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