NOWRAMP
2002
R/V
Townsend Cromwell Retirement and Coral Bleaching
- Updates from the R/V Townsend Cromwell (9/25
- 9/28/02)
Midway
Atoll and Pearl
and Hermes Atoll
Posted
by Stephani Holzwarth
Photography by Jim Watt
Sept
25, 2002. Midway. The fairy terns are one of my favorite
things about this atoll. They nest in the ironwood trees
planted by the US Navy years ago. We watch them fly by with
fish dangling from their bills. Many seabirds swallow what
they catch, and regurgitate it for the chick, but fairy
terns deliver the whole fish to their chick. This requires
fishing close to shore and making lots of trips back and
forth, but may allow the fairy terns to duck under the radar
of the dreaded avian pirates known as frigate birds. Frigate
birds have 6 foot wingspan and steal food from other birds,
by force. They are like the mafia, or tax collectors.
Brian
and I have a game. It is called "what's eating the
slate pencil urchins?" We see urchins flipped over
and their insides devoured during our dives. The uhu uliuli
(spectacled parrotfish) here are huge, and would be a prime
suspect with their powerful mouth and sharp beak. Parrotfish
are herbivorous, so we don't think its them. "How about
porcupinefish? or hogfish?" BZ suggested after looking
for suspects during a tow. Those are the only other fish
that seemed big enough to accomplish the task in the shallow
backreef habitat, but I was doubtful. Porcupinefish have
soft lips, with the hard part of their mouth inside for
crushing small inverts. And hogfish have teeth more like
a dog, good for grabbing but not urchin smashing. A couple
dives later we came up with a better idea- "It's the
pufferfish!" Brian said, and I answered- "I was
just thinking that too!" They've got a strong jaw,
fused beak-like teeth, and I wouldn't put it past one to
eat an urchin.
Sept
26. Pearl & Hermes Reef. Stormy day- low, leaden clouds
in the morning and not a breath of wind, we slid over the
swell without any spray. The water's surface was glossy
like a dark mirror, like a black pearl. I like the pre-storm
calm. Rain and wind squalls pelted us the rest of the day.
We towed over back reef so folded and convoluted that it
formed deep secret chasms and caverns that we could see
into through narrow slots. Interesting habitat. Six butaguchi
(thick-lipped jacks, Psuedocaranx dentex) hovered
under an overhang. A large, pregnant whitetip reef shark
swam across the reef flat in front of me. And I think there
must have been a hatch of baby parrotfish recently because
the shallow reef flats were overrun by small dark juvenile
scarids, each with a black dot on a white tail, looking
like jack food.
Sept
27. Holy cow! Launching and loading the small boats this
morning on the north side of the atoll was a bit of a rodeo.
The wind and swell kicked up last night (fall out from a
powerful low pressure north up by Alaska) making for a messy
sea. Once we crawled around to the inside of the barrier
reef it wasn't so bad. We towed the inner north and east
backreef and verified that most of the Pocillopora
(rose coral) along that area is bleached. The Porites
(lobe coral) has fared much better and there is still living,
zooxanthallae-occupied coral on all of the reefs we filmed,
but the rose coral definitely took a hit. I'm not a coral
expert, but hazarding a guess- the water has been warmer
than I remember it in past years- 80, 81' F, instead of
78, 79' F. Rusty told me that both our CREWS buoys and satellite
measurements of sea surface temperature showed this summer
to be warmer than usual. He said "NOAA's Coral Reef
Watch alerted us a couple of months ago of a potential bleaching
event in the making." I'm curious to see what the CREWS
buoy at Pearl & Hermes recorded for water temperatures
though out the last year. Corals are sensitive to even slight
changes in water temperature.
Sept
28. The education team from the Rapture taxied over
to our ship in a small boat and spent the day aboard the
good ship R/V Townsend Cromwell, documenting one
of her last days of service as a NOAA vessel. I for one
will miss her sorely when she retires and is replaced by
a bigger, beefier, and probably less charming ship. Jonathan,
who celebrated another one of his birthdays aboard today,
adds a little reality to my nostalgia- "Her hull is
thin in a lot of spots, and whenever we need a part for
an engine they have to fabricate it from scratch. She's
done her duty and done it well- earned her retirement."
It's true. Jay, Monica, and Elrod, the engineers, work miracles
to keep the engines humming. None-the less, many of us feel
great affection for this ship that has carried us and scientists
and sailors like us safely across thousands of miles of
ocean and home again. She was and is still a great ship,
old school and very nautical in her bearing, something the
newer ships lack.
The
fish, benthic, and tow teams all worked in the southwest
part of the lagoon today, near Seal Kittery Island. Joe
and Brian towed along the west spur reefs. Joe said it looked
like Mars- a bunch of 5 foot high coral mounds in the grooves
(valleys) between spurs. usty and I towed the backside of
the barrier reef- amazing habitat. We flew across rolling
fields of Montipora (rice coral) plunging into wide
canyons with white sand on the bottom and coral piled up
along both sides. The crazy thing was that Montipora
is usually wonderful shades of blue and purple and golden
brown. There were still patches of bright color, but acres
and acres of it were gleaming white, like snow fields. "It
looks like Whistler!" I said when I came up. Jean Kenyon,
our coral ecologist, points out- some of it isn't bleaching,
and those hardy, lucky, and/or genetically favorable colonies
will reproduce and recolonize the reef. "It's natural
selection, happening right before our eyes," Jean commented.
I wish I could spend the next few decades here, underwater,
watching the changes come about. I wonder what the fish
think of all this white stuff that used to be purple and
blue. Their camouflage won't work
anymore!
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