BL-06: FISH STUDY
MATERIALS LIST:
-Plastic relief model of a fish showing internal organs.
-Fresh fish (intact), (optional, you supply). The following fish are suggested, but use what is available in
the market. Small specimens should be used. Use one kind per class and give one fish to each pair of
students.
a. Top Smelt (one fish for each team)
b. Sanddab
c. Sardine (bait size, approximately 6 to 7")
d. Surfperch
-Preserved specimens
-Poster with designated dwelling niches and laminated photos of fish backed with Velcro
-A pair of sharp scissors for opening the fish to show internal organs
-Clean-up equipment:
-Container of water, sponge, paper towels, Baby Wipes, fresh lemons (you supply)
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FISH STUDY
SOURCE:
BL– 06
Fall 1993
Mary Asazawa
OBJECTIVES:
-Learning to work with partner(s)
-Recognizing external and internal features
-Learning to use external characteristics to determine where a fish lives.
-Understanding how food needs determine place adaptations
-Understanding the influence of shape to survival behavior
SCIENCE THEMES:
Scale and structure, systems and interactions
PROCESS SKILLS:
Observing, comparing, categorizing, relating
GRADE LEVELS:
3—6
FOCUS WORDS:
Pelvic fin
Predator
Tapered
Reproduction
Operculum
Pectoral fins
Swim bladder
Elongated
Brood pouch
Scales
Dorsal fin
Fertilize
Protective
Friction
Gastrointestinal
Anal fin
Hydrodynamic
Spherical
Cartilage
Scavengers
Caudal fin
Streamlined
Camouflage
Estuary Circulatory
Oxygen
Gill raker
BACKGROUND INFORMATION:
A fish that is long compared to its girth, and pointed on both ends is capable of swimming fast. Most
pelagic fishes (travelers of the mid-oceans) such as tuna, have this shape. They are always traveling, and
need fast spurts of speed to capture prey. Schooling fish often have this shape. They also need spurts of
speed to avoid being captured.
Fish such as salmon that travel up raging rivers to spawn must be fast enough to jump waterfalls.
This is a streamlined shape, and does not use the fishes' energy by causing turbulence. These fish may
live at any depth, and may change depths to be where the food is.
The streamlined shape, the laterally compressed (deep body but flat sides) is the shape of the
surfperch. The streamlined herring, anchovies, sardines, and other plankton eaters form schools on the
surface where the photosynthesis of the sunlight causes the plankton to thrive. These fish are usually
dark colored on the back so the seabirds can't see them readily against the darkness of the depth. They
are silvery or white on the underside so the predator fish below them can't see them readily against the
brightness of the sky.
The flyingfish has the same dark above and light below coloration but it also escapes predators by
flight. It is streamlined, and a very fast swimmer. It also has large broad pectoral fins that actually act
like wings. The flyingfish is more like a glider than a bird. This fish leaves the water on the crest of a
wave at very high speed. It then glides on its enlarged wing-like pectoral fins as far as it can until it gets
BACKGROUND INFORMATION: (continued)
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back near the surface. Then, without reentering the water it propels itself again up to flying speed with
the elongated lower lobe of its tail, like a propeller pushes a boat, as it touches the water.
Many fish have shape and color patterns to camouflage themselves. The seahorse and the pipefish
are two examples of this shape. These fishes remain motionless in the seaweed and look so much like
the seaweed that it is difficult for the predator to find them. Papa sea horse and papa pipefish do all the
raising of the children. The female deposits eggs in a kangaroo-like pouch in the male's stomach, where
the eggs become fertilized. They hatch while still in this brood pouch.
The rockfish (erroneously called rock cod and red snapper) approximates streamline, but is husky for
its length. It relies on stalking its prey and then, with a short sudden lunge, captures it. It is often brightly
colored, even though in the depths of its habitat there is often little or no light to show off its color.
These fishes are protected by spiny rays on the dorsal and anal fins and often sharp points on their heads.
Some fish can change their shape when frightened. When a predator is near a balloonfish or a
porcupinefish it inflates itself with water to become a spherical shape, much bigger than normal. These
fish also have spines, like the quills of a porcupine. When they are inflated they resemble a beach ball
with a tail and long hard points sticking straight out all over it. Few predators would take a mouthful of
those needles.
On the bottom of the bays and open ocean live the flat fish. There are many species of flat fish, from
a 700-pound specimen of a halibut to the tiniest sanddab. These fish are somewhat diamond shaped,
although they could be oval shaped, as in the case of the tonguefish. The flatfish starts life with a normal
fish shape, eyes where they belong and a straight mouth. Shortly after birth things start to happen; one
eye starts to migrate to the other side of its head until both eyes are on the same side. The mouths of
some flat fish stay in the birth position, but on some the mouth becomes twisted. They are a dark or
sandy color on top as camouflage when they lay on the bottom with both eyes looking up. Sometimes
they cover themselves with sand waiting for a hapless fish to swim too close.
Another group of flattened fish are the skates and rays; they belong to the same family as the sharks.
Most of these fish could be considered kite shaped. Their shape comes from their large pectoral fins that
join their ventral fins and are referred to as "wings." They have a long, whip like tail often without fins.
They use their wings to move through the water much like a gull flies through the air. Nearly all of these
fish are bottom dwellers.
Two exceptions to this are the manta and the mobula, which are pelagic and filter feeders. These rays
are very large; the manta can weigh as much as 2,300 pounds.
There is a group of fishes that feels safer out of the water than in it. The mudsucker of the
Indopacific is one example. It actually climbs out of the water on mangrove or other tree roots that grow
into the water. It climbs the roots by pulling itself along with its pectoral fins. If danger comes from
above, it returns to the water with one quick flip.
The wrasse is a small fish and would be a tasty morsel for bigger predators, but this fish makes
friends with them by cleaning them of parasites. It swims around, over and under these larger fish
picking off the parasites without fear of being eaten. The wrasse even cleans the inside of the predators’
mouths.
The surgeonfish has a scalpel-like spine on either side of its tail. When flaying this tail around it can
inflict serious incisions on other fish.
