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Fish

Q: What are Fish?
Q: What distinguishes fish from the other animal classes?
Q: What Are Fish Farms?
Q: What are the two main classes into which fishes are divided?
Q: From which features do condrichthyes and osteichthyes get these names?
Q: What are the main features of fishes associated to the habitat where they live?
Q: Comparing to cyclostomes (primitive vertebrates) what are the main novelties presented by fishes?
Q: How different are the swimming strategies in osteichthyes and in chondrichthyes? Why do sharks need to agitate their body to swim while bony fishes do not?
Q: How does the swim bladder of fishes work allowing fishes to control their depth under water?
Q: How do fishes do gas exchange?
Q: Do fishes present an open or closed circulatory system? How many chambers does a fish heart have? How does blood flow throughout the fish body?
Q: How is excretion done in fishes?
Q: What are the lateral lines of fishes?
Q: How different are fecundation in osteichthyes and in chondrichthyes?
Q: Fish identity card. How are fishes characterized according to examples of representing beings, basic morphology, skin, respiration, circulation, nitrogen waste, thermal control and types of reproduction?
Q: How long have you been studying fish?
Q: Is life found at all depths in the ocean?
Q: How many fish species are there?
Q: Which is the oldest fish, as a class?
Q: What is the world's largest fish? The smallest?
Q: What is the most common fish in the sea?
Q: Do fish sleep?
Q: What is an anadromous fish? A catadromous fish?
Q: Why do scientists classify fish?
Q: How is the age of a fish determined?
Q: How long do fish live?
Q: Do some fish give birth to living young?
Q: Do fish breathe air?
Q: How do fish swim? How fast?
Q: Can fish swim backwards?
Q: Do all fish swim in the horizontal position?
Q: Do fish chew their food?
Q: Can fish distinguish color?
Q: Are all fish edible?
Q: How can poisonous fish be distinguished from edible ones?
Q: Are there any poisonous snails?
Q: Why do food fish sometimes have a strong odor?
Q: Is there much salt in fish?
Q: What is the blood-like material found along the backbone in the body cavity of most fishes?
Q: What is the true description of a sardine?
Q: How many kinds of tuna are there, which kind makes up the biggest catch?
Q: Do tunas have scales?
Q: Are saltwater catfish good to eat?
Q: What is the fish listed as "scrod" in New England restaurants?
Q: What are menhaden?
Q: Where are Atlantic menhaden spawned, where do they go after hatching?
Q: What do herring eat?
Q: Are the eyes of flatfishes on the right or left side?
Q: Has any kind of marine or ocean dwelling fish been successfully transplanted from coast to coast in the United States?
Q: How large do ocean sunfish get?
Q: How do porcupine fish inflate themselves?
Q: What is an "exotic" fish?
Q: What fishes are named after other animals?
Q: What kind of fish is a "Bombay Duck"?
Q: How much electricity does an electric eel generate?
Q: What are moray eels and where are they found?
Q: What is pearl essence?
Q: What is the sand collar that one often sees on beaches at low tide?
Q: What is chitin?
Q: What are some confusing fish names?
Q: Why is fishing sometimes called angling?
Q: What is the biggest bivalve mollusk, cephalopod mollusk, and crustacean known to man?
Q: Will fish I catch and release die anyway?
Q: What are factory ships?
Q: Where can I find out about maintaining aquariums?
Q: What is the largest Largest sturgeon on record?
Q:Where can I learn more about endangered species?
Q:What exactly is Persistent Marine Debris, and why is it important?
Q:Are there any good field guides to marine mammals available?

Salmon FAQs

Q: How many species of Pacific salmon are there?
Q: Is it true that salmon return to spawn in freshwater areas where they were born?
Q: what is the difference between the Atlantic salmon and the Pacific salmon?
Q: Are steelhead (rainbow trout) trout or salmon? Q: Where do salmon go in the ocean?
Q: What is a kokanee, or silver trout?
Q: Do landlocked Pacific salmon die after spawning?
Q: How large do salmon get?
Q: What is the oldest known age of salmon and steelhead (in completed years)?
Q: Is a steelhead a salmon or a trout?
Q: How old are salmon when they migrate from fresh water to the ocean?
Q: How many eggs do salmon have?
Q: What are salmon fed in a hatchery?
Q: How many of the young salmon released from hatcheries come back as adults?
Q: Why are fishladders constructed?

