Transcript Salmon - MARRIC

TROUT
Mrs. Garbiel: Oceanography &
Environmental Science
Salmon Family
Scientific Family name is
Salmonidae
Includes three subfamilies:
•Salmon, Trout, and Char
•Whitefish
•Grayling
Economically the most important
family of cold water fishes in
North America
•Sport Fisheries
•Commercial Fishing
•Hatcheries and Fish Farms
Salmon Species
Pacific Salmon
• Pink or Humpback
• Chinook or King
• Coho or Silver
• Chum or Dog
• Sockeye or Red
Atlantic Salmon
• Atlantic Salmon
Salmon
Anadromous
• Spends its life in the ocean but
returns to fresh water to spawn
• Pacific Salmon die shortly after
spawning
• Atlantic Salmon may live to spawn
two or more times
Kokanee Salmon
Landlocked Sockeye Salmon are called Kokanee
Salmon.
Kokanee were originally stocked into Lake Tahoe in
1950. Every fall, thousands of kokanee ascend
Taylor Creek (Tahoe tributary) to spawn.
Trout and Char
Photo courtesy of Mike
Sevon
Trout Facts
All salmonids are characterized by the
presence of an adipose fin
All salmonids require clean, cold water in
which to live and have a low tolerance to
habitat degradation.
Primarily freshwater fish, however, many
species develop seagoing races.
 Can you name the anadromous form of the
rainbow trout?
Steelhead
True Trout
Characteristics:
Black spots on
light background
Stream obligate
spawners
Photo courtesy of Mike Sevon
Nevada’s True Trout:
Cutthroat
– Lahontan
(Threatened
species)
– Bonneville
– Yellowstone
Rainbow*
Brown
Char
Characteristics:
Light spots on dark
background
Prefer colder water than
trout
Spawn in the fall
Can spawn in a lake
environment
Nevada’s Chars:
Lake Trout
Brook Trout
Bull Trout
Lahontan Cutthroat Trout
Cutthroat Trout
• Once the predominant native trout in lakes and
streams across the Great Basin
– Competition with non-native trout and habitat
degradation can be attributed to the decline in
the species
• Recovery activities by NDOW and other agencies
are ongoing to reestablish these fish in their
historic range
Official State Record Cutthroat Trout:
23 pounds 8 ounces (Pyramid Lake, 1977)
Unofficial Record: 41 pounds (Pyramid Lake, 1925)
Rainbow Trout
Photo courtesy of John Rupp
Rainbow Trout
• The most important trout in North America based
on its contribution to sport fisheries
– Comprise over 90% of the hatchery production
from Nevada’s four hatcheries
• Rainbow are native to waters along the Pacific
coast
• All rainbow trout existing in Nevada are introduced
with the exception of the Redband Trout which can
be found in 12-mile Creek in the Northwest corner
of Nevada
• State Record: 16 pounds 4 ounces (Lake Mohave,
1971)
Brown Trout
Photo courtesy of Mike Sevon
Brown Trout
• Imported from Europe in the late 1800s and
stocked throughout the United States. They were
first introduced into the Truckee River in 1895.
• Often described as the wariest and hardest to
catch of all trout
• While they prefer colder water, brown trout can
tolerate temperatures as warm as 75°F and can be
found in slower moving water that would be
unsuitable to other trout
• State Record: 27 pounds 5 ounces (Cave Lake,
1984)
Brook Trout
Photo courtesy of Mike Sevon
Brook Trout
• Native to the Eastern U.S.
• Stocked extensively throughout the U.S.
approximately 100 years ago.
• Usually found inhabiting high mountain lakes and
streams due to their preference for cold water
(rarely found where temps exceed 65°F.)
• Popular with anglers – considered the easiest trout
to catch and the best tasting
• State Record: 5 pounds 10 ounces (Bull Run
Reservoir, 1980)
Lake Trout (Mackinaw)
Lake Trout (Mackinaw)
• Native range is the northern portion of North
America from Alaska to Labrador and includes the
Great Lakes
• Highly prized as a sport fish due to its large size
(World Record – 72 pounds 4 ounces)
• Generally only found in deep, cold lakes
• In Nevada, they’re found in Lake Tahoe where they
have been reported at depths as deep as 1,400 feet
• State Record: 37 pounds 6 ounces (Lake Tahoe,
1974)
Bull Trout
Bull Trout
• Native to the Jarbidge River system north of Elko.
• The Jarbidge is a tributary to the Snake River in
Idaho, however, the populations are separated by
150 miles of unsuitable trout habitat and several
impassable dams.
