Class The Oceans Nektonic Animals

Large shrimp (Arthropods) A few unusual molluscs –Chambered Nautilus –Cuttlefish –Squid A few INVERTEBRATES

Nautilus swimming Octopus thief

- Many are FAST SWIMMERS - Occur at all depths, world-wide - Mostly in the top 200m - Deep-water and bottom dwellers also FISH -- DOMINANT NEKTONIC ORG’S

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Sharks- well adapted (evolved over 300 Million Years ago!) Wide-spread, epipelagicWide-spread, epipelagic Active predators (but some are plankton feeders)Active predators (but some are plankton feeders) Cartilagenous fish: Skeletons of cartilage, not bone

Skates and rays Shallow-bottom dwellersShallow-bottom dwellers Carnivores AND plankton feedersCarnivores AND plankton feeders Cartilagenous fish- more:

skate/raja-clavata/video-10a.html

Epipelagic representatives (commercially fished)Epipelagic representatives (commercially fished) –Tuna, Salmon -- predators –Herring, Anchovy -- plankton feeders Coastal bottom-dwellers (commercially fished)Coastal bottom-dwellers (commercially fished) –Halibut, Sole Bony fish: (includes most eels)

Tuna Swimming

It’s a dog-eat-dog world....

Habitat: Below the photic zone All species are carnivorousAll species are carnivorous Food comes down from photic zoneFood comes down from photic zone Scarce food below about 1000mScarce food below about 1000m CompetitionCompetition Need to attract preyNeed to attract prey Need to eat large prey- as large as possibleNeed to eat large prey- as large as possible Need to conserve energy between mealsNeed to conserve energy between meals Deep-sea Bony fish (>200m = Dark)

General features -- adaptations: Large, light sensitive eyesLarge, light sensitive eyes Small (<10 cm), Low rates of metabolismSmall (<10 cm), Low rates of metabolism Large mouths, well- developed teethLarge mouths, well- developed teeth Luminsecent -- light- producing organsLuminsecent -- light- producing organs –Attraction of prey –Mate selection Deep-sea Bony fish (>200m; Dark)

Cyclothone, Lantern fish: Abundant at mAbundant at m Feed on Euphausids (Krill) and CopepodsFeed on Euphausids (Krill) and Copepods Hatchetfish- Eyes and mouth directed upward Angler fish- Deeper (>1000m) Luminous moveable lureLuminous moveable lure Parasitic male attached to body of femaleParasitic male attached to body of female

Mammals evolved from a common terrestrial ancestor 1. Baleen whales -- filter-feeders (plankton, small fish) 2. All other whales, plus porpoises, dolphins Toothed Fast-swimming predators CETACEANS (order Cetacea)

Baleen

1. Pinnepeds ("feather-footed") –Seals, Sea Lions, Walruses –Habitat: polar, midlatitudes –Require shore and/or sea-ice areas 2. Sea cows -- Manatees, Dugongs: tropical herbivores 3. Sea otters Habitat: cold, coastal waters Nutrition: carnivores of benthos OTHER MARINE MAMMALS

Few species, but successful Representatives: TurtlesTurtles CrocodilesCrocodiles SnakesSnakes Marine IguanasMarine Iguanas MARINE REPTILES

WHY MIGRATION? Migration links regions appropriate for reproduction... regions of feeding for adults Examples: California Grey Whales- Mexico to Alaska MIGRATION OF NEKTONIC SPECIES -- SOME NOTABLE EXAMPLES -- SOME NOTABLE EXAMPLES

More Examples: Pacific Salmon- fresh water spawning Atlantic Eels- salt water spawning- opposite Atlantic Green Turtles- nesting sites vs. foraging

see Naya