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14 Marine Mammals

14 Marine Mammals. I. Marine Mammals A. Sea otters (Order Carnivora) 1. Insulation a. Lack blubber b. Insulated by air trapped in fur c. Vulnerable to hypothermia if fur becomes coated with oil 2. Hunted almost to extinction for their fur.

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14 Marine Mammals

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  1. 14 Marine Mammals

  2. I. Marine Mammals • A. Sea otters (Order Carnivora) • 1. Insulation • a. Lack blubber • b. Insulated by air trapped in fur • c. Vulnerable to hypothermia if fur becomes coated with oil • 2. Hunted almost to extinction for their fur

  3. Long before I came here, the N.W. Indians had hunted the otter along the whole length of the coast from Lower Cal. North, and they must have killed a very large number, as in early times they were so abundant that the Indians killed them with spears. When I arrived here [1833], they were still quite plenty but they were soon hunted out. In hunting the N.W. Indians used buckshot and usually sent several canoes together so that they could almost surround an otter, thereby rendering escape almost impossible. George Nidever, pp 45-46 In 1834, a hunter could obtain about $30 for a good quality sea otter pelt. By contrast, land otter brought a mere two dollars and beaver, which; was extensively hunted in the RockyMountains, brought only four dollars a pelt. (From the Introduction by Bruce Craig) The Life and Adventures of George Nidever [1802-1883], Univ. Cal. Press, 1984

  4. Sea otters (continued) • Eat 15-20 pounds of food (invertebrates) per day • a. Devastating to commercial abalone and sea urchin fisheries • b. Remove large invertebrate herbivores and allow kelp forests to flourish

  5. Typical Daily Consumption of a Californian Sea Otter Milne, 1995, Marine Life and the Sea, p. 232

  6. Jade sculpture of a sea otter eating a scallop Photo by J. OBrien, June 2014

  7. Sea otters (continued) • Intelligent • Use rocks to crack open shells • Trapping program in Channel Islands National Park • (1) Difficult to catch more than once • (2) Professional Navy divers • (a) Non-bubble releasing SCUBA gear • (b) Come from below while animal sleeping • (3) Adults returned to original location

  8. Sleeping Sea Otter Castro & Huber, 2003, Marine Biology, p. 189

  9. II. Marine Mammals (continued) • B. Order Sirenia • 1. Related to elephants • 2. Characteristics • a. Herbivores • b. No rear limbs

  10. Order Sirenia (continued) • Manatees or sea cows • a. Freshwater and estuarine habitats • b. Tropical and sub-tropical habitats • c. Individuals who come this far north run risk of pneumonia in winter

  11. Manatees or sea cows (continued) • Marine Mammal Sighting Network • (1) Dr. Ruth Carmichael – DISL • (2) https://www.facebook.com/mobilemanatees • (3) http://manatee.disl.org

  12. B. Order Sirenia (continued) 4. Steller’s sea cow a. Was found along Pacific Coast b. Ate kelp c. Whalers slaughtered them for food d. Scientists became aware of their existence in 1741, they were extinct by 1768 e. Massive (= 10 tons) f. Major herbivore on kelp (impact of extinction?)

  13. Sketch of Steller’s Sea Cow made by Georg Steller http://en.wikipedia.org/wiki/Georg_Wilhelm_Steller#mediaviewer/File:Extanstellersseacowea.jpg

  14. Steller’s sea cow weighed about 10 tons and fed upon kelp in the Bering Sea. Eaten by whalers, the last individual was killed in 1768. Castro & Huber, 2003, Marine Biology, p. 422

  15. Steller’s sea eagle, Steller’s jay & Steller’s sea lion http://en.wikipedia.org/wiki/Georg_Wilhelm_Steller

  16. C. Pinnipeds • 1. Characteristics • a. Paddle-shaped flippers • b. BLUBBER: Thick hypodermal layer of fat that retains heat

  17. Pinnipeds (continued) • Seals • a. Characteristics • (1) Rear flippers • (a) Cannot be moved forward (Pull themselves with front flippers when on land) • (b) Used for swimming only • (2) No external ear

