Stellwagen's Whales
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Whaling
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Very profitable whaling area during 17th and 18th centuries.
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Right whale = favored species.
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17 species of cetaceans (whales, porpoises, dolphins) visit the bank.
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Use Sanctuary for feeding, nursing, resting.
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5 species of endangered whales:
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Blue whale
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Finback whale
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Sei whale
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Humpback whale
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North Atlantic right whale
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Minke whales, dolphins, and porpoises are found there.
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Rarely seen are killer, and sperm whales.
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Order cetacean (Greek [ketos] and Latin [cetus] for whale)
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Suborders
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Archaeoceti = ancient, extinct whales known only from fossil remains.
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Mysticeti = baleen whales ("mustached whales")
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Baleen filter mouthfuls of water to extract fish and plankton.
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Many use the bank for summer feeding and move south for breeding.
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Odontoceti = toothed whales
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Largest group worldwide = 75 species.
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Capture individual prey with teeth.
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Includes dolphins, porpoises, sperm whales, orca whales
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Evolutionary adaptations
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Former land mammals - migrated to ocean 55 million years ago ????
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Nostrils migrated to top of head (blowhole) to allow efficient swimming.
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Nasal passages and throat are separate allowing mouth to open under water
without animal drowning.
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Almost all body hair lost and replaced by thick layer of blubber for warmth.
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Body became streamlined.
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Forearms evolved into flippers. Hind limbs disappeared.
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Horizontal flattened flukes appeared to propel through water.
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Baleen Whales
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The largest of world's animals.
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Eat some of the smallest fish and zooplankton.
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Baleen
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Thin, long plates embedded in gum.
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250 - 400 plates in each side.
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Comblike with plates separated by 1/2 inch
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Whale opens mouth and fills with water. Squeezes throat muscles to expel
water through baleen.
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Two types of feeders
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Gulpers - take food by mouthful. (Also rorquals)
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Have ventral pleats which allow expansion of throat to let in more water
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Include: blue, finback, humpback, minke, sei.
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May eat 1 ton / day
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Skim feeders - swim with partially opened mouths. Water in the front, out
the sides.
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Include Southern right whale, North Atlantic right whale
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No ventral grooves.
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Species of baleen whales found at Stellwagen
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Finback whales.
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60 - 80 feet long.
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Identified by dorsal fin.
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Very fast - 12.5 m/hr.
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Lowest song (20 hz). Cannot be heard by humans.
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Minke Whales.
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30 ft long.
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Has dorsal fin.
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Stays on surface for only short time.
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White band on dorsal surface of each flipper.
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Often in bank year round (most from March - November)
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Most common baleen in world.
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Humpback Whale.
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35- 50 ft.
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Long wing-like flippers.
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Often breaches - not known why.
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Head covered with bumps (tubercles) = hair follicles.
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Form bubble clouds or bubble nets to feed.
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Lung feed (swim up into a school of fish)
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Lobtail feed= smack the water with fin.
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North Atlantic Right Whale.
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50 feet.
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Critically endangered - 300 left.
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No dorsal fin, V shaped snout, Highly arched mouth, head covered with patches
called callosities.
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Skim feeder.
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Right whale to catch:
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Slow swimmers.
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Large quantity of oil.
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Floated when dead
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Visit bay on way north (here Jan - May)