Transcript Fish Anatomy

Minnesota Fishes/Fishing
Pics Agnatha
Fishing
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Each year about 2 million people, 400,00 of them non-residents, go
fishing in MN.
Minnesota is rich with fish primarily because if offers plenty of room
and a diversity of places for them to live.
It has been reported that Minnesota has 12,034 permanent bodies of
water. This is greater than any other state,except Alaska.
MN also contains about 15,000 linear miles of rivers and streams.
The inland lakes and rivers of MN cover about 4,900 square miles,
which is 6% of the state’s area.
MN waters offer a practically limitless variety of freshwater habitats,
from the deep waters of lake Superior to the shallow waters of prairie
lakes, from rushing streams, and meandering rivers.
Fish Names
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There are 149 species of fishes in MN.
What is a species? A group that maintains an identity separate from
all other kinds. The members of each species can breed freely with
each other to produce normal offspring.
Hybrids: when members of different species interbreed, to produce
offspring. Hybrids are usually sterile.
Each species of plant and animal has two names, one common name
and one scientific.
Example: Walleye (common name) Stizostedion vitreum Scientific
Why use scientific names?
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Each species is given it’s own name and they do not overlap.
Common names on the other hand may vary based on region; the
walleye for example is sometimes referred to as the walleyed pike, or
a jack salmon even though it is neither a pike or salmon.
Scientific names are derived from Latin or Greek words that contain a
genus: (an inclusive group of related species) and a species: (which is
a specific name). The genus name is always capitalized and the
species name lowercase.
Scientific names are assigned by the person who discovers the
species.
Both the scientific name and common name usually tell you some
thing about the species. Walleye (refers to the eyes) Stizostedion:
refers to pungent throat, vitreium: means glass
The Class Osteichthyes: The Boney Fishes
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Lobe-finned fish Known only as a fossil until 1938.
Has paddle-like fins with a fleshy base.
Lungfish Have lungs, internal organs for gas
exchange between air and the blood.
Only a few species are known.
Ray-finned fish Fins are supported by stiff rays
and/or bony spines.
All other bony fish, both freshwater and saltwater,
are in this group.
Classification
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Fishes that are related to each other are grouped into families. There
are twenty six different families of fishes in Minnesota represented by
at least one species.
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What kingdom do all fish belong to?
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What phylum do all fish belong to?
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Give an example of a fish that isn’t boney.
Minnesota Volunteer
Find an article about fish or fishing and discuss the following.
1. What were the main concepts or ideas presented in the article?
2. How are the fish being affected?
3. What/how have humans made an impact?
4. List interesting facts.
5. Presentation
6. Why is the article important? Why did you pick it?
7. You must have one additional question for the class to consider.
Native/Non-native
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135 species of fishes are native to
MN.
14 species have been introduced to
the state either deliberately (such
as: coho salmon, chinook salmon,
brown and rainbow trout).
Why were they introduced?
1958-60’s mosquitofish
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Non-productive species;
Sea Lamprey and carp
Sea Lamprey: Invaded the
Great Lakes via the wetland
canal near Niagara Falls. They
are a predaceous fish that
attack and attaches itself to
other fishes.
Carp: a prolific breeder and
very adaptable.
Fish anatomy
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Caudal fin
Lateral line
Dorsal fin
Eye
Mouth
Operculum
Pectoral fin
Pelvic fin
Scales
Anal fin
Gills
Fish Anatomy
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Scales: scales are made of bone and are there for protection.
Fins: stabilize, propel and sometimes help protect. Paired fins:
pectoral and pelvic Unpaired fins: anal, caudal, and dorsal.
Gills: The gills are feathery structures found along side the head.
They are covered by a bony plate called the operculum. Oxygen
enters the blood at the gills.
Fish Fins & Movement
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Dorsal - top of body - helps keep
the body upright.
Caudal - the "tail fin" - provides
forward motion.
Anal - located just anterior to anus
- helps keep the body upright.