  18. Seals (continued) • b. Elephant seal • (1) Largest pinniped • (2) Can grow to 4 tons http://www.google.com/imgres?imgurl=http://4.bp.blogspot.com/-5W4nKGlD4rg/TtOyi0zQtBI/AAAAAAAACXc/C2JvEby6EE8/s1600/Northern%2BElephant%2BSeal2.jpg&imgrefurl=http://life-sea.blogspot.com/2011/11/northern-elephant-seal.html&h=1016&w=1524&sz=1670&tbnid=oGXX-UCdK20dbM:&tbnh=88&tbnw=132&zoom=1&usg=__5uqJ8z8guQogc7MGMycGKJ_8q28=&docid=RlFhTTMdLeY45M&sa=X&ei=AQy7Ufv4HYOK9gS6qIGoBA&sqi=2&ved=0CE8Q9QEwCw&dur=2330

  19. Elephant Seal Haul-out off California Highway 1 Photo: Jack O’Brien, June 2013

  20. C. Pinnipeds (continued) • Sea lions • Characteristics • (1) Rear flipper can move forward • (2) Anterior flippers assist in swimming • (3) External ears • (4) Long neck • b. “Fur” seals hunted almost to extinction in mid 1800's

  21. Illustration showing anatomical differences between seal lions and seals Castro & Huber, 2003, Marine Biology, p. 188

  22. C. Pinnipeds (continued) 3. California sea lion a. Barking “seals” trained to do tricks b. Protection has resulted in recent range expansion c. Nuisance (1) Haul out on boat docks (2) Sushi bars and parasites

  23. II. Marine Mammals (continued) • D. Cetaceans • 1. Characteristics • a. No hind limbs • b. Tail ends in horizontal FLUKES (Fish have vertical caudal fins) • c. BLOWHOLE: Nostrils on top of head

  24. D. Cetaceans (continued) • 2. Odontoceti = Toothed whales • a. Sperm whale • (1) Feed on squid (Sea monsters?) • (a) How does a creature that has a maximum speed of 2-4 knots and knobby teeth catch prey that swim at 10 knots? • (b) Hypothesized that they stun prey with sound blasts

  25. Sperm Whale with Squid Garrison, 2005, Oceanography, p. 383

  26. 16 ft Long (330 lb.) Squid Captured Off of New Zealand. The Specimen Was Immature Garrison, 2005, Oceanography, p. 365

  27. Sperm whale (continued) • Hunted commercially • (a) Huge forehead contains a cavity (= MELON) containing the SPERMACETI ORGAN • (b) SPERMACETI is a waxy high-grade oil • i Was used in lamps and candles • ii Still used in precision machinery (little breakdown) • iii Still most numerous of the great whales

  28. Skull of a Sperm Whale Showing the Concave Cavity that is Filled by the Spermaceti Organ Sumich, 1992, Marine Life, p. 347

  29. Diagram Illustrating the Melon and Spermaceti Organ of a Sperm Whale Sumich, 1992, Marine Life, p. 348

  30. a. Sperm whale (continued) (3) AMBERGRIS i When sperm whales consume sharp objects, such as squid beaks, their gut produces a sticky substance that protects their digestive organs. ii This mixture is regurgitated, reacts with seawater, and becomes rock-hard iii Collected by beachcombers iv Refined & used in expensive perfumes to “hold” aroma

  31. Ambergris http://www.laboratoryequipment.com/news-Researchers-Make-Perfume-Sans-Whale-Vomit-040612.aspx?et_cid=2580065&et_rid=54631806&linkid=http%3a%2f%2fwww.laboratoryequipment.com%2fnews-Researchers-Make-Perfume-Sans-Whale-Vomit-040612.aspx

  32. Odontoceti = Toothed whales (continued) • Killer whale = Orcinus orca • (1) Intelligent (will flip dog sled teams & seals off floating ice sheets) • (2) One 24 ft. specimen contained 13 porpoises and 14 seals

  33. Odontoceti = Toothed whales (continued) • Dolphins • (1) Over 30 species including 5 freshwater • (2) Elongated snout used to batter predators such as sharks • (3) Cone-shaped teeth • (4) Dorsal fin curved or “hooked” • (5) Make whistle noises by blowing air out blowhole