• Federally listed as Threatened
• State Record: 4 pounds 6 ounces (Jarbidge River
WF, 1985)
• World Record: 32 pounds 0 ounces (Lake Pend
Oreille, Idaho)
Life Cycle
of Salmon and
Trout
Spawning
Spawning occurs in
the spring for
Rainbow and
Cutthroat
All other Nevada
salmonids are fall
spawners
Female seeks out
a suitable
location for her
nest and begins
digging her redd
Video footage courtesy of Manu Esteve, University
of Washington
Factors Influencing Nest Location
Water Temperature
Depth
Velocity
Substrate
Cover for maturing fish
Size of Spawners (Larger fish may choose
larger streams with bigger substrate)
Trout and Char often spawn in the transition
area between pools and riffles where water
velocity is accelerating.
Spawning
Males will fight for
spawning rights to the
female. The most
dominant male will
spawn.
The process of
courtship and nest
building will last for
hours
Only when the female
is ready will spawning
commence.
Video footage courtesy of Manu Esteve, University
of Washington
When the female is
ready, she will
signify the male by
arching her back
and quivering over
the redd (gravel
nest) she has built
with her tail.
The male fertilizes
them by covering
them with a milky
substance known as
milt.
The female
immediately begins
to bury the newly
laid eggs.
Video footage courtesy of Manu Esteve, University
of Washington
Egg Development
Females can lay between 200 to 8,000 eggs (depending
on the size of the fish).
Eggs are extremely
vulnerable to predators,
suffocation and fungus
spores.
Egg development depends
entirely on water
temperature
Rainbow trout eggs will
hatch in about three weeks
at a water temperature of
54°F.
Salmon are born in gravel beds in streams 10 to
700 miles (16 to 1200 km) from the sea. Laid in
the fall, the eggs incubate over the winter,
frequently under several feet (more than a metre)
of snow and ice. Their pink eggs are always
covered from direct sunlight. About a month after
they have been deposited in the gravel, eyes
begin to show. This normally happens in late
November or early December. It is essential
during this time that water flow and temperature
are suitable. The period of greatest mortality in
the salmon's life cycle is in the egg-to-fry stage.
TROUT IN THE CLASSROOM
When
will
they
hatch?
TROUT IN THE CLASSROOM
Water
Temperature
Rainbow Trout
35 °F
40 °F
45 °F
50 °F
55 °F
Days to hatch
-
80
48
31
24
DTU’s
-
640
624
558
552
Brown Trout
Days to hatch
156
100
64
41
-
DTU’s
468
800
832
738
-
Hatch between Feb. 12-14th.
TROUT IN THE CLASSROOM
FACTORS EFFECTING EGG DEVELOPMENT
LIGHT
-Direct sunlight or UV light will effect the
development of the eggs.
30 minutes of light will kill them
-The optimal thing to do is minimize
there light exposure.
TROUT IN THE CLASSROOM
TEMPERATURE
-Fluctuation for developing eggs
is a good thing within range.
2°F to 3°F is an optimal
temperature variation.
Cutthroat Trout Eggs
•
•
•
•
Eyed eggs
22 days old
@ 47 DegreesF
Our eggs were fertilized
on Jan. 13. 2009
Alevin (sac fry) Development
Stay in gravel
1-6 wks after hatching
The embryo produces an
enzyme which dissolves the
egg shell (a white foam on
the surface at hatching
time).
Eggshells need to be
removed to prevent fungus
Change half the water and
use the baster to remove
shells.
Alevin (sac fry) Development
Newly hatched
trout have a yolk
sac that nourishes
the young fish until
it is mature enough
to feed itself.
Sac fry remain in
the gravel until
their yolk sack is
absorbed.
The vitelline vein,
running through the
centre of the sac,
picks up oxygen
from the water.
Cutthroat Trout Alevin(sac fry)
They will remain
in the gravel and
avoid light. Keep
in darkness.
– Sac Fry
– 35 days old
– @ 47 degrees F
Cutthroat Trout Sac Fry
– Sac Fry in late
development
– 44days
– @ 47 Degrees F
Cutthroat Trout Fry
• Fry
• 55 days
• @ 47 Degrees F
Fry Development
Once it is “buttoned-up”, the fry will work their way
through the gravel to the top of the stream bed.
These “swim-up” fry dart to the surface and gulp air
to fill their air bladders.
From this point, they are free swimming fish and
begin to feed.
Fingerlings/Parr
2-5 “
Most hatchery trout are stocked into lakes at this
size
Develops “finger” markings
At about 6” in length called Parr
Smolt
At this point, the
juvenile salmon loses
its vertical markings on
its body and turns
silvery in color. Now
considered Smolt, they
will school together in
large groups. It's at this
time that the young
salmon will adjust their
bodies to saltwater,
allowing them to swim
out into the Pacific
Ocean to feed and grow
into adult salmon.
Juvenile Development
To reach maturity a
juvenile fish must:
•avoid predators,
•Find adequate food
•Survive summer heat
and winter cold
•Release 5-7 days
after “button up”…
Adult
Lahontan Cutthroat Trout – Pyramid Lake
Only about 2% of fertilized eggs survive to become
mature adults.
Most salmonids reach sexual maturity at 3 to 5 years.
Some precocious fish (usually males) mature at 2 years.