Lobster FAQs

Q: How many kinds of lobsters are there in this country, why are different varieties called lobster?
Q: Does the deepwater northern lobster population differ from that found just off the coast?
Q: How far do lobsters travel?
Q: What color is a lobster's blood?
Q: What is "tomalley"?
Q: What is the coral colored material often seen in a cooked lobster?
Q: How does a lobster grow?
Q: How many times must a lobster molt before it reaches market size?
Q: How old is a one-pound lobster?
Q: How many one-pound lobsters are needed for a pound of lobster meat?
Q: How long can a lobster live out of water?
Q: Can a lobster be kept alive in fresh water with ice?
Q: Why does a lobster turn red when cooked?
Q: How can one tell if a boiled lobster was alive when cooked?
Q: Have people been poisoned by eatlng lobsters that were allowed to die before being cooked?
Is it true that a dead lobster deteriorates very rapidly?
What happens when a live lobster is frozen?
Q: Is it possible to raise lobsters on a commercial basis?
Q: What are some other names for lobsters?
Q: Where are lobsters caught?
Q: What do lobsters eat?
Q: How is the health of the lobster resource?
Q: Where do lobsters live?
Q: When do lobsters mate?
Q: Are lobsters different colors?
Q: Can lobsters grow new legs?
Q: Do lobsters have teeth?
Q: Can lobsters smell their food?
Q: Do lobsters lay eggs?
Q: Do many young lobsters survive to old age?
Q: What is the largest lobster ever caught?
Q: If a lobster gets in the trap first does it chase crabs out?
Q: Have Maine lobsters been successfully transplanted to the west coast?
Q: I've heard that lobsters molt, but I've never seen a cast-off shell. Why?

Crab FAQs

Q: Can crabs swim?
Q: How do crabs grow?
Q: How much does a blue crab increase in size on molting?
Q: What is the difference between soft and hard shell crabs?
Q: How old does a blue crab get?
Q: What is a "coconut crab"? Where do they live?
Q: Is a stone crab harmed when its large claw is broken off?
Q: What are the small crabs found inside oysters?
Are they harmful to oysters?
May humans eat them?

Shark FAQs

Q: Can shark meat be used as food for humans?
Is it true that the meat of the hammerhead shark is poisonous?
Q: Is the blue shark really blue?
Q: What attracts sharks? Which are most dangeous?
Q: What sea creatures other than sharks may be dangerous to swimmers?
Q: Do sharks have bones?
Q: Do sharks have good eyesight?
Q: Are sharks always hungry?
Q: Are sharks considered to be a fish?
Q: Do sharks only eat meat?
Q: How many senses do sharks have?
Q: If sharks have cartilage instead of bones how can they fossilize?

Shrimp FAQs

shrimp shrimp shrimp
Q: How do prawns, crayfish, and shrimp differ?
Q: Is there more than one kind of shrimp?
Q: How big do shrimp grow?
Q: How long do shrimp live?
Q: How many eggs does a shrimp produce in one spawning?
Q: How much shrimp is produced in the United States, where is the largest catch taken?
Q: What are the commercially important shrimp on the east coast of the United States, what are their ranges?

Shellfish FAQs

Q: What do oysters and clams eat?
Q: Clams seem to squirt water through their siphons. What purpose does the siphon serve?
Q: What causes a reddish color in the liquor of shucked oysters and clams?
Q: How does the consumer know that shellfish are safe to eat?
Q: How does a clam shell grow?
Q: How do clams establish themselves on the sea bottom?
Q: How do clams reproduce?
Q: How are soft-shell clams harvested?
Q: How are scallops caught?
Q: What is the biggest clam caught and eaten in the United States?
Q: What are oyster borers?
Q: How do oysters produce pearls?
Q: What is oyster spat?
Q: Is it safe to eat oysters during the months without R's?
Q: How does a scallop move?
Q: What purpose do the holes along the edge of an abalone shell serve?
Q: How unsafe are shellfish from polluted waters?
Q: Will cooking make sewage-polluted shellfish safe to eat?
Q: Is it possible to purify shellfish from sewage polluted water for safe eating?
Q: Do shellfish contain mercury levels dangerous to man's health?

