Life in the Sea Member Manual1
Neil Crenshaw and Bill Clifton2
Life in the Sea Member Manual (4H MEM 30) is a project guide is for 4-H members ages 10 and up. 4-H'ers will learn about dolphins, manatees, seals and sea lions, penguins, treasures from the sea, Caribbean / Atlantic coast tide pool, and coral reefs. In addition to this project guide 4-H'ers can complete the accompanying record book (4H MER 02).
In EDIS this publication is DLN 4H 187.
Visit the 4-H Youth Development Curriculum Web Site for more information on related project materials.
Click here to print or view the entire project.
Foreword for the Leader
Because of many requests for marine science projects from those counties located in the central part of Florida, we realized a need for some type of 4-H marine activity in that area of the state. 4-H Agents and volunteer leaders were having to drive many miles so their 4-H'ers could engage in marine activities.
Sea World, located in the central part of Florida, has a tremendous resource of information, exhibits and personnel relating to marine science education and seemed a good source to tap.
Sea World agreed to help develop and organize a 4-H Marine Education Project activity series that could be conducted on the grounds of Sea World or at any other oceanarium in Florida. The title Life in the Sea was chosen for this 4-H project.
The Life in the Sea Project contains seven activities which can be started by visiting an oceanarium and finished through club work or individual research at home or in a library. It is not necessary to visit Sea World in order to begin or even complete the project or any of its activities. Many of the activities in this project can be done by visiting any of the aquaria located throughout Florida such as Marineland south of St. Augustine, Seaquarium south of Miami, Ocean World in Ft. Lauderdale or Gulfarium in Ft. Walton Beach.
It is suggested that before you visit any oceanarium to work on this project with a group of 4-H'ers that you first contact the particular oceanarium's public relations office. In the case of Sea World in Orlando, you should contact the Florida 4-H marine education specialist in Gainesville, Florida so your visit can be scheduled.
This project also has a Life in the Sea Project Record for 4-H members (4-H - 359) and a Leader's Guide (4-H - 358).
We gratefully acknowledge the assistance of Dr. Jim Northrop and B. J. Allen, 4-H Staff, for reviewing this publication, Steve Shippee, of Florida's Gullarium for reviewing the penguin activity, Roger Tory Peterson for his penguin drawings, the U. S. Fish and Wildlife Service for their drawing and information on seals and sea lions, Dr. David K. and Melba C. Caldwell, University of Florida's Whitney Laboratory at Marineland of Florida for reviewing the dolphin activity, John Hewitt, Curator of Fish at Sea World lor reviewing the Caribbean/Atlantic Coast Tidepool activity, Ed Asper, Corporate Curator at Sea World for reviewing all mammal activities and the penguin activity, the National Oceanic and Atmospheric Administration for supplying the information on coral reefs, Crown Publishers, Inc. for supplying the information on mollusks and Sea World, Orlando, Florida for supplying the photographs.
Dolphins
Dolphins
Dolphin Facts
1. Mammal Characteristics:
A. They breathe air with lungs.
B. Their hair is in the form of scattered bristles located on top of the snout of the infant.
C. They are warm blooded. Their body has no sweat glands. Water acts as a cooling agent. When they are out of the water (stranded) their body heat will soon cause them to die. Most of their heat exchange takes place in their flippers, fluke and dorsal fin which are supplied with large blood vessels near the surface of the skin.
D. They give birth to living young. They suckle their young for about one year before the baby is fully weaned.
2. Distribution:
A. They are found in all oceans of the world and in some rivers and lakes.
B. They like to travel in groups and are very social.
C. They are strictly aquatic and even give birth to their young in the water.
3. Eyes, Ears, Nose and Throat:
A. Eyes are located on the sides of the head but can be directed partially forward in order to see straight ahead.
B. It is not known whether they can see colors.
C. They have no external ears but their sense of hearing is very acute.
D. They depend largely on echolocation in detecting objects.
E. They have no sense of smell. The nostrils open through a single opening (blowhole) located on top of the head.
F. The blowhole connects directly to the lungs. The mouth does not connect with the lungs. The mouth connects only with the stomach.
4. Fins, Flippers and Flukes:
A. They have no hind limbs. The fluke (tail fin) has no skeletal appendages.
B. The fluke is in a horizontal plane (side to side). In fish the tail fin is in a vertical plane (up and down).
C. Front limbs are called flippers, used in balancing and steering.
D. Most have a small fin on the back (dorsal fin).
5. Feeding Habits:
A. They use echolocation for finding and securing food.
B. They feed on fish, octopus and squid.
C. Their teeth are conical and pointed for holding onto the prey.
D. They swallow their food whole, almost always head first.
6. Reproduction:
A. Gestation period is from 11 - 16 months depending on the species.
B. Only one offspring is born each time. The baby of the bottlenosed dolphin measures about 3½ feet at birth and weighs about 30 Ibs.
C. The baby dolphin must reach the surface immediately after birth for air. The baby nurses from the mother's milk which is forced into its mouth. At first the baby must breathe while suckling but later it can nurse while under water.
Notice the absence of any nostrils on the snout of the dolphin. This enables it to breathe while swimming fast. Also notice that the eyes are located on the sides of its head, there are no external ears, no hind limbs, and the tail fluke is placed horizontally (side-to-side).
In this photo sequence you can see the birth of a porpoise (bottlenosed dolphin). The tail of the baby emerges from the mother first and the head last. This helps to keep the baby from drowning in the process.
7. Communication:
A. They can produce sounds on land as well as in the water and are very vocal. They whistle, squawk and click.
B. Sounds originate within a nasal sac system just beneath the blowhole. The nasal sacs are air-filled pouches between which air passes back and forth.
C. Sound waves leave the concave skull. The concavity of the skull aids in directing the sound like a narrow beam. The more concave a dolphin's skull, the more directed the beam of sound can be.
D. The echolocation sounds are emitted in pulses and focused on a distant object by a fatty protrusion on the forehead called the melon. The melon contains fatty tissues which can change in composition permitting control of sound. The result is a kind of sound lens.
E. When the sound hits a distant object it bounces back. Dolphins receive the sound through their lower jaw. Sound is transmitted from the lower jaw to the animal's brain. The result is an indication of the size and location of the object.
F. Dolphins respond to tones of 150,000 cycles per second. Humans can hear tones up to only 20,000 cycles per second.
G. A dolphin's echolocation is so keen they are able to find half a vitamin pill on the bottom of a pool, while blindfolded.
8. Scientific Terminology:
A. Dolphins belong to the class Mammalia and the order Cetacea.
B. There are approximately 90 species of Cetaceans living today.
C. One of the most common dolphins in this area is the Atlantic bottlenosed dolphin, Tursiops truncatus.
9. Longevity:
A. The longevity (length of life) varies between the various species.
B. The Atlantic bottlenosed dolphin is known to reach an age of 25 years or more.
10. Dolphins and the law:
A. The Marine Mammal Protection act of 1972 protects all marine animals including the dolphins from being molested by anyone in the United States. This act provides a moratorium on the taking and importation of marine mammals and marine mammal products.
Echolocation in dolphins is very important in finding food. Sound leaves the melon and is received by the lower jaw.
Bibliography Of Suggested Readings
Books
Dolphin: The Myth and the Mammal, Antony Alpers, Houghton Mifflin, Boston, Mass., 1961.
Mind In The Waters, Joan Mcintyre, Charles Scribner's Sons, New York, 1974.
The Secrets of the Dolphin, Helen Kay, The Macmillan Co., New York, 1964.
Toothed Whales in Eastern North Pacific and Arctic Waters, Seattle: Pacific Search, 1971.
The Whale, Leonard H. Matthews, Simon and Schuster, New York, 1968.
Whales, Dolphins and Porpoises, Kenneth Norris, University of California Press, 1966.
Whale Primer, Theodore Walker, San Diego: Cabrillo Historical Association, 1962.
