Finding Nemo Viewing Guide Some of the Animals Who Appear in the Movie Clownfish -- Nemo and Marlin belong to one of about 27 species of clownfish (Amphiprion ocellaris ). Clownfish are small and often brightly colored. They belong to the damselfish family. They are 2 - 5 inches (5 - 12.5 cm) long. They live in tropical waters. Clownfish are often sheltered by an anemone with whom they have a symbiotic relationship. In fact, most of the scientific literature refers to them as "anemone fish." Clownfish are not immune to the poison in the anemone's tentacles and at first appear to be stung by them. Scientists believe that by dancing up against the tentacles for a time clownfish develop a protective mucous covering. Clownfish eat leftovers from fish consumed by anemone, planktonic crustaceans, and algae. Clownfish also eat the dead tentacles of their host anemone. Eggs are laid in large batches, usually near and sometimes within the host anemone. Clownfish are not eaten by man but their bright colors make them popular for saltwater aquariums. Divers have damaged many reefs looking for prime specimens. Clownfish live in the tropical parts of the Pacific and Indian Oceans or where warm, tropical waters are carried by currents, such as the east coast of Japan. Pacific Blue Tang -- Dorey's real life models ( Paracanthurus hepatus ) are members of the surgeonfish family. They were given this name because sharp, moveable spines on both sides of their tails were thought to resemble surgeons' scalpels. These spines are for defense. A fisherman trying to hold a blue tang can suffer a deep and painful wound if the fish tries to escape by giving a twist of its tail. The fish are blue with a yellow tail and a black stripe along the upper portion of their body. They live on zooplankton and can grow to be about 12 inches (31 cm) long. Pacific blue tangs are found in the central and Indo-Pacific from Africa's east coast to Micronesia. A different species of surgeonfish, found in the Atlantic Ocean and without a yellow tail, is also called a blue tang. It eats only algae. Loggerhead Sea Turtles -- Usually about 3 feet (1 m) in length and weighing 350 to 400 pounds (182 kg) loggerhead sea turtles (Caretta caretta ) reach maturity at between 16 and 40 years. Sightings of 5 foot long turtles weighing as much as 1000 pounds have been recorded. Loggerheads mate in late March through early June. Eggs are laid throughout the summer in shallow pits dug in open beaches. After laying her eggs the female turtle covers them with sand and leaves. Biologists are not sure where juvenile turtles grow, but it is thought they inhabit floating islands of seaweed where they feed and grow to young adult size. Loggerheads live in most of the tropical and temperate coastal waters around the globe. They are, for example, the most common turtles in the Mediterranean, in the oceans around the U.S., and in the coastal ocean waters of Brazil etc. In the Atlantic, their range is from Newfoundland to Argentina, including the Gulf of Mexico, and Caribbean Sea. Their major nesting beaches in the United States are in South Carolina, Georgia, and Florida. The loggerhead is named for its disproportionately large head (when compared with other turtles), which may measure 9 inches wide (25 cm). It has a heart- shaped reddish brown shell. The usual life span is 30 - 50 years. Loggerheads have powerful jaws designed to crush shellfish. They eat mollusks, such as shrimp, horseshoe crabs, blue crabs, clams, and mussels. They also eat invertebrates and some types of sea grasses. Loggerheads can see well underwater and are believed to have an acute sense of smell. They breathe air and when active must swim to the surface after a few minutes. When they are resting, they can remain underwater for as long as two hours. Loggerheads migrate the breadth of the Pacific Ocean, often traveling along ocean currents. Loggerhead turtles are a threatened species. Their population has declined as they drown in fishing nets and as land animals, such as raccoons, cats, and dogs, prey upon their eggs. Development also harms turtles by encroaching upon their beaches and confusing the innate directional signals of hatchlings. Concepts from Biology The term the food chain describes the fact that each living creature survives by feeding on plants or other animals. Plants or other autotrophic organisms are always the base of the food chain. The heterotrophs that eat the plants are one trophic level or link up the food chain. When the plant-eating animal is killed and eaten by another animal, it is said that the animal that is eating is higher on the food chain than the animal being eaten. In the