Hypoxia as a novel method for preventing movement-induced mortality during translocation of turtle eggs

Relocation of turtle eggs for research or conservation purposes is associated with significant risk, because they are prone to movement-induced mortality resulting from damage to embryonic membranes. Hypoxic incubation of eggs after oviposition maintains embryos in pre-ovipositional embryonic arrest and delays development. Whether or not this extended developmental pause also delays the onset of sensitivity to movement-induced mortality remains unknown. In previous studies eggs have been incubated in hypoxia using heavy and expensive Perspex chambers. We tested whether extending pre-ovipositional embryonic arrest through hypoxic incubation protects embryos from movement-induced mortality and we investigated more practical and cost-effective methods for transporting eggs under hypoxic conditions. Olive ridley sea turtle (Lepidochelys olivacea) eggs were randomly divided among four different treatments after oviposition; a control (normoxic) treatment, Perspex containers or ziplock bags filled with nitrogen gas, or vacuum-sealed bags. Eggs remained in their respective treatment for three days before being removed from their container or bag and placed into artificial incubators. Some eggs from each treatment were inverted when removed from their respective treatment in order to test their susceptibility to movement-induced mortality. We found a reduction in hatching success in the hypoxic treatments (20-43%) compared with the control (68%). However, all methods of hypoxic incubation delayed development and protected against movement-induced mortality. We conclude that plastic bags filled with nitrogen or vacuum bags can be used for maintenance of hypoxia in turtle eggs, thus providing a simple and cost-effective method for transportation of eggs for conservation and research purposes.