1. Selected Adaptive Strategies: Bioluminescence  Fishes - important nektons  Many are deepsea predators  Need their own light to attract prey  … to attract mates  luciferin + luciferase

3. More Nekton Strategies  predator/prey  must be swift and efficient swimmers  move swiftly to –eat –avoid being eaten.  Thus fish have evolved to maximize their ability to move through water.

4. Caudal (Tail) Fins most important for speed flared to increase vertical thrust (Figure 9-22)

5. ROUNDED fin (e.g., flounder) very flexible, slow-speed manuevering

6. TRUNCATE fin (e.g., angel fish) somewhat flexible, manuevering

7. FORKED fin (e.g., goatfish or herring) somewhat flexible, manuevering

8. LUNATE fin (e.g., blue marlin or tuna) very rigid, no good for manuevering, built for pure speed

9. HETEROCERCAL fin (“uneven tail) most of mass & surface area in upper part to produce lift pectorals balance to aid lift limits manueverability

10. Caudal Fins  rounded –very flexible, manuevering  truncate & forked –somewhat flexible, manuevering  lunate –very rigid, propulsion  heterocercal –“uneven tail” for lift and propulsion

11. Built for Speed  speed related to body length –4-foot yellowfin tuna, 46 mph –13-foot bluefin tuna, 90 mph (theoretically) –9-foot porpoise, 25 mph –30-foot killer whale, 34 mph

13. Squid: traps water in mantle and forcefully jettisons it from siphon in head

14. active predator of fish arms to capture tentacles to bring to beak both lined with suckers

15. They Exist! up to 20 feet long!

16. Colossal Squid Captured Wellington, NZ, April 2003 330 pounds - 16 feet long