Many say the pearl of the Waikīkī Aquarium’s collection isn’t an oyster, but rather its giant clams that can grow to be hundreds of pounds.
Some may recall that seven of the aquarium’s beloved clams were stolen in 2007, and all were bereft when the aquarium’s remaining 40-year-old giant clam died in 2022.
Thanks to a gift from the Federated States of Micronesia, the aquarium received dozens more clams last year. Scientists still have a lot to learn about these marvelous bivalves that play important roles in coral reefs across the Indo-Pacific.
Ryan Nevatte, a postdoctoral researcher at Macquarie University in Australia, shared his new research into the genetic diversity of giant clams.
"When we were looking at the clams from the Coral Sea, we were finding that there was no evidence of genetic structure across that big stretch of the Coral Sea. Whereas in the Cook Islands, we were finding that there was evidence of genetic structure with the clams," he said.
The distance from the furthest south point and the furthest north point in both areas covered the same amount of distance, about 1,300 kilometers, or nearly 810 miles.
"So we were finding, because the Cook Islands is comprised of two island groups, you have a southern group and a northern group, one of the sites in the northern group had evidence of genetically distinct clams compared to ones that were in the southern islands," Nevatte told HPR.
He said that from a conservation standpoint, the Coral Sea clams could be managed as one "interconnected population," while the Cook Islands' two groups may need to be managed as separate populations.
In some places, giant clam populations have not been thriving due to over-harvesting and climate change, Nevatte said.
"We've seen some recent studies showing that clams that bleach so just like corals, the clams will actually expel their little photosynthetic algae when they're under heat stress, and there have been issues with their reproduction post-bleaching," he said.
Nevatte said the clams are important for coral reef environments as they provide food, shelter and habitat for a bunch of different organisms.
"They filter a lot of seawater, so they prevent eutrophication of that seawater, and they act as these reservoirs for the photosynthetic algae. So corals rely on these photosynthetic algae, and the clams are actually able to release these algae in their feces, which can be picked up by corals and incorporated into their tissue," he said.
The new study was published in the journal "Ecology and Evolution." To read it, click here.
This interview aired on The Conversation on Nov. 12, 2024. The Conversation airs weekdays at 11 a.m. on HPR-1.
