1. Fishes of Nova Scotia

2. Fish Facts Here are some neat facts about fish you may not know!
The largest fish is the whale shark, which grows to more than 50 feet in length.
The smallest fish is the goby.  It is about half an inch at adulthood.
There are more than 20,000 identified species of fish.
You can tell how old a fish is by counting the growth rings on its scales just like you count the rings on a tree.
Sturgeons live to be 50 or more years old.
The average discharge from an electric eel is 350 volts of electricity, but as much as 650 volts have been measured.
The most poisonous fish is the stonefish.  It's poison is powerful enough to kill a human.
The slowest fish is the seahorse which travels at 0.01 mph
The oarfish is the longest bony fish in the world reaching a length of 50 feet.
The bluefin tuna is among the fastest marine fish to live in the oceans. An adult can swim up to 55 miles per hour..

3. Fish are special
Fish come in all shapes, colors, and sizes.  They are some of the most diverse animals that live in the sea.  
Fish lived on earth before dinosaurs.  They are one of the oldest groups of animals. 

4. What is a fish?
This is a difficult question to answer because fishes have a huge variety of body forms.
The popular concept of a fish as an animal that has fins and scales, and lives in water, is not strictly correct. Many species of fishes such as the clingfishes lack scales, and others such as some species of eels have no fins. Some fishes such as the lungfishes can spend considerable time out of water.
All fishes have a backbone or a notochord, and all breathe using gills. Some animals that are not fish, such as the axolotls also breathe using gills. These animals however have fully formed limbs that are lacking in fishes.

6. Fish Shapes Fish have six main body shapes:
1. flat (rays, skates, flounder, sole) 2. fusiform (sharks, salmon, barracuda, tuna)
3. eel like or elongated (eels, lamprey, needlefish)
4. compressed (butterfly fish, angelfish)
5. round (porcupine fish)
6. ribbon (cutlass)

7. flat (rays, skates, flounder, sole)

8. fusiform (sharks, salmon, barracuda, tuna)

9. eel like or elongated (eels, lamprey, needlefish)

10. compressed (butterfly fish, angel fish)

11. round (porcupine fish)

12. ribbon (cutlass)

13. Fish Anatomy

14. Gills Operculum = gill cover, protects the gills.
Jawless fish, sharks and rays have gill slits.
Water passes through the mouth and over the gills of the fish. As the water passes over the gills, oxygen enters the fish’s bloodstream and is carried throughout its body.
The nostrils of a bony fish are used for smelling and not for breathing.

15. Fins
Bony fish have fins that are used for swimming, stability, and steering.
The dorsal and anal fins keep the fish level in the water and keep it from rolling.
The caudal fin helps propel the fish forward and steer.
The pelvic fins help keep the fish level in the water.
The pectoral fins help the fish steer and brake.

16. Swim bladders
An internal air sac (organ) which can contain more or less air according to the needs of the fish at the time
More air helps the fish become more buoyant, while less air allows the fish to swim down to deeper levels.
Only found in boney fish, not sharks etc.

17. What fishes live in N.S.? Alewife American Shad
Smallmouth Bass Rainbow Smelt
Striped Bass White Sucker
Brown Bullhead Brown Trout
American Eel Lake Trout
Atlantic Mackerel Rainbow Trout
White Perch Speckled Trout
Yellow Perch Atlantic Whitefish
Chain Pickerel Lake Whitefish
Atlantic Salmon

18. Atlantic Salmon

19. Atlantic Salmon They are anadromous.
This means they spend part of their life feeding and growing during long migrations in the sea, and then return to reproduce in the fresh water stream where they hatched (moving from fresh to saltwater)

20. Salmon look different at different times in their lives!
Salmon in saltwater: blue, green or brown on the back and silvery on the sides and belly. On the upper body you can find several x-shaped black marks or spots.
Salmon in freshwater: bronze-purple in colour and sometimes with reddish spots on the head and body.
Salmon finished spawning (kelts): very dark in colour
Young salmon (parr) in freshwater: 8-11 dark bars on the side with a red spot between each one
Young salmon leaving fresh water for the sea (smolts): silvery in colour and usually about cm (5-8 in) long.
Atlantic salmon can be easily confused with both brown trout and rainbow trout.

21. Spawning
Atlantic salmon that are ready to spawn begin moving up rivers from spring through fall.
Spawning occurs during October and November usually in gravel-bottom
Spawning occurs in the evening and at night. The female digs a nest (redd) cm (6-14 in) deep in the gravel by turning on her side, flipping her tail upward and pulling the gravel up until a hole is excavated. After the female and male spawn in the redd, the 5-7 mm eggs are buried with gravel by the female.
Adults do not die after spawning. Exhausted and thin, they often return to sea immediately before winter or remain in the stream until spring.
Some will survive to spawn a second time but few survive to spawn 3 or more times.

22. Eggs
Salmon eggs develop slowly (about 110 days) over the winter while water flowing through the nest keeps the eggs clean and oxygenated.
In most of our rivers the eggs survive quite well and are protected from freezing or silt.
The eggs hatch in the spring, usually April, and the young salmon (alevins) remain buried in the gravel for up to 5 weeks while they absorb the large yolk sac.
Alevins

23. Parr
If they make it through this stage, the young salmon that emerge are about 2.5 cm (1 in) long in May or June.
During this freshwater stage before they migrate to sea they are known as parr
They eat mainly water insects but will also eat other invertebrates when available.
Salmon parr may be eaten by many kinds of predators including trout, eels, other salmon, mergansers, kingfishers, mink, and otter. During the winter parr stay under rocks on the bottom of the stream.

24. Smolt When it becomes silver-colored, it will be called a smolt.
After growing for a while, the smolts swim downstream to the sea.
When smolt reaches the estuary, a process begins in which their body changes, allowing them to soon live in salt water

25. Maturing at Sea, then Returning Home
The salmon lives in the sea until maturity (1 to 7 years, depending on the species
They then return to the place where they hatched and continue the cycle.
No one knows how salmon return home -perhaps they remember the distinctive set of smells along the way. On their journey home, they do not eat at all, they often change color, their muscles soften, and they will often die soon after spawning.