Food habits and distribution of the Lake Taal sea snake (Hydrophis semperi Garman 1881) and the sympatric little file snake (Acrochordus granulatus Schneider 1799) in Lake Taal, Philippines

Abstract

Our knowledge about the food habits of sea snakes and how it is associated with their distribution has seen much development through its description across a number of species available through published literature except for the key threatened species such as Hydrophis semperi. This paper aims to describe the food habits of H. semperi through gut content and stable isotope analyses. We also compared data with the Little File Snake, Acrochordus granulatus, sympatric with H. semperi. Recorded captures of H. semperi suggest that the sea snake tends to occur in the littoral zones and the shallower portions of the limnetic zone. Gut content analysis of H. semperi have shown that gobies and eels are primary prey items. Halfbeaks (Family Hemiramphidae) were recorded as one of the Lake Taal Sea Snake's prey items which is considered as a new prey record for sea snakes. These extracted gut contents are confirmed to be the temporal food preference of H. semperi given our detected stable isotope signatures. It appears that A. granulatus and H. semperi share common prey items suggesting possible diet overlap and resource competition. This study reports the first account of the endemic Lake Taal Sea Snake's distribution and food habits which poses implications towards its conservation as it occurs in a restricted ecosystem that has undergone considerable habitat alteration.