Honolulu Star-Advertiser © Susan Scott
Friday, February 22, 2008
Last weekend during our calm, sunny weather, Hanauma Bay offered its finest entertainment. I snorkeled there two days in a row, and during those swims the breathtaking scenery and continual action made me feel I was watching a movie.
Parrotfish chomped on coral rock, goatfish wiggled their whiskers in the sand and a cornetfish swam alongside me, using my body for camouflage.
And then came a plot twist: A gang of seven omilu (bluefin trevally) rushed past me doing something I’d not seen before. These predators were working together to chase down a moray eel.
I don’t know whether that yellowmargin moray had been fishing, but being out in the open at midday was a mistake. Those omilu turned the hunter into the hunted.
Omilu belong to a family of fast-swimming fish called jacks. In some parts of the world, jacks are known as trevally, and in Hawaii many are called ulua. Juvenile ulua are called papio in Hawaiian.
About 140 jack species swim in the world’s tropical waters; 23 of those are found in Hawaii. Among these are opelu and akule (scad), kahala (amberjacks) and lai (leatherback).
The omilu I saw hunting are to me the most beautiful of all jacks. Omilu bodies are iridescent silver and turquoise, and their fins are bright blue. In sunlight these colors are so bright that when I stopped snorkeling and treaded water to wait for my friends, I didn’t wonder where the omilu went. They glowed like underwater neon signs.
I’ve seen these 2- to 3-foot-long blue beauties often in this area of the bay and wondered if they’re the same fish or if this is a particularly good hunting area for omilu.
They’re likely the same fish. When researchers tagged and released omilu near Coconut Island, 75 percent stayed within about one-fifth of a mile of their release spots. Months later the same fish were still there.
Such site fidelity makes these fish easy targets of fishers who like omilu, and ulua, because they fight so hard for their lives.
Once, the good-tasting ulua were common on Hawaii’s menus, but an increase of ciguatoxin in Oahu’s reef fish made the safety of eating ulua questionable, and markets for them plummeted.
Ciguatoxin travels up the food chain without harming the fish, therefore, the larger the fish, the more chance of it carrying the poison. There’s no easy way of telling which fish has it.
Some people still catch and eat ulua, but this is risky. Ciguatera poisoning doesn’t kill you, but it sure can make you sick, and symptoms sometimes last for months.
Omilu were once the most common jacks on tropical Pacific reefs, but overfishing has reduced the numbers drastically in most island groups, including Hawaii. The only places most of us see them now is in marine preserves.
The omilu diet is 96 percent fish, but nowhere did I find that they eat moray eels. They didn’t eat the one I saw them chasing, because the eel, about 2 feet long, slithered into a hole and disappeared. The omilu hung around for a second and then sped away, as if it had all been a game.
With movies, once you’ve seen them, the suspense is over. You know the end. On the reef, though, the drama never ends.
In the category of best entertainment on Oahu last weekend, the hands-down winner for me is Hanauma Bay.