SUGGESTED INTRODUCTION:
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Using the San Francisco Bay relief map, ask the students if they can find all the ways that water gets
into the bay. Explain that the bay is an estuary (body of water enclosed by land except for passage
ways that can receive saltwater from the ocean and fresh water from run-off and streams/rivers.)
Ask them if they can tell how the water coming into the bay might be changed by humans or by
weather. Ask if they think the bay is different from the way it was one hundred years ago. Have them
give some examples of differences.
ACTIVITIES:
Time: 20 minutes
Directions:
Use the fresh salmon head to point out tongue, teeth, operculum, gills, gill rakers &
filaments
EV should have some of the fresh fish cut open for internal organs study.
Divide students into pairs (or 3 if necessary).
Give each team a fresh market fish (to minimize fishy smelling hands, have the children
keep the fresh fish inside a clear plastic baggie)
SAY: We will now try to determine what a fish is. We have here some fish that I bought in the
fish market, and we have some preserved specimens of fish.
DO: Pass out one fresh market fish to each pair of students.
ASK: What do all fish have in common?
RESPONSE: They all have eyes.
They all have a mouth.
They all have fins.
They all have a tail.
They all have gills.
They all have scales. (NOTE: If you have a catfish point out that this fish and some other
fish do not have scales.)
They are all slimy.
(Allow as many similarities as the students can find. Add a few of your own if you can.)
NOTE: There are exceptions to each of these features. Example, the blind cave fish and the
scaless catfish mentioned above.
DO: Place some of the preserved fish on the table. What are some of the differences?
RESPONSE: Allow as many differences as the students can find. Some differences may be; "This fish
has both eyes on the same side of its head."
"This fish is long and skinny."
"This fish is kind of round." (Could be a surfperch.)
DO: Give time for student responses.
ASK: Is a shark a fish? Is a whale a fish?
RESPONSE: A shark is a fish. It has most of the features that are common to all fish. But it does not
have bones. A whale is a mammal the same as humans.
ASK: What is meant by a bony fish?
DO: Pass around the preserved bony fish skeletons (mounted in clear contact paper)
RESPONSE: A fish that has hard bones. Most market fish are bony fish
ASK: What is meant by a cartilaginous fish? Have them wiggle their ear lobes, tips of noses
and point out this is also cartilage.
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RESPONSE: A fish that does not have a bony skeleton, that is, it has no bones. In place of bones it has
cartilage. Sharks, skates and rays are cartilaginous.
ASK: Do all sharks look alike? Use the book North American Fish for photos of sharks.
RESPONSE: There are many different species of sharks. Many of them have the typical shark shape,
but some sharks look quite different.
The angel shark is flat with large pectoral fins which resemble wings.
One shark is called the guitar fish because his body resembles a guitar.
The hammerhead has eyes spread far apart on a head that resembles a hammer.
The thrasher shark looks like the typical shark except the upper lobe of its tail is as long
as its entire body.
ASK: Are all sharks dangerous?
RESPONSE: Only a few of the larger sharks are dangerous. But the largest of all sharks, the whale
shark, will not harm anything larger than the smallest of shrimp.
ASK: Why does a fish die when taken out of water?
RESPONSE: A fish has gills which absorb dissolved oxygen out of the water. The gills must be wet in
order to function. As soon as the fish is taken out of the water the gills can no longer
gather enough oxygen, and the fish suffocates. Some fish have adapted to breathing air.
The walking catfish of Florida, for example.
DO: Expose the gills of the salmon head. Point out the color. Show how the water, loaded
with oxygen, can flow through the mouth and out through the gills.
DO: Point out the scales and the operculum (protective gill cover) on the salmon head.
ASK: Why don't fish need eyelids?
RESPONSE: Our eyelids’ main function is to keep the surface of the eye clean.
ASK: What keeps the fish's eye clean? (water)
ASK: Does no eyelids mean no naps? (fish do sleep)
ASK: How can you tell the age of fish?
RESPONSE: By counting the rings on its scale, somewhat like tree rings.
ASK: What are the functions of scales?
RESPONSE: Scales are small bony plates that attach to a fish like shingles on your roof. They protect
the fish from bumps and scratches. They also reduce the friction as the fish swims
through the water.
ASK: Why is a fish slimy?
RESPONSE: The slime is a lubricant, it makes the fish slippery and reduces the friction between the
fish and the water. This gives the fish speed with less energy. The slime also protects the
fish against infection if wounded
ASK: What are the functions of fins?
RESPONSE: Some fish have more fins than others. The fins of one specie of fish might be placed
differently from those on other specie. On most fish the caudal fin, which is the tail fin,
is used for swimming. The dorsal fin is the fin on the back of the fish, and the anal fin is
underneath the belly of the fish near the tail. These fins are used for stability; they keep
the fish from turning over. The pectoral fins are used for steering; they are on the sides
closer to the gills.
ASK:
Do fish school?
RESPONSE: Not like you do, but fish school (hang out in large groups) for various reasons. Usually
they school for breeding and/or protection. When a predator fish sees a single fish, he
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DO:
ASK:
RESPONSE:
DO:
DO:
ASK:
ASK:
RESPONSE:
ASK:
RESPONSE:
DO:
ASK:
DO:
ASK:
RESPONSE:
DO:
ASK:
RESPONSE:
can just gobble it up. But when he sees a dense school of fish continually changing
direction, he cannot fix on a single fish, so he gets none. Fish often form schools for
migration.
Show the poster with the different feeding levels and one of the laminated photos of a
fish.
Can you guess at what feeding level this fish would be found by looking at its shape and
coloration? Wait for some guesses and then have a student attach it to the correct level.
Streamlined fish are designed to be fast ;they would not be low down in the mud. Fish
that eat phytoplankton (small plants) or zooplankton (small animals) must be near the
surface where they can get their food, but they are more easily seen, so speed saves them
from getting eaten and their coloration helps to. How?
Have the students each take a laminated fish photo and try to determine, by the shape
and asking what the fish likes to eat, where to place it on the feeding level poster.
Allow some time for responses
Why is a flat fish, with eyes on top of its head, best adapted for living on the bottom? If
all the different fish ate in the same level, what would happen to the food?
