Hello from the beautiful Pacific Ocean island nation of Palau — “beautiful” being an understatement, especially when it comes to Palau’s ocean life. I remember the first time I swam through the swarming reefs of Palau several years ago, I felt like a kid IN an aquarium. Everything I’d ever wanted to see was right before my eyes, and in abundance!
I’m in Palau this week to work with coral reef managers from across the Pacific as part of the Conservancy’s annual reef resilience training program. These managers have come from places like Fiji, Papua New Guinea and Kosrae to learn the latest techniques and management strategies for making reefs more resilient against the host of threats they face, including overfishing and rising sea temperatures.
But I’ll be in the water at least some (but not enough!) of this trip, and one of the common things one sees in the reefs of Palau is giant clams (genus: Tridacna) such as the one in the picture above. There are seven species of giant clams just in Palau (there are only nine globally), and all are as shockingly beautiful as this one, with neon purple, green, blue, orange blaring at you as you swim over. (My husband, marine scientist Brian Silliman, took this photo the other day.)
These clams get their color from the same tiny plants that corals get their color from — zooxanthellae. Clams also have the same symbiotic relationship with zooxanthellae that corals do: these tiny plants live in the clam’s outer tissues and provide nutrients to the clam via photosynthesis. Think of them as an underwater greenhouse with doors that open and close.
The relationship is so beneficial to these clam that it allows the clam to get really, really big. The first time I saw the biggest giant clam species (Tridacna gigas), I immediately thought of horror-movie images of man-eating clams — they are that huge. Of course, that clams could eat humans is just a legend: the flesh of the giant big clam is so meaty that it can’t even close its shell tightly. Still…
I’ll be sharing more from Palau in the next few days, so stay tuned.
Stephanie Wear is a marine scientist with The Nature Conservancy’s Global Marine Team. She is working to improve tools that build resilience in coral reef communities so that coral reefs survive the impacts of a changing climate.