  34. c. Dolphins (continued) (6) Atlantic bottle-nosed dolphin, Tursiops truncatus (a) Marine parks (b) US Navy uses them to recover objects in ocean https://en.wikipedia.org/wiki/File:NMMP_dolphin_with_locator.jpeg

  35. 2. Odontoceti (continued) • d. Porpoises • (a) Less than 10 species • (b) Relatively blunt snout • (c) Flat, spade-shaped teeth • (d) Triangular dorsal fin • (e) Humans unable to hear noises

  36. Harbor Porpoise, Phocoena phocoena http://animals.nationalgeographic.com/animals/mammals/harbor-porpoise/

  37. D. Cetaceans (continued) • Mysticeti = baleen whales • a. BALEEN • (1) Fibrous plates hang down from upper jawbone

  38. Baleen Plates from a Calfornia Gray Whale Nybakken, 2005, Marine Biology: An Ecological Approach, Fig. 3.35c, p. 134

  39. BALEEN (continued) • (2) Feeding method • (a) Gulp water • (b) Force water out through baleen with tongue • (c) Small prey retained in baleen

  40. The Feeding Process of a Baleen Whale (a) Cross-section showing feeding apparatus; (b1) Water and plankton enter when tongue depressed; (b2) Mouth closes, tongue elevates and pushes water out. Zooplankton retained on baleen plates Nybakken, 2005, Marine Biology: An Ecological Approach, Fig. 3.35a,b, p. 134

  41. Mysticeti = baleen whales (continued) • Blue whales thought to be the largest animals that ever lived • c. Humpback whales • “Sing” • (2) Herd schools of fish by blowing curtains of bubbles

  42. The whale may ... circle below the fish, blowing a ring of fizzing bubbles to act as a net, then rise up through the center... The lower jaw swings out from the upper jaw to open at a 90-degree angle, or even wider; one to three dozen grooves, or pleats, on the throat expand; and what was a sleek whale becomes a living vat swollen by as many as 15,000 gallons of water churning with fish. ... humpbacks do all this in coordinated groups... As they converge to scoop up the food, they are likely to be screaming--filling the water with prolonged, piercing shrieks that seem designed to further disorient the panicky, trapped targets. Gentle grazers of plankton pastures? Try predators par excellence, carnivores that, depending upon how you interpret bubble netting, may qualify as makers and users of tools. Douglas Chadwick, 1999, National Geographic, 196(1):126

  43. Douglas Chadwick, 1999, National Geographic, 196(1):127

  44. Mysticeti = baleen whales (continued) • d. California gray whale • (1) Bottom feeder • (a) Lie on side and scoop up benthic mud containing invertebrates • (b) Leave feeding depressions in the benthos • (c) Observed squeezing kelp blades in mouth

  45. Benthic Feeding Pits Are Created by the Feeding Activities of California Gray Whales Sumich, 1992, Marine Life, p. 342

  46. d. California gray whale (continued) • (2) Migrate • (a) Bering Sea in Arctic Circle • Over 100 miles/day • Aggregate in Scammon’s Lagoon (and others) in Baja California (Mexico) • i Mate • ii Calving

  47. Annual Migration of the California Gray Whale Lerman, 1986, Marine Biology: Environment, Diversity and Ecology, p. 272

  48. E. Diving adaptations • 1. Retention of oxygen • a. High concentration of RBCs and hemoglobin • b. Myoglobin in muscles • 2. BRADYCARDIA: Reduced heart rate reduces oxygen consumption

  49. BRADYCARDIA or slowing of the heart rate exhibited by a bottle nosed dolphin during a dive. Nybakken, 2005, Marine Biology: An Ecological Approach, Fig. 3.32, p. 131

  50. Diving adaptations (continued) • Why don’t marine mammals get “the bends” • Bends is a condition that can occur in people breathing air under pressure • (1) Victim cannot straighten joints • (2) First seen in underwater workers building support columns for large bridges • (3) SCUBA divers

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