Using the feeding level poster and laminated fish photos have the students make a food
chain. Tell them the tiny phyto and zoo - plankton are the first link of the chain. Then,
have them decide in which order the fish are linked in the chain.
The herbivores (surface feeders) are the second link, then perhaps striped bass (first
order carnivores), leopard shark (second order carnivores), flounder (scavenger), and
worms (decomposers).
How do fish use their swim bladders?
The fish has a little balloon in its stomach. He can blow it up more, or let some air out.
The fish must make himself a very little bigger or smaller by how much he blows up that
balloon.
When he is the right size he can rest at whatever depth he is in without either floating up
or sinking down.
Open one of the pre-cut fresh fish and show where the swim bladder is in the fish. Also,
find the air bladder on the plastic relief model.
What else is inside the fish?
Locate the stomach, the liver and the heart. Also locate these organs on the plastic relief
model.
Where are the lungs?
There are no lungs. The fish breaths by passing water over its gills.
See if you can identify any other internal organs that you can match with the plastic relief
model
Do fish see color?
Boney fish do, but sharks do not.
ASK:
What do fish eat?
RESPONSE: Different fish eat different things:
-Scavengers eat anything they can find, dead or alive.
-Predators catch live food. Some catch swimming fish, some feed on crabs, worms, or
clams.
-Filter feeders eat plankton. They take water in their mouths and expel it through their
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gill rakers. These fish are usually surface dwellers, because the plankton they eat needs
sunlight to grow.
-Grazers nibble on coral, sponge or algae.
-Decomposers eat dead organisms, clean up the bottom of detritus.
ASK: How are new fish born?
RESPONSE: All fish lay eggs. Some are deposited into the water or are glued onto seaweed, where
they are fertilized. Some eggs are fertilized inside the female and the young are born live,
such as the surfperch. Some are deposited in the brood pouch of the male and held there
until they hatch, such as the pipefish. There are fish called "mouth breeders," they carry
their eggs in their mouth, and even after the eggs hatch they allow the fry to take refuge
in their mouth.
ASK: Can you determine the sex of your fresh fish?
RESPONSE: Sex is often hard to tell in fish. Unlike birds both males and females may be brightly
colored. Sometimes one sex is larger than the other, but this too differs between different
species. If the fish has fresh eggs inside what sex is it?
SUGGESTED CONCLUSION:
We have looked at some of the kinds of fish found in the San Francisco Bay. What is another
name for the bay (estuary)? Water flows into the bay from what sources?
Which of the fish we looked at do you like the best, why? Do all fish look the same, live in the
same place in the water, eat the same things? Why are there these differences?
RESOURCES:
Robins, Richard C. American Nature Guides – Saltwater Fish, Smithmark Publ., N.Y.
1992
Parker, Stevens
Fish – An Eyewitness Book, A.A. Knopf, 1990
Wilson, Josleen
North American Fish, National Audubon Society, 1991
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FISH STUDY
Grades K — 3
Questions That can be Asked:
1.
Why does a fish die when taken out of water?
• Unable to breath air.
• A fish uses oxygen dissolved in water.
2.
How can you tell the age of fish?
• By counting the rings on its scale; just like tree rings.
3.
What are the functions of scales?
• Protection.
4.
What are the functions of fins?
•Pectoral fins—for direction
•Dorsal fin and anal fin—for balance; vertical stability
• Caudal fin—for swimming
5.
Why do fish school?
•Schooling fish present a big surface to predators as defense/protection from being eaten.
6.
Do fish sleep?
•Yes. They find a safe spot to sleep. They sleep with their eyes open because they have no
eyelids.
7.
How do fish use their swim bladders?
•By increasing or decreasing the amount of gas in the swim bladder they can adjust their mass to
the mass of the water they are swimming in. By this control they can remain at one depth without
effort.
8.
Do fish see color?
•Boney fish can, but sharks cannot.
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Story of Amazing Fish
Ask what a fish would look, like or do, to fit the following amazing fish:
Traveler:
King salmon, Steelhead trout.
Tide Rider:
Grunion swims up on the beach on a large wave at extreme high tide. Eggs are laid and
fertilized on the sand. The grunion swims back to sea on the next wave.
Balloon:
Puffers, porcupinefish, balloonfish.
Flyingfish:
Hanger on:
Sea House
Baby sitter:
Sea horse, Pipefish
Tree climbers:
Mudsucker
The dentist:
Wrasse
Sharp shooter:
Archer fish
Surgeon:
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Grades K—3
Fishy Shapes
Matching fish to its shape.
Objective:
◊ Learning to work with partner(s)
◊ Identify fish by its shape
◊ Beginning understanding the influence of shape to behavior and adaptation such as
camouflage, silvery coloration with darker top side
◊ Placement of eyes, mouth
Directions:
Divide students into pairs (or 3 if necessary)
Materials:
A set of shapes cards and one fish for each pair of students.
Use pipefish, batray, Pacific halibut, balloonfish, herring.
Time:
Introduction to "What a Fish Is - - - 2 Minutes
Matching - - -3 Minutes
Sharing - - - 10 Minutes
Summary - - - ? Minutes
Questions to bring up:
1. Which shape is streamlined for fast swimming?
•Tapered ends and slim elongated body.
STREAM
LINES
Jacksmelt, Striped Bass,
Salmon, Shark
When a fish is designed for fast
swimming his shape is such that
the water is not desturbed very
much.
2.
Which shape slows swimming?
•Kite shape of batray
•Diamond shape of sole
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3.
Which shape is protective?
•Spherical - - -Balloonfish (puffed up)
4.
How does shape determine the location of eyes and mouth?
•Flat fish have eyes on top of body such as batray and halibut.
5.
Which shape is used as camouflage?
•Bay pipefish
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What is a Fish?
Activity with market fish and preserved fish
using fresh specimen and dried fish parts.
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Obtain:
1. Salmon head — for gills, tongue, teeth, nostril and eyes.
2. Market fish:
Top Smelt (one for each pair of students) (10)
Sanddab
Sardine (bait size)
Surf perch
3. Preserved spaceman
Pipefish
Sculpen
Leopard shark
4. Poster or photos
Schooling fish
Introduction:
What is a fish?
