26 Jul
2006 - Mar del Plata, Argentina – WWF associate
organization Fundación Vida Silvestre Argentina
(FVSA) has increased its research efforts for
a second year following continuous kelp gull attacks
of southern right whales off the waters of Argentina’s
Valdés Peninsula, one of the world’s most
important breeding grounds for this whale species.
According to researchers studying
this bizarre phenomenon, the gulls gouge through
the skin of the whales’ backs to feed on skin
and blubber, causing lesions along their spines
and affecting whale behaviour.
Such behaviour was first registered
by British researchers in 1969. Ten years later,
a study registered 151 attacks from gulls on whales
in this area. And in the 11000s new investigations
reported an increment of 60 per cent — about 80
per cent of the attacks seem to be targeted at
female whales and their calves.
“The whales, particularly the
calves, are wasting a lot of energy by swimming
away and diving deep underwater to escape the
attacks,” explained Alejandro Arias, WWF-FVSA
Marine Programme Species Coordinator.
“This is significant because
it seems to be preventing them from creating a
layer of fat so crucial for their long migration.”
It is estimated that mother
whales spend about a quarter of their day fleeing
gull attacks, using up energy reserves which could
be better spent protecting and producing milk
for their calves.
A WWF-FVSA research project
aims to further determine the effects of the kelp
gull attacks on southern right whales, particularly
focusing on possible modification of regional
distribution of whales. Researchers will also
study kelp gull populations and the effect the
attacks may have on the whale-watching industry.
“The scientific evidence will
serve as a basis for designing a management plan,
together with the local authorities, to mitigate
the negative effects of this situation,” said
Arias.
END NOTES:
• Kelp gulls (Larus dominicanus)
nest along 3,400km of Argentina’s coast, with
some 75,000 reproductive couples. The Valdés
Peninsula boasts six colonies, with several of
them having increased their size considerably
over the past few decades as a result of rich
food sources available to them at garbage dumps
and in the effluent of fish processing plants.
• Up to 10,000 southern right
whales (Eubalena australis) are distributed in
the southern hemisphere in three sub-populations
with nursery areas found in the waters off of
Argentina, Australia and South Africa.
• Every year, between May and
December, more than 2,000 whales inhabit the Valdés
Península. Some 100,000 tourists participate
in whale-watching trips, contributing to an industry
worth up to US$16 million.
Florencia Lemoine, Marine Programme Communications
Coordinator