The World of the Bottlenosed Dolphin, David K. Caldwell and Melba C. Caldwell, J. B. Lippincott Co., Philadelphia and New York, 1972.
Magazine Articles
"Dolphin," The Florida Naturalist, Marilyn Tipton, Oct., 1973, pp. 5-8.
"Dolphins Cross the Sea - By Ship," Sea Frontiers, Paul S. Hirschman, Nov.-Dec., 1968, pp. 332-335.
"The Dolphin Myth is Really True!" National Wildlife, Robert Claiborne, Feb.-Mar., 1972, pp.29-31.
"Exploring the Lives of Whales," National Geographic, Victor Scheffer, Vol. 150, No.6, Dec., 1976, pp. 752-767.
"First the Whales ... Now the Porpoises?" National Wildlife, George Reiger, Feb.-March, 1974, pp. 18-19.
"The Imperiled Giants," National Geographic, William Graves, Dec., 1976. pp. 722-751.
"The Littlest Ugly Dolphin," Sea Frontiers, Melba C. Caldwell and David K. Caldwell, Jan.-Feb., 1972, pp. 24-29.
Oceans, No.4, 1977. This edition of Oceans magazine is devoted to Cetaceans. Articles such as, "The Cetacean's Brain," "Strandings," "Echolocation," "Whale Protection," are included.
"The Playful Porpoises," Skin Diver, Hillary Hauser Anderson, Feb., 1974. p. 50.
"Porpoises: Our Friends in the Sea," National Geographic, Robert Leslie Conly, Vol. 130, No. 3, Sept., 1966, pp. 396-425.
"Whales, Giants of the Sea," National Geographic, Remington Kellog, Vol. 1, No.1, 1940, pp. 35-90.
MANATEES
Manatee
Manatee Facts
I. Mammal Characteristics:
A. They breathe air with lungs.
B. Hair appears as bristles on the upper lip and slightly scattered over the body.
C. They are warm blooded.
D. They give birth to living young. The mother suckles her young with a pair of mammary glands located under her flippers. Young are born in the water.
II. Distribution:
A. Manatees are found along the coast and in coastal rivers of the southeastern part of the United States, the West Indies to the northern part of South America, the Amazon and the western part of Africa.
B. In the United States they have been seen from as far north as Cape Hatteras to as far west as New Orleans. Formerly they were seen along the coast of Texas, but have not been seen there in recent years.
C. They inhabit coastal regions of tropical areas and often go into rivers.
D. During the winter months in Florida they come to the spring·fed inlets along the coast to feed and to maintain their body warmth. They can be found sporadically in the St. Johns River, Suwannee River, Crystal and Homosassa Rivers, Blue Spring, Manatee River, Charlotte Harbor and the coastal waters, rivers and bays from Ten Thousand Islands to the Everglades National Park.
E. They are very social and like to gather in groups of 15 to 20.
F. Little is known about their seaward migration during the summer months.
III. Body:
A. They resemble a gray blimp with a small head and a squarish snout having a split upper lip. The upper lip's halves are capable of moving separately in order to tear off bits of vegetation.
A manatee comes to the surface to breathe. Unlike the dolphin, the manatee's nostrils are located at the end of its snout. A manatee cannot breathe and swim fast at the same time. That's why they are often run over by motor boats. What other differences and similarities do you see between the manatee and the dolphin?
B. They get up to about 14 feet long and weigh up to 1500 Ibs.
C. Their skin is about 2 inches thick but the animal is still very sensitive to cold water.
D. They are highly susceptible to colds and pneumonia. They appear unable to withstand water temperatures below 65°F for any length of time. They are often killed when severe cold spells occur.
IV. Fins, Flippers and Flukes:
A. The front limbs are paddle-shaped flippers.
B. There are no hind limbs. The fan-shaped tail has no skeletal appendages.
C. The tail is a horizontally flattened fin. It is rounded and not notched as in the sea cows.
D. Amazingly, these animals can swim at speeds of almost 30 mph for short bursts, using powerful strokes of their flattened tails.
E. There is no dorsal fin.
V. Eyes, Ears and Nose:
A. Their eyes are small.
B. Manatees have no external ears.
C. The nostrils are located at the tip of the snout.
VI. Feeding Habits:
A. Manatees feed mainly at night but will feed during the day.
B. The front flippers bring food in toward the mouth and the split upper lip helps to tear food and direct it into the mouth. Food is then chewed by the rear molars. Manatees cannot bite you.
C. They can stay submerged for periods of up to 16 minutes eating vegetable matter along the bottom.
D. They feed on marine as well as fresh water plants such as lush grasses and water hyacinths. They have also been seen eating land plants that hang over the water.
E. In captivity they will feed on lettuce and other such vegetables. They can eat up to 100 Ibs. of food per day.
VII. Reproduction:
A. Gestation period lasts about 12 months.
The female will produce only one or two calves every two or three years.
B. Baby manatees are about three feet long and weigh about 30 Ibs.
C. Both the mother and father manatee care for the baby from one to two years. The baby nurses for about one year. It can nurse underwater.
A mother manatee with her calf. Manatees care for their young for about two years. The young manatee reaches maturity in about three or four years and may remain with the herd for a long time.
D. Baby manatees Iike to use their flippers for swimming whereas the adults use their tails. Babies reach maturity in about three or four years.
A newborn manatee is being held by a biologist. Baby manatees are about 1 meter (3 feet) long and weigh about 13.5 kilograms (30 pounds). They have a thick layer of blubber (fat) to help protect them from cold water.
VIII. Longevity:
A. Manatees have lived for 25 years in captivity.
B. It is thought that their natural life span may be longer than 25 years.
IX. Scientific Information:
A. Manatees belong to the class Mammalia and the order Sirenia.
B. Sirenians are the only herbivorous marine mammal in the world.
C. Manatees are often called "sea cows." The true sea cow (dugong) a close relative to the manatee, occurs only in the Indo-Pacific area.
D. There are two major differences between manatees and sea cows. A sea cow's tail is deeply notched but in manatees the tail is evenly rounded. The upper lip is more deeply cleft in manatees than in sea cows.
E. The Florida Manatee's scientific name is Trichechus manatus.
F. Despite their size and previous abundance, scientists today know relatively little about manatees.
X. Manatees and the Law:
A. Their only enemy is man and they are currently considered to be endangered.
B. The meat of the manatee has excellent quality and is very tasty.
C. The skin makes very good leather.
D. It has been estimated that the manatee population today is about 1,000.
E. Many manatees are killed by being run over by motor boats. They are also shot, poached and vandalized.
F. Manatees are protected by the state of Florida with a $500 fine and a six-month prison term for molesting or killing a manatee; by the federal Marine Mammal Protection Act of 1972 with a $20,000 fine and a one year prison term, and by the Endangered Species Act of 1973.
Bibliography Of Suggested Reading
Books
Marine Mammals, Richard John Harrison, London: Hutchinson & Company, Ltd., 1965.
Mammals Of The Sea; Biology and Medicine, Sam H. Ridgway, Editor, Charles C. Thomas Publishers, Springfield, III., 1972.
Mammals Of The World, Ernest P. Walker, The Johns Hopkins Press, Baltimore, 1964.
Magazine Articles
"Endangered Species: The Manatee," The Florida Naturalist, Howard W. Campbell, April, 1976, pp. 15-20.
"Florida's Manatees, Mermaids in Peril," National Geographic, James A. Sugar, Vol. 136, No.3, Sept., 1969, pp. 342-353.
"The Florida Manatee, Myth vs. Truth," Sea Frontiers, John E. Reynolds III, July-Aug., 1976, pp. 207-214.
"Manatees, Sirens of the Sea," Oceans, Joyce Edelbrock, Nov.-Dec., 1975, pp 66-69.
"Precarious Survival of the Florida Manatee." Oceans, John E. Reynolds III, Sept.-Oct., 1977, pp.50-53
"Sea Cows That Would Not Breed," Sea Frontiers, Duane Valentry, Sept.-Oct., 1973, pp. 290-291.
