Effects of low light and high temperature on pediveligers of the fluted giant clam Tridacna squamosa

ABSTRACT

This paper examines the responses of the fluted giant clam Tridacna squamosa pediveligers to elevated temperature and reduced light levels. In a light reduction experiment, a total of 104,000 T. squamosa pediveligers were exposed to four different levels of shading for approximately one month. The most heavily shaded treatment, at 0.4% of ambient light, had significantly lower survival than the other groups, which all received 1% or more of ambient light. In a second experiment, for approximately two weeks 13,000 T. squamosa pediveligers were divided among three treatments: one at ambient temperature averaging 29.5 °C, and two with elevated temperatures averaging 32.2 °C and 34.8 °C. The elevated temperature treatments resulted in near total mortality. The highest temperature survived by any pediveliger was 32.8 °C. Our results indicate a potential synergetic effect, with turbidity causing giant clam pediveligers to settle in shallower water―where they will likely be exposed to higher temperatures.

KEYWORDS:

• Bivalve
• climate change
• urban coral reef
• stress
• Tridacninae

Acknowledgments

We thank the Tropical Marine Science Institute staff, especially Serena Teo, and members of the Experimental Marine Ecology Laboratory, DBS, NUS, for their advice and support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported National Parks Board CME grant number [R-154-000-568-490] and the National Research Foundation, Prime Minister’s Office, Singapore under its Marine Science Research and Development Programme [Award No. MSRDP-05];National Research Foundation, Prime Minister’s Office, Singapore [MSRDP-05].