Q2-Spring-2016_Alert-Diver

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Corsica. It includes territorial waters of all three nations,
but much of it is in international waters or areas beyond
national jurisdiction (ABNJ). With the Pelagos Sanctuary
as an example, the United Nations has created a process
to establish additional MPAs in ABNJ, which cover 40
percent of the earth’s surface.
Marine mammals found within sanctuary waters
include fin whales, sperm whales, Cuvier’s beaked
whales, long-finned pilot whales, striped dolphins, short-
beaked common dolphins, common bottlenose dolphins
and Risso’s dolphins. Fin whales and striped dolphins are
the most abundant. Sperm whales in the Mediterranean,
like fin whales, constitute a distinct subpopulation
characterized by a unique vocal repertoire (and possibly
a smaller body size). Unlike male Atlantic sperm whales,
which make enormous migrations between high-
latitude feeding areas and low-latitude breeding areas,
Mediterranean sperm whales are believed to spend their
lives within the Mediterranean.
Scientists did not recognize the abundance of
whales in this region until Notarbartolo di Sciara
began studying cetaceans there in the late 1980s. Many
divers, however, still believe “the Med is dead.”
“That’s not true,” said Sylvan Oehen, a member of
the Tethys Cetacean Sanctuary Research team. “The
Mediterranean is overfished for some species, but the
primary productivity is still there, and it supports a
lot of life.”
Photographer Danny Kessler was surprised and
intrigued when he learned about the Tethys research
while on a family vacation in Sardinia. He had assumed
that the clear blue waters of the Mediterranean
indicated a sterile environment, not realizing that
ocean giants were diving deep to utilize food resources
hundreds or thousands of feet below the surface. He
was also amazed when Cetacean Sanctuary Research
director Sabina Airoldi showed him maps of seasonal
upwellings, and he learned that the fleet-finned fin
whales could dash hundreds of miles to get from one
temporarily productive area to another.
Numbers of fin whales in the sanctuary have been
declining in recent years, but this may simply reflect
movement out of the Ligurian Sea into other parts of
the Mediterranean. Sperm whale numbers, however,
appear to be increasing within the sanctuary. Similarly,
common dolphin numbers have crashed, but striped
dolphins are abundant. Overfishing of the primary
prey species of common dolphins is suspected in their
decline. Striped dolphins eat a much wider variety
of prey and are thus able to prosper. Risso’s dolphin
populations have declined since 2005, with abundance
estimates in 2012 and 2013 only half of the average.
Risso’s dolphins and Cuvier’s beaked whales feed
primarily on squid, but Tethys’ studies showed that the
two species were using entirely different habitats.
Almost nothing was known about Cuvier’s whales in
the Mediterranean before Tethys began its research in
1999, collaborating with other researchers to describe
a resident population of about 100 of these rare
animals feeding in a deep canyon region off Genoa.
Long-finned pilot whales, once commonly found
in large pods, are now rarely seen in the sanctuary.
The researchers are particularly excited when they
encounter a pod, not just for the opportunity to add
points to the database, but also because these whales
are much friendlier than most cetaceans in the area
and than pilot whales in most other parts of the world.
Tethys researchers have also been involved in research
seeking to manage severe threats to bottlenose-dolphin
populations in the nearby Adriatic and Ionian seas.
While marine mammals continue to be its primary
focus, Tethys is involved in research concerning a
wide variety of species. A collaborative study with
the University of Salento is looking at the increasing
abundance of sea jellies in the Mediterranean
and the resulting ecological, social and economic
consequences. A study of giant devil rays (Mobula
mobular) provided the first estimates of their
abundance in the northwestern Mediterranean, and
this work is continuing with Palestinian partners to
show the effects of a fishery for the species off Gaza.
These studies in collaboration with the Italian National
Institute for Environmental Protection and Research
and the International Whaling Commission are funded
by the Italian Ministry of the Environment and use
aerial surveys to census the rays and cetaceans as well
as loggerhead turtles, bluefin tuna and swordfish.
Marine animals here as elsewhere face a variety
of threats, but the unique international structure
of the sanctuary poses great challenges to enacting
regulations to manage those threats. Thus, Tethys
works with user groups such as ferry operators,
whale-watching companies and fishermen to try to
mitigate the threats.
Most important, the
organization continues
its research to enhance
our knowledge of these
species’ biological needs
and of how they are being
affected by a changing
marine environment. AD
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GET INVOLVED
Every summer Tethys opens
research cruises to volunteers
who both assist with the
research and help cover the
cost of the expeditions.
For more information,
see