Pamphlets
Manatee, the Vanishing Floridian, Vi Stewart, Office of Education and Information, Florida Department of Natural Resources Tallahassee, FL 32301.
Protect The Manatee, Marine Advisory Program, G022 McCarty Hall, University of Florida, Gainesville, FL 32611.
Review of the Ecology and Life History of the Florida Manatee, Applied Biology, Inc., Atlanta, GA March, 1977.
SEALS AND SEA LIONS
Top-Sea Lion; Bottom-Seal
Seal and Sea Lion Facts
1. Differences between Seals and Sea Lions
A. Locomotion in water:
Seal: sculls hind flippers back and forth, uses front flippers for steering.
Sea lion: uses hind flippers for steering, uses front filppers in an up and down "flying" motion.
B. Locomotion on land:
Seal: "humps" along like a caterpillar pushing with its front flippers.
Sea lion: "gallops" on all four flippers, flippers rotate under body (seals cannot do this).
C. Ears:
Seal: have no external ear flaps. Have ear holes (more streamlined).
Sea lion: Have ear flaps.
D. Play behavior
Seal: alert "sitting-up" position (like prairie dogs).
Sea lion: toss and catch objects in mouth or jousting matches, chest to chest with neck weaving, nipping and barking.
A young male elephant seal with his head out of the water. These animals can dive to a depth of several hundred meters in search of fish. Notice the absence of external ear flaps, a characteristic of seals.
E. Sunning behavior:
Seal: separate
Sea lion: all piled together or in groups.
2. Mammal Characteristics:
A. Seals and sea lions breathe air with lungs.
B. Usually well covered with hair. When the animal is wet, though, the hair is difficult to see.
C. Are warm blooded.
D. Give birth to living young on land.
3. Distribution:
A. Occur along most coasts of the world and some go up rivers or live in lakes.
B. Are most numerous in polar and temperate waters.
C. Are very social and usually found in groups.
4. Body:
A. Have a streamlined body and all four limbs are developed into flippers. Both front and hind flippers have leg bones similar to other carnivores. The hands and feet are elongated and flattened for swimming.
B. How they use their flippers for locomotion is one way to distinguish seals from sea lions. Seals cannot bend their hind flippers under their bodies. On land they must "hump" along, undulating their bodies like caterpillars as they push with their front flippers. In the water, seals use their hind flippers for propulsion, sculling them back and forth to thrust their streamIined bodies rapidly through the water.
C. The largest is the elephant seal, getting up to 2.5 tons, (2.25 metric tons), and the smallest is the ringed seal, getting up to 200 Ibs. (90 kg.)
D. There is a thick layer of blubber between the thick skin and the muscles. This layer of blubber helps them to endure the cold polar waters. The layer of blubber also is used for a source of reserve energy, buoyancy and padding.
5. Eyes, Ears and Nose
A. Seals and sea lions have large brown eyes with thick curved lenses, which make them nearsighted on land, but enable them to see very well underwater. They have pupils which are adapted to open very wide to let more light in while diving. They have eyelids which protect their eyes when on land, and a set of clear membrane eyelids which cover the eyes when underwater.
B. These animals have very good hearing and are thought to use echolocation sonar to detect underwater objects and to determine their size and shape. Seals have only ear holes on the sides of their heads, which add to their streamlining. Sea lions have small ear flaps like land mammals.
C. The nose of seals and sea lions is on the front of their snout, like land mammals, and not on top of the head like whales and dolphins. However, like the whales' and dolphins' blowholes, the nostrils of seals and sea lions close when they dive (they hold their breath) and must be consciously opened to breathe.
D. On the snout of seals and sea lions are whiskers which are equipped with sensitive nerves. The whiskers act as antennae and detect movement in the surrounding water as well as temperature and pressure. On land, by pushing their whiskers forward they can touch objects to identify what they are like-much as we use our fingers to tell a smooth grape from a rough piece of wood.
6. Scientific Information
A. Seals and Sea lions belong in the class Mammalia and order Pinnipedia.
B. "Pinni" - "Pedia," means flippered foot.
C. The world's population of pinnipeds is estimated at 15 to 25 million individuals.
7. Longevity
A. Pinnipeds live for about 40 years in the wild.
B. Their enemies include; man, killer whales, walruses (also a pinniped) and polar bears.
8. Feeding Habits
A. Feeding can occur either during the day or night but certain polar seals feed in total darkness for four months out of the year.
B. The diet of seals and sea lions consists of fish and squid.
C. A 200 lb. seal eats about 15 Ibs. of food per day.
D. Their teeth are adapted for grasping and tearing rather than for chewing.
9. Reproduction
A. All pinnipeds give birth to their young on land or ice.
B. The gestation period is from 8 to 12 months, depending on species.
C. Only one pup is usually born and on rare occasions twins are born.
Sea lions can make bellowing roars as well as barking sounds. They feed mainly on fish but may also eat squid. This female sea lion looks as though she is really telling him off!
D. Newborn seals and sea lions can swim but usually do not have enough blubber to protect them against the cold water.
E. Pinnipeds mature in about five years.
10. Examples of Seals (from America's Rare Sea Mammals, Fish and Wildlife Service, Dec., 1968)
A. Elephant Seal-This seal is well named: the bulls sometimes weigh 2.5 tons (2.25 metric tons). They have a ridged flexible snout 15 inches (37.5 cm) long that becomes much longer when the animal is angry. During the winter, the older, larger bulls maintain harems of several cows, and at this time the black pups are born.
Elephant seal
Elephant seals feed in deep water at considerable distance from land. Their food is largely animals of deep waters, such as squids, small sharks and rays.
8. Hawaiian Monk Seal-Monk seals are the only tropical-water seals in the world. In the 1,000-mile-long chain of islands in the Pacific on which they breed-from Kure Island to French Frigate Shoals-the Hawaiian monk seals have been so reduced that they do not number more than 2,500 animals. Two factors endanger the monk seal; its extreme tameness and man's encroachment on its breeding islands. The bulls, covered with dark-brown hair and often 7½ feet (2.25 m) long, are larger than their light-colored mates. The black-furred pups are born in the winter. By May, they lose their black coats but many are still following their mothers in late June.
Monk seal
Much time is spent by the seals basking on the sandy beaches, lying on their sides or backs. Their heads in the shadow of a shrub. When disturbed, they rollover and stare at the intruder, then lumber off, their sides coated with sand. If cornered, they may put on a mock show of anger, barking and lurching forward with mouth wide open.
C. Saddleback or Harp Seal-The saddleback seal is also called the harp seal. This seal is found near the north pole. During the breeding season they can usually be found on drifting ice packs in the North Atlantic and Arctic oceans. The pups, which are usually born in March, have a snowy white coat to help them blend in with the icy white background.
The young harp seal has been hunted for years by humans for its beautiful white pelt. During the earlier years (1600s) hunting of the seal was unorganized. Later, when hunting became organized, the population of the harp seal declined. Gangs of men would land on isolated ice packs of the north and kill the newborn harp seals for their hides. Due to uncontrolled killings of the seals in the 1950's their populations quickly dropped. Today, hunting is controlled and there is a limit to how many seals a hunter can kill. The good news is that the seal's population is on the rise again.
Unusual seals – but not uncommon
As the young harp seal grows its white coat is replaced by a darker one. As it matures the coat then changes to a grayish yellow on the upper part of the body and a silver below with a dark band running between the shoulders to the back. They reach maturity in about eight years and feed on crustaceans (crabs, shrimps, etc.) and fish.
A group of young sea lions lie on the deck of their pool to bask in the noonday sun
11. Examples of Sea Lions (from America's Rare Sea Mamma/s, Dec., 1968)
A. Steller Sea Lion-This sea lion is commonly seen on rocks off California's coast. They range from the Bering Sea to the Channel Islands in California. They like to bask on rocks and dive into the sea. They are excellent swimmers.
