Kauai's Reefs: Teeming with Life
The boat rocked from port to starboard and back again, as regular as a metronome. A diminishing south swell that shut out all dive boat operations for the past week still churned the water—and my stomach. That may have explained my deadpan response to Captain George’s dive jokes, but that wasn’t all. It was early.
I am not a morning person. By the time I usually rise, my husband is up, dressed, drinking his freshly-brewed Columbian Supremo coffee and making a sandwich for his lunchbox. Whenever I rise, I am not the most chipper person, preferring to retreat to my chair on the lanai with a cup of herbal tea and the local newspaper—The Garden Island—to read the daily news and, my favorite, the letters to the editors. While the latter are vocal, providing a pulse on the mood of the island’s people, they are also letters and, therefore, silent. I like that.
George is a morning person. “What does a mermaid eat for lunch?” he asked, as the boat swayed, and I scuttled for a seat. I signed up for this early morning dive charter to research Hawaii’s reefs in celebration of the “International Year of the Reef.”
George didn’t wait for an answer. “Peanut butter and jellyfish,” he said and launched his second joke, “What do you call a mermaid who won’t share her lunch?”
As the owner of Fathom Five Divers, George Thompson has logged thousands of hours on a boat. He has his sea legs. So, he floated from his captain’s chair to the back of the boat to hoist my tank onto my back.
“Shellfish,” he said.
I slipped my fins over my dive booties, wrestled into my buoyancy compensator vest with its bulky tank of air and tested my regulator to make sure the air was flowing.
Mask on, I rolled backward into the sea. The last words I heard were, “What do you call a.…” And I descended to eighty feet of peace and quiet.
Sightseeing Below the Sea on Kauai
Under water, I can sometimes hear the crackling sound that shrimp make, but, usually, the only sound I hear is that of my breathing, as I draw air in and out of the regulator in my mouth. It’s a comforting sound.
Before George started reeling off his “dumb diving jokes,” as the rest of us dubbed them, he asked everyone to search for lobsters on our dives.
The lobsters that inhabit the relatively warm waters of Hawaii are not the kind you find at restaurants across the country. Lobsters divide into two groups: Those with enlarged pincers on the first pair of legs—like the American Lobster found in restaurant holding tanks—and those without—like the spiny lobster found in Hawaiian waters. But just because the lobsters crawling around the bottom of the Pacific do not have large pincers does not make them inedible. Lobsters, known as ula in Hawaiian, are eaten raw and cooked. They are prized. One story I’ve read says lobsters were substituted for pigs during ancient Hawaiian days in sacrifices to the gods.
In Hawaii, Lobsters Are Protected
Two things make lobsters vulnerable to over-fishing today: One, their tasty meat; and, two, their ease of catch.
Lobsters are nocturnal bottom-dwellers. They scramble over the sandy, ocean floor adjacent to the reef, foraging for food during the night when they are easy to catch in traps and tangle nets. So easy that the commercial catch in Hawaii went from 40,000 pounds in 1948 to 4,800 pounds in 1968.
Even though adult female lobsters spawn four times a year and produce up to half-a-million eggs at a time, it takes almost a year for those eggs to hatch and develop into a something recognizable as a lobster.
So, the State of Hawaii prohibits the take of the spiny lobster during May, June, July and August. (Basically, as local fishermen like to say, if it’s an “R” month, it’s a lobster month.) However, undersized and “berried” females are illegal to take, no matter the month.
During the day, lobsters sleep, tucked under ledges and wedged into nooks and crannies on the reef. Unlike nighttime, lobsters are not easy to catch during daylight hours. When I spot a lobster during a day dive, it’s usually because I just happen to spy their antennae poking out of a crevice. Since they’re up all night, my guess is lobsters, like me, are not morning critters; they do not want to be disturbed too early. Yet George’s dive shop participates in a research study that is trying to figure out if the lobster population in the main Hawaiian Islands feeds that in the northwest Hawaiian Islands, now known as the Papahanaumokuakea Marine National Monument, or vice versa.
If we find a lobster, George wants us to bring it up to the boat, where he will take measurements and a single leg and, then, release the lobster, even though it’s September—an “R” month and legal to take. “But don’t stick your hand in a hole to go after a lobster,” George said. Because lobsters aren’t the only critters that like to sleep in holes. I’ve heard it said that if you see a lobster with only one visible antenna, it means the other antenna is pointing back into the hole keeping track of an eel.
Eels. Those long, slender, snake-like critters with teeth. They thread their bodies through the reef as tightly as a fan belt wrapped around an engine.
To understand how an eel weaves its body through the reef, it helps to understand how the reef develops.
It Takes the Work of Plants and Animals
In Hawaii, two organisms are responsible for reef building.
The first is a plant. Coralline algae are stony seaweeds that produce calcium carbonate (limestone). As they grow, they cement sand, shells, rocks and old coral skeleton, producing the reef framework. Much of Hawaii’s reefs are made up of coralline algae, which is a plant but often confused with hard coral, an animal. Light tan to pink in color, coralline algae is hardy enough to withstand the impact Hawaii’s pounding surf, unlike the second organism contributing to the reef’s architecture.
