CHAPTER 14 Animals of the Pelagic Environment

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

How to avoid sinking Float Float Microscopic zooplankton have shells or tests Microscopic zooplankton have shells or tests Radiolarians Radiolarians Foraminifers Foraminifers Copepods Copepods Macroscopic zooplankton Macroscopic zooplankton Krill (resemble mini-shrimp or large copepods) Krill (resemble mini-shrimp or large copepods)

How to avoid sinking Floating macroscopic zooplankton Floating macroscopic zooplankton Cnidarians Cnidarians Hydrozoan (Portuguese man-of-war) gas-filled float Hydrozoan (Portuguese man-of-war) gas-filled float Scyphozoan (jellyfish) soft low-density bodies Scyphozoan (jellyfish) soft low-density bodies Fig. 14.7a

How to avoid sinking Fig Active swimming Active swimming Fish, squids, sea turtles, marine mammals Fish, squids, sea turtles, marine mammals Swim by trapping water and expelling it Swim by trapping water and expelling it Swim by curving body from front to back Swim by curving body from front to back

Fin designs in fish Paired vertical fins as stabilizers Paired vertical fins as stabilizers Paired pelvic fins and pectoral fins for “steering” and balance Paired pelvic fins and pectoral fins for “steering” and balance Tail fin (caudal) for thrust Tail fin (caudal) for thrust

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

Fin designs in fish Fig a

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

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

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

Adaptations of deep-water nekton Mainly fish that consume detritus or each other Mainly fish that consume detritus or each other Lack of abundant food Lack of abundant food Bioluminescence Bioluminescence Large, sensitive eyes Large, sensitive eyes Large sharp teeth Large sharp teeth Expandable bodies Expandable bodies Hinged jaws Hinged jaws

Adaptations of deep-water nekton Fig

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

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

Marine mammals Carnivora Carnivora Prominent canine teeth Prominent canine teeth Sea otters Sea otters Polar bears Polar bears Pinnepeds Pinnepeds Walruses Walruses Seals Seals Sea lions Sea lions Fur seals Fur seals

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

Marine mammals Cetacea Cetacea Whales, dolphins, porpoises Whales, dolphins, porpoises Stream-lined bodies for fast swimming Stream-lined bodies for fast swimming Specialized skin structure for fast swimming Specialized skin structure for fast swimming

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

Cetacea Fig

Cetacea Suborder Odontoceti (toothed) Suborder Odontoceti (toothed) Dolphins, porpoises, killer whale, sperm whale Dolphins, porpoises, killer whale, sperm whale Echolocation to determine distance and direction to objects Echolocation to determine distance and direction to objects Determine shape, size of objects Determine shape, size of objects

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

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

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

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

End of CHAPTER 14 Animals of the Pelagic Environment