Is a shark a fish?
Looking at and feeling a real fish given to each /or pair of students.
A. External features:
1. Placement of eyes, mouth and nostril
2. Gills—use fish head and exposed gills, mouth with teeth, tongue, scales,
operculum, gill rackers and (vessell?) Dissect—one of bottom gill
3. Fins—purpose is swimming
4. Operculum and scales
5. Lateral lines—like ultrasound pores, pick up energy discharges (xxx?)
B. Internal features:
1. Skull
2. skeleton
3. Gastrointestinal tract
4. Air bladder
Types of feeders and placement of mouth:
Scavengers
predator
filter—plankton
grazer—coral, sponge, algae
deposit (detritus)
Relate to light levels and habitat
Schooling
Camouflage
Coloration—shading, bright warning color, sleeping and feeding related to light
Reproduction
Lays eggs
Brood pouch—pipefish
Live birth—Surfperch
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Grades :
4—6
Who Lives Where?
surface, middle or placing fishes in their dwelling niche.
Object of activity:Playing Ich.
1. Learning to use external characteristics to determine where a fish lives.
2. What a fish eats is a factor in where a fish lives
3. Coloration and size of fish influence if surface or bottom dweller.
Direction:
—Using poster with designated dwelling niches.
—Give each student a picture of a fish to decide with use of list of determining factors.
—Have student place his or her fish on poster board and have student share how decision was
made.
—Discuss additional pertinent information.
—Reinforce important factors
Materials for Who Lives Where?
1. Poster of day habitat:
Sun
Water with zones marked
Eel grass on slope
Color code marked for each level
2. 24 samples of fishes to chose from—recommend a couple of surface dwellers, pipefish,
surfperch and one more from middle dwellers (your choice).
3. For bottom dweller choose five samples. Recommend bat ray, leopard shark, staghorn sculpin
and two flatfish of your choice.
4. List of factors that students will use—give one to each student.
For EV's use:
• Fishes listed according to dwelling niche.
• Information on fishes on list.
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Who Lives Where:
Surface dwellers
1. Small silvery fish eat plankton that needs sunlight for photosynthesis.
Lives in schools
Middle dwellers
1. Big eyes and big mouth to eat smaller fish.
They have darker colored upper halve and lighter colored bottom half
2. Looks like a pipe and lives in eel grass.
Bottom dwellers
1. Flat like pancake with eyes on top side and mouth twisted on head. Brownish on top
side and white underneath. Eats crustaceans, worms, crabs, and clams.
2. Has gill slits and mouth underneath and eats anything. Able to detect minute amount
of blood in the water
3. Kite shape with tale fin lang and whiplike.
Can this be put 2 to a sheet to be used by student for criteria for decision making?
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Some Common Bay Fish:
Top dwellers — (schooling fish)
Pacific Herring
Northern Anchovy
Topsmelt
Jacksmelt
Middle dwellers — (may also be found at top and low level)
Striped Bass
Barred Surfperch
Shiner Perch
Pipefish
White Croaker
Three Spine Stickelback
Balloon Fish
Coho Salmon
Green Sturgeon
Low level and bottom dwellers (found in both areas)
Bat Rays
Brown Smoothhound Shark
Leopard Shark
Spiny Dogfish
Staghorn Sculpin
Yellow Goby
Arrow Goby
Plainfish Midshipman
California Halibut
Pacific Halibut
Starry Flounder
Starry Skate
California Tonguefish
Speckled Sanddab
Pacific Sanddab
Rex Sole
Diamond Turbot
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Background Information:
Common Bay Fishes
A. Surface dwellers:
Identification:
Length to 9 inches, rarely over 7 inches. A fairly thinish, blue or green on back and silvery on
belly.
Range and Habitat:
The most common anchovy in California. Extremely large mouth characteristic. Feeds on
plankton. Supports a large commercial fisheries industry. Spawns in the south San Francisco bay
during the spring and summer.
Comments:
A schooling fish usually found 100 miles off shore. Remains at the water’s top level.
Anchovies are vital food for larger fishes as well as sea birds and marine mammals.
Northern Anchovy — Engraulis moreax
Pacific Herring — Clupea Pallasi — Length to about 18 inches. At one time schools of herring
were widespread on California coast. Populations has been declining each year. San Francisco
Bay is a fishery for herring eggs. Sticky eggs are laid on seaweed, eel grass and kelp.
Jacksmelt —Atherinopsis californiensis — To 171/2 inches. Schools in murky water over sand
bottoms. (Topsmelt and Jacksmelt are not actually members of the smelt family, but belong to
the silverside family.)
Eggs are laid all year attached to seaweed
Topsmelt — Atherinops affinis — Not a true smelt. Closely related to the Jacksmelt. Maximum
length 14 inches, average 7 inches. Common in the south San Francisco Bay. Feeds on plankton
and small crustaceans.
B. Middle dwellers:
These fishes may be found in all levels. When small and young, they are found near the surface
to feed on plankton.
Striped Bass. —Morone saxatilis — To 4 feet. Greenish on back and silvery sides with 6 to 9
black stripes. Hatch in Sacramento/San Joaquin Rivers Delta. Live in San Pablo and San
Francisco bays and shallow open rocky coast. Population has been decreasing in bay. The
Striped Bass can only be taken by sport fishermen, and cannot be sold in the market. (Recent;y
this fish has been a product of mariculture. These fish when properly marked can be found in the
market.
White Croaker — Genyonemus limeatus — To 161/2 inches. A schooling fish. Moves inshore
during summer months and off shore in winter. These are silvery fish with slightly yellow-bronze
backs. Found from Surf zone to about 600 feet.
Main catch from piers and small boats, and by barge fishermen.
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Bay Pipefish — Syngnathus leptorghnchus — Length to 13 inches, average in the south bay 6
inches. Feeds on crustaceans. Fairly common,rarely caught.
