Large-scale die-off of sea urchins discovered off Kaumakani
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Posted:
Saturday, February 18, 2012 12:30 am | Updated: 9:58 pm, Thu Feb 23, 2012.
Large-scale
die-off of sea urchins discovered off KaumakaniVanessa Van Voorhis - The Garden Island | 51
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PORT ALLEN — While conducting a recent diving tour along Kaua‘i’s
southern coast, a diver made an alarming discovery: a field of dead heart sea
urchins on the ocean floor.
“It’s a massive die off of urchins,” said Linda Marsh, owner of
Bubbles Below Kaua‘i dive company. “This is a dive site we normally go to, and
this die off is a sudden thing. We have seen evidence of it miles away.”
Marsh, the veteran diver who made the find, called in a report on
Feb. 3 to Don Heacock, Kaua‘i’s biologist for the state Department of Land and
Natural Resources Division of Aquatic Resources and to Thierry Work, wildlife
disease specialist for the U.S. Geological Survey’s National Wildlife Health
Center in Honolulu.
“We’re always concerned when urchins die because of what happened
in the Caribbean,” Work said. “The Caribbean has lost 80 percent of its coral.
The massive coral die off was preceded by a massive die off of urchins. They
are a keystone species and an early warning system for large-scale changes in
the ocean.”
Marsh led Work and Heacock to the dive site on Feb. 5, and the
biologists began a two-day field investigation that included surveys and sample
collections. They documented 149 urchin shells littering a 25- by 4-meter sandy
stretch, Work’s USGS Port Allen trip report states. Sixty-eight percent of the
mortalities were skewed to the smaller (younger) classes.
Dead urchins were found 241 meters southwest and 147 meters
southeast of their dive boat moored offshore but, ultimately, the area was too
large to fully survey, even with underwater scooters. Based upon their
observations and available data, they estimate 52,000 individual heart urchins
have recently died off.
The biologists collected 28 specimens of sick and dying urchins.
Seventeen of them were suitable for further analysis and sent to California to
be processed for cross-section microscopic examination.
“I did see something like this in the past in Johnston Atoll
because of a protozoan infection,” Works said. “That’s the only other urchin
die off I’m aware of.”
The cause of the Caribbean die off of urchins and coral was never
determined, Works said, but what they do know is that urchins play a critical
role in the health of coral reef ecosystems and that population crashes may
have “important upstream consequences.” Urchins are grazers that keep the algae
at bay and a food source for other marine creatures.
They are also useful in laboratories to measure and test toxicity
because they absorb chemicals directly through their shells, Heacock said.
Because they are highly eco-sensitive, they are the equivalent of “canaries in
an oceanic coal mine,” he said.
Heacock hypothesized that genetically modified seed corn crops and
related chemicals used for their abundant production along the west and
southwestern shores of Kaua‘i may be a contributing factor.
“We can only speculate about what’s killing them right now,” he
said, “but here’s something to think about: Kaua‘i produces more GMO seeds than
anyplace. Now, there are a whole bunch of people in the genetic engineering
camp that say GMO crops need less pesticides, but the new wave of crops is more
toxic than ever before.
“The BT corn is meant to kill,” Heacock said. “It has an
insecticidal protein in the corn. In the Midwest, they found the residue from
GMO corn is related to aquatic insect deaths, which are food for baby fish.”
Kaua‘i seed companies constantly till and grub their soil, which
is full of these chemicals, he said. When it rains, the loosened red topsoil
flows into streams and rivers that eventually flow out into the ocean and onto
coral reefs.
Works said that during his dives near Port Allen the water was
cloudy but not red or silty.
“Cloudy water does not mean pesticides,” he said. “It’s easy to
start spinning stories. What we need is hard data. This is a detective type of
story, with a crime scene and a dead person. We don’t want a preconceived
notion to determine what killed the victim. The ideal thing is we arrive at a
cause of death, but often times we can’t figure out what killed them. We can
figure out what didn’t, such as infectious disease,” Works said.
“Even though what happened in the Caribbean looks similar, I’m not
saying it will happen here. We’re just trying to stay ahead of the curve. The
major message to the public is to report their findings. We have Eyes of the
Reef Network reporting online for unusual mortality events. This particular
event we never would have known about without Linda Marsh.”
Marsh said, “It’s a really good thing dive companies are keeping
an eye on this and reporting it. We took the right step forward by contacting
Thierry and Don. Hopefully, we can stop the point-source pollution.”
The Eyes of the Reef Network website is www.reefcheckhawaii.org/eyesofthereef.htm. To reach the
Department of Health Clean Water Branch for Kaua‘i, call 241-3323.
• Vanessa Van Voorhis, staff writer, can be reached at 245-3681,
ext. 251, or by emailing vvanvoorhis@thegardenisland.com.
