The Aquarium of the Bay is conveniently located next to PIER 39 at The Embarcadero

25 Jun The Aquarium of the Bay is conveniently located next to PIER 39 at The Embarcadero

Question
Biology 1B

Aquarium of the Bay Field Trip – 20 Questions by Dr. McCray

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Getting There
The Aquarium of the Bay is conveniently located next to PIER 39 at The Embarcadero and Beach Street in San
Francisco’s Fisherman’s Wharf. The Aquarium is usually open 10am to 6pm Monday through Thursday, and 10am to
7pm Friday through Sunday. You should receive one free student ticket (courtesy of the Aquarium’s Partners for
Higher Education Program) from your instructor. Additional tickets can be purchased for $16.50 (adults) or $8
(children ages 3-11 and seniors 65+). For the latest information on hours and tickets refer to the Aquarium of the Bay
website: http://www.aquariumofthebay.com/
If taking Public Transit, visit www.511.org to get directions. The F Line (MUNI) stops right across the street from
the Aquarium entrance.
These are Mapquest instructions assuming you are driving from Merritt College:
Take I-580 W toward San Francisco/Berkeley
Take I-80 W toward San Francisco.
From I-80 take the Fremont St exit. Keep right at the fork and follow signs for Folsom St.
Turn left at Folsom Street.
Turn left at The Embarcadero.
Public parking facilities are available across from the main entrance at the PIER 39 garage. The garage is open 24
hours a day, 7 days a week. Please note that Aquarium of the Bay does not validate parking, but many PIER 39
restaurants do. The Parking Rate is $7 per hour without validation. If you validate your parking stub at one of the
nearby stores or restaurants then you can get one hour discounted.
BRING THIS HANDOUT AND YOUR LAB NOTEBOOK!
Read through this entire handout before you arrive to the Aquarium, since completing the activities described will
require that you look for many things on display at each of the various tank exhibits. The handout addresses five
general topics:
I. CHARACTERISTICS OF THE SAN FRANCISCO BAY
II. INVERTEBRATES
III. FISH
IV. UNIQUE ADAPTATIONS OF CHONDRICHTHYES
V. TO EAT OR NOT TO EAT

I. CHARACTERISTICS OF THE SAN FRANCISCO BAY
The displays for this topic are located on the top floor not far from the Aquarium entrance.

Activity/Question 1: Use the computer panel in the National Marine Sanctuary display to describe these San
Francisco Bay characteristics. Write your descriptions in your laboratory notebook.
Depth.
Temperature.
Size of Watershed.
Visibility.
II. INVERTEBRATES

Invertebrates are “animals without backbones.” Almost 2 million identified species are invertebrates, accounting for
more than 98 percent of the animal kingdom. They live in an incredibly diverse range of habitats both on land and in
water. Among the more recognizable marine and coastal invertebrates are octopus, squid, lobster, crabs, clams,
scallops, starfish, sea worms, corals and anemones. While invertebrates are remarkably diverse animals, there are two
basic body plans. Those having radial symmetry (corals and anemones) are rounded bodies arranged around a central
mouth. These animals typically spend their lives in one place (sessile) and wait for food to come to them. Those having
bilateral symmetry are those with two halves that mirror each other, with a distinct front and back. Bilateral symmetry
characterizes most invertebrates. They can have several pairs of eyes and other specialized organs that can smell, touch
and taste. Crabs and squid are good examples of bilaterally symmetrical invertebrates.

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Aquarium of the Bay Field Trip – 20 Questions by Dr. McCray

