Foraging behavior and food selection of giant Mudskipper (Periophthalmodon schlosseri) at Kuala Gula, Matang Mangrove Reserve, Perak, Malaysia

Abstract

An in-situ behavioral study of giant mudskipper (Periophthalmodon schlosseri) was conducted in the coastal mudflat of Kuala Gula, Matang Mangrove Reserve, Perak. Observations were made based on scan and focal sampling methods during low tides. The main objective of this study was to understand the foraging behaviors and food selection by assessing the time spend and the frequency of each behavioral activity of this species in the field. The field observations identified five major feeding activities (Searching and Stalking (M1), Leaping and Capturing (M2), Tearing (M3), Moving to Safer Place (M4), and Playing With Prey (M5)) exhibited by P. schlosseri where these five feeding activities were later grouped in three different phases occurring consecutively such as Phase 1 or Searching Phase, Phase 2 or Capturing Phase and Phase 3 or Handling Phase. The results showed that, only 9.7% (835min) of the times were spend on feeding activities. In Phase 1, despite many attempts of capturing preys, only about 58% of the trials succeeded. Results showed that the giant mudskipper is a generalist carnivore that preyed on crab (Uca spp.) during the day and shifted to insect at night during low tides. Worms also taken by this species both in day and night during low tides, although the frequencies were slightly lower than crabs and insects possibly due to the difficulty of capturing them. The highest time spend on searching and stalking preys (397min) and the least time was on capturing for both day and night (H=7.96, df=4, p<0.05). However, the total time spend and efforts (frequencies) on feeding activities were slightly higher during the day compared to the night. Although the total time spend on feeding activities were slightly higher during the day, the allocations of time (mean) of these activities were similar to one another indicating that the species might have a strategy of minimizing the foraging costs (energy spend) in order to maximize the profit.