Animals of the Pelagic Animals of the Pelagic EnvironmentEnvironment

Staying above the ocean flooro Gas containers Shells - rigid gas containers ex. celphalopods

Swim BladdersSwim Bladders• Internal organ to maintain buoyancy. Internal organ to maintain buoyancy. Expands or contracts ( add or removes Expands or contracts ( add or removes

gas)gas)a.a. Gas exchange through blood to control Gas exchange through blood to control

height in water columnheight in water column

o Floating heterotrophs (Zooplankton) - surface 1. Microscopic zooplankton – primary consumers, herbivores or omnivores. a. Radiolarians – single celled, silica shells, intricate ornamentation to ↑ surface area so they don’t sink.

b. Foraminifera – single celled, calcium carbonate shells

c. Copepods – shrimp-like crustaceans, largest biomass of plankton, important link in many marine food webs.

2. Macroscopic - seen with “unaided eye” a. Krill – crustacean, resemble mini shrimp or large copepods, over 1500 species. Abundant near Antarctica, critical link in food web.

b. Cnidarians - soft bodies, tentacles armed with stinging cells (nematocysts) 1). Hydrozoans

2). Scyphozoans (jellyfish)

c. Tunicates – barrel-shaped with openings at each end. Most are pelagic, usually transparent.

Benthic tunicatesPelagic tunicates

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Swimming Organisms Swimming Organisms • Fish, squids, sea Fish, squids, sea

turtles, marine turtles, marine mammalsmammals

• Swim by trapping Swim by trapping water and water and expelling it, e.g., expelling it, e.g., some squidsome squid

• Swim by curving Swim by curving body from front to body from front to backback

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Swimming Motion and General Swimming Motion and General Fish FeaturesFish Features

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Fin Designs in FishFin Designs in Fish• Paired vertical fins Paired vertical fins

as stabilizersas stabilizers

• Paired pelvic fins Paired pelvic fins and pectoral fins and pectoral fins for “steering” and for “steering” and balancebalance

• Tail fin (caudal) for Tail fin (caudal) for thrustthrust

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Fin Designs in Fish Fin Designs in Fish • Rounded caudal Rounded caudal

fins fins – FlexibleFlexible– Maneuver at slow Maneuver at slow

speedsspeeds

• Truncate fins Truncate fins and and forked fins forked fins – Useful for both Useful for both

maneuvering and maneuvering and thrustthrust

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Fin Designs in Fish Fin Designs in Fish • Lunate fins Lunate fins

– Rigid, little Rigid, little maneuverabilitymaneuverability

– Efficient propulsion Efficient propulsion

for fast swimmersfor fast swimmers

• Heterocercal fins Heterocercal fins – Asymmetrical,Asymmetrical,– Lift for buoyancy Lift for buoyancy

(shark)(shark)

http://www.seaworld.org/aquademics/tetra/mouthsfins.htm

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Adaptations for Finding PreyAdaptations for Finding Prey

• MobilityMobility

• Lungers Lungers wait for prey and pounce wait for prey and pounce (grouper).(grouper).– Mainly white muscle tissueMainly white muscle tissue

• CruisersCruisers actively seek prey (tuna). actively seek prey (tuna).– Mostly red muscle tissueMostly red muscle tissue

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Lungers and Cruisers Lungers and Cruisers

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Cold-Blooded vs. Cold-Blooded vs. Warm-BloodedWarm-Blooded• Most fish are cold-blooded – Most fish are cold-blooded – poikilothermic poikilothermic

– Bodies same temperature as environment Bodies same temperature as environment – Not fast swimmersNot fast swimmers

• Some are warm-blooded – Some are warm-blooded – homeothermic homeothermic – Found in warmer environmentsFound in warmer environments– Helps them capture preyHelps them capture prey– Faster, stronger – Tuna and Mackeral SharksFaster, stronger – Tuna and Mackeral Sharks

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Adaptations of Deep-Water Adaptations of Deep-Water NektonNekton

• Mainly fish that consume Mainly fish that consume detritusdetritus or each or each otherother

• Lack of abundant foodLack of abundant food• Bioluminescence Bioluminescence

– photophoresphotophores• Large, sensitive eyesLarge, sensitive eyes• Large sharp teethLarge sharp teeth• Expandable bodiesExpandable bodies• Hinged jawsHinged jaws• Counterillumination Counterillumination

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Adaptations to Avoid Adaptations to Avoid PredationPredation

• Schooling Schooling

– Safety in Safety in numbersnumbers

– School may School may appear as single appear as single larger unitlarger unit

– Schooling Schooling maneuvers maneuvers confuse predatorconfuse predator

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Adaptations to Avoid Adaptations to Avoid Predation Predation • Symbiosis Symbiosis – two or – two or

more organisms more organisms mutually benefit mutually benefit from associationfrom association