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Echinoderms. The word "echinoderm" means "spiny skin" in Latin, as most of them have spines or bumpy, rough
skin. Animals that belong to this Phylum include sea stars, sea urchins and sea cucumbers.
Cnidarians. The word "cnidarian" means "stinging cells" in Latin, as most of the members of this group are able to
sting and have tentacles. Animals that belong to this Phylum include sea anemones, jellyfish, and corals.
Cnidarians have radial symmetry and a single body opening that serves as mouth and anus. There are two body forms,
the medusa and the polyp. A polyp is almost plant-like in its form and is usually sessile, attached to the surface of
something hard (a rock, pier piling, or another animal). A sea anemone is a typical example of a cnidarian polyp
form. A medusa form describes a drifting or swimming (motile) bell shape. A typical example of a medusa is the
jellyfish. Some cnidarians spend portions of their life cycle in both types of body forms.
Arthropods. The word "arthropod" means "jointed appendage" in Latin, as they have legs that have joints. Arthropods
make up the largest phylum of animals, with about one million known species and many more yet undiscovered. To
put things in perspective: of all the animals on Earth, three out of four are arthropods! Arthropods can
generally be identified by the following characteristics: a segmented body; bilateral symmetry; jointed appendages;
and a hard external skeleton or exoskeleton. The majority of marine arthropods are crustaceans (they belong to the
subphylum Crustacea). This group includes well known arthropods such as shrimp, crabs and lobsters, as well as
lesser known animals such as copepods and krill (both important forms of plankton). The majority of arthropods at
Aquarium of the Bay include crabs and barnacles. These animals are highly adapted to living in the San Francisco Bay
because they can handle lower salinity water typical of an estuary such as the Bay, high currents, and murky water.
Many of these animals have low profile bodies, so they can usually hide in the sand or mud, or live clinging to another
object such as a rock or a pier piling.
Molluscans. The word "mollusca" means "soft bodied" in Latin. Animals that belong to this Phylum have soft bodies
often protected by a hard shell. This group includes snails, mussels, clams, chitons and octopus.

Activity/Question 2. Construct a table in your notebook listing the four major invertebrate groups described
above. For each phylum list one representative you found in the aquarium, describe the habitat where you found it,
whether it is sessile or motile, any activity you observe taking place, and any other interesting things of note about
that species.

Table headings to include in your notebook. Leave plenty of space for your notes:
Name (if available, if not then
Your
Sessile? Motile?
Behavior
describe the animal)
Drawing

Special Notes
(optional)

III. FISH
Behavioral Adaptations: Schooling
Some schooling fish are on display in the first exhibit tank (circular display). However, you may find it easier to
answer these questions after you have seen the schooling behavior in the “Under The Bay” tanks, where there is more
room for fish to swim.
The word “fish” covers a huge diversity of animals that have been on Earth for more than 500 million years and range
in size from finger-length minnows to 45-foot whale sharks. There are thought to be more than 20,000 species of fish.
The Pacific Coast is home to over 900 species from the Gulf of Alaska to Baja California. There are three main groups
of fish – bony fish of class Osteichthyes (for example perch and carp), cartilaginous fish of class Chondrichthyes
(including sharks, skates, and rays) and jawless fish of superclass Agnatha (lampreys and hagfish). All fish are
members of Phylum Chordata, Subphylum Vertebrata.
A school is defined as a group of fish mutually attracted to one another and usually includes fish of about the same
size. Schooling is a common social behavior pattern among fish; 25% of all fishes school throughout their lives and
half of all fishes spend at least part of their lives in schools. Schooling behavior increases in situations where they are
vulnerable to capture in large numbers. It is believed that fish use touch or lateral line receptors (for sound and water
movement) and visual cues to maintain their position in a school.

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Aquarium of the Bay Field Trip – 20 Questions by Dr. McCray

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At the Aquarium of the Bay you will see at least two displays featuring schooling fish. One of them is the central
cylindrical aquarium – the first tank exhibit encountered near the aquarium entrance. Take a look at these schooling
fish on display. Later you will have another opportunity to watch schooling fish as you proceed downstairs to the
“Under the Bay” tanks.
Here are some interesting facts to consider regarding schooling:
Fast-traveling schools assume a wedge shape, while feeding schools assume a circular shape.
Fish that move as a single unit are called “polarized” schooling fish. Those that tend to swim in a less compact
shape are “non-polarized.”
Most schools break up at night.
Similar behavioral strategies are found among terrestrial animals known to form “herds.”
Here are some possible advantages proposed for schooling behaviors:
Hydrodynamic efficiency. Fish may gain some advantage from the vortices of other fish. Fish produce a slime
coat to protect their skin. Accumulated slime in the water between members of the school may also help to reduce
drag. (Drag = slowing due to friction or turbulence.)
Reduced risk of predation. This may be particularly so if the group engages in complicated evasive maneuvers
while swimming in a school.
Increased efficiency of food finding.
Increased reproductive success. It is much easier to find a mate if you’re already in a large social group!
Predators that attack schooling fish are known to employ some of these strategies:
Attack at low light levels
Swim along with the school and grab fish that make swimming errors, get separated from the school or are
sick/injured.
Fish predators swimming in schools have better success in catching schooling fish for the same reasons a school of
plankton-eating fish have better success catching plankton. It is not uncommon for a school of predators to drive
the school of prey to the surface, where the prey are also vulnerable to seabirds from above.

