Monday, September 21, 2009
The Sanibel Stoop - A Guide to Shelling
The entire west coast of Florida abounds with molluskan sea life, especially offshore along the vast extent of the shallow continental shelf of the Gulf of Mexico.
Sanibel and Captiva Islands both jut out into the rich waters of the gulf and offer a natural catch-all for the billions of shells cast up during strong northwestern winter blows. Come summer, the gentle southerly breezes set up offshore currents that take away most of the shells that shellers have not already added to their collections.
Seashells have always dominated the lives and activities of most people in this semitropical garden. Over a thousand years ago, the native Calusa Indians harvested millions of large whelks for food and used the emptied shells for tools and weapons. Many of the nearby islets and ancient village sites of these now-extinct people are built of mounds of these broken whelk shells.
Early Spanish explorers, sailing out of Cuba, frequently visited the protected bays of what is now Lee County, and in lieu of elusive gold and pearls, they stocked up with water, deer meat, fish and colorful seashells. As the area opened up to Spanish and later English settlers from the north, the barrier islands gained fame as a secluded haven for farming, fishing and shelling.
By the time a small ferry boat for automobiles had been established in 1928, Sanibel had already become famous as a vacation spot for shellers. The “Sanibel Stoop” was a familiar phrase used to describe the position used by shellers while collecting their treasured finds. The abundance and variety of marine shells attracted scientists from Harvard, Chicago and the Smithsonian Institution. New discoveries led to the publication of scientific accounts and field identification books.
But the charm and irresistible lure of shelling is embodied in the common names of Sanibel’s best-known shells: the angel wing (a clam that burrows deeply in the mud), the banded tulip (a snail shell shaped like an unopened tulip bearing spiral bands), the lightning whelk (bearing zigzag, lightning-like color streaks), and the rose petal tellin (a delicate, pink bivalve used in shellcraft). Even the three kinds of cockle shells have descriptive names: prickly, strawberry, yellow and egg cockles.
Seashells are a natural, vibrant part of nature. They are the outer, protective houses of soft, living animals. As the animal grows, it gradually adds liquid shell material to the edge of its shell. Color pigments are added by special glands just before the new layers harden.
Most gastropods (one-shelled conches, whelks and periwinkles) have separate sexes, with females laying their eggs either loosely in the water or within small chains of leathery capsules. These “rattlesnake” chains, containing hundreds of “baby” shells, are frequently cast up on the gulf-side beaches. The bivalves (two-shelled clams, oysters and scallops) may have separate sexes or possess both male and female organs in the same individual. Most bivalves shed millions of eggs and sperm freely into the ocean’s water, usually in the springtime.
There are about 275 kinds of shells found in the shallow waters of Sanibel and Captiva Islands. Another 500 species live far out in the Gulf of Mexico in depths ranging from 80 to 2,000 feet. Each species has its preferred habitat and ecological requirements. The half-inch, colorful coquina clam lives only along a fairly narrow band of sloping sand beach where the waves can bring them oxygen and food during high tide. The small angulate periwinkle seems happier in mangrove trees and on wharf pilings.
In size, sea snails, like the Florida horse conches, may reach a length of almost two feet, but the vast majority of local species never exceed an inch. Most mollusks live for several years. The lightning whelk becomes mature and may lay eggs at the age of three. They may live for 15 to 20 years and reach a maximum size of 18 inches. Scallops, on the other hand, live only for two years before dying of “old age.”
Mollusks are an important part of the web of life found in the sea. They are a major source of food for bottom-feeding fish and for many aquatic birds. Some snails are effective scavengers and keep the seascape clear of dead sea animals. Billions of clams and oysters are constantly filtering and “purifying” our local waters. Without relatively undisturbed and pollution-free populations of shells, the natural environment could not maintain its normal health. For these reasons, local laws prohibit the collecting of live shells and sand dollars within the city limits of Sanibel. This includes the exposed sand flats at low tide. After a winter northwest storm, many dead shells may be cast upon the gulf beaches.
The unique Bailey-Matthews Shell Museum, devoted to explaining the “miracle of the mollusk,” is now located in the center of Sanibel Island on Sanibel-Captiva Road, just one mile west of Tarpon Bay Road. Its numerous colorful and educational exhibits depict local habitat panoramas, explain the biology of shells and the history of Florida fossils and tell how shells have affected our lives in medicine, agriculture, shellfisheries, art, religion and even in shell craft. There is an extensive library and friendly experts are on hand to assist members and scientific visitors with identification and information. All school and tour groups are welcome but do require advance reservations. There is an intriguing gift and shell book shop, but they sell no shells. The hours of this unique museum are from 10am until 4pm daily (except major holidays), and there is plenty of free parking. Adult admission is only $7, children aged 5 to 16 are $4, and those 4 years old and under are admitted free. Museum members are also admitted free. New members are welcome. You can also purchase memberships for yourself or for your family for an entire year. The annual single membership is $25; the family membership is $40. For more information on museum hours, tour schedules, and membership info, please call 239-395-2233 or 888-679-6450.