Biogeography

Guest lecturer: Dr. Ana Širović (asirovic@ucsd.edu)

SIO 133: Marine Mammal Biology

Is the ocean homogenous?

Tagging of Pacific predators (TOPP)

Yellow: females Red: males • Northern elephant

seal distribution:

– Pupping on beaches

– Foraging in open ocean

Biogeography

• Determined by:

– Ecology: food availability, temperature

– Evolutionary biology: historical range

Ocean zones (biomes)

Seasonal variability of ocean zones • Temperate region

– Wind important factor

Seasonal variability: coastal upwellings

• California Current system

Bailey et al. 2010

Blue whale tracks

Seasonal variability: coastal upwellings

• California Current system

Bailey et al. 2010 Block et al. 2011

Blue whale tracks

Seasonal variability: polar region

• Light important

– Productivity high in summer

• Seasonal presence common

Prey aggregation • Affected by oceanographic features: fronts,

eddies, ocean bottom

From Tynan et al. 1998

Blue whale catches

Krill concentration

Species distribution

• Cosmopolitan species

– E.g. Killer whales (Orcinus orca)

From Hoelzel 2002

Blue whale stocks

From McDonald et al. 2006

Species distribution

• Anti-tropical distribution

– E.g.: Long-finned plot whales (Globicephala melas)

From Hoelzel 2002

Anti-tropical distribution

From Hoelzel 2002

Species distribution • Pan-tropical species

– E.g. Spinner dolphins (Stenella longirostris)

From Hoelzel 2002

Species distribution • Circumpolar species

– E.g. Beluga whales (Delphinapterus leucas)

From Hoelzel 2002

Species distribution • Endemic species

– E.g. River dolphins

From Hoelzel 2002

Migratory species

• Prey driven: Most rorquals

• Ice driven: polar species – e.g. beluga, narwhal, bowhead

Block et al. 2011

Month of year

Temperature-defined distribution

• E.g. Short and long-finned pilot whales

Source: Duke University, OBIS-SEAMAP

Gender-variable distribution

• E.g. Sperm whales (Physeter macrocephalus)

Source: whaletrackers.com

Coastal species • E.g. Porpoises

From Hoelzel 2002

Plate tectonics & early records

From Berta et al. 2006 1 – early cetaceans 2 – early sirenians

Evolutionary biogeography: cetaceans Geologic events | Marine mammal events | Location

From Berta et al. 2006

Tethys

Southern hemisphere

N Pac. Arctic N Atl.

Evolutionary biogeography: pinnipeds Geologic events | Marine mammal events | Location

From Berta et al. 2006

Walrus | Sea lion | Phocid

N Pac. equator S Pac.

N Pac. Pan. seaway N Atl.

Origins of anti-tropical distribution?

From Hoelzel 2002

Globicephala melas