Threespine Stickelback — Gasterosteus aculeatus — Length to 4 inches. Three sharp spines
precede the soft dorsal fin. Found throughout the northern hemisphere. Feeds primarily on
insects, crustaceans and algae. Breeds in late spring and early summer. Found in ocean, brackish
and fresh water.
Barred Surfperch — Amphistichus argenteus — To 17 inches. Often found in small schools in
pounding surf zone. 8 to 10 yellow or rust colored irregular bars on the side.
Feeds exclusively on sand crabs, occasionally eats clams, mussels, and fish eggs.
A sport fish—illegal to trade commercially
Shiner Surfperch — (Cymatogaster aggregata) — Length to seven inches. Common. One of a
number of surfperches found in the South San Francisco Bay. Female has three yellow bars on
sides, interspersed with black. Male in breeding season almost black. Feeds on crustaceans and
other invertebrates. Bears live young.
3. Bottom dwellers
Bat Rays — Myliobatis californicus — To 6 feet wide. Has large raised head, heavy jaws, dark
brown color, long whip-like tail with caudal fin and stinger at base of tail. They seek out inshore
bays and sloughs.
Feed on worms, shrimp, clams, abalone and crabs.
Brown Smoothhound Shark — Mustelus henlei — Length to 38 inches.
This is a bronze-brown shark, closely related to the Leopard shark. Found on sand of mud
bottoms, from intertidal to 650 feet. Abundant in San Francisco bay.
Smoothhounds are schooling fish near bottom and schools are often of one sex. Feeds on crabs,
shrimp and fish.
Spawns inshore spring and summer.
Leopard Shark — Triakis semifasciata — Length to 6 feet. A common shark of the San
Francisco Bay. A large nursery exists in the south Bay. Scavenger, feeds on almost anything.
Hangs out on or near bottom.
Schooling fish, often with smoothhound and dogfish sharks.
Most Leopard shark stay in San Francisco Bay through the year.
Spawning from March to June.
Feeds on crabs, clams (they bite off siphons), fish and fish eggs of herring, Topsmelt and
Jacksmelt.
Staghorn Sculpin — Leptocottus armatus — Length to 12 inches, average 7 inches. Named for
its antler-like preopercle spine. Often called "bullhead". An important bait fish for striped bass.
Bottom dwelling.
Spawning occurs in bays, October to March, in estuaries and marshes. Staghorn sculpin follow
the tides.
Feeds on small crustacean and worms.
Predators are herons and harbor seals. Used as bate by striped bass fishermen.
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Yellowfin goby — Acanthogobius flavimanus — Length to 9 1/2 inches. introduced during the
early 1960's from Southeast Asia. Formally called the Oriental Goby. Feeds on small fish and
crustaceans. Has a established population in San Francisco Bay. Bottom dwelling.
Plainfin Midshipman — Porichthys notatus — Length to 15 inches. Lives at least 7 years. Gill
covers sharp. Spin and rows of dots on side and bellies. Dots are photopores which produce bluegreen light. Throat photopores in this species form "V" shape in throat area. Prefer sand and mud
bottoms.
Most feeding at night. Feeds on krill, mysid, shrimp amphipod and squid.
5. Flatfishes:
All flatfishes begin life like all other fishes—with one eye on each side of the head. Within a few
days one eye starts to migrate toward the other side, and the mouth becomes twisted and its
metamorphosis promotes living on the bottom. Camouflage and ability to bury themselves in the
sand make it difficult to see. Body colored on topside and white on blind side.
Most flatfishes are carnivores eating smaller fishes and crustaceans.
Pacific Sanddab — Citharichthys sordidus — Length to 16 inches. A brown left eyed flatfish
with yellow, orange or reddish brown spots. Primarily soft-bottom dweller. Small ones are found
inshore, and general inshore migrations during summer. Will swim well above bottom in search
of food. Eats most anything they can find such as copepods, krill, shrimp, squid. small fishes and
worms.
Rex Sole — Glyptophalus zachirus — Length to 23 inches. Small mouthed,right-eyed flat fish.
Has long pectoral fin on eyed side.
California Halibut — Paralichthys californiaus — Length to 5 feet and weight to 60 pounds.
Eyes on either right or left side of head. Highly arched lateral line over the pectoral fin. Caudal
fin indented near upper and lower lobes. Strong sharp teeth and big mouth.
Lives on bottom. Has a habit of burring itself, often with only eyes and mouth unburied.
Young live in estuaries and adult in open ocean.
Feeds on fish, squid and octopus. Smaller individuals eat bottom dwelling invertebrates such as
amphipods and copepods.
Predators: sea lions, angle sharks and electric rays.
Population decline with loss of nursery grounds and by over fishing by commercial and sport
fishermen,
Diamond Turbot — Hypsopsetta guttulata — Length to 18 inches. Dark Diamond shaped, right
eyed flatfish. Dark green, brown or greenish on eyed side with light blue spots. The white blind
side has yellow rim near mouth. Small fish most common in estuaries and bay. Spawn from
September to February. Feeds on clam syphons, worms and small crustaceans.
Starry Flounder — Platichthys stellatus — Length to 3 feet and weight to 20 pounds.Named for
patches of star-shaped scales on the pigmented side. a member of the right-eyed flounder family,
Pleuronectidac. Feeds on crustaceans, and small fish. Can change its coloration to match its
surroundings.
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California Tonguefish — Symphurus atricauda — Length to 8 1/4 inches. Slim body with tiny
eyes and mouth. Slimy. Found over sand and mud.
Feeds on amphipods, crabs, worms and bottom dwelling organisms.
Usually lift eyed, right eyed tonguefish have been found.
References:Goodsin, Fishes of the pacific coast. Stanford Press. 1988
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FISH STUDY – KIT CONTENTS
North County Kit
July 1997
Specimens
1. Bay pipefish
2. Leopard shark
3. Shiner surf perch
4. Staghorn sculpin
5. Striped bass
6. Topsmelt
7. Long-jawed mudsucker
Other Contents
Bas relief model depicting internal and external fish anatomy
Painted model to show fish feeding levels
Color photos of fish with Velcro back to place at appropriate level on painted model
5 sets of fish shape cut-outs to be used with color photos of fish that have information about the fish
and are used to match the photo to the cut-out shape
Flow the fish puppet, who helps children answer the question, “What is a fish?”