• CommensalismCommensalism – – less dominant less dominant organism benefits organism benefits without harming without harming hosthost

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Adaptations to Avoid Adaptations to Avoid PredationPredation• MutualismMutualism – both – both

organisms benefitorganisms benefit– Example: clown Example: clown

fish and anemonefish and anemone

• ParasitismParasitism – – parasite benefits at parasite benefits at expense expense of host of host

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Adaptations to Avoid Adaptations to Avoid Predation Predation

• SpeedSpeed

• PoisonsPoisons

• MimicryMimicry

• TransparencyTransparency

• CamouflageCamouflage

II. Marine Mammals A. Carnivora 1. Sea Otters a. Lack layer of blubber, but have extremely dense fur. b. Hunted to the brink of extinction in 1800’s c. Eat various shellfish and crustaceans – use rocks to break open shells. d. Commonly inhabit kelp beds 2. Polar Bears a. massive webbed paws = excellent swimmers

Kelp Forest QT Video

b. Thick fur, each hair is hollow (insulation) c. Large teeth and sharp claws d. Diet – mainly seals 3. Walruses a. Large bodies b. Tusks – both male and female, used for territory fight- ing, hauling out, and stabbing prey

4. Seals – aka true seals or earless seals a. Lack prominent ear flaps b. Smaller, less prominent front flippers c. Prominent claws on foreflippers d. Different hip structure, can not move their rear flippers underneath their bodies. e. Do not move well on land, slither like a caterpillar. f. Propel through water using back and forth motion of their rear flippers.

Seal QT Video

B. Sirenia

1. Manatees – coastal areas of Atlantic (tropical) a. Diet – vegetarian shallow water grasses b. Compete with humans for space c. endangered 2. Dugongs – tropical regions of Indian Ocean and Western Pacific a. Diet – same as manatees b. Compete - same c. endangered

C. Cetacea 1. Characteristics a. Elongated skulls b. Blowholes on top of skull c. Very few hairs d. Fluke – horizontal tail fin used for propulsion 2. Modifications – to ↑ speed a. Streamline bodies b. Specialized skin structures that ↓ pressure difference to reduce drag and turbulence 3. Modifications - for deep diving a. Specialized structures to use O2 efficiently b. Ability to resist nitrogen narcosis 4. Suborder Odontoceti – toothed whales a. Difference between dolphins and porpoises

1). Porpoises are smaller and have a more stout body shape 2). Porpoises have blunt snout, dolphins longer 3). Porpoises have small- er more triangular (or no) dorsal fin. Dolphin – sickle-shaped = falcate 4.) Porpoises have blunt or flat teeth. Dolphin are conical

*Killer whales have conical teeth and are put in the dolphin family. b. Characteristics 1). prominent teeth – hold and orient fish and squid 2). Form complex, long-lived social groups 3). 1 external nasal opening (blowhole) 4). Best developed sound ability *sperm whales – most vocal 5). Echolocation

6.) Intelligent - ? a). Communicate with each other using sound b). Large brain sized relative to body size

c). Highly convoluted brain – characteristic shared and considered highly intelligent d). Some dolphins have assisted drowning humans in the wild. e). Dolphins have been trained

Sperm whale Killer whale

Pilot whale

Narwhals

Bottlenose Whale

Beluga

5. Suborder Mysticeti – baleen whales a. Worlds largest – blue, finback and humpback

Humpback

Blue Whale

WS

b. Only bottom feeder – grey whale

c. Larger than odontocetes – difference in food source d. Baleen – hangs from upper jaw, made of keratin. Fill mouth with water & prey then force water between baleen trapping their prey.

e. 3 Families 1). Gray Whales – short, coarse baleen, no dorsal fin a). Migration – 22,000 km round trip journey every year. Feed in cold ↑ latitudes water, breed and give birth in warm tropical waters of Baja, California. b). Endangered but removed in 1993 > 20,000. NA Gray Whales – extinct, Japan - extinct

Gray Whale Migration Video, Reading and WS

2). Rorqual Whales – short baleen a). Balaenopterids – long slender bodies, small sickle-shaped fins and smooth-edged flukes.

Minke Whale

Bryde’s Whale

Sei Whale Fin Whale

Blue Whale

b). Megapterids - humpback, robust bodies, long flippers, flukes with uneven trailing edges, tiny dorsal fins & tubercles on head.

Humpback Whales

3). Right Whales – long fine baleen, broad triangular flukes, no dorsal fins a). Most threatened with extinction

b). Right and bowhead whales

Right Whale

Bowhead Whale