1. Nekton
The nekton can swim against an ocean current and include most fish, sharks, whales, seals, dolphins, squid, etc.
We will discuss the characteristics and adaptations of whales and fishes only.

2. Whales
Whales are marine mammals that breathe air, are warm-blooded, and feed milk to their young, just like humans
There are two main groups of whales:
those with teeth
those with baleen

3. Toothed Whales
These include dolphins, porpoises, killer whales, belugas, and sperm whales
Sperm whales are the largest toothed whale. They can dive to great depths (1000m) and stay under for an hour. They feed mostly on squid.

4. Baleen Whales
Include all the largest species of whales - blue, fin, sei, humpback, minke, right
They have plates of baleen that hang from each side of the upper jaw instead of teeth, which they use to sieve krill out of the water
An average humpback will eat tons of krill per day

5. Interesting Whale Facts
Blue whales are the loudest animals on Earth! Their call reaches levels up to 188 dB. This whistle can be heard hundreds or perhaps even thousands of miles away. The blue whale is louder than a jet, which reaches only 140 decibels!

6. Interesting Whale Facts
Orcas are the fastest whales, reaching speeds of up to 48 km/hr
Humpback whales sing the most complex songs – only males sing
Narwhals have the longest tooth – 7-10 feet long

7. Adaptations of Whales Streamlined bodies Powerful tail flukes
Thick blubber layer to keep warm
Twice as many red blood cells as other land mammals
During dives - heart rate slows to conserve O2
Water-tight seals on blowholes

8. Video: Mammals of the Sea

9. Fish
Fish are cold-blooded animals and possess gills for breathing and fins for swimming
They live near the surface to the ocean depths, in warm water and icy water
There are two main groups of fish:
Cartilage fish (sharks, skates and rays)
Bony fish (tuna, cod, halibut, etc)

10. Cartilage Fish
Cartilage fish lack bones and have a skeleton made out of cartilage (the stuff that is in your nose)
Cartilage fish are negatively buoyant – will sink if they stop swimming
Skates and rays have flattened bodies and wing-like fins

11. Sharks
Most sharks have several rows of teeth, but some are planktonic filter feeders (whale shark, basking shark)
Predatory sharks have a keen sense of smell and are able to detect vibrations in the water to locate prey

12. Sharks in Our Waters
Basking
Great White
Porbeagle

13. Other Cartilage Fish
                                                

14. Bony Fish
Bony fish display the greatest diversity of all the vertebrates
Possess air-filled swim bladders to aid in buoyancy
86 million tons of fish are taken each year for food

15. Bony Fish, cont’d
Sight and hearing are well-developed to obtain prey and avoid predators
Bony Fish also have a lateral line system which is a series of pores along the side of the fish. It is used to detect vibrations in the water

16. Some Unusual Bony Fish
                                   

17. Adaptations of Fish Hydrodynamic torpedo shaped bodies
Well-developed muscles for swimming
Fins specialized for the particular fish’s mode of life
Countershading (dark on the dorsal side; light on the ventral) – aids in camouflage from prey and predators

18. Label the Fish Parts

19. Types of Caudal Fins
Slow
Fast

21. Video: Fish