Fish skeletons on clear contact paper
Fish eggs on clear contact paper
Fish books with good color photos to show examples of kinds of fish
Handy wipes to wipe off fish smell, if you decide to bring a whole dead fish
REMEMBER – IF YOU DO GET A WHOLE DEAD FISH TO DISSECT, YOU MAY NEED TO
CALL YOUR LOCAL FISH STORE TO RESERVE YOUR FISH AT LEAST ONE DAY IN
ADVANCE
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STREAM
LINES
Jacksmelt, Striped Bass,
Salmon, Shark
When a fish is designed for fast
swimming his shape is such that
the water is not disturbed very
much.
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Identification: Silvery with darker gray back.
— Rows of dark spots on sides and three vertical yellow bars (absent in males).
— Males blackish in breeding season (winter and spring).
Range and Habitat: Alaska to Baja California.
— Mostly in bays and sloughs, especially around seawalls and pilings.
— Enters fresh water.
Comments:
— Found 50 ft. or less in surf zone and common to 200 feet depth.
— Shiners school during day and disperse at night.
— Lives to 6 years.
— Females mature after one year.
— After mating, male sperm lives in female ovaries 2 to 3 months and eggs develop
internally and live young shiners are born in July.
— Feeds on plankton, such as copepods, amphipods and fish eggs during the day.
Shiner Surf Perch (Cymatogaster aggregata)
Identification: Silvery with darker back and no spots.
— Length to 18".
— Single dorsal located directly over the pelvic fins.
Range and Habitat: Inshore waters.
— North Pacific, from San Diego, California to Arctic-Alaska on the Caifornia coast.
— On the Asian coast from Kurile Islands to Japan and Korea.
Comments: This, and the very similar Atlantic herring, C. harengus, which occurs from
western Greenland and Labrador to North Carolina, are prized food fishes, both for the
flesh and roe, and as a source of fish oil.
— Stocks in both oceans are now reduced; over fishing blamed.
— Scales cycloid (grow in cycles usually annually).
— Female lays 9,000 to 154,000 eggs. Peak spawning in January and February.
— The roe is deposited on rocks and seaweed. It is dredged up from the inshore waters of
San Francisco bay to be sold to Japan as a prized delicacy.
— In the fall young herrings leave for the sea and mature in 2 or 3 years.
— Feeds on plankton (filter feeders).
Pacific Herring (Clupea pallasi)
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Identification: Length to 14 1/2 "
— Small dorsal fin above anus.
— Broad silver stripe along side.
Range and Habitat: British Columbia to northwestern Mexico inshore waters, bays. (A.
a. affinis is the San Francisco Bay Topsmelt.)
Comments: A schooling specie of commercial and limited angling importance.
— Tolerant of changes in salinity and tolerates fresh water.
— Behavior: A schooling fish. A surface dweller found in kelp beds and along sandy
shores.
— Lives about 8 years. Female lays eggs on aquatic plants, especially eel grass.
— Predators: A large number of marine fish eat topsmelt.
— The topsmelt is not a true smelt, but belongs to the silverside family.
Topsmelt (Atherinops affinis, affinis)
Identification: Length to 20"
— Body: elongate, robust, slightly depressed covered with spines.
— Spines long, depressible. Those on top of head longer than those on body.
Snout blunt, mouth small with a single tooth in jaw, fused to form a parrotlike beak
— Tan with many black spots.
Range and Habitat: Worldwide in tropical waters. and versatile in choice of habitats,
being found in creek waters of mangrove swamps, on reefs, and on sandy bays.
— Rarely deeper than 3 fathoms.
Comments: Noted for its ability to swell its body with water or air, the spines being
erected by the resultant pressure.
— This species and the related porcupinefish.
— Skin and viscera can be very poisonous and should not be eaten.
—D. hystrex, are commonly dried, shellacked and sold as curios.
—Their powerful beaks enable them to crush strong mollusks like the queen conch, crabs
and urchins.
-Like puffers, skin and viscera can be poisonous and should not be eaten.
-Feeds on crustaceans.
Balloonfish (Diodon holocanthus)
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Identification: Dark greenish above, silvery on sides.
— Bold black stripes along sides.
— Length to 4 ft., weight to 78 lb.
Range and Habitat: Gulf of St. Lawrence to northeastern Florida and Gulf of Mexico in
coastal waters, bays and and estuaries, running up rivers. Some permanent freshwater
populations. Introduced to Pacific coast where it is now established from British
Columbia to Baja California. Widely introduced elsewhere.
Comments: A premier food and sport fish. World record 78 lb 8 oz (35.6 kg) but known
to reach 125 lb. (57 kg.). Atlantic stocks are seriously depleted.
-Population in bay has been declining.
-Hatch in rivers. Spends most of their lives in estuaries, bays, and coastal waters.
-Spawning occurs in early spring from April to September in the Sacramento/San Joaquin
rivers delta.
-Female lays 11,000 to 2 million eggs each year.
-Feeding pattern: Juvenile feed on plankton and as it grows eats increasingly larger fish.
Striped Bass (Morone saxatilis) / (Rocus saxatilis)
Identification: Length to 14". Very elongate.
— Snout long. Mouth small and terminal.
— Olive-gray or brownish without bands. (Can change color to match virtually any
seaweed background.)
— No pelvic fins. Caudal fin very small.
— Covered with bony plates.
Range and Habitat: Alaska to Baja California, in bays and sheltered waters.
— Only pipefish found north of California.
Comments: Commonly exhibited in aquaria.
— Lives in eelgrass beds. Like seahorses swims and rests standing up.
— Lives in marshes, bays and sloughs.
— Female transfers eggs into male's brood pouch.
— Eggs hatch in 8 to 10 days.
— Breeding period March through July.
— Young leave brood pouch in 3 weeks.
— Feeds on small crustacean, small grayling, or small gobies.
— Sucks up water to bring in prey.
Bay Pipefish (Syngnathus leptorhynchus)
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Identification: Generally very dark brown on eyed side, somewhat mottled.