Steller sea lion
The bull has a harem of many cows. They breed in the Bering Sea during July and off the coast of California during the summer. Breeding takes place right after the birth of the pups. The gestation period is 12 months. One pup is born per female. It takes the pups about one week to learn how to swim and catch food.
B. California Sea Lion- This sea lion is most often trained to do tricks in circuses and oceanariums. The California sea lion is more southern in its distribution compared to the Steller sea lion. Considerable numbers of these animals have been shot by fishermen who consider the sea lion a threat to their livelihood. However, analysis of the sea lion's stomach contents reveals that they eat those fish that commercial fishermen do not want.
California sea lion
C. Northern Fur Seal-Although this animal is called a seal it is actually a sea lion. Each spring the fur seals return to their rookeries on the Pribilof Islands. The belligerent beachmasters arrive first, select their stations, and await the cows that form their harems. In June the younger cows and bulls begin to appear-the bachelor bulls forming large pods apart from the family groups. As wave after wave of fur seals hauls out on the beaches, the rookeries fairly hum with activity.
Northern fur seal
In late June the pups are born. For the next three months their mothers are busy nursing the black-furred, bleating pups and feeding far at sea. On her return, each mother seeks out her pup, refusing to care for any other. Soon the youngsters spend many hours playing together. It is late August before they timidly enter the water. Although a sea mammal, the little fur seals must learn to swim, and at first they paddle about with their front feet. Apparently, they do not learn to feed at sea until their mothers abandon them prior to the southward migration in September. By then their black coats have turned a silvery gray and they are ready for life in the sea. (America's Rare Sea Mammals)
D. Guadalupe Fur Seal-Like the Northern Fur Seal this is also a sea lion. Far to the south, along the Mexican and southern California costs, a close relative of the northern fur seal has not fared so well. Killed by the thousands during the 1880's for its beautiful fur, by 1900 the Guadalupe fur seal was nearly gone from the islands along the Californian and Mexican coasts.
Guadalupe fur seal
For many years it was thought extinct, but in 1949 and again in 1951, lone bulls were seen near Saint Nicolas Island, California. Then in 1954 a group of 14 fur seals was found on Guadalupe Island, Mexico. Possibly with careful management and protection the Guadalupe fur seal may survive.
Walruses are a separate family from the sea lions (family Otariidae) and the seals (family Phocidae). Walruses (family Odobenidae) can turn all four of their limbs forward for walking on land. Notice how this young walrus has its front limbs rotated for support.
Bibliography Of Suggested Reading
Books
All Kinds of Seals, Bruce Kohn, Random House, New York, 1968.
Sea Lions and Walruses, Alice Seed, Pacific Search, Seattle, 1972.
Seals, Sea Lions and Walruses, Victor Scheffer, Stanford University Press, 1961.
Seals of the World, Judith King, British Natural History Museum, London, 1964.
Seals of the World, Gavin Maxwell, Houghton Mifflin, Boston, Mass:, 1954.
The Year of the Seal, Victor Scheffer, Charles Scribner's Sons, New York, 1970.
Magazine Articles
"Birth of a Harbor Seal," Natural History, Peter M. Knudtson, May, 1974, pp. 30-37.
"The Case Against Seals," Sea Frontiers, E. S. Iverson, Vol. 13, No.1, Jan.-Feb., 1967, pp. 22-32.
"Harp Seals," Sea Frontiers, George E. Toles, Vol. 16, No.2, Mar.-April, 1970, pp. 66-70
"Killers in the Surf," Audubon, John Wilson, Sept., 1975, pp. 2-27.
"Seal Haven, California Marine Mammal Center," Oceans, Dick Thompson, No.3, May-June, 1978, pp. 59-61.
"Seals in Peril," Sea Frontiers, Maurice Burton, Vol. 15, No.3, May-June, 1969, pp. 160-169.
"The Seals of San Miguel ISland," Oceans, Peter C. Howorth, No.5, Sept.-Oct., 1976, pp. 38-43.
"Song of the Seal," Audubon, George Reiger, Vol. 77, No.5, Sept., 1975, pp. 6-27.
"Steller's Sea Lion," Oceans, Lou Barr, No.4, July-Aug., 1975, pp. 18-21.
"Stalking Seals Under Antarctic Ice," National Geographic, Carleton Ray, Vol. 129, No.1, Jan., 1966, pp. 54-65.
"Sun, Sand and Sea Lions," Natural History, G. Causey Whittow, Aug.-Sept., 1974, pp. 56-63.
"Tropical Seals," Sea Frontiers, G. Causey Whittow, Vol. 17, No.5, Sept.-Oct., 1971, pp. 285-287.
"The Weddell Seal," Scientific American, Gerald L. Kooyman, Vol. 221, No.2, August, 1969, pp. 100-106.
Pamphlets
America's Rare Sea Mammals, United States Department of The Interior, Fish and Wildlife Service, Washington, D. C. 20240, reprinted December, 1968.
The Northern Fur Seal, Ralph C. Baker, Ford Wilke, and C. Howard Baltzo, United States Department of The Interior, Fish and Wildlife Service, Washington, D. C. 20240, circular 336, April, 1970.
PENGUINS
Penguin
Penguin Facts
1. Characteristics
A. Penguins are sometimes described as "little men dressed up in tuxedos".
B. They are birds but cannot fly. Their wings are called flippers.
C. Penguins lay eggs, breathe air with lungs, have feathers and are warm blooded.
D. Their feathers are short and stiff.
E. The penguin's body is somewhat torpedo shaped with a black back and a white belly. Penguins swim like sea lions, with their flippers, but stroke only a few times (to achieve amazing speed) and then glide with wings out-stretched like other birds fly.
2. Scientific Terminology
A. Penguins are in the class Aves (Birds) and the family Spheniscidae.
B. There are a total of 17 different species of penguins identified in the world today
3. Habitat
A. All are in the Southern Hemisphere. There are no penguins in the world's Northern Hemisphere.
B. They like to live in the cooler parts of the southern oceans.
C. Penguins spend many months far out at sea swimming and feeding. They spend more time at sea than any other bird. About 75 percent of a penguin's life is spent in the ocean.
D. The penguin that is found further north than any other is the Galapagos penguin. It sometimes reaches as far north as the equator.
4. How are penguins protected against the cold?
A. Not all penguins are cold weather creatures. Many penguins, such as the Jackass penguin, Peruvian penguin, Magellanic penguin, and Galapagos penguin prefer hot climates. They do, however, limit their range to coastlines fed by cold water currents.
B. Penguins which live in severe cold weather (- 50F) pull in their neck and flippers (wings.) and tuck their toes under their feathers. This makes them look like a black and white ball. By doing this they reduce their surface area thereby conserving body heat.
The largest of the penguins is the Emperor penguin. Penguins in captivity require cold temperatures, sea water in which to swim, and plenty of fish and squid to eat. Notice how this big fellow is using his tail to balance on.
C. They balance on their heels and stiff tails. By using this "tripod" stance, only a minimum part of their bodies touches the cold, ice covered ground.
O. Since penguins are warm blooded their body temperature tends to remain constant. The average body temperature is around 100°F (38°C), which is a little lower than most birds.
E. When they are in sub-freezing water their tiny stiff feathers overlap one another like shingles. This keeps out the water. Below the feathers and next to the skin is a thick layer of down. The fine, soft down acts as a "wetsuit" and along with the layer of fat, keeps the penguin from freezing to death in the cold water.
F. The thick layer of fat under their skin not only protects them against the freezing temperatures of the air and water but also is a source of stored food and water. When the bird is out at sea for a long time, the thick layer of fat helps to supply the penguin's body with food and fresh water.
G. Penguins group together. A group is called a rookery. Some rookeries may consist of a thousand or more penguins. Being in a rookery helps them to stay warm.
