1. CHAPTER 14 Animals of the Pelagic Environment

2. How to avoid sinking Increase buoyancy Gas containers
How to avoid sinking
Increase buoyancy
Gas containers
Rigid container such as shells (internal or external) or…
Swim bladder
Fig. 14.2

3. How to avoid sinking Float – less dense than SW or neutral
How to avoid sinking
Foraminifers
Float – less dense than SW or neutral
Microscopic zooplankton have shells or tests
Radiolarians
Foraminifers
Copepods
Macroscopic zooplankton may have oil droplets
Krill (resemble mini-shrimp or large copepods)
Fish egg with oil droplet
Krill

4. Figure 14.6

5. How to avoid sinking Floating macroscopic zooplankton Cnidarians
Hydrozoan (Portuguese man-of-war) gas-filled float
Scyphozoan (jellyfish) soft low-density bodies

6. Figure 14.7a

7. How to avoid sinking Active swimming
Active swimming
Fish – swim by curving body from front to back
Fig. 14.9

8. How to avoid sinking Active swimming – Squid
Unknown deep sea squid
Active swimming – Squid
Swim by trapping water and expelling it
Also swim by using fins

9. How to avoid sinking Active swimming sea turtles use flippers
marine mammals use up/down tail movements
Sperm whale

10. Fin designs in fish
Vertical fins as stabilizers – dosral and anal fins
Paired pelvic fins and pectoral fins for “steering” and balance
Tail fin (caudal) for thrust

11. Fin designs in fish
Rounded caudal fins flexible, maneuver at slow speeds
Truncate fins and forked fins, useful for both maneuvering and thrust
Lunate fins rigid, lots of thrust for fast swimmers
Heterocercal fins asymmetrical, lift for buoyancy (shark)

12. Fin designs in fish
Fig a

13. Adaptations for finding prey
Adaptations for finding prey
Mobility
Lungers wait for prey and pounce (grouper)
Mainly white muscle tissue
Cruisers actively seek prey (tuna)
Mostly red muscle tissue

14. Adaptations for finding prey
Swimming speed
Speed generally proportional to size
Can move very fast for short time (mainly to avoid predation)

15. Adaptations to finding prey
Most fish cold-blooded but some are warm-blooded
Homeothermic-body temperature above sea water temperature
Modifications in circulatory system
Mainly in fast-swimming fish

16. Adaptations of deep-water nekton
Mainly fish that consume detritus or each other
Lack of abundant food
Bioluminescence
Fishing lures
Large, sensitive eyes
Anglerfish w/ males
Lanternfish

17. Adaptations of deep-water nekton
Large sharp teeth
Expandable bodies
Hinged jaws
Gulper eel

18. Adaptations of deep-water nekton
Fig

19. Figure 14.12

20. Adaptations to avoid predation
Schooling
“Safety in numbers”
School may appear as single larger unit
Schooling maneuvers confuse predator

21. Marine mammals Land-dwelling ancestors Warm-blooded Breathe air
Marine mammals
Land-dwelling ancestors
Warm-blooded
Breathe air
Hair/fur
Bear live young
Mammary glands for milk

22. Marine mammals Carnivora Prominent canine teeth Sea otters Polar bears
Marine mammals
Carnivora
Prominent canine teeth
Sea otters
Polar bears

23. Marine mammals Carnivora Pinnepeds Walruses Seals
Marine mammals
Carnivora
Pinnepeds
Walruses
Eat crustaceans with tusks
Seals

24. Marine mammals Carnivora Pinnepeds Sea lions Fur seals
Marine mammals
Carnivora
Pinnepeds
Sea lions
Fur seals

25. Marine mammals Sirenia Herbivores Manatees
Marine mammals
Sirenia
Herbivores
Manatees
Coastal areas of tropical Atlantic Ocean
Dugongs
Coastal areas of Indian and western Pacific Oceans

26. Marine mammals Cetacea Stream-lined bodies for fast swimming
Cetacea
Stream-lined bodies for fast swimming
Specialized skin (dermal ridges) structure for fast swimming
Whales
Toothed - carnivores
Baleen – filter feeders

27.
Cetacea
Fig

28. Marine mammals Dolphins vs. porpoises Dolphins (Delphinidae)
Marine mammals
Dolphins vs. porpoises
Dolphins (Delphinidae)
35 species
Beaks
melon (fatty organ in forehead)
Prominent, curved dorsal fin
conical, undifferentiated teeth
Range in size from 1.5 m Hector's dolphin to 9 m killer whales
Porpoises (Phocoenidae)
6 species
Lack prominent beak
laterally compressed teeth
More triangular dorsal fin
Bottlenose dolphin
Harbor porpoise
education/images/harbourporpoise/teeth2_small.gif

29. Cetacea Adaptations for deep diving Use oxygen efficiently
Cetacea
Adaptations for deep diving
Use oxygen efficiently
Able to absorb 90% of oxygen inhaled
Able to store large quantities of oxygen
Able to reduce oxygen required for noncritical organs
Muscles insensitive to buildup of CO2
Collapsible lungs

30. Adaptations for deep diving
Sperm whales can dive up to 1 hour, 52 min. and to 3 km deep

31. Cetacea Suborder Odontoceti (toothed)
Cetacea
Suborder Odontoceti (toothed)
Dolphins, porpoises, killer whale, sperm whale
Echolocation to determine distance and direction to objects
Clicks produced in nasal air sacs are focused by the melon
Echos received thru lower jaw  middle ear
Determine shape, size of objects

32. Intelligence in toothed whales
Intelligence in toothed whales
Large brains relative to body size
Communicate with each other
Brains convoluted
Trainable
Are they intelligent?

33. Cetacea Suborder Mysticeti Baleen whales
Fig
Right whale baleen
Baleen whales
Blue whale, finback whale, humpback whale, gray whale, right whale
Fibrous plates of baleen sieve prey items
Vocalized sounds for various purposes
Right whale feeding

34.
Gray whale migration
22,000 km (13,700 mi) annual migration from coastal Arctic Ocean to Baja California and Mexico
Feeding grounds in Arctic (summer)
Breeding and birthing grounds in tropical eastern Pacific (winter)
Fig

35. Whales as endangered species
Fewer whales now than before whaling
International Whaling Treaty
Hunting of gray whale banned in 1938
Gray removed from endangered list in 1993 as population rebounded
Fig

36. Marine reptiles Sea turtles Prey depends on species
Marine reptiles
Green
Sea turtles
Prey depends on species
Greens eat seagrass
(gut flora digests cellulose)
Loggerheads eat conch
Leatherbacks eat jellyfish
Nest on beaches: predation, lights on dunes
Many overexploited
Loggerhead
Leatherback

37. Marine iguanas of Galapagos Islands
Feed on submerged algae
Dive for up to 20 minutes
Must surface before they become too cold and can’t climb out of water

38. Truly aquatic - reproduce in water - live-bearers
Sea snakes of Pacific
Highly poisonous
Truly aquatic - reproduce in water - live-bearers

39. End of CHAPTER 14 Animals of the Pelagic Environment