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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 Killerdolphin whale False Focena killer comune whale Rough-toothed dolphin Globicephalo... Risso’s dolphin Pilot whale Harbor porpoise Cuvier’s beaked whale Sperm whale... ...Sperm whale CETACEA: Baleen whales Fin whale Right whale Sei whale Humpback whale CARNIVORA: Pinnipeds Otariidae sea lions, fur seals, etc Phocidae true seals sagittal crest snout Otariidae eye ear pinnae whiskers mane tail scrotum fore flippers hind flippers Phocidae or True seals snout eye ear claws whiskers (vibrissae) fore flippers hind flippers tail 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 MESONICHIDAE PROTOCETIDAE 50 MILLION YEARS AGO DORYDONTIDAE 45 MILLION YEARS AGO SQUALODONTIDAE 40 MILLION YEARS AGO 35 MILLION YEARS AGO 30 MILLION YEARS AGO DELPHINIDAE 25 MILLION YEARS AGO 20 MILLION YEARS AGO 15 MILLION YEARS AGO DIVERGENCE ADAPTATIONS ADAPTATIONS Dog ADAPTATIONS Underwater life: • Streamlined body • Fins • Head and skull • Eyes and ears • Heat conservation • Salt balance • Buoyancy • Genital protrusion, etc ADAPTATIONS • breathing system Nostril migration ADAPTATIONS • breathing system ADAPTATIONS Perfectly adapted to marine environment! What are the differences? DIFFERENCES DIFFERENCES baleen jaw tongue ventral grooves DIFFERENCES Feeding feeding Humpback whales Feeding Gray whales Feeding Gray whales Feeding Other whales DIFFERENCES Teeth DIFFERENCES Teeth HOW DO YOU DETERMINE THE AGE OF A DOLPHIN AND A WHALE? Feeding Group waiting to feed Dolphins feeding Sentinel 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 Blue whale Heart = Tongue = Distribution cold waters tropical waters rivers Group sizes Small schools Large schools Single/Pairs Groups Schools, pods & herds • Advantages • Disadvantages SOCIAL BEHAVIOR Fission-fusion societies Complex societies Alliances and Superalliances Courtship & Mating Not easily distinguishable.... mammary slit female navel genital slit anus male Birth Long term bonds Cetaceans’ sensory world • Sight • Smell • Taste • Touch • Sound Cetaceans’ sensory world SOUND • Communication whistles • Echolocation clicks Cetaceans’ sensory world Song of a whale Dolphin whistles Brain and intelligence Modern humans=7.06 Great apes=1.91 Odontocetes=3.78 Social learning “Culture” Sponge carrying Self-recognition 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 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 Noise and disturbance 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 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!
