Meeting Abstract

S5-1.7  Thursday, Jan. 5  New perspectives on the extent of terrestriality in three species of sea kraits and their habitat selection TU, Ming-Chung*; LIU, Yu-Ling; National Taiwan Normal University; National Taiwan Normal University biofv026@ntnu.edu.tw

Three species of sea kraits, Laticauda spp., require fresh water, and both the evaporative water loss rate on the land and the extent of terrestriality differ among them. Laticauda semifasciata has the greatest water loss rate and least extent of terrestriality, while L. colubrina exhibits the reverse and L. laticaudata is in between. These sea kraits tend to be more abundant at places where there are sources of fresh water. Nevertheless, they are rarely found at river mouths where there is plenty of fresh water. Clearly, more than one factor influences their habitat selection. To clarify the factors, we investigated the number of each species of sea krait at six different habitats and the availability of each type of habitat on Orchid Island, Taiwan. The six types of habitats were high coral reef without fresh water (HR) and with fresh water (HRF); low coral reef without fresh water (LR) and with fresh water(LRF); sand or gravel coast, which has no coral reef without fresh water (NR), and with fresh water (NRF). The extent of safety for retreat – from high to low – is HR, LR and NR among these habitats. More than 75% individuals of each species were found in HRF. We found no sea kraits in NRF and NR. The most available habitat is LR, but no L. laticaudata or L. semifasciata were found in this habitat. We found 3.3 and 16.7% of L colubrina in LR and HR, respectively. For L colubrina, the second abundant habitat was HR. Whereas for L. laticaudata and L. semifasciata, the second abundant habitat was LRF. Both safety of the retreat site and fresh water appear to be important to the habitat selection of sea kraits. Laticauda colubrina is characterized by a higher extent of terrestriality and depends on fresh water less than do the other two species.