The group visited a marine lab on Aitutaki today and met with Charlie Waters. Charlie recently finished a PhD focused on the giant clams of the Cook Islands. These clams were heavily overfished until they became functionally extinct (could not reproduce in the wild). Clams are important filter feeders in the reef ecosystem and are an important food source for octopus, porcupine fish, parasitoid snails, humans and multiple other animals.
The clams engage in a symbiotic relationship with phytoplankton (photosynthesizing plankton). The clams rely on the plankton for energy and have trouble surviving without the phytoplankton.
The lab has tried to implement reintroduction of multiple species of clams but poaching continues to ruin the efforts. In an attempt to come up with a solution, Charlie believes the best method is to educate youth and tourists on respecting the reef system. Hopefully these educational programs will eventually allow a successful reintroduction of these beautiful animals to their natural habitat.

We went snorkeling in the lagoon of Aitutaki Island and explored some of the smaller Islands in the lagoon called “motus”. The first was named Motu Ketiu and had multiple species of birds nesting on the Motu. I was able to identify red footed boobies, brown boobies, red tailed tropic birds, white tailed tropic birds, common terns, and I was excited to see my first frigate birds.
The next Motu was a newly formed sand bar that had a few coconut saplings (locally called “huto”). We had lunch and made our first UAV launch from this particular Motu.
We then ventured to a large Motu where the Tasmanian Empire Airways Limited had set up a stopping point in the early 1950s. Here we tested our sandy beach protocol and found that the beaches on these motus are low in diversity unless coring is done in knee deep water, where multiple species of tube worms and crustaceans were found.
Overall, quite a few discoveries were made today that filled the group with anticipation for the future research yet to be done.

I had the joy of observing one of my personal favorite invertebrate species today. The fiddler crab is an interesting crab species that is known for it’s oversized claw. Only the males have the large claw and use it to impress female crabs by waving. In order to avoid scaring the crabs, I sat and stayed still to watch them eat and continue building their burrows. When they were assured that I was no threat, some males began waving to impress some of the females in the group but many focused on eating and wouldn’t have
any mating shenanigans.
This is a female:

Our days spent on Rarotonga proved to be full of excitement and a great introduction to the Cook Islands’ culture. We were able to experience the 50th anniversary performances at the island’s auditorium. I have learned that the Cook Islanders have 3 names for coconuts and relied on the coconut tree for food, drink, baskets, and clothing throughout their history.
The reef biodiversity is immense and full of clams that can live longer than humans and weigh over 50 pounds. I have had the privilege of seeing more species of fish in one trip than my entire life.
Now that we are in Aitutaki, every look out of a window fills us with anticipation for the work to come.

This species of Kingfisher is endemic to Mangaia Island, the southern most Cook Island. Despite it’s relations, this species does not usually eat fish. Most of its diet consists of lizards and skinks. This species’ mating habits are also different than most, they often breed in pairs or trios and switch between polygyny, polyandry, and monogamy. Because the Mangaia Kingfisher is endemic, it is vulnerable to introduced species and habitat fragmentation. More than half of the Cook Islands’ endemic land birds are extinct and better management of land resources can reduce the threat of extinction for birds like the Kingfisher.

Can’t wait for this trip!