Activity/Question 3: Write the common name (or, if not available, write a description) of two fish at this
aquarium engaging in schooling behavior. (Write this into your laboratory notebook.)
Activity/Question 4: Many schooling fish tend to be silvery. What may be an advantage to this?

Activity/Question 5: Describe the shape of the school formed by this species. Does the school swim in a
consistent way or does it seem to change often in its configuration and direction? (Write this into your laboratory
notebook.)

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Aquarium of the Bay Field Trip – 20 Questions by Dr. McCray

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Morphological Adaptations of Fish: BODY
The displays for this topic are located in various tanks on both floors of the Aquarium of the Bay.
There is great diversity of fish habitats and a great diversity of evolutionary adaptations that allow fish to thrive in
these habitats. Yet all fish are still visibly identifiable as fish. Before you proceed to the tanks be sure you have
acquainted yourself with terms that describe the morphology of fish. The following pages will require you to make
detailed observations of morphological and behavioral adaptations of fish for feeding, defense, and reproduction.

Figure 1. Two types of fish bodies: mid-water fast swimmer (left) and bottom dweller (right).
Flatfish (shown in Figure 1, right) are born upright like most fish. As larvae they swim upright and their eyes are
located on either side of the head. During development, one side of the body becomes the top while the other side
becomes the bottom, and one of the eyes migrates from one side of the head to the other so that both eyes are on the
top. Typically the “eye side” will be cryptically colored (camouflaged) while the belly side is pale. The mouth may
develop a twist in some species, perhaps to make feeding easier. Many of the over 500 species of flatfish are
important to commercial fisheries. Flatfish families are organized by; 1) which side of the body their eyes are found
(left or right), and 2) whether or not they have large teeth. Species of flatfish vary greatly in size. For example, while
many species are smaller than the size of your palm, the largest Halibut can weigh over 600 pounds.

Activity/Question 6: Write down the name (or, if not available, describe in your own words the appearance)
of two species of flatfish seen at the Aquarium of the Bay. Note where in the tank you found it, and on what side
of its body the eyes are located (right or left). Write your answers into your laboratory notebook.

Biology 1B

Aquarium of the Bay Field Trip – 20 Questions by Dr. McCray

Figure 2. Body forms in fishes: a) elongate, fusiform or basslike; b)
anguilliform, eellike; c) ovate or truncated; d) compressiform, thin, narrow,
deep or perchlike; e) depressiform or flattened; and f) hemispherical or
globiform.

Figure 3. Various shapes of the caudal fins of bony fishes. Caudal fins are the
“engines” of the fish: a) indented; b) rounded; c) double truncate; d) square;
e) forked; f) pointed with fin present; g) pointed with fin not differentiated;
and h) naked, without rays on tip.

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Aquarium of the Bay Field Trip – 20 Questions by Dr. McCray

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Figures 2 and 3 in this handout provide illustrations for terms used to describe body and fin shapes. Those terms are
repeated in tabular form here but you should make sure to consult those illustrations to reacquaint yourself with the
shapes and structures so you can answer the questions that follow.
Terms to Describe Body Shape
Fin Terms
Terms to Describe Fin Shape
Fusiform
Pectoral fin
Indented
Anquilliform or Attenuated
Pelvic fin
Rounded
Ovate or Truncated
(thoracic or abdominal)
Double truncate
Compressed or Compressiform
Anal fin
Square, truncate or straight
Depressed or Depressiform
Adipose fin
Forked
Globiform or Hemispherical
Caudal or tail fin
Pointed with fin present
Finlets
Pointed with fin not differentiated
Dorsal fin
Naked, without rays on tip
Body Shape (Figure 2) allows you to predict the fish’s likely swimming style. Some fish swim at high speeds because
they either need to catch food, avoid predators, or to maintain their position in strong currents. Fast fish have
streamlined bodies resembling a torpedo shape, and tails that have a very narrow area to the base of the tail to
minimize drag (Figure 3). Fish that don’t need a burst of speed have evolved less streamlined bodies. The body of a
slower fish is typically deeper and flatter, ideal for maneuvering between plants. Fish with fatter and more rounded
bodies are more stable in fast flowing water.
Very fast swimming fish additionally have special fin adaptations including finlets and keels. Finlets (Figure 1, left)
are little median fins dorsally and ventrally that help to reduce drag. A keel is a lateral protuberance on the caudal end
that offers stability while swimming at great speeds. Since this is an aquarium that only specializes in fish found in the
San Francisco Bay, there are probably no fish here with finlets and/or a keel. Those are mostly found in pelagic (open
ocean) species such as tuna.