H. Some penguins such as the Gentoos and Chinstraps, gather plant material and build shelters. The Jackass penguins dig tunnels in the ground to escape the cold winds and to lay their eggs.
This family of Peruvian penguins now makes its home at Florida's Gulfarium. These penguins do not require cold temperatures as do their Antarctic cousins the Adelie and Emperor penguins.
5. Movement on Land
A. On land penguins look very awkward but they actually are well coordinated. They tend to "waddle" along on their short legs. But when necessary they can jump over one-foot-high obstacles, and when alarmed they can run rather fast.
B. If they are in a hurry they can slide along the snow on their bellies while using their feet and stiff flippers to move. When doing this they look like a sled or a toboggan. In fact, this is called "tobogganing".
Some enemies of the penguin are the seal, killer whale and shark.
6. Movement in the Water
A. On land penguins are clumsy, but in the water they are graceful.
B. They use their flippers (wings) as paddles when swimming under water while their short, stiff tails and stubby feet are used as rudders to steer.
C. They can swim up to speeds of 25 miles per hour (22 knots).
D. Swimming motion is much like a porpoise's. Penguins move up and down in the water, breaking the surface with their backs. They often leap out of the water for some distance when swimming fast. As they come to the surface or leap out of the water, they take a breath of air before going back down. Air is taken into their lungs through nostrils located on their beaks.
E. Because of the motion of the flippers, they look like a bird flying underwater.
7. Enemies
A. Adult penguins have no natural enemies on land.
B. In the water their enemies are sharks, seals, and killer whales.
C. Gulls and skuas will eat the eggs. When the eggs hatch, they will eat the chicks. The parents must protect the eggs and the chicks until the chicks are big enough to swim and fend for themselves.
D. In the 1800s men hunted penguins for their oil. Today, penguins are protected by the U.S. government from being killed by American citizens. Great Britain and Russia also have agreed to protect penguins, but as Antarctica has no government of its own, citizens of other nations are not prohibited from killing penguins unless their governments pass laws protecting penguins.
8. Feeding
A. Penguins travel in groups in the water and on land. Many eyes are better than just one pair of eyes. Grouping protects them against their enemies and also helps them in finding food.
B. Their eyes are adapted for seeing under water. Penguins are nearsighted on land and this contributes to their awkward and comical movements on land.
Skua
C. Some of the deeper diving penguins feed on squid. The Emperor penguin can dive to a depth of 800 feet (245 meters) and has been known to stay under water for as long as 18 minutes.
D. They usually feed on things that can be found close to shore such as small fish and shrimp called krill.
Diving penguin
9. Reproduction
A. Penguins mate and hatch their eggs on land.
B. Most penguins lay two eggs. The Emperor and King penguins, though, lay only one egg per season.
C. Male and female adults look alike except for size. The male penguin is generally a little larger than the female.
D. During the mating season (early spring) they are very vocal and make loud noises.
E. They usually mate with the same partner each year.
F. To the human ear, all of the penguins sound alike. To the penguin, though, each noise is different. A penguin can distinguish its mate from all the rest by the sound of the voice.
Squid
G. In captivity penguins have been noted to mate twice a year.
H. The penguins pair up and stay close to each other. Some penguins make a nest out of rocks. The rocks help to prevent the eggs from rolling away.
Here, a parent Adelie penguin is watching over its chicks. Adelies, being Antarctic penguins, require cold temperatures. The plumage of penguins is very short and dense and covers the whole body of the bird. Beneath this coat of feathers lies a thick layer of blubber which provides insulation as well as a storage organ for both food and water.
I. The Emperor penguin doesn't make a nest. The mother puts her one egg on her feet and covers it with a large fold of stomach skin.
J. The eggs must be protected by one of the parents at all times against the skuas. Skuas, known as "eagles of the Antarctic", are related to sea gulls.
K. The two parents take turns sitting on the eggs to protect them and to keep them warm. Keeping the eggs warm is called incubation. While one parent is incubating the eggs the other parent is out in the ocean feeding on fish and shrimp.
L. Incubation period varies between 30 to 65 days, depending on the kind of penguin.
M. Baby penguins, called chicks, feed on regurgitated food from the parents.
N. The young must practice swimming in order to prepare for migration to northern seas for the winter months.
O. Penguins become sexually mature about three to five years after hatching.
10. Longevity
A. No one really knows how long penguins live, but it is estimated that they live for about 30 years.
11. There are seventeen species of penguins. (from "Penguins of the World," Audubon, March, 1973, by permission of the artist.)
Chinstrap penguin. The only penguin with a narrow black line under the chin.
Figure 39.
Gentoo penguin. Also known as the Johnny penguin. Lives close to the Antarctic.
Figure 40.
Yellow-eyed penguin. Its eyes are a pale amber. Is found around New Zealand.
Figure 41.
Adelie penguin. lives by the millions on the rim of the Antarctic continent.
Figure 44.
King penguin. Second largest penguin. Probably the most beautiful of all penguins. They are very tame and gentle with an unbounded curiosity.
Bibliography of Suggested Readings
Books
Another Penguin Summer, Olin Sewall Pettingill, Jr., Charles Scribner's Sons, New York, 1975.
Penguins, John Sparks and Tony Soper, Taplinger Publishing Co., New York, 1967.
Penguins: Past, Present, Here and There, George Gaylord Simpson, Yale University Press, New Haven and London, 1976.
Sea Birds, Davicj Saunders, Gosset & Dunlop, Inc., New York, 1973.
The Secret Life of Animals, Lorus Milne, Margery Milne, and Franklin Russell, E. P. Dutton & Co., Inc., New York, no date.
The Ocean World of Jacques Cousteau, The Danbury Press. (a twenty volume set with many references to penguins), 1973.
Magazine Articles
"Adelie and Emperor Penguins", Frank S. Todd, Oceans, No.3, May-June, 1977, pp. 20-25, Fort Mason, California.
"Birds that Refuse to Freeze", Katherine Muzik, and Michael Fedad, Sea Frontiers, pp. 223-233, Vol. 22, No.4, July-Aug., 1976, The International Oceanographic Foundation, Miami, Florida.
"Life on the Brink", William Curtsinger, and Rapho Gullumette, Audubon, Vol. 75, No.2, March, 1973, New York, N.Y.
"Penguins and Their Neighbors", Roger Tory Peterson, National Geographic, Vol. 152, No. 2, August, 1977, pp. 237-255, Washington, D.C.
"Penguins of the World", Roger Tory Peterson, Audubon, Vol. 75, No.2, March, 1973, New York, N.Y.
TREASURES FROM THE SEA
A pearl diver at Sea World displays some sea shells that are found around the world. The diver is holding Florida's state shell, (a) the Florida horse conch. Other shells are: (b) queen conch, (c) volute, (d) melon shell (Melo), (e) whelks, (f) bear's paw clam, (g) spider conchs, (h) tridacna, (i) spiny oyster, (j) helmet, (k) abalone, (I) crown conch, (m) cowries, and (n) egg cowries.
MOLLUSKS
The mollusks are a group of animals which include such well known creatures as snails, clams, oysters, periwinkles, scallops, squid, octopuses, slugs and whelks. In general they are soft·bodied animals that usually produce an external shell composed of a limy material, calcium carbonate.
The mollusks are divided into classes - two of which are well known to people for their value as food, jewelry and beauty. The univalves (Gastropods), which include snails, conchs, and periwinkles; the bivalves (Bivalvia), which include the clams, oysters and scallops.
There are about 70,000 different kinds of living mollusks having a wide variety of habitats. They are mostly marine, living along seashores or in shallow waters, but some occur down to 35,000 feet and others are found out in the open sea. Various snails and some bivalves inhabit fresh and brackish waters, and other snails and slugs are terrestrial. Most are free·living creatures that creep slowly. Some attach to rocks, shells, or wood, some burrow, others float, and the squid and octopus swim freely.
