Marine Mammals Life history, ecology and conservation

WHO ARE THEY?

Cetacea whales, dolphins, and porpoises Carnivora polar bears, otters, seals, sea lions, walruses Sirenia manatees and dugongs

CETACEA: Toothed whales

Bottlenose dolphin Striped dolphin Common dolphin

Risso’s dolphin Focena comune Globicephalo... Killer whale False killer whale Rough-toothed dolphin

Risso’s dolphin Harbor porpoise Pilot whale

Sperm whale... Cuvier’s beaked whale

...Sperm whale DNADNA

CETACEA: Baleen whales

Fin whale Right whale Sei whale Humpback whale

CARNIVORA: Pinnipeds Otariidae sea lions, fur seals, etc Phocidae true seals

Otariidae ear pinnae eye sagittal crest snout whiskers mane fore flippers tail scrotum hind flippers tail whiskers (vibrissae) fore flippers claws snout eye ear Phocidae or True seals

CARNIVORA: Pinnipeds Odobenidae walruses

CARNIVORA: Ursidae polar bears

CARNIVORA: Mustelidae sea otters, weasels, minks, etc

SIRENIA: Trichechidae manatees Dugongidae dugongs, Stellar’s sea cows

This presentation will focus......on dolphins and whales (cetaceans)!

Some terminology....

FROM LAND TO SEA 50 MILLION YEARS AGO 45 MILLION YEARS AGO 40 MILLION YEARS AGO 35 MILLION YEARS AGO 30 MILLION YEARS AGO 25 MILLION YEARS AGO 20 MILLION YEARS AGO 15 MILLION YEARS AGO MESONICHIDAE PROTOCETIDAE DORYDONTIDAE SQUALODONTIDAE DELPHINIDAE

DIVERGENCE

ADAPTATIONS

Dog

ADAPTATIONS Underwater life: Streamlined body Fins Head and skull Eyes and ears Heat conservation Salt balance Buoyancy Genital protrusion, etc

Nostril migration ADAPTATIONS breathing system

ADAPTATIONS breathing system

ADAPTATIONS Perfectly adapted to marine environment!

What are the differences?

DIFFERENCES

baleen ventral grooves tongue jaw DIFFERENCES

feeding Feeding Humpback whales

Feeding Gray whales

Feeding Gray whales

Feeding Other whales

Teeth DIFFERENCES

Teeth DIFFERENCES

HOW DO YOU DETERMINE THE AGE OF A DOLPHIN AND A WHALE?

Feeding Group waiting to feed Sentinel Dolphins feeding Sentinel

Feeding Bottlenose dolphin

Feeding Common dolphin

Feeding Killer whale

Feeding Sperm whale

Feeding OTHER CAPTURE TECHNIQUES: “crater feeding” “fish whacking” “strand feeding”

How dolphins find their prey?

How echolocation works? Returning echo Sound emission

Where is the food?

Migration...

... and residency

How dolphins move

Great variety of cetaceans

Tongue = Heart = Blue whale

Distribution cold waters rivers tropical waters

Group sizes Small schools Large schools Single/Pairs

Groups Advantages Disadvantages Schools, pods & herds

SOCIAL BEHAVIOR

Fission-fusion societies

Complex societies

Alliances and Superalliances

Courtship & Mating

Not easily distinguishable.... female male navelanusgenital slit mammary slit

Birth

Long term bonds

Cetaceans’ sensory world Sight Smell Taste Touch Sound

Cetaceans’ sensory world SOUND Communicationwhistles Echolocationclicks

Song of a whale Dolphin whistles Cetaceans’ sensory world

Modern humans=7.06 Great apes=1.91Odontocetes=3.78 Brain and intelligence

Social learning “Culture”

Self-recognition Sponge carrying

Unique mammals

As humans increase their exploitation of marine resources, individual dolphins, porpoises and whales suffer, their societies are disrupted, and their populations decline (Whitehead et al. 2000)

Worldwide threats to cetaceans WHAT ARE THE MOST IMPORTANT ANTHROPOGENIC THREATS TO MARINE MAMMALS?

Present exploitation Aboriginal hunts Hunts in or by developing countries Whaling for scientific purpose Live capture

By-catch “It refers to the incidental capture of non-target species in fisheries” (Whitehead et al. 1999) Effects nearly every cetacean species

By-catch Often unsustainable Primary cause of population decline May bring species close to extinction 560 <200

Habitat loss and degradation Serious threat to inshore, freshwater species

Pollution Oceans as infinite trash dumps...!?!

Competition with fisheries likely to be a threat BUT... conclusive evidence is lacking due to complex ecosystem dynamics

Humans: use sounds in same wide range of frequencies to explore oceans Noise is incidentally produced by most marine activities Humans have potential to interfere acoustically with the lives of cetaceans Noise and disturbance

Collisions with ships Significant impact on mid/large cetaceans in areas of high/fast ship traffic

Global climate changes “It’s generally agreed that the Earth’s climate is changing systematically in response to human activities” (Intergovernmental Panel on Climate Change 1995) “These changes are likely to affect virtually all life, including cetaceans” (IWC 1997)

Thank you!