Pelvic - paired fins on ventral
surface - turns fish left or right and
backward.
Pectoral - paired fins behind the
gills - moves fish up or down.
Adipose (catfish & trout) - a fleshy
fin between dorsal and caudal fins no motion.
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Lateral line: A row of scales with sensory
depressions down each side of the fish.
This system detects vibrations in the water.
Chromatophores: structures containing
pigment to provide color patterns.
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Swim bladder:
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A thin-walled sac along the top of the abdominal
cavity containing a mixture of oxygen, carbon
dioxide, and nitrogen obtained from the bloodstream.
The swim bladder usually produces neutral
buoyancy, but some fish are able to adjust their
buoyancy by slightly changing the amount of gas in
the swim bladder.
Almost all fish have a swim bladder. Those without
one, like sharks and freshwater darters, sink if they
stop moving their fins.
Circulatory system
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Atrium - the collecting
chamber.
Ventricle - the pumping
chamber.
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Arteries - thick-walled blood
vessels that carry blood under
high pressure away from the
heart.
Veins - thin-walled blood
vessels that carry blood under
low pressure toward the heart.
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Capillaries - small blood
vessels that connect arteries
and veins.
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Fish have a 2 chambered heart
how many chambers does a
human heart have?
The Brain
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Forebrain:
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Midbrain:
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Olfactory lobes (1) - respond to
smell.
Cerebrum (2) - respond to smell
and other sensory information.
Optic lobes (3) - largest lobes process information from the visual,
auditory, and lateral line systems.
This part of the brain is also
responsible for turning the animal's
body toward or away from a
stimulus.
Hindbrain:
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Cerebellum (4) - muscle
coordination.
Medulla oblongata (5) - regulates
internal organs.
Gas Exchange
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Gills: external tissue rich
with blood vessels to
exchange gases with the
water.
Operculum - a hard plate
on either side of the head
that protects the gills and
opens at the rear to allow
water to flow through the
mouth and over the gills.
Fish senses
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Sight: Well developed eyes. Fish that are colorful probably have
colored vision. Nocturnal fish have larger eyes so they are better able
to see in low light conditions.
Smell: fish smell by using nares. Nares are similar to our nostrils.
Taste: fish have taste buds in the lining of their mouths. Some fish
use whiskers (barbels), which are covered with taste buds.
Hearing: Fish do have ears but you cannot see them. Their inner ears
are well developed and pick up sound waves in the water through the
fishes body.
Lateral line: a system which helps fish feel movements in the water. It
is actually a row of tiny holes in the skin, which runs along the entire
side of the fish. There are tiny hairs in the system which are sensitive
to vibrations. This system helps fish swim in schools, avoid predators
and find food.
Senses continued
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Electricity: some fish have holes in their
head which allows them to detect electrical
currents. This sense aids them in finding
prey in the dark or muddy water.
Senses
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Of the five senses which on do you think is
the worst for fish?
Motion
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Motion
Spawning: the external fertilization of fish
eggs.
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In many Minnesota fish
species, the male uses his fins
to make a depression to use as
a "nest".
He then tries to guide a female
to the nest to release her eggs.
He swims over the eggs and
releases his milt, a fuid
containing the sperm. This
"external fertilization" is
inefficient, but having the eggs
in the depression helps.
In most cases, the female will
guard the nest until the eggs
hatch. After that, the hatchlings
are on their own.
What months do walleyes
spawn?
How do fishing regulations
protect spawning fish?
How Big do they get?
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For the following fish find the Minnesota record it’s weight, when it was
caught and where it was caught.
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Walleye
Esox masquinongy
Esox lucius
Oncorhynchus tshawytscha
Salvelinus namaycush
Cyprinus carpio
Acipenser fulvescens
Microterus salmoides
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Classification of Fish
Do fish have eyelids?
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Most fish have large eyes to help gather light
in dim surroundings.
In bright surroundings, this causes fish to
seek shadows.
No eyelids