Pearly Oyster
Of major economic importance are the clams, oysters, squid and others serving as food for humans; the shells of freshwater clams that are cut into buttons; and a few bivalves that produce pearls. Some snails and slugs feed on cultivated plants thereby competing with man for food.
Malacology is the science that deals with mollusks; Conchology is the study of shells, especially those of mollusks. Shell collecting is a popular hobby and has added significantly to the knowledge of mollusks. Pearls, both natural and cultured have been prized by humans for thousands of years.
How A Pearl Is Formed
Probably every kind of shelled mollusk is capable of forming a pearl. The pearl is simply an isolated concentration of shelly material made by the mantle, which is the same organ that produces the main shell of the mollusk. The pearl formed, therefore, quite often resembles the shell of the oyster from which it came.
The creation of the pearl may be considered an accident caused in nature. Pearls are formed when some foreign body or substance becomes imbedded in the mantle tissue. Unless the foreign object can be ejected by the mollusk within a few days, it will be covered over by succeeding layers of shelly material.
Pearls usually are not round. Some pearls are dumbbell·shaped, some elongate and others are shaped like a disk. Most of the naturally formed pearls begin as an invasion of a very small marine organism such as an egg of a marine worm. Sometimes a single grain of sand may serve as a stimulant for the gradual production of a pearl.
Pearls are about 91% calcium carbonate. The rest of the pearl is made up of about 3% water and 6% of a material called conchiolin. Growth may vary according to the type of organism producing them and the water temperature. Pearls of gem quality from the mother-of-pearl oyster may take from six to eight years to reach a diameter of ten millimeters. This type of pearl is made up of an aragonite form of calcium carbonate which is laid down in thin leaves, all of the same thickness, being separated by equally thin leaves of the conchiolin substance. The leaves are laid down in a horizontal plane around the nucleus, and this combination of structures produces an iridescent refraction. The different shades of pearls, such as, pink, cream, blue and black, are due to the nature of the chemical layers and the introduction of pigment into the aragonite.
Cultured Pearls
It was only a matter of time before man's ingenuity developed both an artificial and cultured pearl, and it was the Japanese in the early 1900s who mastered the technology of producing cultured pearls. Through trial and error methods the research workers discovered that large beads, from two to seven millimeters in diameter, made from freshwater mussel shells from the Mississippi River, seem to work best as a nucleus when inserted into the shell of the oyster. This type of nucleus seemed to be the least likely to be rejected by the oyster. Pearl oysters are removed from the water and placed in the shade for about half an hour or until the shell opens far enough to allow the careful insertion of a large plug of wood. A shell bead nucleus, together with a small piece of mantle tissue from another donor oyster, is pushed inside each gaping oyster. The tissues are smoothed back into place and allowed to close. Then the oysters are returned to the water. Only about 40% of the entire pearl harvest has some marketable value, and fewer than 10% are of gem quality.
Bibliography of Suggested Reading
Books
The Collector's Encyclopedia of Shelfs, S. Peter Dance, McGraw-Hili Book Company, 1974.
Handbook of Shelfs, Gene Comer, Great Outdoors Publishing Co., St. Petersburg, Fla.
Handbook for Shell Collectors, Walter Freeman Webb, Lee Publications, Mass., 1948.
Kingdom of the Seashell, R. Tucker Abbot, Crown Publishers, Inc., 1972.
Seashells of the World, R. Tucker Abbot, Golden Press, New York, 1962.
The Story of Pearls, Shohei Shirai, Japan Publications, Inc., 1970.
Magazine Articles
"Ama", Oceans, Edwin Karmoil, No.6, 1978
CARIBBEAN/ATLANTIC COAST TIDEPOOL
Barnacles
The tidal zone is perhaps the earth's most densely populated area. A variety of plants and animals live here in an area which is both sea and land, and never quite the same from one moment to the next. It is an environment which frequently imposes unique and often austere conditions on its inhabitants. From the ceaseless heavy pounding of the waves, organisms must have ways to protect themselves from being swept away. Since the sandy beach represents an unstable environment, its residents must include only the most specialized of organisms that are able to survive in and among the sand particles. Apart from the never-ending wet/dry cycles, the sand beach is constantly being rearranged along with its inhabitants as a result of the pounding surf and winds. The constant changing of water level due to tides means the animals living here must be able to burrow down into the sand to escape the drying effects of air. Hard, impermeable shells or hard exoskeletons to slow down evaporation are common designs solving that problem. Other organisms contract their bodies or form large, tight groups to reduce the amount of surface area exposed, thereby reducing dessication. Some have special organs or "feet" that enable them to grasp and hold onto solid objects.
Because the tide pool is often a semi-enclosed, shallow depression filled with sea water, the salinity levels are constantly changing. Evaporation of water is continually increasing the salt concentration, and heavy rains and mixing of sea water and fresh water runoff cause a diluting effect.
Organisms here must have a wide tolerance or special organs to maintain their needed salt water balance. Just as the salinity is subject to many changes, the temperature of the water may go through wide fluctuations, again requiring wide tolerance of the inhabitants of the pool.
The Caribbean or Florida tidal zone is composed of a number of different habitats. The interface of land and sea can vary from soft sand to mud flats, various vegetation types such as mangroves, to coquina rock. The degree of protection and exposure to open surf will vary. Any particular area can be divided into upper, middle, and lower tidal zones each with a characteristic distribution of organisms.
The distribution of organisms throughout the intertidal zone is determined by several factors, one of which is the amount of time organisms are exposed to the air during the daily tidal cycle. The high intertidal or splash zone contains plants and animals capable of surviving long periods of exposure to air with a minimum amount of water. In the middle intertidal zone organisms spend roughly 50 percent of their time exposed to air and 50 percent covered by water. The lower intertidal zone contains a large number of organisms, many of which can tolerate only a brief period of exposure. Below the lower intertidal is the subtidal region where we find the constant presence of sea water. Here the growth of marine plants is often dense and provides cover and foraging space for many species of fish. Many fish remain in the subtidal area during low tide and follow the returning tide back into the intertidal zone to feed.
Tide zones of the Atlantic coast and some animals and plants which live in these zones. Many of these plants and animals may be found in tide pools as well as in open water and in reef areas.
GLOSSARY
ECOSYSTEM -The organisms (plants and animals) together with the physical features in a particular environment.
ENVIRONMENT -All the things (conditions, circumstances, & influences) that surround and affect organisms.
ECOLOGY -The study of the relationships between plants and animals in their environment.
ORGANISM -Any living thing.
INTERTIDAL -That area between high tide and low tide.
SALINITY -The amount of dissolved salts in water.
HABITAT -An area of the environment where a particular organism lives.
Bibliography of Suggested Reading
Atlas of the Oceans, Rand McNally, New York, Chicago, San Francisco, 1977.
Caribbean Reef Fishes, John E. Randall, T.F.H. Publications, Inc., Neptune City, N.J., 1968.
Caribbean Reef Invertebrates and Plants, Patrick L. Colin, T.F.H. Publications, Inc. Neptune City, N.J., 1978.
Ecology of the Intertidal Zone, Marine Advisory Publication 57-LE/2246, California Sea Grant, University of California.
The Rise and Fall of the Seas: The Story of the Tides, Ruth Brindze, Harcourt, Brace, Javonovich, Inc.
Seashore Life of Florida and the Caribbean, Gilbert L. Voss, E. A. Seaman Publishing Co., Miami, Fla. 1976.
Life in the Sea, Gunnar Thorson, McGraw-Hili Book Company, New York, N.Y., 1976.
A Field Guide to the Atlantic Seashore, Kenneth L. Gosner, Houghton Mifflin Company, Boston, Mass. 1979.
CORAL REEFS
Cubbyu (Equetus acuminatus). Dark stripes, alternately wide and narrow, distinguish the cubbyu, a member of the drum and croaker family. During the day, this fish groups with others and they hide beneath rocky ledges. Size: to 9 inches. Range: tropical western Atlantic.