— Blind side lighter brown.
— A right eyed flounder, family Pleuronectidae.
— Lateral line arched in front. Edge of caudal puduncle shallowly concave.
— Females length to 8'-9" and weight to 800 lb.
— Male length to 4'-6" and weight to 50 lb.
Range and Habitat: North Pacific, from Bering Sea to southern California.
— Depth from near shore to deep water {3600 ft. (1097 m)}.
Comments: Important commercial and sport fish.
— Stock was nearly depleted due to over fishing. The fishery is now regulated and the
stock is rebuilding.
— Most are caught by long lines.
-Cold water fish.
— Oldest known female was 42 years old. Oldest known male 27 years old.
— Spawning: November through January along the Pacific coast.
— Females produce 100,000 to 2.8 million eggs.
— Feeds primarily on fish, crabs, octopuses.
Pacific Halibut (Hippoglossus stenolepis)
Identification: Right-eyed flounder, family Pleuronectidae.
— Mouth small, ending in front of eye. Eyes large.
— Pectoral fin (eyed side) blackish, larger than head.
— Length to 23 1/4 ".
—Lateral line straight.
Range and Habitat: Bering Sea to Baja California on soft bottom from 60 ft. (18.3 m)
to 2,100 ft. (640 m.).
Comments: Important food fish.
— Males move inshore in summer.
— Females grow faster and larger and live longer.
— Spawning is from January through August.
— Feeds on small crustacean and worms.
— Predators: harbor seals and elephant seals.
Rex Sole (Gylptocephalus zachirus)
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Identification: Disk very broad, pointed, wing-like. Head deep, blunt. Tail long,
whiplike with spine at base behind small dorsal fin.
Range and Habitat: Oregon to Mexico.
— Seeks out inshore bays, sloughs, flat rocky bottom and kelp beds. Found commonly
intertidal to 100 feet.
Comments: Swims by "flapping" its wing-like pectoral fins.
— Eats shellfish and crustaceans.
— Related species occur on both coasts of North America. They sometimes gather in very
large schools (to 1255) in the nonbreeding season.
— Buriy themselves in sand with only eyes protruding.
— Breed during summer. Female produces 2 to 12 young. Young rays are carried by
mother 9 to 12 months.
— Digs and flays "wings" to uncover worms, shrimp, clams, and fish such as herring,
shiner, perch, mudsuckers.
— The sting ray's tail is long and whiplike and bears a strong spine at its base. It usually
lies partly buried in the sand. If stepped on or seized, it lashes out vigorously with its tail
and attempts to drive the spine into the intruder. The spine is grooved and is associated
with poison glands. The wound is extremely painful. The spines are serrated and solid,
thus cutting and tearing the flesh as well as injecting poison. More serious stings result
from encounters with these species than with any other fish. The powerful poison is
produced by glands derived from epithelial cells in the integumentary sheath surrounding
the spine. It affects the heart and the nervous system of mammals and can cause
depressed respiration.
Bat Ray (Myliobatis californicus)
Identification: Spinous and soft dorsal fins separated.
— length to 2 1/4".
— Very large mouth, the gape extending behind the eye.
— Tan or grayish with small rows of black spots on fins.
Range and Habitat: British Columbia to Baja California in estuaries, bays, tidal creeks
and sloughs on muddy bottom.
— Enters fresh water.
Comments: The family Gobiidae, of which this and the neon goby are representative, is
one of the two families of fishes with more than 2,000 species, of which 72 occur on
North American coasts, mostly in warm water.
— Adult gobies eat diatoms, algae (green), titimmids, and eggs.
— When they find a piece of food too big for them to eat, they carry it and drop it in front
of a crab. When the crab breaks it up the goby eats the pieces.
Arrow Goby (Clevelandia ios)
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Identification: Length to 38 inches and weight to 33 lb.
— Dark spots on upper back and upper lobe (only) of caudal fin. Silvery, with metalic
blue back.
— Adipose fin present.
— An identifying feature of the Coho salmon is the white to gray gums at the base of the
teeth.
— During spawning run, males have hooked jaws and broad red stripe on side and often a
dark belly.
Range and Habitat: Gulf of Alaska to Baja California. Breeding occurs only as far
south as Monterey, California.
— Inshore waters at mid-depth or near surface.
— Introduced into New England waters and well established in Great Lakes.
Comments: A valuable food and sport fish.
— Also called sliver salmon.
— Cohos, like all salmons, are anadromas (hatches in fresh water, migrates to ocean and
returns to fresh water in 2 to 3 years to spawn.
— At sea feeds on fishes such as herrings, anchovies, sand larvae, rock fishes and
invertebrates such as krill and squid.
— Eaten by white sided dolphin and some fishes.
Coho Salmon/Silver Salmon (Oncorhynchus kisutch)
Identification: Length to 15 ft. weight to 1182 lb.
— Generally dusky, purplish to almost black above becoming paler on the sides and
below.
— Upper jaw very long, flattened, sword-like 1/3 the body length.
— One broad keel on side of caudal peduncle. First dorsal fin rigid. No pelvic fins.
— First dorsal fin large and widely separated from the second.
— Caudal fin lunate, lobes very long.
Range and Habitat: Worldwide; on coast from northern Newfoundland and Oregon
southward.
—Oceanic, basically mesopelagic.
— Depth to 334 fathoms, but entering surface waters in cold part of range, otherwise
usually below the thermocline.
Comments: A premier food and sport fish.
— Lives 15 years
— Behavior: solitary
— Reproduction: females produce up to 6 million eggs.
—Feeds on pelagic fish or squid at night over deep water and bottom.
Swordfish (Xiphias gladius)
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Identification: Head length greater than body depth.
— Gill covers not united under head.
— Length to 6".
— Metallic bluish or greenish above becoming silvery on sides and belly.
Range and Habitat: Surface water of San Francisco Bay
— Subspecies of the northern anchovy (Engraulis mordax).
Comments:
—Travels in large schools.
— An important food source for other fish, birds and mammals
—Feeds on plankton
— Spawns throughout the year
— Eggs are elliptical and float near the waters surface.