Cetacean FAQs

Q: What is a cetacean?
Q: How many species of cetaceans in U.S. waters are protected?
Q: How big is a Blue Whale?
Q: What does a Bowhead Whale eat?
Q: What is the 2nd largest whale?
Q: Which whale would I most likely see whale watching?
Q: What makes the right whale right?
Q: Do any whales have teeth?
Q: What do whales eat?
Q:How many young does a whale give birth to at one time?
Q:What are the main threats to whales these days?
Q:Where do harbor porpoise live?

Pinniped FAQs

Q:What are Pinnipeds?
Q:How many Pinnipeds are on the Endangered Species List?
Q:Are Hawaiian monk seals coming back?
Q:How many Caribbean monk seals are left?
Q:How are Steller Sea Lions doing?
Q: What is is the rarest of all sea turtles?
Q: Do turtles get stranded like whales?
Q:How long can sea turtles stay underwater?
Q:Where do sea turtles breed?
Q:Are sea turtles endangered?
Q:Where does the green sea turtle live?
Q:What is the major cause of the continued decline of of the hawksbill sea turtle?
Q:What is the largest sea turtle?
Q:What is a Turtle Excluder Device (TED)?

1. Fish are ectothermic, aquatic vertebrates.
2. Their skin is generally covered with scales.
3. Their limbs are modified into fins for swimming.
4. They breathe with gills.
5. They lay eggs that must be in water.

You probably knew most of this already, didn't you? The term "ectothermic" may be new to you. It means "external temperature" in Latin. The simpler term is "cold-blooded", that is, it has a body temperature equal to the surrounding environment. You know that fish are cold-blooded if you ever picked one up: they are as cold as the water they were swimming in. Even if you go swimming and are shivering with cold, you are always warmer than the water.

Fish are vertebrate animals that live in water, have streamlined. muscular bodies, and are cold-blooded. Most fish breathe using gills.

There are three classes of fish:

* Class Agnatha (jawless fish) - these primitive fish have no jaws, do not have paired fins, and have a skelton made of cartilage (not bone). Examples: hagfish, lampreys.
* Class Chondrichthyes (cartilaginous fish) - these fish have a skeleton made of cartilage, paired fins, and no swim bladder. Their skin has tooth-like scales (called denticles). Fertilization of eggs is internal. Examples: sharks, skates, rays.
* Class Osteichyes (bony fish) -these fish have a skeleton made of bone and paired fins. They also have teeth that are fixed onto the upper jaw. They have a swim bladder (an air filled sac that helps them with buoyancy) that opens into the gullet. Bony fish do not have to swim to breathe (to push water through the gills). Most fish are bony fish.

Fish Farming

What are Fish?
Fish are aquatic vertebrates (animals with backbones) with fins for appendages. They "breathe" by means of gills.
Fish make up the largest of the vertebrate groups with well over 20,000 species. Most taxonomists recognize 45 orders and 435 families of bony fishes. They can be found in a great variety of habitats in lakes, streams, oceans and estuaries.

What distinguishes fish from the other animal classes?
Fish are a class of aquatic vertebrates. The combination of gills, fins and the fact that they live only in the water make fish different from all other animals.

Fish spend all of their lives in the water and are cold-blooded with the exception of Tuna family and the Mackerel shark family.

What Are Fish Farms?
Fish farms are factories where fish are produced in much the same way that cattle or potatoes are produced on other farms.

1. What are the two main classes into which fishes are divided?

Fishes are divided into two main classes: chondrichthyes, fishes with cartilaginous skeletons (sharks, rays, dog-fishes), and osteichthyes, bony fishes (tuna, sardines, salmons).

2. From which features do condrichthyes and osteichthyes get these names?

“Chondros” means cartilage, “ictis” means fish (both from the Greek); the name chondrichtians is for fishes with cartilaginous endoskeleton. The name osteichthyes comes from the existence of a bony endoskeleton in these fishes (“osteo” means bone, from the Greek too).