A coral reef is one of the natural wonders of the world. It is an integrated community containing the most colorful, most luxurious, and most varied forms of life found any place on earth. The exquisite beauty and breathtaking colors of an underwater coral garden equal or surpass the splendor of natural areas that exist on land.
Florida's reefs are the most extensive living coral tracts that border the continental United States. Among them are the John Pennekamp Coral Reef State park, the world's first and one of the most beautiful underwater parks, and the Biscayne National Monument. Both of these reef tracts are marine preserves protected by state and federal laws.
Florida's reefs exist at the northernmost fringe of coral reef development and are subjected to natural stresses far in excess of other Caribbean reefs, Yet, they have survived through thousands of years of attack by natural enemies and the buffeting from storms and hurricanes - and their structures have helped build part of the state of Florida.
However, Florida's reefs are one of the world's most popular underwater attractions - and thoughtless people can do more damage to a reef in a year than its natural enemies have cause over many years. Man-caused damage may even tip the balance in favor of the forces of destruction and doom this irreplaceable natural wonder to extinction.
Florida's corals belong to all of America. They need your help. This is their story and tells what we all must do to help preserve and protect a fragile natural resource.
A "Housing Project" For Marine Life
Florida stinging anemone (Stoichactis spp.l. This anemone is often a host to numerous crustaceans and fishes. Both the anemone and the various animals who dwell in and around its protective tentacles may enjoy the benefits of increased food and less exposure to predators. Size: to 1 foot. Range: tropical Atlantic Ocean.
Unlike the vegetation of land communities where plants outnumber animals, very few of the things growing on a coral reef are true plants. It is a topsy-turvy world in which animals often look like plants, creating a coral "forest" with a diversity of forms and shapes that rival the lush growth of a tropical jungle.
Cowrie (Cypraea spp.). The handsome shells of these mollusks thicken as the animals age. When viewed in motion, the living animal's mantle often envelopes the entire shell, obscuring its beautiful markings. The most striking cowries are found in the tropical oceans. Size: to 4 inches. Range: worldwide in temperate and tropical seas.
The architects and master builders of the reefs are billions of tiny organisms called polyps, some no larger than a pinhead. These secrete a tiny skeleton which is the basic structure of the reef. Almost one hundred different species decorate the ocean floor with an infinite variety of intricate patterns which appear as the spires and pinnacles of pillar corals, "tree and shrubs" of stonehard elkhorns, huge boulders that look like giant brains, and delicate, flower-like figures of lettuce and leaf corals.
Hermit crab (Pagurus spp.) Discarded snail shells provide strong, portable homes for the soft-bodied hermit crabs. When threatened, these common tide pool inhabitants retreat inside their shells and with their pincer claws, effectively block the shell's entrance. Size: to 4 inches. Range: temperate and tropical coastal waters.
New colonies and new coral structures are constantly being built on top of the dead skeletons of older colonies. But the rate of growth is very slow. Branching corals such as staghorn and elkhorn may grow at a rate of three to eight inches a year. A basketball-size brain coral, however, may be up to fifty years old.
Sergeant major (Abudefduf saxatilis). This little "warrior" of the sea boldly defends its home territory and nest. Probably the most common of the damselfish family, it can change its coloration to match a light or dark background. Size: to 7 inches. Range: tropical waters of both Atlantic and Pacific.
These are the "Buildings" of the reef which serve as an underwater "housing project" for a dazzling array of marine life. The maze of openings formed by corals provide a safe nursery for young fishes and a shelter for lobsters, crabs and shellfish. Intermixed and surrounding the hard corals are plant-like gorgonians, the soft corals with graceful shapes of sea fans, sea plumes and sea whips.
Sea cucumber (Holothuria spp.). In an amazing effort to elude a predator, this invertebrate turns partly inside out to expel the respiratory trees and parts of the intestine. By leaving the tangled mass of body parts behind, the sea cucumber often makes good its escape. Size: to 40 inches. Range: tropical and subtropical waters worldwide.
Rainbow-hued reef fish dance among the corals creating changing patterns of moving color. Microscopic organisms and a host of other animals find refuge in crevices and crannies. Giant predators such as sharks, barracuda and grouper prowl the reefs in search of food, and sharp-beaked creatures such as parrot fish, which pulverize coral skeletons into fine-grained particles, serve as willing workers in nature's "sand factory."
Long-spined sea urchin. (Diadema spp.). Commonly found clustered in the cavities of coral reefs, this urchin walks on the tips of the shorter spines located on its oral surface. The hollow, needle-like spines are fragile and probably poison-filled. Size: to 1 foot. Range: tropical eastern Atlantic.
This is the coral reef, a massive structure formed over countless thousands of years and so complex and integrated it makes man's architectural and engineering achievements seem puny by comparison.
Redspotted hawkfish (Amblycirrhitus pinos). These small, colorful fishes spend most of their time resting on the coral reefs. The lower fin rays of the hawkfish's pectoral fins are thickened, and when extended, are used as feelers. Size: to 4 inches. Range: tropical Atlantic.
The Reefs' Value to Man
Giant elkhorn coral (Acropora palmata) is a master builder of most shallow Water Caribbean reefs. Its dense, palmate branches may reach a span of ten feet or more.
Florida's coral reefs are not only precious for their breathtaking beauty, they also provide free services that are vital for the protection and economic welfare of humans. Among these are:
Storm Protection: The corals form a natural and self-repairing breakwater that shelters the land against the violence of ocean storms and hurricanes. Their porous structure is ideal for absorbing and dissipating the energy of oncoming waves.
Food Production: The reefs provide food and shelter for much of the marine life that makes the Florida Keys one of the world's finest commercial and sport fisheries.
Tourism: The economy of the Keys almost entirely depends on tourism, and the coral reefs are its backbone. They not only attract millions of sightseers and skin divers every year, the reefs also support the fishes that attract the fishermen, and protect the integrity of the islands that people come to enjoy.
Nature's Sand Factory: Corals and calcareous algae are major sources of sand. Fishes alone, browsing on these organisms, contribute an estimated 2112 tons of sand per acre every year. This sandy sediment is essential for the growth of seagrass meadows that are the habitat for thousands of organisms. Most of these, including crustaceans (crabs, shrimp), mollusks, (clams, conch, helmets), grazing fishes and similar marine life cannot exist without a hard sandy bottom.
Also, a portion of the coral sand is washed to shore where it helps build some of Florida's white, sandy beaches.
Scientific Research: Many authorities say that we know more about the surface of the moon than we do about the world under water. Florida's reefs serve as a living laboratory attracting scientists from allover the world who study and learn about the strange inhabitants of this world.
Threats To The Reefs
Reef-building corals are very particular about their requirements. They occur only off the east coasts of the world's continents, seldom farther north or south of the equator than 22 degrees, in crystal clear water with maximum light penetration, and rarely at depths exceeding 200 to 250 feet.
Some of the inhabitants of a coral reef. Bull shark, spade fish, green sea turtle, snapper, French anglefish, grouper and triggerfish. Can you spot these and others?
They cannot withstand long exposure to water temperatures colder than 68 degrees F, are seldom found on soft or shifting bottom sediments or in constantly turbid water with dim light, and cannot tolerate great changes in salinity, temperature or water quality.
In Florida the Keys protect the reefs, just as the reefs protect the land. Our best reefs are located opposite large islands which shelter them from violent fluctuations in water temperature and salinity due to storm water runoff from the mainland. Opposite the large openings between islands where there are no protective barriers no reefs occur.
Where the sandy floor of the ocean meets a coral reef we usually find a variety of life. Stingrays, porkfish, schools of grunts and snappers, spadefish, sponges and algae are just a few of the many living things that depend on a coral reef.
Dredging, filling, channelization and pollution can drastically alter natural flow patterns and destroy the natural protection of the land.
