ALL AT SEA - The New Wild: Why Invasive Species will be Natures Salvation - page 27

and conservationist Jacques Cousteau on the shores of the Mediterranean. After seeing all the aquari-
ums, with their magnificent specimens of marine life, we descended into the vaults where they kept the
sick fish, prepared displays, and did the museum's plumbing. My guide, an in-house scientist, explained
how they took water for the tanks from the sea just outside the walls of the museum. “And do you dis-
charge the waste into the sea too?” I asked. He looked a little uneasy. “Yes. Did you have anything in
mind?” I did. “ Caulerpa ,” I replied.
I had been in Monaco twenty years before to interview marine biologist Alexandre Meinesz, from
the nearby University of Nice. Back then he publicly accused Cousteau's aquarium of causing ecologic-
al meltdown in the Mediterranean. One of Meinesz's students had gone diving and spotted a small patch
of bright green weed on the seabed right outside the museum. It resembled Astroturf and was close to
the pipe used to discharge used water from the aquariums. The weed was previously unknown in the
Mediterranean. It turned out to be Caulerpa taxifolia , an algae native to the Indian Ocean. It had been
imported to Europe a decade earlier for use in aquariums at the Wilhelma Zoo in Stuttgart, Germany,
from where Cousteau took some to brighten up his displays in Monaco. Evidently, some had escaped. 9
Nobody removed the patch of weed on the seabed. For five years, it grew only slowly. But after
1989, it rapidly spread down the coast, blanketing two hundred miles of the Riviera from Toulon in
France to Imperia in Italy. Soon it turned up in the Balearic Islands and as far south as Tunisia in North
Africa and east as Croatia. Meinesz raised the alarm. It was killing the underwater meadows of sea
grasses, where hundreds of fish species spawned and fed, he said. It had mutated, growing to more than
twice its normal size and generating a higher dose of caulerpicin, a toxin that kills fish, sea urchins, and
anything else that eats it. “We could be seeing the beginning of an ecological catastrophe,” he told me
one sunny morning at his campus office.
A panic began. Marine biologists around the world went on alert for the mutant algae. In 2000, it
turned up in a lagoon in San Diego, probably after release from an aquarium close by. A team of snorkel-
ing scientists was down there within days, ripping it up with their bare hands and applying chemicals.
They called themselves a “self-appointed ad hoc management team of exceptionally committed loc-
al managers.” A local corporation even donated six million dollars to support their efforts. 10 Meinesz,
meanwhile, wrote a best-selling topic, Killer Algae . Caulerpa had “devastated the Mediterranean eco-
system [and] defeated the French navy,” he wrote. If only Cousteau's crew in Monaco had done the
same as the San Diego snorkelers, the sea would have been saved, he suggested. But the aquarium was
still denying responsibility. 11
Fast forward to 2013, when my guide at the museum was still not prepared to admit his employers'
responsibility. “It may not have come from here,” he insisted. “There are other places in the Mediter-
ranean where they use Caulerpa , and anyhow it is disappearing now,” he said. The tour continued. But I
was intrigued. Not much had been written about the “killer algae” lately, so I checked the literature. Had
Meinesz's dire predictions come true? No, they had not. Caulerpa was disappearing as fast as it had ar-
rived and was entirely gone from large areas, as Meinesz agreed when I approached him. The Caulerpa
binge in the Mediterranean was largely over. The algae were dying in many areas. The demise had been
going on along the Riviera almost since Meinesz's topic hit the stores. In 2003, there was less than a
tenth as much Caulerpa as Meinesz had recorded a decade before. Published papers have since reported
its disappearance from the shores of Italy and Croatia. 12
What had happened? When writing up my interview with Meinesz in 1992, I had called John
Chisholm, an Australian marine biologist at the Oceanological Observatory of Villefranche-sur-Mer, in
the south of France. Chisholm told me that he thought the noxious weed was simply taking advantage of
a Mediterranean ecosystem badly damaged by pollution. “ Caulerpa grows in sediments rich in organic