Class 36 -- The OceansClass 36 -- The Oceans

Nektonic AnimalsNektonic Animals

Large shrimp (Arthropods)Large shrimp (Arthropods)

A few unusual molluscsA few unusual molluscs–Chambered NautilusChambered Nautilus–CuttlefishCuttlefish–SquidSquid

A few INVERTEBRATESA few INVERTEBRATES

http://youtu.be/L8qwRCs_7x0

Nautilus swimming

http://youtu.be/x5DyBkYKqnM

Octopus thief

- Many are FAST SWIMMERSMany are FAST SWIMMERS

- Occur at all depths, world-wide- Occur at all depths, world-wide

- Mostly in the top 200m- Mostly in the top 200m- Deep-water and bottom dwellers alsoDeep-water and bottom dwellers also

FISH -- DOMINANT NEKTONIC ORG’SFISH -- DOMINANT NEKTONIC ORG’S

http://www.mbayaq.org/efc/cam_menu.asp

http://www.youtube.com/watch?v=4SBv_wLxp78

Sharks- well adaptedSharks- well adapted

(evolved over 300 Million Years ago!)(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 fishCartilagenous fish: : Skeletons of cartilage, not boneSkeletons of cartilage, not bone

Skates and rays Skates and rays •Shallow-bottom dwellersShallow-bottom dwellers•Carnivores AND plankton feedersCarnivores AND plankton feeders

Cartilagenous fish- moreCartilagenous fish- more: :

http://www.arkive.org/thornback-skate/raja-clavata/video-10a.html

•Epipelagic representatives (commercially fished)Epipelagic representatives (commercially fished)–Tuna, Salmon -- predatorsTuna, Salmon -- predators–Herring, Anchovy -- plankton feedersHerring, Anchovy -- plankton feeders

•Coastal bottom-dwellers (commercially fished)Coastal bottom-dwellers (commercially fished)–Halibut, SoleHalibut, Sole

Bony fishBony fish: (includes most eels): (includes most eels)

http://youtu.be/6lv51E-q1xU

http://youtu.be/h_bhZ8z7ft8

Tuna Swimming

It’s a dog-eat-dog It’s a dog-eat-dog world....world....

Habitat: Below the photic zoneHabitat: 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) Deep-sea Bony fish (>200m = Dark)

General features -- General features -- adaptations:adaptations:•Large, light sensitive Large, light sensitive eyes eyes •Small (<10 cm), Low Small (<10 cm), Low rates of metabolismrates of metabolism•Large mouths, well-Large mouths, well-developed teethdeveloped teeth•Luminsecent -- light-Luminsecent -- light-producing organsproducing organs

–Attraction of preyAttraction of prey–Mate selectionMate selection

Deep-sea Bony Deep-sea Bony

fish (>200m; Dark)fish (>200m; Dark)

Cyclothone, Lantern fish:Cyclothone, Lantern fish: •Abundant at 200-1000mAbundant at 200-1000m•Feed on Euphausids (Krill) Feed on Euphausids (Krill) and Copepodsand Copepods

HatchetfishHatchetfish- Eyes and mouth - Eyes and mouth directed upwarddirected upward

Angler fish- Deeper Angler fish- Deeper (>1000m)(>1000m)•Luminous moveable lureLuminous moveable lure•Parasitic male attached to Parasitic male attached to body of femalebody of female

Mammals evolved from a common Mammals evolved from a common terrestrialterrestrial ancestorancestor

1. Baleen whales -- filter-feeders (plankton, 1. Baleen whales -- filter-feeders (plankton, small fish)small fish)

2. All other whales, plus porpoises, dolphins2. All other whales, plus porpoises, dolphins

ToothedToothed

Fast-swimming predatorsFast-swimming predators

CETACEANS (order Cetacea)CETACEANS (order Cetacea)

Baleen

1. 1. PinnepedsPinnepeds ("feather-footed") ("feather-footed")–Seals, Sea Lions, WalrusesSeals, Sea Lions, Walruses–Habitat: polar, midlatitudesHabitat: polar, midlatitudes–Require shore and/or sea-ice areasRequire shore and/or sea-ice areas

2. 2. Sea cowsSea cows -- Manatees, Dugongs: tropical -- Manatees, Dugongs: tropical herbivoresherbivores

3. Sea otters3. Sea otters

Habitat: cold, coastal watersHabitat: cold, coastal waters

Nutrition: carnivores of benthosNutrition: carnivores of benthos

OTHER MARINE MAMMALSOTHER MARINE MAMMALS

Few species, but successful Few species, but successful

Representatives:Representatives:•TurtlesTurtles•CrocodilesCrocodiles•SnakesSnakes•Marine IguanasMarine Iguanas

MARINE REPTILESMARINE REPTILES

WHY MIGRATION? Migration links ....WHY MIGRATION? Migration links ....

... regions appropriate for reproduction... regions appropriate for reproduction

... regions of feeding for adults... regions of feeding for adults

Examples:Examples:

California Grey Whales- Mexico to AlaskaCalifornia Grey Whales- Mexico to Alaska

MIGRATION OF NEKTONIC SPECIESMIGRATION OF NEKTONIC SPECIES -- SOME NOTABLE EXAMPLES-- SOME NOTABLE EXAMPLES

More Examples:More Examples:

Pacific Salmon- fresh water spawningPacific Salmon- fresh water spawning

Atlantic Eels- salt water spawning- oppositeAtlantic Eels- salt water spawning- oppositeAtlantic Green Turtles- nesting sites vs. Atlantic Green Turtles- nesting sites vs.

foragingforaging

http://www.conserveturtles.org/index.phphttp://www.conserveturtles.org/index.php

see Nayasee Naya