Download Initial studies of small cetaceans in Madagascar and Gabon: Recent

Marine Mammals in
Madagascar:
Current Knowledge and Climate Change
Salvatore Cerchio
Cetacean Conservation
And
Research Program
Wildlife Conservation Society
American Museum of Natural History
Marine Mammal Diversity
• Pinnipeds
– 2 species (accidental)
• Sireniens
– 1 species - Dugong
• Cetaceans
– 7 Mysticetes, 3 confirmed
– 21 Odontocetes, 12 confirmed
Mysticetes:
Baleen Whales
• Humpback Whale
• Southern Right Whale
• Blue Whale
– Potential overlap of 2 subspecies
• Brydes Whale, likely
– Species ID uncertain
• Fin Whale, suspected
• Minke Whale, suspected
Mysticetes:
Potential Impact of Climate Change
• Perturbation of Antarctic Ecosystem
– Humpback and True Blue Whales
• Potential local effects for some species that
may feed in Madagascar waters
– Pygmy Blue Whale
• Perturbation of migratory patterns due to
circulation and SST changes
• All SPECULATIVE
Odontocetes:
Toothed Whales and Dolphins
Good data limited to two CCRP field sites:
• Antongil Bay
– 3 species observed
• Only Bottlenose dolphin regular/resident
• Southwest (Toliara/Anakao region)
– At least 8 species observed
– At least 3 can be considered regular/resident
•
•
•
•
Indo-Pacific humpback dolphin
Bottlenose dolphin (inshore form / Indo-Pacific species?)
Spinner dolphin
(Spotted dolphin, Risso dolphin, Pilot whale…)
SW Bathymetry
• Submarine Canyon
• Closest point of deep water to coast of
Madagascar
• Presence of some deep water species
–
–
–
–
–
–
Spotted dolphin
(Spinner dolphin)
Pilot whale
Risso Dolphin
Bottlenose dolphin (offshore form)
Pygmy killer whale
• Near shore shallow water species
– Humpback dolphin (obligate)
– Bottlenose dolphin (inshore form)
– Spinner dolphin
Impacts on Coastal Dolphins:
Hunting around Toliara and Anakao
• Direct takes of small cetaceans in
Madagsacar primarily on West
Coastal regions, at least north to
Mahajunga
• Best documentation in southwest
• Toliara region
• Focus of work in village of
Anakoa, population of 3000-5000
• Dolphins taken for food as well as
local sale
Interview Data – Anakao 1999
(N. Andrianarivelo)
Estimated Dolphin Mortalities 1974-1999
Species
Direct Take
Spinner Dolphin
1850-2550
Bottlenose Dolphin 1700-1900
Humpback Dolphin 20-70
Unidentified dolphin 400
Total
3970-4920
“Stranding”
900-950
90-240
30-35
100
1130-1350
Anakao – Recent Dolphin Take
(Y. Razafindrakoto & N. Andrianarivelo)
October 2005
100-200 Stenella longirostris
Driven against reef and stranded
Concealed from authorities
Meat sold in villages to N and S
Excess buried
Odontocetes:
Potential Impacts of Climate Change
• Impacts on ecosystem and prey
resources
– Possibly more significant for
inshore species
• Bi-directional Synergies
– Dolphin populations already
depleted from hunting – could be
further stressed by CC reduction
in prey species
– Removal of top predator –
complex effect on coral reef /
coastal communities also stressed
by CC
• Again SPECULATIVE
Gaps in Knowledge / Future Directions
• Obvious conservation concern /
emergency in SW region
• Very little known about cetacean
distribution and status throughout
almost all other regions
• Prelim data from Nosy Be indicate
potential healthy population of
coastal species
• NEED extensive surveys and
baseline data collection
• NEED studies targeting potential
impact of Climate Change
• NEED work within local
communities to ameliorate hunting
pressure and promote sustainable
resource use