Fishes - Behavior Migration Anadromous Spawn in fresh water Spend most of life in ocean

1. 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

2. Fig. 8.22

3. 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

4. Fig. 8.24

5. Fig. 9.1

6. 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)

7. 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

9. 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

10. 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

11. 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

13. Gannet • 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

14. 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

15. 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

16. Fig. 9.7

17. 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

18. Fig. 9.7

19. 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

20. Fig. 9.7

21. 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

22. Fig. 9.7

23. 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

24. Fig. 9.8

25. 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

26. Fig. 9.8

27. 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

28. Fig. 9.8

29. 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

30. Fig. 9.8

31. 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

32. Fig. 9.8

33. 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

34. Fig. 9.8

35. 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

36. Fig. 9.8