Figure 4. Terminology of various mouth and snout forms: a) lower jaw
projecting beyond the upper jaw, a surface feeder; b) a tubular jaw with
jaws at the tip; c) inferior, bottom-feeding mouth; d) swordlike beak; e)
terminal; and f) extended upper jaw with lower lip inferior.

Activity/Question 7. Write the name or, if not available, describe a fish that swims very quickly. Use the
terminology above to describe its morphology. Do the same for a slow-moving fish. Write all your observations
into your notebook.

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Morphological Adaptations of Fish: MOUTH/JAW SHAPE & POSITION
Mouth shape and position (Figure 4) can tell you a great deal about the type of prey items a fish will likely eat as well
as its mode of food capture.
Terminal: directly on the front of the body. This is typical of mid-water dwellers.
Inferior: overhanging – mouth opens ventrally. This is typical of bottom dwellers who eat foods on the benthos
(substrate).
Superior mouth: projecting lower jaw – mouth opens dorsally. This type of mouth suits fish who feed on items found
near the surface.
Tubular snout with jaws at the tip – consistent with “picker” style of feeding (like many reef fishes).
Barbels and “whiskers” are specialized fleshy structures near the mouth that assists in sensing prey items in the
benthos.

Activity/Question 8:
Copy the table headings below into your laboratory notebook, leaving ample space for drawings and notes of your
observations. You must locate 4 examples of the 8 fishes listed below and determine their body shape, mode of
swimming (propulsion fins), and mouth shape. Use those observed characteristics to make predictions about the habitat
and prey of the fish (small vs. large) in nature. Some information may be available on interpretive signs near the
display tanks. You can do more than 4 if you wish, and if time permits.
Table headings to include in your notebook. Leave plenty of space for your notes:
Name of Fish
Body Shape
Propulsion Fin(s) –
Mouth Shape
dorsal vs. caudal
fin
Pipefish
Wrasse
Some tropical fish (top floor
hexagonal tank) of your choice
Leopard shark
Cabezon or Rockfish
Bat ray
Halibut, Sole or Flounder (not
always visible)
Anchovy or sardine (whatever is
available)

Predicted habitat
and prey type

Fish Communication Using Colors and Patterns
The displays for this topic are located in various tanks on both floors of the Aquarium of the Bay.
The colorful fish found in the hexagonal tropical tank (top floor of the aquarium, not far from the entrance) are not
found in – or anywhere near – San Francisco Bay, but they provide contrast to illustrate how the species of the clear,
warm tropics rely on bright coloration and symbiotic relationships for protection from predators, whereas the species
of the murkier, colder waters of the Bay Area have evolved to use camouflage to avoid predation.
Fish communication involves visual signals of color, pattern and subtle movements of the body and fins.
Balance must be struck between the need to be visible for intraspecies communication (intraspecies means “among
members of the same species”) and the need to avoid detection by predators. Some noteworthy trends of fish
coloration and patterns follow:
Poster Colors. View the fishes occupying the hexagonal tropical tank, paying special attention to the bright colors
and dramatic patterns. These colorations are generally thought of as some kind of “territory advertisement.” But there
are other possible functions also. They may play roles in sex and courtship as signs of sex, status and maturity. Many
species with “poster colors” engage in a predator avoidance strategy called the “flash effect.” Predators can become

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confused if a poster colored fish first displays its broad side, but then as the fish suddenly turns its body to display its
more narrow profile it seems to “disappear” from the predator’s view. At least in a few of the fish known for their
poster colors they may just as easily be called examples of aposematic coloration. Aposematic coloration gives a
visual equivalent of telling predators “I am poisonous!” or “I’m too spiny for you to eat!”
Red Coloration. When viewing the fish native to the San Francisco Bay, you may notice some that display red
coloration. Red wavelengths are the first to get screened out as light enters the water. Red fish tend to be nocturnal or
live at depths where red light is pretty much absent from the water. This means that in their natural light levels (depth
or darkness) they are cryptic and blend in with their surroundings. For certain tidepool-dwelling fishes their red color
helps them blend in with surrounding red algae. In other locales, shallow-water freshwater fishes tend to limit the use
of conspicuous red markings to mating activities. In these cases the red stands out well when viewed from short
distances but the red markings become more difficult to see the further away the beholder is. It is commonly thought
that the short-distance viewing of red is great for displaying to potential mates while offering decent hiding from
predators further away.