Northern Anchovy (Engraulis mordax nanus)
Identification: Gray to olive-brown, sides paler, belly silvery.
— Breeding adults reddish on head and belly.
— Length to 4".
— Body shape tapers to each end with the rear portion slender.
— Three stout dorsal spines widely separated.
— Tail fin triangular.
— Sides covered with bony plates
Range and Habitat: Marine, estuarine and fresh water.
— Usually in vegetation.
— In Atlantic, from Hudson Bay to Chesapeake Bay.
— In Pacific, from Bering Sea to Northern Baja California
Comments: A very aggressive fish that defends his nest against fish many times its own size.
— It moves readily from seawater to brackish to fresh water.
— Feeds on any small animals,vertebrates or invertebratse.
— Male constructs nest on the bottom from plant fragments and strips of algae.
Three-spine Stickleback (Gasteroteus aculeatus)
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Identification: Elongated compressed
— Length to 12 ", weight to 21/2 pounds
— Iridescent blue to gray above, sides silvery
— Very small chin barbels (might be absent)
Range and Habitat: Vancouver Island to San Juanica Bay, Baja California.
— A schooling fish in shallow water over sandy bottom.
Comments: A market fish of minor importance.
— Caught in large quantities by pier fishermen.
— They are referred to as "kingfish" by pier fishermen on the central California coast.
— Spawn in summer mounts.
White croaker (Genyonemus lineatus (Ayres))
Identification: Length to 12" Body elongate; heavy, stout shoulders tapering to small caudal peduncle.
— Pectoral fins large bared with yellow and black.
— Distinguished by the large black spot on dorsal fin.
— color dark green to brown on back; silvery to yellowish on belly.
— Very strong antler-like spine on cheeks
Range and Habitat: Northwest Alaska to northern Baja California.
— Common close to shore in bays.
— Enters brackish and fresh water at stream mouths
Comments: Of no commercial value except as a bait fish for sport fishing.
— Considered a nuisance and a bait stealer by pier fishermen.
Pacific Staghorn Sculpin (Leptocottus armatus)
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Identification: Distinguished by the short, sharp, pointed teeth set in five or more rows.
— Slender body and caudal peduncle.
— First dorsal well in advance of pelvic fins.
— Base of second dorsal beginning slightly in advance of anal fin.
— Length to 3 ft.
— Color brownish to brassy back fading to lighter sides and whitish belly.
Range and Habitat: Cool Bay, Oregon to Baja California. Most abundant shark in San Francisco Bay
and Humboldt Bay.
Comments: An excellent food fish.
— Bare live young (ovoviparous)
Brown Smoothhound (Rhinotriacis Hinlea)
Identification: Iridescent gray marked with black saddles across the back followed by spots on sides
and on tail. Belly pale.
—Fins not pointed.
— First dorsal fin in front of pelvis.
— Length to 5 ft.
Range and Habitat: Oregon to Baja California.
— Common in shallow water.
— San Francisco Bay is an ideal nursery ground; immatures often caught in the slough in front of the
Interpretive center at the Palo Alto Baylands.
Comments: Gives birth to living young (ovoviperous)
— A harmless blunt-toothed shark
— Feeds on crustaceans and any fish it can catch.
— an excellent food fish.
Leopard Shark (Triakis semifasciata)
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Identification: Snout slightly pointed, posterior outline circular.
— Two dorsals set well back on tail.
— Large spines from between spiracles in continous row along center of back and top of tail to first
dorsal fin; smaller spines over body and sides of tail.
— size to 21/2 ft.
— Color : Grayish brown with many darker spots over body.
— Eye spots large, dark center ringed with yellow and encircled with small, dark spots. Eye spot
sometimes followed by dark, round spot.
Range and Habitat: Occurs San Diego to Alaska in deep water.
— Common north of Point Arena, Mendocino County.
Comments: Considered excellent food fish.
Starry Skate (Raja stellulata)
Identification: A flatfish, to 81/4 " long.
— Tapers like an arrow to a narrow point at the tail.
— Eyes on left side, eyes and mouth very small.
— color brownish with dark vertical bars extending from dorsal and anal fin toward center of body.
White on blind side.
— No pectoral fin or lateral line.
Range and Habitat: Humbolt county to Panama. 5 foot to 600 foot depths
Comments: Bury themselves in sand or sandy mud; for this reason they are seldom seen.
— Of no commercial value, so not studied extensively and little data available.
California Tonguefish (symphurus atricauda)
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Identification: Length to 15"
— Distinguished by the extended and protruding eyes widely separated set forward on top of head.
— Head large and broad and somewhat flattened.
— Numerous rows of photophores on head and along body.
— Scaleless body, purple-bronze above, yellow-white below.
Range and Habitat: From Alaska to Baja California.
— Over sand and mud.
— Depth to 200 fathoms.
Comments: Comes into shallow water during the late spring to spawn. At this time the males make a
humming, or"singing" noise to call females for mating. This noise is loud enough to disturb residents on
houseboats in the Sausalito harbor.
— Eggs are deposited in crevices and hard surfaces
— The male becomes emaciated while guarding the eggs and young, so that the mortality rate among
egg-tending males tends to be high.
— The photophores sometimes flash when caught by a fisherman.
— Feeds at night on other fishes and crustaceans
Plainfin Midshipman (Porichthys notatus)
Identification: Length to 16" Extremely compressed.
— Eyes on left side.
—Eyed side brown, with darker brown mottling and sometimes dull orange spots. Blind side off-white
to pale brown
— Dorsal fin origin over eyes. anal fin origin bellow pectoral fin.
— Anal and dorsal fins extend almost to tail.
— Lateral line straight.
Range and Habitat: Baja California to Alaska
— On sandy bottoms at depths of 10 to 100 fathoms, occasional specimens occur in shallower water.
Comments: Feeds on a wide range of small fishes, squids, crustaceans, and other invertebrates.
— Spawning takes place during summer and early autumn.
— Each female probably spawns more than once in a season.
— Can change body color to match the sand it is resting on.
Pacific Sanddab (citharichthys sordidus)
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