ENVI121 F05 L20

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Fishes - Behavior Migration Anadromous Spawn in fresh water Spend most of life in ocean Ex – Salmon (seven species) in Pacific Ocean Spawn in shallow areas of rivers/streams Semelparous (adults die after spawning) Young migrate downstream to ocean after 0-5 years Spend 3-7 years in ocean before returning to home stream Homing behavior enabled by olfactory imprinting Habitat degradation and loss has greatly reduced salmon populations

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Fig. 8.22

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Fishes - Behavior Migration Catadromous Spawn in ocean Spend most of life in fresh water Ex – Eels (16 species) in Atlantic Ocean Spawn in Sargasso Sea (400-700 m or deeper) Semelparous Eggs hatch into leptocephalus larvae Larvae spend a year or more as plankton then undergo metamorphosis into juveniles Adults spend 10-15 years in fresh water before migrating to Sargasso Sea to spawn

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Fig. 8.24

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Fig. 9.1

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Marine Reptiles Secondarily marine Ectotherms and poikilotherms Sea Turtles Unable to retract head or legs into shell Legs modified as flippers for swimming Eight species – Mainly warm water Some migrate or may appear in temperate waters Diet varies among species Benthic invertebrates – Kemp’s ridley, loggerhead, flatback (also jellyfish) Sponges – Hawksbill Jellyfish – Leatherback Sea grasses – Green, black (also jellyfish) Diverse – Olive ridley (crustaceans, jellyfish, algae)

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Marine Reptiles Sea Turtles Mate offshore Lay eggs on land at night Dig hole in sand and lay up to 160 eggs Incubation period ~ two months Gender of hatchlings determined by incubation temperature Warm  Females Cool  Males Females return to same beach each year DNA evidence that site fidelity spans generations Require 10+ years to reach sexual maturity All species endangered or threatened Overhunting – shell, meat Development – Loss of beaches Accidents – Collisions with boats, entanglement in nets, etc. Use of TEDs

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Marine Reptiles Sea Snakes 55 species – Mainly tropical (Indian, Pacific) Coral reefs, open ocean Bodies flattened laterally (3-4 feet long at maturity) Paddle-shaped tail Immense lungs (extend into tail) Can dive to 150 m (typically ~5 m) Can hold breath for 2+ hours! Ovoviviparous Few species lay eggs on shore Venomous Closely related to cobras Venom typically used to kill small prey (fishes, squids) May hunt in schools Some actively trap prey; others lie in wait Not aggressive – humans rarely bitten Few natural predators (seabirds, sharks, saltwater crocodiles) – threatened by humans

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Marine Reptiles Marine Iguana One species – Galápagos Islands Males colored more brightly than females Different populations (different coloration) on various islands Feed on algae Can dive to 15+ m Can hold breath for 30-60 minutes Eliminate salt through salt glands near nostrils Good swimmers Long, laterally flattened tail Territorial Males fight to establish territories Males maintain harems Females dig nests in sand for eggs

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Marine Reptiles Saltwater Crocodile One species – E Indian Ocean, W Pacific, Australia Mostly inhabit mangrove forests Largest crocodile species - Males larger than females May reach 23+ feet and 1000+ kg Diverse diet Crustaceans, snakes, birds, mammals Aggressive and potentially dangerous to people Slow to reach sexual maturity Males mature at 15-16 years; females at 10-12 years

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Seabirds About 300 species Spend a significant part of life at sea Feed on marine organisms Webbed feet for swimming Endotherms and homeotherms Allows seabirds to live in a wide variety of conditions Need considerable food to maintain body temperature in cold regions Feathers help conserve body heat Gland above base of tail produces oil that birds add to feathers with preening Trapped air provides insulation and buoyancy Hollow bones Facilitate flight Nest on land Often colonial Frequently mate for life Gannet

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Seabirds Diversity Body Form Flightless penguins with rudimentary wings Albatrosses with 12+ foot wingspans Except for gulls, most seabirds are adapted to life in/on the ocean, can’t walk well on land and are vulnerable to mobile land predators Lifestyle Flightless cormorants Frigatebirds that depend completely on extensive flight Diet Small zooplankton – Prions Fishes – Penguins Squids – Petrels Benthic invertebrates – Razorbill Other birds – Petrels Resource partitioning is common (minimizes competition) Geographic Range Restricted to limited region – Storm petrels Traverse thousands of kilometers – Albatrosses

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Seabirds Beak Shape Short, heavy, hooked beak Holding and tearing prey too large to be eaten whole Best for shallow feeding and eating other birds Ex - Petrels Short, heavy, streamlined beak Grabbing prey, usually to ingest whole Streamlined shape doesn’t interfere with swimming Ex – Penguins, razorbills Straight, narrow beak Grabbing prey to ingest whole Used by plunge divers – doesn’t interfere with dive Ex – Boobies, terns Elongated lower beak Used for feeding while flying Lower beak used to catch prey Ex - Skimmers

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Fig. 9.7

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Seabirds Beak Shape Short, heavy, hooked beak Holding and tearing prey too large to be eaten whole Best for shallow feeding and eating other birds Ex - Petrels Short, heavy, streamlined beak Grabbing prey, usually to ingest whole Streamlined shape doesn’t interfere with swimming Ex – Penguins, razorbills Straight, narrow beak Grabbing prey to ingest whole Used by plunge divers – doesn’t interfere with dive Ex – Boobies, terns Elongated lower beak Used for feeding while flying Lower beak used to catch prey Ex - Skimmers