Activity/Question 9: Name (if available) and sketch a fish exhibiting red coloration. If the information is
available, describe the natural habitat of this species. (Write this into your laboratory notebook.)

Activity/Question 10: Name (if available) and sketch a fish exhibiting poster colors. If the information is
available, describe the natural habitat of this species. (Write this into your laboratory notebook.)

Disruptive coloration. Colors and patterns disrupt the outline of fish to make them less visible. Many of these fishes
are found associated with aquatic plants. Vertical bars on the bodies of these fish probably help them blend in with the
vertical orientation of plants.

Activity/Question 11: Name (if available) and sketch a fish exhibiting disruptive coloration. If the
information is available, describe the natural habitat of this species. (Write this into your laboratory notebook.)

Camouflage. Slow-moving bottom fishes are able to match their backgrounds very well. Flounders, sole and halibut
are famous for this ability. In laboratory settings some of these fish can even do a decent job of matching the pattern of
a checkerboard.

Activity/Question 12: Look again at your drawings/descriptions of the flatfish. What anatomical adaptation
do you see in this fish that would give it an advantage in blending into its environment?

Countershading. Most fish display this. Being dark dorsally helps them avoid visual detection by predators attacking
from above, while being light ventrally helps them similarly avoid detection by those attacking from below.

Activity/Question 13. Look for countershading in specimens of the “Under the Bay” overhead tank display.
Name (if available) and sketch into your lab notebook one example of a fish that exhibits countershading.

Eye ornamentation. Fish can either disguise their eyes or make them more conspicuous. Eyes are a focus-point for
predators and are important in visual communication among individuals of the same species. There are two strategies
for eye ornamentation in fish:
Disguise the eyes. This is most common. Fish display pigmented lines that appear to cross the eye region.
These lines tend to run vertical on deep-bodied species but horizontal on slender-bodied species.
Emphasize the eyes. This is perhaps most obvious in reef fish that have lots of small crevices to hide in case
they are noticed by predators. Eyes are made more obvious through bright colors and in some cases eye rings.

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Aquarium of the Bay Field Trip – 20 Questions by Dr. McCray

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Activity/Question 14: Name (if available) and sketch a fish that features eye ornamentation to disguise the
eyes. If such a fish is available, name and sketch one fish that features eye ornamentation that emphasizes or
exaggerates the eyes. (Write this into your laboratory notebook.)

Eye spots. A large number of fish display dark spots that resemble eyes in shape and are surrounded by lighter
pigmentation to help these spots stand out. In many cases these “false eyes” are positioned at the base of the tail,
presumably to trick potential predators. These spots may also help in intraspecies communication also, such as during
schooling or courtship.

Activity/Question 15: Name (if available) and sketch a fish that features eye spots or “false eyes.” Hint: you
may find a good example from class Chondrichthyes somewhere in this aquarium. (Write this into your laboratory
notebook.)

Lateral stripes. Usually a single, midlateral band seen in schooling fishes. May help school members maintain their
position and confuse predators by making it harder to visually pick one out of the crowd.

Activity/Question 16: Name (if available) and sketch a fish that features lateral stripes. (Write this into your
laboratory notebook.)

Polychromatism. Different populations may feature certain color “morphs” such as gold vs. plain, bright vs. dull.
Brightly colored morphs may be preferred by potential mates, may be more aggressive in feeding, but may also be
more vulnerable to predators.
Special patterns. Some spots or patterns play a specific role in reproduction, as in certain cichlid fish. Cleaner fishes
on reefs tend to have special coloration to advertise their services. Some fish mimic the coloration of other fishes or
invertebrates.
Photophores. These are spots that produce light. They feature most prominently in mid- or deep-depth ocean dwellers.
Photophores may play roles in intraspecific communication and at least in some cases may help confuse predators
looking at them from below in the darkness.
IV. UNIQUE ADAPTATIONS OF CHONDRICHTHYES
The…