Download Marine Mammals in Madagascar

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Toothed whale wikipedia, lookup

River dolphin wikipedia, lookup

Bottlenose dolphin wikipedia, lookup

Dolphin wikipedia, lookup

Transcript
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