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<DIV align=left>Dolphin strandings in Peru elude explanation</DIV>
<DIV align=left><FONT size=2>Barbara Fraser</FONT></DIV>
<DIV align=left><FONT size=2>Ecoamericas - April 2012</FONT></DIV>
<DIV align=left><FONT size=2></FONT> </DIV></FONT></FONT><FONT size=7
face=AkzidenzGroteskBE-XBdCn><FONT size=7 face=AkzidenzGroteskBE-XBdCn>
<DIV align=left><FONT size=2>N</FONT></FONT></FONT><FONT
face=Garamond-Book><FONT face=Garamond-Book>early three months after dolphins
began beaching themselves on Peru’s northern coast in droves, officials still
don’t know</DIV>
<DIV align=left>what caused the massive die-off, and some experts say the deaths
may remain a mystery.</DIV>
<DIV align=left> </DIV>
<DIV align=left>Although early reports indicated as many as 2,800 common
dolphins (Delphinus capensis) and Burmeister’s porpoises (Phocoena</DIV>
<DIV align=left>spinipinnis) beached on the coast of the Piura and Lambayeque
regions, the official count as of mid-April was 877, according to Vice Minister
of Fisheries Patricia Majluf. “We know very little,” Majluf says.
“Unfortunately, this type of event is occurring more frequently around the
world. No one knows if it’s a consequence of climate change, pollution” or other
factors.</DIV>
<DIV align=left> </DIV>
<DIV align=left>The strandings have coincided with dolphin beachings in the
United States along the Louisiana coast and on Cape Cod, Massachusetts, although
a spokesperson for the U.S. National Oceanographic and Atmospheric
Administration called the events unrelated.</DIV>
<DIV align=left> </DIV>
<DIV align=left>Explaining a stranding takes detective work, but scientists say
that in about half the cases, no answer is found. Some experts assert the
gradual increase in the number of beachings reported in Peru, which peaked in
March, suggests the cause was disease or a biotoxin, perhaps from an algae
bloom.</DIV>
<DIV align=left> </DIV></FONT></FONT><FONT size=3
face=AkzidenzGroteskBE-BoldCn><FONT size=3 face=AkzidenzGroteskBE-BoldCn>
<DIV align=left><FONT size=2><STRONG>Weighing possible
causes</STRONG></FONT></DIV>
<DIV align=left></FONT></FONT><FONT size=2 face=Garamond-Book><FONT size=2
face=Garamond-Book></FONT></FONT> </DIV>
<DIV align=left><FONT size=2 face=Garamond-Book><FONT size=2
face=Garamond-Book>In an April report to Peru’s Congress, Majluf said lab tests
had ruled out heavy metals and poisoning from agricultural chemicals.</DIV>
<DIV align=left>The report says a combination of warmer-thanusual ocean
temperatures and significant river runoff, because of heavy rains in the Andes,
was creating ideal conditions for algae blooms off Peru’s coast, but that no
significant blooms had been observed. Tests ruled out three marine biotoxins
associated with algae blooms; but the report notes there are several hundred
such toxins, so the tests are not conclusive.</DIV>
<DIV align=left> </DIV>
<DIV align=left>Disease is another possible cause of the die-off. Armando Hung,
dean of the School of Veterinary Medicine at Cayetano Heredia University in
Lima, said April 20 that he had ruled out brucellosis, but was still awaiting
results of tests for leptospirosis and morbillivirus. He added, however, that
samples were taken from only two cadavers, which were in an advanced state of
decay that could complicate analysis.</DIV>
<DIV align=left> </DIV>
<DIV align=left>When reports first surfaced in Peru in February, media and some
environmentalists were quick to blame offshore oil operations,</DIV>
<DIV align=left>though there were no reports of oil leaks or slicks. Carlos
Yaipén-Llanos, a veterinarian and president of the nonprofit Scientific
Organization for the Conservation of Aquatic Animals (Orca), examined some of
the dead animals and said he suspected acoustic impact from offshore seismic
testing, because he found broken ear bones in the dead dolphins he
examined.</DIV>
<DIV align=left> </DIV>
<DIV align=left>BPZ Energy of Houston began seismic exploration—which involves
firing blasts of air at the ocean floor—in February off the coast of the Tumbes
region, north of the beaches where the strandings occurred. A BPZ spokesman said
dead dolphins were reported on the beaches before the testing began, and that
the company was complying with all Peruvian regulations.</DIV>
<DIV align=left> </DIV>
<DIV align=left>Darlene Ketten, senior scientist at Woods Hole Oceanographic
Institution in Massachusetts, says there was a “low probability” that the
dolphin deaths were due to seismic exploration. Ketten, who has studied dolphin
strandings around the world, said ear bones could be broken when a necropsy is
done, and only an X-ray or CAT scan could identify ear damage.</DIV>
<DIV align=left> </DIV>
<DIV align=left>“Strandings of this size are usually related to toxins,” Ketten
says, adding, however, that about half of dolphin strandings go unsolved. </DIV>
<DIV align=left> </DIV>
<DIV align=left></FONT></FONT><FONT size=3 face=AkzidenzGroteskBE-BoldCn><FONT
size=3 face=AkzidenzGroteskBE-BoldCn><FONT size=2><STRONG>“Atypical” for
acoustic-impact</STRONG> </FONT></FONT></FONT></DIV>
<DIV align=left> </DIV>
<DIV align=left><FONT size=2 face=Garamond-Book><FONT size=2
face=Garamond-Book>Brandon Southall, former director of the NOAA ocean acoustics
program, also said the Peru strandings were “atypical” for a case of acoustic
impact. “Investigations [of strandings] are painfully slow because you have to
sift through all the possibilities,” he says. The dolphin detective work in Peru
is even more complicated because there is so little marine research in the
country, says Majluf,</DIV>
<DIV align=left>a zoologist who spent several years studying sea lion colonies
on the country’s southern coast. (See “Time to map Peru’s marine ecosystems,
Majluf says”—EcoAméricas, April ’03.) She says it is impossible to compare the
number of beachings this year with past years because reliable records have
never been kept.</DIV>
<DIV align=left> </DIV>
<DIV align=left>Yaipén-Llanos worries that some residents of fishing villages
where dolphins have beached cut up the carcasses and took the meat</DIV>
<DIV align=left>home to eat. Because they are high in the food web, dolphins can
have high concentrations of heavy metals and chemicals such as DDT, PCBs,
dioxins and flame retardants, especially in their blubber. Those metals and
chemicals can also accumulate in the bodies of humans who eat the carcasses.
They could also weaken the immune systems of marine mammals.</DIV>
<DIV align=left> </DIV>
<DIV align=left>Ultimately, the strandings in Peru may prove to have a
combination of causes. Says Peter Ross, a researcher at the Canadian</DIV>
<DIV align=left>Institute of Ocean Sciences in Sidney, British Columbia: “Many
times, at the top of the food chain, there might be a smoking gun, but often we
find that it’s two or three or four factors.”</DIV>
<DIV align=left></FONT></FONT><FONT size=2 face=AkzidenzGroteskBE-BoldCn><FONT
size=2
face=AkzidenzGroteskBE-BoldCn> </DIV></FONT></FONT></FONT><BR>
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