CHAPTER 14 CHAPTER 14 Animals of the Pelagic Animals of the Pelagic

EnvironmentEnvironment

How to avoid How to avoid sinkingsinking

Increase Increase buoyancybuoyancy Gas Gas

containerscontainers Rigid Rigid

container container such as such as shells shells (internal or (internal or external) external) oror

Swim Swim bladderbladder

Fig. 14.2

How to avoid How to avoid sinkingsinking FloatFloat

Microscopic zooplankton have shells Microscopic zooplankton have shells or testsor testsRadiolariansRadiolariansForaminifersForaminifersCopepods Copepods

Macroscopic zooplanktonMacroscopic zooplankton Krill (resemble mini-shrimp or large Krill (resemble mini-shrimp or large

copepods)copepods)

How to avoid sinkingHow to avoid sinking Floating Floating

macroscopic macroscopic zooplanktonzooplankton

CnidariansCnidarians Hydrozoan Hydrozoan

(Portuguese (Portuguese man-of-war) man-of-war) gas-filled gas-filled floatfloat

Scyphozoan Scyphozoan (jellyfish) (jellyfish) soft low-soft low-density density bodiesbodies

Fig. 14.7a

How to avoid sinkingHow to avoid sinking

Fig. 14.9

Active swimmingActive swimming Fish, squids, sea Fish, squids, sea

turtles, marine turtles, marine mammalsmammals

Swim by Swim by trapping water trapping water and expelling itand expelling it

Swim by curving Swim by curving body from front body from front to backto back

Fin designs in fishFin designs in fish

Paired vertical fins as stabilizersPaired vertical fins as stabilizers Paired pelvic fins and pectoral fins for Paired pelvic fins and pectoral fins for

“steering” and balance“steering” and balance Tail fin (caudal) for thrustTail fin (caudal) for thrust

Fin designs in fishFin designs in fish Rounded caudal finsRounded caudal fins flexible, flexible,

maneuver at slow speedsmaneuver at slow speeds Truncate finsTruncate fins and and forked finsforked fins, useful , useful

for both maneuvering and thrustfor both maneuvering and thrust Lunate finsLunate fins rigid, lots of thrust for rigid, lots of thrust for

fast swimmersfast swimmers Heterocercal finsHeterocercal fins asymmetrical, lift asymmetrical, lift

for buoyancy (shark)for buoyancy (shark)

Fin Fin designs designs in fishin fish

Fig. 14-10a

Adaptations for finding preyAdaptations for finding prey MobilityMobility LungersLungers 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

Adaptations for finding preyAdaptations for finding prey

Swimming speedSwimming speed Speed generally proportional to sizeSpeed generally proportional to size Can move very fast for short time Can move very fast for short time

(mainly to avoid predation)(mainly to avoid predation)

Adaptations to finding preyAdaptations to finding prey

Most fish cold-blooded but some are Most fish cold-blooded but some are warm-bloodedwarm-blooded Homeothermic-body temperature above Homeothermic-body temperature above

sea water temperaturesea water temperature Modifications in circulatory systemModifications in circulatory system Mainly in fast-swimming fish Mainly in fast-swimming fish

Adaptations of deep-water Adaptations of deep-water nektonnekton Mainly fish that consume detritus or Mainly fish that consume detritus or

each othereach other Lack of abundant foodLack of abundant food Bioluminescence Bioluminescence Large, sensitive eyesLarge, sensitive eyes Large sharp teethLarge sharp teeth Expandable bodiesExpandable bodies Hinged jawsHinged jaws

Adaptations of deep-water Adaptations of deep-water nektonnekton

Fig. 14-14

Adaptations to avoid Adaptations to avoid predationpredation SchoolingSchooling

““Safety in numbers”Safety in numbers” School may appear as single School may appear as single

larger unitlarger unit Schooling maneuvers confuse Schooling maneuvers confuse

predatorpredator

Marine mammalsMarine mammals

Land-dwelling ancestorsLand-dwelling ancestors Warm-bloodedWarm-blooded Breathe airBreathe air Hair/furHair/fur Bear live youngBear live young Mammary glands for milkMammary glands for milk

Marine mammalsMarine mammals CarnivoraCarnivora Prominent canine teethProminent canine teeth Sea ottersSea otters Polar bearsPolar bears PinnepedsPinnepeds

WalrusesWalruses Seals Seals Sea lionsSea lions Fur sealsFur seals

Marine Marine mammalsmammals

SireniaSirenia Herbivores Herbivores ManateesManatees

Coastal areas of tropical Atlantic OceanCoastal areas of tropical Atlantic Ocean Dugongs Dugongs

Coastal areas of Indian and western Coastal areas of Indian and western Pacific OceansPacific Oceans

Marine mammalsMarine mammals

Cetacea Cetacea Whales, dolphins, porpoisesWhales, dolphins, porpoises Stream-lined bodies for fast Stream-lined bodies for fast

swimmingswimming Specialized skin structure for fast Specialized skin structure for fast

swimmingswimming

CetaceaCetacea

Adaptations for deep divingAdaptations for deep diving Use oxygen efficientlyUse oxygen efficiently

Able to absorb 90% of oxygen inhaledAble to absorb 90% of oxygen inhaled Able to store large quantities of oxygenAble to store large quantities of oxygen Able to reduce oxygen required for Able to reduce oxygen required for

noncritical organsnoncritical organs Muscles insensitive to buildup of Muscles insensitive to buildup of

carbon dioxidecarbon dioxide Collapsible lungsCollapsible lungs

CetaceaCetacea

Fig. 14.19

CetaceaCetacea Suborder Suborder OdontocetiOdontoceti (toothed) (toothed)

Dolphins, porpoises, killer whale, sperm Dolphins, porpoises, killer whale, sperm whalewhale

Echolocation to determine distance and Echolocation to determine distance and direction to objects direction to objects

Determine shape, size of objectsDetermine shape, size of objects

Intelligence in toothed Intelligence in toothed whaleswhales

Large brains relative to body sizeLarge brains relative to body size Communicate with each otherCommunicate with each other Brains convolutedBrains convoluted Trainable Trainable Are they intelligent?Are they intelligent?

Baleen whalesBaleen whales Blue whale, finback whale, humpback Blue whale, finback whale, humpback

whale, gray whale, right whalewhale, gray whale, right whale Fibrous plates of baleen sieve prey itemsFibrous plates of baleen sieve prey items Vocalized sounds for various purposesVocalized sounds for various purposes

CetaceCetaceaaSuborder Mysticeti

Fig. 14.24a

Insert Fig. 14-26

Gray whale Gray whale migrationmigration 22,000 km (13,700 22,000 km (13,700

mi) annual mi) annual migration from migration from coastal Arctic coastal Arctic Ocean to Baja Ocean to Baja California and California and MexicoMexico

Feeding grounds in Feeding grounds in Arctic (summer)Arctic (summer)

Breeding and Breeding and birthing grounds in birthing grounds in tropical eastern tropical eastern Pacific (winter)Pacific (winter)

Whales as Whales as endangered endangered speciesspecies

Fewer whales now Fewer whales now than before whalingthan before whaling

International International Whaling TreatyWhaling Treaty

Hunting of gray Hunting of gray whale banned in whale banned in 19381938

Gray removed from Gray removed from endangered list in endangered list in 1993 as population1993 as population reboundedrebounded Fig. 14.27

End of CHAPTER 14End of CHAPTER 14Animals of the Pelagic Animals of the Pelagic

EnvironmentEnvironment