Coral is a community of individual animals called polyps, all connected to each other by a thin layer of tissue. As each coral polyp grows, it secretes calcium carbonate which hardens to create a rigid cuplike skeleton—or calyx—around each polyp. These calyces join to form solid structures of many shapes and sizes, including tables, plates, branching fingers, bushes, lobes and mounds. The telltale characteristic of coral colonies, which helps distinguish it from coralline algae, is the repeating pattern of calyces lined up one after another like rooms in a hotel.
Hawaii’s Unique Reefscape
I’ve been diving and snorkeling around Hawaii for almost 20 years and, until now, I’ve paid scant attention to the reef itself. I guess I figured reefs were rocks and those things growing on them were plants.
Honestly, I thought Hawaii’s reefs were rather bland. Because there weren’t any neon yellows, pinks, purples and oranges catching my eye like that in the Caribbean, I turned my attention to the critters swimming in and amongst the reef. Like the juvenile yellowtail wrasse, bluestripe snapper and Hawaii’s state fish, the well-known Picasso triggerfish, known in Hawaiian as humuhumunukunukuapuaa. Now, they are colorful. Call me shallow, but I guess I was only attracted to outwardly characteristics. Oh, and size too. You can’t miss the graceful green sea turtles. They grow up to 400 pounds, and they like to snooze under ledges around the reef.
In my defense, I’ve always heard it was the volcanic substrate that made diving in Hawaii interesting. That is, the caverns, caves and tunnels created as the successive lava flows that formed these islands erode. And, truly, Hawaii’s underwater landscape is like meandering through an old Victorian home, one room leads to another and another.
Today, my attention was turned to the reef, the place some 5,000 animal species call home in Hawaii. That’s where one of my dive buddies, Terry, spotted the whitemouth moray eel. It was so tightly wound around the branches of cauliflower coral that it looked like the coral had grown around the eel. But coral grows heartbreakingly slow, maybe one-quarter inch per year, so that was impossible.
A Lack of Coral Diversity
Cauliflower coral is one of Hawaii’s six common corals. All six are relatively ordinary in color, which explains the limited color range on the reef. Cauliflower coral forms branching cream or tan colonies. Lobe coral grows in large yellow-green mounds. A relative of lobe coral, finger coral produces shades of gray and develops, as the name suggests, in finger-like protrusions. Rice and sandpaper rice coral shapes in sheets and plates in tans and browns.
What’s more interesting than Hawaii’s lack of color on the reef is its lack of diversity. Hawaii boasts only six common corals and sixty-six species of hard corals total. That compares to over 500 hard corals elsewhere in the Pacific. Scientists explain this lack of variety to isolation. Hawaii is one of the most isolated bodies of land in the world. As everyone who visits Hawaii knows, it’s not easy to get here. Same goes for corals.
The other thing that limits the number of coral species around Hawaii is the species’ fragility. Reef corals are notoriously fussy. They live within a narrow tropical band around the equator, preferring an average water temperature between 65 and 85 degrees Fahrenheit. They like clear, well-lit water and salinity close to 35 parts per thousand. While corals want their watery home to move, they do not want it to rage, just as we like cooling trade winds but not a hurricane. So, the winter waves for which Hawaii is famous allow for only the hardiest of corals to survive here. There are few frilly, lacy soft corals in Hawaii. Those that do grow here are considered rare and found in deep water.
A Reef is a Reef is a Reef. Not.
On my two dives with Captain George, I learned something else about Hawaii’s reefscape: No two reef ecosystems are the same. They change as quickly as the terrestrial topography around Hawaii. Whereas the north shore of Kauai receives more rain and is redolent with lush, tropical plants, the dry, west side of Kauai resembles more a desert, complete with cacti.
As we moved from Turtle Bluffs dive site to Sheraton Caverns, a mere few miles apart on Kauai’s south shore, I noticed a change in reef ecology. Whereas Turtle Bluffs was primarily characterized by coralline algae and a few wire corals, I spotted many more mounds of lobe coral and heads of cauliflower coral at Sheraton Caverns. According to George, that’s because a slight change in salinity, water temperature and nutrient and chemical runoff influences what lives in the area, just as different land-based plant species prefer different soil types.
Hawaii Is Home to Some Unique Characters
While Hawaii’s isolation may limit its species diversity, that same characteristic has spawned an endemism epidemic. Twenty percent of marine invertebrates and 25% of fish life are endemic to Hawaii; that is, found here and no where else.
Take the lobsters for which George had us searching. I never did find one, but another dive buddy, Mark, spotted a spiny lobster embedded in a crevice. Of the three spiny lobsters in Hawaii, one—the banded spiny lobster—somehow evolved into its own unique species, making it endemic to the area. I’m not sure whether Mark’s was the endemic variety or not. All I know is that Mark came up empty-handed—and with all five fingers in tact. Maybe Mark had heard the diver’s old saw about the one visible antenna.