3. What are the main features of fishes associated to the habitat where they live?

Fishes are all aquatic animals and thus they have a hydrodynamic elongated body suitable to move under water, without limbs and with fins. The habitat conditions the branchial respiration too.

4. Comparing to cyclostomes (primitive vertebrates) what are the main novelties presented by fishes?

Compared to cyclostomes, evolutionary novelties presented by fishes are: pectoral and pelvic fins, symmetric and paired; the presence of mandibles.

5. How different are the swimming strategies in osteichthyes and in chondrichthyes? Why do sharks need to agitate their body to swim while bony fishes do not?

Bony fishes have a specialized organ called a gas bladder, or swim bladder, whose interior can be filled with gas liberated from gas glands. The swim bladder works as a hydrostatic organ since it varies the relative density of the body regulating buoyancy and the depth of the animal in water.

Chondrichthyes do not have swim bladders and thus they must continuously agitate their body to keep swimming and maintain their depth in water. As an additional swimming aid, in chondrichthyes the liver is big and oily; this feature helps to reduce their body density relative to water.

6. How does the swim bladder of fishes work allowing fishes to control their depth under water?

From Hydrostatics it is known that an object does not sink if its density is equal or less than the density of the fluid in which it is immersed.

When the swim bladder is filled by gas it reduces the density of the fish body and when it is emptied this density is increased. So this mechanism controls the fish depth under water.

7. How do fishes do gas exchange?

Fishes “breath” through gills. Gills, or branchiae, are highly vascularized organs specialized in gas exchange under water and present in aquatic animals (marine annelids, crustaceans, fishes and tadpoles). Gills are a respiratory organ (analogous, for example, to lungs) containing very thin lamellae with many apparent blood vessels in direct contact with water.

In osteichthyes the gills are covered by a bony flap that protects them called operculum. In chondrichthyes there are no opercula.

8. Do fishes present an open or closed circulatory system? How many chambers does a fish heart have? How does blood flow throughout the fish body?

As in every vertebrate the circulatory system of fishes is closed, i.e., blood flows only within blood vessels.

The fish heart has only two consecutive chambers: a thin-walled atrium and a muscular ventricle. The arterial (oxygenated) blood comes from the gills and gains arteries towards tissues, then venous blood is collected by veins and reaches the atrium of the heart passing to the ventricle that pumps the venous blood towards the gills to be again oxygenated.

9. How is excretion done in fishes?

Fishes have a pair of kidneys that filtrate the blood. Bony fishes excrete nitrogen as ammonia, NH3, (they are ammoniotelic) and cartilaginous fishes excrete urea as nitrogen waste (they are ureotelic, like adult amphibians and mammals).

10. What are the lateral lines of fishes?

The lateral lines of bony fishes are sense organs that extend along both sides of the animal body. They make contact with the environment by a series of specialized scales that transmit information about pressure variation and vibrations in the surrounding water.

11. How different are fecundation in osteichthyes and in chondrichthyes?

In chondrichthyes fecundation is internal by means of copulation. In osteichthyes fecundation generally is external and the gametes are released in the water, where they can fecundate their counterpart and form the zygote.

12. Fish identity card. How are fishes characterized according to examples of representing beings, basic morphology, skin, respiration, circulation, nitrogen waste, thermal control and types of reproduction?

Examples of representing beings: sharks, rays, sardines, tuna, salmons. Basic morphology: hydrodynamic body, fins; cartilaginous skeleton in chondrichthyes, bony skeleton in osteichthyes. Skin: with scales in osteichthyes and placoid scales in chondrichthyes. Respiration: branchial. Circulation: closed, incomplete, heart with two chambers. Nitrogen waste: urea in chondrichthyes, ammonia in osteichthyes. Thermal control: heterothermic. Types of reproduction: sexual, internal fecundation in chondrichthyes, external in osteichthyes.

http://www.enchantedlearning.com/subjects/fish/printouts/

http://www.nefsc.noaa.gov/faq/

http://www.newworldencyclopedia.org/entry/Fish