ocean the base of the food chain is phytoplankton or algae that live near the surface of the water (to get maximum sun) and carry out photosynthesis. The term "plankton" comes from the Greek word "planktos" which means "drifting." Phytoplankton encompass microscopic organisms to seaweed. Phytoplankton are eaten by small fish and by zooplankton , a class of plankton-eating microscopic organisms that include single celled protists, larvae of larger animals, and tiny crustaceans. The zooplankton are then eaten by small fish and some whales. The small fish are eaten by larger fish and those are eaten by even larger fish and so on up the food chain. A species is at the top of its food chain if there are no animals who kill and eat it regularly. For example sharks, lions, human beings, and elephants are said to be at the top of their food chains. Whales were at the top of their food chain until man started to hunt and kill them. An animal that catches another animal and eats it is called a predator. Most fish are predators. Predators must have some advantage over their prey , the animals they eat, in order to capture them. For example, the predator must be faster or must use surprise and ambush. Some predators just sit and wait. Stonefish and scorpion fish are covered with small patches of bright color that look like a colony of algae . The rest of their body is camouflaged to look like the sea floor. Small fish come to eat the algae not recognizing the larger outlines of the predator. Corals are also predators that sit still and wait for their prey. Their tentacles have a poison that kills or injures its prey and draws it into the coral's mouth. Some predators, such as the moray eel, hide in holes or tunnels in the coral reefs and ambush their prey as it swims by. There are as many different strategies for catching prey as there are predators in the ocean. The most efficient and fearsome predator of all is man who, through livestock raising, fish farming, hunting and fishing, preys upon more species than any other animal. Most species in the ocean are also prey to other animals. Corals, for example, are eaten by parrotfish, butterfly fish and a starfish called the crown of thorns. In one day, a single crown of thorns starfish can eat all the coral polyps in an area the size of a dollar bill. Most species that are prey to others also have strategies to A fish with eyespot avoid being captured. These include speed, diversionary markings camouflage , disruptive patterns (which break up the outline of a fish and make it harder for predators to see it) and eyespots (markings on various parts of the body that look like eyes which take attention away from the fish's head), counter- shading, in which the fish looks dark on top and light on the bottom (contrary to what other fish expect in an environment in which light comes down from the surface of the water), hiding, schooling, and dispersal. Dispersal means having many young and dispersing them over a wide area so that some will survive to carry on the species. Often, the defenses employed by prey animals are aimed at preserving the species rather than individual members of the species. Just as predators employ many different strategies for catching prey, there are many different strategies for avoiding capture. Scavengers are creatures who keep the environment clean by eating the flesh and bone that predators leave behind. Scavengers don't usually kill their own prey. In the ocean, scavengers such as shrimp, crabs, and sea cucumbers keep the ocean floor clean by eating bits and pieces of fish that the predators leave behind. All animals constantly interact with other animals and plants. Some of the different types of relationships are: symbiotic, commensal, parasitic and predatory. Symbiosis occurs when two different animal species help each other. Here are just a few examples. (1) Clownfishes live within the stinging tentacles of anemones. The anemone provides protection and food for the clownfish who in turn cleans the anemone of debris. Clownfish may even swim out onto the reef and with their bright colors lure other fish to their host anemone to be stung and trapped in the tentacles. (2) When a hermit crab carries an anemone on its shell, little fish won't bite the hermit crab for fear of being poisoned and eaten by the anemone. The anemone gets a free ride to places in which it can find new sources of food. (The hermit crab knows that the anemones protect it. When the hermit crab changes its shell, it will stroke the anemones on its old shell to get them to move to the new shell.) (3) Several types of fish clean the bodies of other fish, eating parasites and dead scales.