top predators and ocean interaction in southern …...top predators and ocean interaction in...
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Top predators and Ocean interaction in Southern Oceans and archipelago islands
Azwianewi Makhado,
M. Seakamela, N. de Bruyn, P. Ryan, P. Pistorius & R. Crawford
Oceans and Coasts
Marion-centredview of the
world
Prince Edward Islands
Antarctic Circumpolar
Current
1. Because we are obliged to do
so
2. Unique research opportunities
3. Climatechange
5. Student training
4. Conservation
Research at the PEIs
1. To assess and monitor population sizes, trends and conservation status of Top predators at the
Prince Edward Islands. – Population ecology and conservation
2. To understand key driver of poor conservation status of some species at the Prince Edward Islands
and advise remedial measures - Species assessment and management
3. To assess the usefulness of different indices as indicators of environmental change in Southern
Ocean ecosystems – Climate change
4. To contribute to CCAMLR’s and ACAP - International engagements
5. To build on capacity within the southern ocean region - Training
Temperature trends
in the sub-Antarctic
region
Sub-Antarctic among the fastest warming regions.Since 1960, rainfall has decreased 40% and temperature
has warmed 0.21oC per decade
Many marine top predators have a poor and deteriorating
conservation status
2014
CR EN VU NT LC
e.g. seabirds
1984
VU LC
1. CR- critically endangered2. En- endangered3. VU- vulnerable4. NT- near threatened5. LC- least concern
28 species of seabird breed at the Prince Edward Islands; 16 on the surface, 12 in burrows. The table shows the contribution of the Prince Edward Islands to the world populations of the 16 surface-nesting species
40% of all Wandering Albatrosses(Vulnerable)
24% of all Sooty
Albatrosses and 33 % Crozet shag(Endangered)
Monitor the health of the
Southern Ocean by tracking top
predator:
• population size
• body condition
• reproduction• growth rates• diet• pollutants
Trends in numbers shows that the conservation status of
some species at the Island are of conservation concern
aaa
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Wandering albatross
Southern giant petrel
Light Mantled albatrossSooty albatross
Crested penguins
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Southern Rockhopper Penguin
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Macaroni Penguin
Numbers of both species of crested penguin breeding at Marion Island have decreased – the Southern Rockhopper Penguin is regionally Endangered; the
Macaroni Penguin is Vulnerable
Predators may indicate change in ecosystems where lower trophic levels are not monitored and assist in
Island ecosystem interaction i.e. nutrient cycles
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Gentoo Penguin Crozet Shag
E.g. numbers of Crozet Shags and Gentoo Penguins breeding at Marion Island have shown decreasing trends – both are benthic feeders eating similar prey. The
congruent trends suggest possible ongoing change in the benthic marine environment. Regionally the Crozet Shag is Critically Endangered and the Gentoo
Penguin is Endangered
Southern elephant seal populations: one of the longest tagging seals in the world
1988 1990 1992 1994 1996 1998 2000 2002 2004
Census year
0.0
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Scale
d n
um
ber
of
fem
ale
s
Macquarie IslandFitted SE
Marion IslandFitted SE
www.marionseals.com
4. Climatechange
Sub-Antarctic among the fastest warming regions.Since 1960, rainfall has decreased 40% and temperature has
warmed 0.21oC per decade
Seals dived to deeper depths when foraging in warmer waters.
Both male and female seals spent less time at targeted dive depths in warmer water, and were
presumably less successful foragers when diving in warmer water.
Continued warming of the Southern Ocean may result in the distribution of prey for southern
elephant seals shifting either poleward and/or to increasing depths, presumably increasing
energy utilization while searching for prey.
Fur sealsAssessment of foraging success and population trends
a. Attendance patterns
b. Population growth
c. Pup growth
d. Foraging
Overwintering distributions of crested penguins in the South Indian Ocean (collaboration with France)
Macaroni (red and pink lines), Southern Rockhopper (yellow and white) and Northern Rockhopper (green) Penguins. Locations: Marion (circle), Crozet (triangle), Kerguelen
(lozenge) and Amsterdam (square) islands. Macaroni and Southern RockhopperPenguins at island groups have different winter feeding grounds
Partitioning of foraging grounds of yellow-nosed albatrosses
Spatial management of oceans expected to play an important role in biodiversity conservation
Controlled zone light grey; restricted zones dark grey
The Prince Edward Islands Marine Protected Area was proclaimed in April
2013
New challenges and Opportunities
Land-breeding marine predators as bio-indicators of change in western Dronning Maud Land, Antarctica
• Circumpolar Comparative study on the breeding ecology and foraging
behavior of some seabirds species breeding in SO i.e Skua etc.
• Population structure and contemporary gene flow in two sympatrically-
breeding Southern Ocean predators with contrasting demographics
• Interactive effects of multiple stressors and environmental change on
marine predators across the Antarctic Polar Front
• Seals from Space: satellite-based censuses of pack-ice seals in Dronning
Maud Land, Antarctica
DISTRIBUTION AND ABUNDANCE OF HUMPBACK WHALES OFF COAST OF SOUTH AFRICA
Interesting Observations
Eradication isfeasible
1. Because we are obliged to do
so
2. Unique research opportunities
3. Climatechange
5. Student training
4. Conservation
THANK YOU