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Fig. 9.7

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Seabirds Beak Shape Short, heavy, hooked beak Holding and tearing prey too large to be eaten whole Best for shallow feeding and eating other birds Ex - Petrels Short, heavy, streamlined beak Grabbing prey, usually to ingest whole Streamlined shape doesn’t interfere with swimming Ex – Penguins, razorbills Straight, narrow beak Grabbing prey to ingest whole Used by plunge divers – doesn’t interfere with dive Ex – Boobies, terns Elongated lower beak Used for feeding while flying Lower beak used to catch prey Ex - Skimmers

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Fig. 9.7

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Seabirds Beak Shape Short, heavy, hooked beak Holding and tearing prey too large to be eaten whole Best for shallow feeding and eating other birds Ex - Petrels Short, heavy, streamlined beak Grabbing prey, usually to ingest whole Streamlined shape doesn’t interfere with swimming Ex – Penguins, razorbills Straight, narrow beak Grabbing prey to ingest whole Used by plunge divers – doesn’t interfere with dive Ex – Boobies, terns Elongated lower beak Used for feeding while flying Lower beak used to catch prey Ex - Skimmers

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Fig. 9.7

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Seabirds Prey Capture Aerial pursuit Chase other birds; harass them into dropping prey Ex – Jaegers, frigatebirds Surface plunging Dive to capture near-surface prey Ex – Pelicans, boobies Dipping Snatch near-surface prey Ex – Gulls Pattering “Walk” along surface, grabbing near-surface prey Ex – Storm petrels Pursuit plunging Shallow dive with some pursuit of prey underwater Ex – Shearwaters Pursuit diving with wings Pursue prey underwater using wings to swim Ex – Penguins, puffins Pursuit diving with feet Pursue prey underwater using feet to swim Ex – Cormorants

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Fig. 9.8

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Seabirds Prey Capture Aerial pursuit Chase other birds; harass them into dropping prey Ex – Jaegers, frigatebirds Surface plunging Dive to capture near-surface prey Ex – Pelicans, boobies Dipping Snatch near-surface prey Ex – Gulls Pattering “Walk” along surface, grabbing near-surface prey Ex – Storm petrels Pursuit plunging Shallow dive with some pursuit of prey underwater Ex – Shearwaters Pursuit diving with wings Pursue prey underwater using wings to swim Ex – Penguins, puffins Pursuit diving with feet Pursue prey underwater using feet to swim Ex – Cormorants

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Fig. 9.8

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Seabirds Prey Capture Aerial pursuit Chase other birds; harass them into dropping prey Ex – Jaegers, frigatebirds Surface plunging Dive to capture near-surface prey Ex – Pelicans, boobies Dipping Snatch near-surface prey Ex – Gulls Pattering “Walk” along surface, grabbing near-surface prey Ex – Storm petrels Pursuit plunging Shallow dive with some pursuit of prey underwater Ex – Shearwaters Pursuit diving with wings Pursue prey underwater using wings to swim Ex – Penguins, puffins Pursuit diving with feet Pursue prey underwater using feet to swim Ex – Cormorants

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Fig. 9.8

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Seabirds Prey Capture Aerial pursuit Chase other birds; harass them into dropping prey Ex – Jaegers, frigatebirds Surface plunging Dive to capture near-surface prey Ex – Pelicans, boobies Dipping Snatch near-surface prey Ex – Gulls Pattering “Walk” along surface, grabbing near-surface prey Ex – Storm petrels Pursuit plunging Shallow dive with some pursuit of prey underwater Ex – Shearwaters Pursuit diving with wings Pursue prey underwater using wings to swim Ex – Penguins, puffins Pursuit diving with feet Pursue prey underwater using feet to swim Ex – Cormorants

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Fig. 9.8

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Seabirds Prey Capture Aerial pursuit Chase other birds; harass them into dropping prey Ex – Jaegers, frigatebirds Surface plunging Dive to capture near-surface prey Ex – Pelicans, boobies Dipping Snatch near-surface prey Ex – Gulls Pattering “Walk” along surface, grabbing near-surface prey Ex – Storm petrels Pursuit plunging Shallow dive with some pursuit of prey underwater Ex – Shearwaters Pursuit diving with wings Pursue prey underwater using wings to swim Ex – Penguins, puffins Pursuit diving with feet Pursue prey underwater using feet to swim Ex – Cormorants

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Fig. 9.8

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Seabirds Prey Capture Aerial pursuit Chase other birds; harass them into dropping prey Ex – Jaegers, frigatebirds Surface plunging Dive to capture near-surface prey Ex – Pelicans, boobies Dipping Snatch near-surface prey Ex – Gulls Pattering “Walk” along surface, grabbing near-surface prey Ex – Storm petrels Pursuit plunging Shallow dive with some pursuit of prey underwater Ex – Shearwaters Pursuit diving with wings Pursue prey underwater using wings to swim Ex – Penguins, puffins Pursuit diving with feet Pursue prey underwater using feet to swim Ex – Cormorants

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Fig. 9.8

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Seabirds Prey Capture Aerial pursuit Chase other birds; harass them into dropping prey Ex – Jaegers, frigatebirds Surface plunging Dive to capture near-surface prey Ex – Pelicans, boobies Dipping Snatch near-surface prey Ex – Gulls Pattering “Walk” along surface, grabbing near-surface prey Ex – Storm petrels Pursuit plunging Shallow dive with some pursuit of prey underwater Ex – Shearwaters Pursuit diving with wings Pursue prey underwater using wings to swim Ex – Penguins, puffins Pursuit diving with feet Pursue prey underwater using feet to swim Ex – Cormorants

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Fig. 9.8