Visitor Damage: Another serious threat to the reefs is damage caused by careless or uninformed visitors. More than one million fishermen, sight-seers and skin divers visit the reefs each year, and the individual damage from boat anchors, specimen collecting and other visitor activities, when multiplied by hundreds of thousands, is more than the slow-growing corals can stand.
A common belief is that breaking off a piece of coral does no more damage than pruning a tree or a shrub. This may be true of a healthy reef environment in which conditions are ideal for regrowth. In Florida, however, the reefs are already at the borderline of survival in their fight against natural forces of destruction. Under these conditions, seemingly insignificant damage such as abrasions, cuts, scrapes, scratches and breakage, invites invasion by algae and other organisms that can spread rapidly and destroy the entire colony.
The living tissue of stony corals is only a thin outer skin consisting of thousands of tiny polyps which cover the interior skeleton. A "wound" in this skin is similar to a wound in a human skin in that it can become "infected" by marine organisms. Some of these grow and multiply at a astronomical rate, attacking the coral polyps like a disease, stripping the coral of its living tissue until only a bleached, white skeleton remains.
One of these enemies is a species of blue-green algae, Oscillatoria submembranaceae. In laboratory experiments healthy, undamaged coral specimens repeatedly rejected blue-green algae. But when the coral was cut with a knife and the algae placed in the "wound," it grew and spread until it killed the entire coral colony.
In a coral reef community the forces of construction and destruction are constantly at work. Under healthy, natural conditions the constructive forces stay ahead and the reefs continue to grow. However, if man-caused damage tips the balance in favor of the forces of destruction, Florida's reefs will die.
The inhabitants of a coral reef community are dependent upon each other for their needs just as the citizens of a modern city are. When the corals die, other marine life must either migrate or starve. Dead coral structures, like abandoned buildings, will eventually decay and erode into rubble infested by parasites and algae.
Common inhabitants of a Florida coral reef are the moray eel and spiny lobsters. These animals need the crevices, holes and protection of coral reefs for hiding and for finding food.
Do's And Don'ts For Coral Protection
There is little man can do to protect the reefs from natural stresses - but we can do a great deal to help protect them from man-caused damage.
Florida designated the Keys as "an area of critical State concern" and all forms of development and construction, including dredging, filling, channelization and pollution, are restricted by stringent rules and regulations enforced by state officials.
Only enlightened individuals, however, can supervise and enforce the common sense rules of conduct required to protect the corals from the damage caused by careless or uniformed visitors.
Do's and Don'ts for coral protection are:
1. Anchor damage: Boat anchors destroy more coral than any other visitor-related cause and are listed as the reef's "public enemy number 1".
DON'T drop an anchor directly on a reef. It not only breaks up coral when it hits, the rope and chain continue slashing at the coral while anchored, and the anchor tears up more coral when it is pulled up.
DO drop the anchor in a sandy patch. (The water over a reef appears dark, sandy areas are light colored.) Use a type anchor that will hold in sand, payout at least four times as much line as the depth of water you are in.
2. Coral collecting: Florida law limits the quantity of live coral that may be collected. Even this small amount is discouraged, however, and many scientists believe that a complete ban is necessary to preserve the reefs. Living coral is far more valuable than dead souvenirs or home decorations - so Florida has outlawed all commercial collecting within State controlled waters.
The federal government has prohibited the removal or destruction of coral - living or dead - from all areas of the continental shelf inside a three mile limit. This includes virtually all of Florida's coral reefs.
Special protective regulations are enforced in the marine preserves such as The John Pennekemp Coral Reef State Park, The Biscayne National Monument, and the recently established Florida Keys Coral Reef Marine Sanctuary. Visitors to these areas should contact park personnel for their regulations.
DON'T take specimens of coral - living or dead - from Florida's reefs.
DO inform friends and acquaintances of the reason for these regulations. Take photographs of the reefs if you want a souvenir.
3. Shell collecting: Collectors look for live sea shells found hiding beneath rocks and coral on the bottom. Conscientious persons replace loose rocks in their original position. Others use prybars to dislodge and turn-over entire coral heads, a practice almost as destructive as commercial coral collecting.
DON'T dislodge or turn over live coral specimens.
DO confine shell hunting to loose rocks and dead coral in areas outside protected reefs. Always replace the rock in its original position or an entire shell colony may be left exposed and will be destroyed.
4. Sitting and standing on coral: This is a common practice of snorkelers in shallow water, and of scuba divers at all depths. It causes breakage of branching corals and injury to the living tissue of head corals.
DON'T sit or stand on live coral formations.
DO use a float, life vest, or similar support - or stand on sandy bottom - if you need a rest.
5. Holding on: many divers conserve air and steady themselves by holding to the bottom and pulling themselves from place to place.
DON'T grab or hold onto living corals; it can injure delicate tissue.
DO use dead coral or bottom rocks to steady yourself.
6. Boat operation: Large areas of coral have been destroyed and boats damaged due to careless operation in shallow water.
DON'T run at high speed among coral reefs or attempt to navigate among shallow coral formations.
DO watch for surface swirls, white caps and water coloration that indicate the location of shallow, isolated coral heads. Navigate slowly and carefully in reef areas to avoid the possibility of striking a projecting reef formation - or injuring a surfacing scuba diver.
7. Lobster fishing: Careless handling of lobster traps can cause extensive damage to coral reefs. Scuba diving lobster hunters have also been known to break up corals in attempts to dislodge a crawfish from its hiding place.
DON'T drop lobster traps too close to coral formations. Don't break off pieces of coral or turn over heads to get at a hidden crawfish.
DO avoid all practices and activities that can cause coral damage such as breakage, cuts, abrasion, scratches, and similar "wounds" to the living tissue which are an invitation to "infection" by marine organisms that can destroy the reefs.
Only an informed and enlightened public can protect Florida's coral from this kind of damage. We ask your cooperation in spreading the message of "enjoy, but don't destroy the fragile coral reefs".
Bibliography of Suggested Reading
Books
Atlantic Reef Corals, F. G. Walton Smith, University of Miami Press, 1971.
Atlas of the Oceans, Rand McNally, New York, Chicago, San Francisco, 1977.
Exploring the Reef, Robert P. S. Straughan, A. S. Barnes & Company.
The Living Reef, Jerry & Idaz Greenberg, Seahawk Press, Miami, 1972.
Secrets of the Seas, Reader's Digest, The Reader's Digest Association.
Magazine Articles
"A Place to Live," Sea Frontiers, R. Thresher, Vol. 21, No.5, 1975.
"Australia's Great Barrier Reef," National Geographic, Ron & Valerie Taylor, June, 1973.
"Corals in Trouble," Florida Naturalist, Timothy O'Keefe, June, 1978.
"Dazzling Corals of Palau," National Geographic, Thomas O'Neil, July, 1978.
"How Corals Came to be Known as Animals," Sea Frontiers, James E. Murphy, Vol. 19, No.5, Sept.-Oct., 1973.
"Marvels of a Coral Realm," Natural Geographic, W. A. Stark II, Nov., 1966.
"Probing the Deep Reefs Hidden Realms," National Geographic, W. A. Stark II, Dec., 1972.
"The Reef: Yesterday - Today - Tomorrow," Oceans, J. Burrell, Vol. 9, No.3, 1976.
"Reef Life in the Bahamas," Oceans, R. A. Martin, Vol. 8, No.6, 1975.
"Symbionts of Sea Fans & Sea Whips," Oceans, Leon P. Zann, Vol. 10, No.1, 1977.
Footnotes
This document is 4H MEM 30 of the Florida 4-H Youth Development Program, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Printed October, 1990; Reviewed January 2009.
Publication Contact: Nancy Johnson, 4-H Publication Coordinator, 4-H Youth Development Program, Florida Cooperative Extension Service, Insitute of Food and Agricultural Sciences, University of Florida.
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For more information on obtaining other extension publications,
contact your county Cooperative Extension service.
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University of Florida, IFAS, Florida A. & M. University Cooperative
Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy,
Interim Dean.
