~ The Eel ~
The eel is an elongated, serpentlike fish of the order Anguilliformes, comprising nearly 600 diverse species. These species, including the conger eel and moray, are grouped into about 20 families.
Eels inhabit shallow coastal waters throughout the world. Most eels have no scales and are protected by a layer of slippery mucus. Their dorsal and anal fins run from close to the head to the often nonexistent tail fin and provide the thrust for these agile swimmers. Most species are less than 3 feet long.
CONGER EEL: Conger eels occur in all oceans. They have long, scaleless, snakelike bodies with continuous dorsal, caudal, and anal fins, as in other typical eels. The average length is between 3 and 6 feet. One conger eel, however, is known to grow up to 9 feet long and is found as deep as 820 feet. Conger eels live in rocky crevices where the water is about 100 feet deep, but they breed in temperate waters that are 6000 to 9000 feet deep. The eggs float free in middle depths until the larvae hatch. Their name particularly applies to a species found in the Atlantic Ocean. Conger eels make up the family Congridae, but the name particularly applies to the species Conger conger.
FRESHWATER EELS: Freshwater eels return to the ocean to spawn. Freshwater eels make up the family Anguillidae. These eels are the most prized as food and are often sold in markets. They have dense capillary systems close to the skin that can absorb oxygen directly from air or water. The eels hatch from eggs as leptocephali, which are transparent, very thin, leaflike larvae bearing little resemblance to the adults. They drift about the ocean surface for as long as three years, feeding on plankton, then metamorphose into round-bodied young eels called elvers, or grass eels, and feed on fish, crabs, and other invertebrates until they reach full, adult size. The migration and reproduction of freshwater eels remained a mystery until the 20th century, when their spawning beds were discovered in the Sargasso Sea between Bermuda and Puerto Rico.
When the very similar European eel (classified as Anguilla anguilla) and the American eel (classified as Anguilla rostrata) reach maturity in freshwater lakes and rivers, they take watercourses, sometimes slithering overland through dewy grass, to reach the ocean, where they swim or drift with currents for as long as a year until they reach the sluggish, weed-filled Sargasso. Here the eels spawn in deep water. Before dying, the female produces as many as 20 million free-floating eggs. The leptocephali drift with the Gulf Stream, taking one year to reach North America and three years to reach Europe. By this time they have become elvers and accumulate at the mouths of rivers in great masses. The yellow elvers swim upstream and feed on lake-bottom and river-bottom animals until they become adults. At maturity their bodies become black and silver.