 35 nests in Shidvar Island. In this Island, most nests were in northern beach which has a relatively steep slope. In this slope energy costs and probability of females and hatchlings predation is low. In addition hawksbills preferred to nest amongst vegetation. Of the environmental evaluated, slope appears to have the greatest influence on nest site location, because it is associated with nest elevation and hatching success is higher from nests closest to suitable elevation. It is believed that sea turtles may use multiple cues for nest site location and use a threshold that must be reached for each environmental factor before the turtle initiates nest excavation.

Hawksbill turtle (Eretmochelys imbricata (is one of endangered sea turtles that spawns in Persian Gulf coasts. This study has done during reproductive season of this species (March 2005 to June 2006)in Shidvar Island that is one of most important nesting area in Iran. During this study, nesting parameters of 35 female hawksbill turtles such as nests depths, number and weight of eggs, incubation time and hatching success rate were measured. In this island, clutches had an average of 92 eggs per clutch with mean of mean egg weights 32.94g and a mean of egg diameter of 38.49 mm. the average of incubation time and hatching success were 57.3 and 73.6% respectively. These data show that hawksbill eggs and hatchlings in Shidvar Island and also other parts of Persian Gulf are bigger and larger than other parts of world. These data confirm that Shidvar Island is of tremendous biodiversity importance. This is enhanced by the fact that it is not subject to human habitation and is relatively free from eggs and hatchlings predators. The likelihood that successful conservation of this island can play a positive role in safeguarding regional hawksbill populations is high.