“Megalops atlanticus”
You have to feel for the Tarpon, they’re the classic victims of their own success. Just one look at them and you know this is a fish that’s been around for a while. Fossilized evidence confirms it with roughly 125 million years of evolutionary development under their belts, these fish have become one of the ocean’s most efficient predators. They thrive in either saltwater or freshwater, they can tolerate oxygen-poor environments thanks to their unique air bladder, they can move at huge speed when hunting prey and that bucket-sized vacuum for a mouth ensures that when something goes in, it stays in. Ironically, this incredible physiology that has allowed them to survive for so long is exactly what has turned them into such a prized sport fish. Externally, the almost vertical, silvery sides made up of large scales are the most distinctive feature. The Tarpon has a superior mouth with the lower mandible extending far beyond the gape. The fins contain no spines, but are all composed of soft-rays. The dorsal fin appears high anteriorly and contains 13-15 soft-rays with the last ray greatly elongated into a heavy filament. The caudal is deeply forked and the lobes appear equal in length. The anterior portion of the anal fin is deep and triangular. The fin has 22-25 soft-rays with the last ray again elongated as in the dorsal fin, but shorter and only present in adults. The Tarpon has large pelvic fins, and long pectoral fins containing 13-14 soft-rays. The synonym “Silver King” refers to the predominant bright silver color along the sides & belly of the Tarpon. Dorsally, Tarpon usually appear dark blue to greenish-black. However, the color may appear brownish or brassy for individuals inhabiting inland waters. The dorsal & caudal fins have dusky margins and often appear dark. Tarpon populate a wide variety of habitats, but are primarily found in coastal waters, bays, estuaries and mangrove-lined lagoons within tropical, subtropical & temperate climates (45° N-30° S). The normal habitat depth extends to 98 feet (30 meters). Although a marine fish, Tarpon can tolerate euryhaline environments (0-47 parts per thousand) and often enter river mouths & bays and travel upstream into freshwater. In addition, Tarpon can also tolerate oxygen-poor environments due to a modified air bladder that allows them to inhale atmospheric oxygen. The only variable that seems to limit their choice of habitat is temperature and research shows tarpon to be thermophilic. Rapid decreases in temperature have been known to cause large Tarpon kills. During such temperature drops, Tarpon usually take refuge in warmer deeper waters.
The Tarpon employs different feeding techniques depending upon its level of growth and development. Tarpon breed offshore in warm, isolated areas. Females have high fecundity and can lay up to 12 million eggs at once. Stage I larvae absorb nutrients directly from seawater through the integument. Zooplankton (copepods & ostracods), insects and small fish compose the diet of stage II & III Tarpon larvae and small juveniles. As Tarpon grow, they move away from zooplankton as a chief food source and prey more exclusively on fishes (especially poecilids and cyprinodontids) and larger invertebrates such as shrimp & crabs. While juvenile Tarpon are planktivorous, adult Tarpon are strictly carnivorous and mostly feed on mid-water prey such as mullets, pinfish, marine catfishes, needlefish, sardines, shrimp and crabs. Tarpon feed during both day & night. Since the Tarpon have minute teeth only, they usually swallow the prey whole. In Florida, the commercial sale of Tarpon is prohibited. Recreationally, the Tarpon provides a huge industry for charter captains. In the Florida Keys, many of these guides make the bulk of their earnings from April through June, the prime months for Tarpon migrations. Recreational anglers must obtain a Tarpon tag (purchased prior to catching) in order to possess a Tarpon. However, most Tarpon guides & anglers esteem the Tarpon and nearly always release the fish unharmed. Most mortality attributed to human activity occurs from injuries incurred when being landed, such as “gut hooking” or sharks that take advantage of the hooked fish. Though conscientious anglers attempt to break the line to release the Tarpon from restraint, sharks occasionally leave the angler with only half of the fish. Although this is considered an important game fish, the flesh is not highly prized in the United States, the natives of Panama, the West Indies and Africa consider the Tarpon a delicacy and sell it on a small scale. Female Tarpon can grow to lengths of over 8.2 feet (2.5 meters) and reach weights of near 355 pounds (161 kilograms), with the males generally smaller. Tarpon are slow-growing fish and do not obtain sexual maturity until reaching an age of 6-7 years and a length of about 4 feet (1.2 meters). Tarpon weighing about 100 pounds (45.4 kilograms) typically fall between 13-16 years of age. Male Tarpon attain lifespans of over 30 years, while females may live longer than 50 years. A female Tarpon held in captivity at the John G. Shedd Aquarium in Chicago, died in 1998 at the age of 63. Tarpon inhabit a large range on both sides of the Atlantic Ocean. The range in the Eastern Atlantic Ocean extends from Senegal to the Congo. In the Western Atlantic Ocean, the fish primarily inhabit warmer coastal waters concentrating around the Gulf of Mexico, Florida and the West Indies. However, Tarpon are not uncommon as far north as Cape Hatteras and the extreme range extends from Nova Scotia in the north, Bermuda and to Argentina to the south. Tarpon have been found at the Pacific terminus of the Panama Canal and around Coiba Island.
