Day 17: Snorkeling in a Kwajalein tide pool, or: What it’s like to swim in an aquarium

When I first started telling people I would be moving to Kwajalein, I never knew what reactions to expect. I got a lot of “That sounds great for you, but we’ll really miss you.” But one response from a computational biologist stands out in my mind:

“Why would you move there? There can’t be very much species diversity, right?”

I laughed it off when the man said it, but the real absurdity of his question hit home last weekend. We had learned the tide would be really low, so we decided to get our snorkel gear together and take a dip in some snorkeling pools we’d heard about on the ocean side of the island.

We loaded our gear onto the bike trailer and pedaled down the oceanside street near the where the fish hook shape of the island curves west. We found a shaded bench tucked in the foliage along the beach overlooking the reef and our destination: the American pools.

Japanese pools
Jake took this photo of the American pools from a helicopter. The pool we swam in is out of photo to the left.

During World War II, the Japanese occupied the island for much of the Pacific conflict. While they were here, they dug pits, either to use the rock to expand the tiny island or to make an invasion more difficult. After the Americans took the island, they also dug pools in a different area of the to the north. Then, in its constant sweep across the rock, ocean water deposited coral and reef creatures in the pools, and life reclaimed the deep reef pits as their own. Now, the pits are known as the Japanese pools and the American pools.

Last weekend was a negative tide, when the water recedes below average sea level. At very low tide marks, the reef pools become separated, each a self-contained ecosystem. In this way, with the passage of time and the indifference of nature, the mechanics of war are connected with a family snorkeling trip, a perspective that hits home often on an island steeped in World War II history.

On our trip, we picked our way carefully across the sharp reef, watching for sea urchins. At the edge of the pool, we put on our gear: masks, snorkels and fins. Then we dangled our legs over the edge of the pool and pushed off into the water.

Brad snorkeling
Brad is all geared up and ready to get in. He was the first in the water.

When Brad was two, we moved to Monterey, Calif. We had a membership to the Monterey Bay Aquarium, and we visited once a week. Brad and I used to spend hours in front of the aquariums on our weekly visit, looking for bright orange clownfish, broad-winged rays and sleek sharks. Now, eight years later, the glass is gone, and we’re swimming in a tank alongside parrotfish, tangs, pipefish, an eel, triggerfish, butterflyfish and angelfish.

Along the sides of the pool, brown and yellow-patterned pipefish – the cousins of the sea horse – snaked in and out of layers of coral stacked like mushrooms in a rotting log along the sides of the pool. Bright purple gobies poked their heads out of holes and shiny black sea cucumbers clung to the the sides.

Pipefish in Japanese pool
A pipefish finds its way along the side wall of the pool.

The south side of the pool was shallow, the water warmed by a hot mid-morning sun. The bottom flashed with sunlight and quick bursts of black and white striped damselfish and violet and yellow surgeonfish winding their way through a blue, red and yellow spiky coral forest. We floated lazily, watching tiny spotted wrasses flit from spike to spike or a yellow and brown honeycombed grouper peer at us from behind a rock. A rusty-red triggerfish faced us, flaring its dorsal fin and protecting its territory. A group of translucent needlefish bobbed at the surface, a surprise when we looked up and ahead instead of facedown. A puffer darted across a bare patch of sand. One section of coral tilted up from the bottom, creating an island in the pool that we swam around. The sun-facing side of the coral island teemed with colorful life, bursts of black-faced rabbitfish, blue fusiliers and red and white striped hawkfish eating and defending and surviving. On the shadowed side lurked bigger versions of the same fish, their eyes shining in the dark.

The deeper side of the pool on the north – my guess is 20 feet, but I’m asking around for a more expert depth – had open, sandy patches breaking up the coral carpet that stretched up beneath us into the warmer shallows. (Update August 20, 2018: I talked with a local dive expert. The deepest any of the pools reaches is 10-12 feet.) A large turquoise and fuchsia parrotfish patrolled the deeper water, aggressively biting off chunks of coral and scattering smaller fish in its wake. Triggerfish, following straight lines and making sharp corners, appeared to be following a road while we watched from above. Because of the depth, the water was colder and darker. Sunlight slanted through about five feet, illuminating the sparkling sand and bits of shell sifting down to settle at the bottom of the pool before the light faded to deep blue darkness.

fusiliers in Japanese pool
Fusiliers school at the top of the pool near the reef.

We floated, we pointed, our masks leaked, and when we got tired and the waves were starting to pour back into the pool with the rising tide, we climbed out of the pool, exhausted. We sat on our fins to protect our legs from the reef, warming our skin in the sun and trading stories about our favorite sightings.

I remembered the species diversity comment, and it suddenly struck me as a funny understatement. I had just observed what could be hundreds of different species contained in the same area as an Olympic-size pool.

We carried our gear back to the bench and got out snacks and water, warming our skin in the sun and discussing our underwater discoveries. Brad’s favorite sighting was the pipefish, and Nora was proud to be the first to spot the large parrotfish in the pool. We loaded the bicycle cart and pumped back to our house, already planning our next snorkeling adventure.


EDITED August 22, 2018: I learned from the director of the snorkel club that I have been confused regarding which tide pools were dug by the Japanese and which by the Americans. I’ve edited this blog post to reflect my mistake: we were in the American pools.