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Ocean
Watch
Monday, April 10, 2000
Rare species now
visible at Hanauma
OVER the last month, several friends have told me that
the numbers and types of fish inside the reef at Hanauma Bay are way down
from the past.
Last week, I went to see for myself and had the same
experience. The keyholes (open spaces between the reef flats) were nothing
like they once were. Due to the fish-feeding ban started in the bay a few
months ago, those teeming, nipping schools of fish have left for greener
pastures.
This was disappointing since it was those swirls of
colorful fish in the bay that, years ago, steered me toward marine
biology. I wanted to learn their names, what they ate and how they
survived. Besides that, swimming in the midst of all those species was
fun.
TODAY, the bay is still fun. You may have to look
harder to find fish but when you do spot some, you might be pleasantly
surprised.
I was.
When I swam over a seemingly barren stretch of sand, a
rare razor wrasse suddenly appeared. These wrasses are hard to find
because when threatened, they plow headfirst into the sand, then
"swim" beneath it. This behavior makes for good hiding, but it
is also useful in catching one of their favorite meals, garden eels.
To catch an eel, the razor wrasse sometimes dives
directly into the eel's burrow and grabs it. Another tactic is to sneak
beneath the sand to the side of a burrow, then snatch the eel when it
peeks out.
If you get lucky enough to see one of these sand
divers, you won't forget it. Razor wrasses bear striking brown and white
bars on their bodies, accentuated with black spots. On their back, belly
and head are frilly fins that remind me of lionfish.
Since I have only seen a few razor wrasses in my life,
this was a thrilling sight. And brief. Before I could alert my swimming
partners, the fish lunged into the sand and disappeared.
The bay's "empty space" sheltered other fish
I had not before seen inside the reef. A moray eel, its body as big around
as my calf, was wound like a pretzel into a small, freestanding rock
formation. We could see the eel's body from several sides of the rock but
never saw its head. White spots dotted the robust brown body.
THE ability to make tight curves in their bodies serves
morays for more than just shelter. When a moray catches a fish too big to
swallow whole, many species employ a behavior called knotting.
With its tail, the eel makes two simple knots in its
long body. Then, with the too-large prey clenched firmly in its teeth, the
moray backs its head through the knots. When the fish gets stuck in the
tight space, the moray can then rip off a mouthful of flesh. Other times,
when the captured fish gets to the moray's knot, the moray will tighten
it, breaking the fish's bones and squashing it flat. The meal is then
small enough to swallow.
The twisted eel I saw was probably a whitemouth moray,
although without seeing the inside of its mouth, it's hard to say for
sure. Distinguishing morays can be hard since members of even the same
species often display wide color variations.
Some fish, such as one called a comet, count on
mistaken identity. Comets are a grouperlike species from Indonesia (not
found in Hawaii) that mimic whitemouth morays. This chocolate brown,
white-spotted fish has a narrow body and long, continuous fins. By looking
like eels, comets may be safe from potential predators who don't want to
mess with a moray.
No, the fish don't swarm at Hanauma Bay like they used
to. But their absence has cleared the way to see new ones.
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