Scientists ask: Where have all the dolphins gone?
Pastor Dale Morgan
Scientists ask: Where have all the dolphins gone? *
Aug 23 09:56 AM US/Eastern
Sightings by marine scientists of dolphins in the north Atlantic's Bay
of Biscay have dropped off by 80 percent compared to the same period in
2006, a wildlife conservation group said Wednesday.
The alarming drop in numbers of the Bay's three most common species of
dolphin -- the striped, bottlenose and common -- can be attributed to
one or both of two causes, Clive Martin, senior wildlife officer for the
Biscay Dolphin Research Programme, told AFP.
"We know for a fact that by-catch is killing thousands of dolphins every
year," he said, referring to commercial fishing operations in the bay,
which is formed by the northern coast of Spain and the eastern French
seaboard up to the tip of Brittany.
Martin singled out French "pair trawlers" that sweep the ocean with huge
nets twice the size of a football pitch strung out between them as being
especially lethal to the marine mammals.
"Dolphins are sometimes trapped hundreds at a time, and are asphyxiated"
when they cannot come up for air, he said. Most dolphins typically
replenish their lungs with fresh air every five minutes or so, he explained.
The second -- and probably more important -- reason that dolphins have
disappeared is that there is simply very little left for them to eat.
"Anchovy fishing in the Bay of Biscay has progressively failed, and this
year there is a complete ban by Spain, France and the United Kingdom on
the fishing of anchovies," a principal food source for dolphins, Clive said.
He speculated that the roving sea mammals -- which swim in pods
numbering in the dozens for bottlenose dolphins, and sometimes in the
thousands for the common dolphin -- had moved west toward the
mid-Atlantic looking for food.
A sharp decrease in the presence of many seabirds that also feed on fish
-- such as auks, shearwaters and gannets -- lends support to this
explanation.
The Bay of Biscay Research Programme has been systematically recording
dolphin sightings along the same route from Bilbao, Spain to Portsmouth,
England for 13 years.
Compared to the comparable period in 2004 and 2005, dolphin sightings in
2007 have decreased by 50 percent, he said.
The Bay of Biscay hosts a greater variety of dolphin populations than
any other part of the world's oceans. Clive suggested that policy makers
should consider transforming the area into a sanctuary for marine life.