Shrimp Are America’S Most Pink Shrimp Are Slightly Narrower Hard
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Shrimp are America’s most pink shrimp are slightly narrower hard. The spermatophore is glued valuable and most popular seafood. than those of brown shrimp. White to the underside of the female, South Carolina is home to three shrimp do not have grooves and and spawning occurs almost species of the penaeid shrimp: typically have much longer antennae immediately. Eggs of both species brown shrimp (Farfantepenaeus and a long rostrum (horn). are fertilized as they are ejected past aztecus), white shrimp (Litopenaeus Life History the spermatophore, and sink to the setiferus), and pink shrimp Brown, white, and pink shrimps ocean floor. After about 12 to 24 (Litopenaeus duorarum). Brown and have similar life cycles. Spawning hours, they hatch into tiny larvae white shrimp are more common usually occurs in the ocean, ranging that rise into the water column. than pink shrimp. All three taste the from near the beaches to several The initial larval stage, during same. miles offshore. A single female which the shrimp looks like a In South Carolina waters, other produces between 500,000 and tiny mite, is followed by about small species of shrimp, such as 1,000,000 eggs and may spawn 10 larval phases before reaching grass shrimp, are easily confused several times. Brown shrimp spawn the post-larval stage after about with juveniles of penaeid shrimp but during October and November, and two weeks. Postlarvae look like have no commercial or recreational occasionally later. White shrimp miniature adult shrimp. Brown value. Rock shrimp, named for their typically spawn in the spring and shrimp postlarvae remain in the thick, hard shells, occur in South early summer. The exact timing of ocean bottom sediments during Carolina’s offshore waters and are the spawning period depends on the winter. As the ocean warms commercially fished off Florida’s water temperature. in late February and March, these East Coast. The mantis shrimp (not During mating, the male postlarvae become active and ride a true shrimp) is a flattened, inshore transfers a packet of sperm, called tidal currents into the estuaries. crustacean sometimes incorrectly a spermatophore, to the female. White shrimp postlarvae move into called “rock shrimp.” Mantis shrimp Brown and pink shrimp mate the estuaries about two weeks after can be eaten, but have little meat of when the female’s exoskeleton is spawning, usually in late May and poor quality. soft, immediately after molting. June, moving further in with each Identification of Shrimp The spermatophore is covered high tide. Death rates are very high Species by two “plates” that hold it in for larval and juvenile shrimp; less All three of the edible shrimp place. Females may spawn days than one or two percent of the eggs species look very similar, but you later. White shrimp mate between spawned survive to adults. can tell them apart if you look molts when the exoskeleton is closely. White shrimp has a lighter color than brown or pink shrimp. eye carapace 1st abdominal segment rostrum 2nd abdominal segment Tail flippers (uropods) on white 3rd abdominal segment shrimp are black near the base 4th abdominal segment with bright yellow and green along 5th abdominal segment the edges. Brown shrimp tails are 6th abdominal segment red, dark green, and occasionally light blue in color. Pink shrimp antennae have a light purplish-blue tail, and telson usually a dark red spot on the side of the abdomen. Brown and pink shrimp have grooves along the upper midline of the head and the uropods upper midline of the lower region walking legs (5 pairs) of the abdomen. The grooves on swimming legs (5 pairs) Nursery Habitat can walk short distances, when during the large tides associated Postlarval shrimp settle out in the migrating long distances, they swim with new and full moons. shallow waters in the upper ends as much as two to five miles a Shrimp seldom live more than of salt marsh tidal creeks. Shrimp day. To escape predators, a shrimp eight or nine months. The record stay in this “nursery habitat” contracts its abdominal muscles, white shrimp (just over ten inches) for about two or three months, which causes the tail to snap, and was caught by a commercial growing to about four inches long. propels the shrimp backwards. shrimper off Seabrook Island During high tide, juveniles move White shrimp commonly use this in July 1979. That shrimp was into the marsh grass to feed and method to jump from the water. probably about 14 months old. escape predators. At low tide, As shrimp become larger, they Food when the water level is below the leave the nursery area and move Shrimp are bottom-feeding salt marsh grass, shrimp gather in toward the ocean on the outgoing omnivores, eating most organic creek beds. The smallest shrimp tide, particularly at night. Shrimp materials – animal or plant – they stay close to the creek bank while move from the shallow estuary encounter at the bottom. Smaller larger juveniles prefer deeper creeks into coastal rivers when shrimp pick food off the sediment water. In unusually clear water, they are about four inches long. while larger shrimp become shrimp seek the deepest areas They continue to grow as they predators, feeding on polychaete available to avoid predatory birds, move into the lower reaches of worms, amphipods, nematodes, fish, and crabs. sounds, bays and river mouths crustacean larvae, isopods, Both brown and white shrimp where they gather just before copepods, small fishes, grass prefer muddy bottom, but pink moving into the ocean. shrimp, fiddler crabs, and square- shrimp do best on a sand/shell When white shrimp are in the back crabs. Shrimp also eat other bottom. In South Carolina’s mostly staging areas, they feed in nearby shrimp. muddy estuaries juvenile and adult shallow areas at night. Brown Disease pink shrimp are scarce, although shrimp, on the other hand, prefer Several diseases affect shrimp. their post larvae are relatively to stay in deeper waters at night. In One of the most common, cotton common. years when shrimp are abundant, disease, is caused by a single Growth they migrate into the ocean when cell protozoan parasite called a Young shrimp grow quickly, up they are between four and five microspordian. These tiny animals to 2.5 inches per month, molting inches long. When the population invade various tissues of the their exoskeleton as they grow. is smaller, however, shrimp may shrimp, turning the affected areas Small shrimp molt several times be six inches or more before they grey or white. Cotton disease per week, but molting slows as leave the estuaries. When shrimp may affect only the head or the they become larger. Shrimp can are more concentrated in the tidal reproductive system but often tolerate a wide range of salinities. creeks, growth rates slow due spreads throughout the shrimp’s The ideal nursery habitat has to competition for limited food, entire muscular system. Cotton salinity about 25 to 40 percent or each shrimp spending more disease is most common in large seawater for white shrimp and time protecting its space instead white shrimp, but can affect small 35 to 65 percent seawater for of feeding. Low salinities due white shrimp, as well as other brown shrimp. Shrimp can do to heavy rainfall cause juvenile species. At times, up to 15 percent well, however, in salinities near shrimp to leave nursery areas early, of the population of white shrimp 100 percent seawater (such as in reducing growth and survival. has cotton disease. Minor infection Murrell’s Inlet) or in 10 percent In a wet year, the majority of (white shrimp having small specks seawater (such as the Cooper River white shrimp move into the ocean of diseased tissue) may reach levels near Charleston). in August, about a month early. of 70 or 80 percent, but these Offshore Migration This can result in a poor shrimp specks are usually isolated to the Shrimp move three different baiting season and a poor harvest head. Large individuals with cotton ways, using either their walking by commercial trawlers in October, disease often have a dark blue or legs, swimming legs, or with a which is normally one of the better black band across the abdomen. sudden tail snap. While shrimp months for shrimping. Areas most Shrimp with cotton disease are not severely affected are Charleston harmful if eaten, but the disease Harbor and Winyah Bay, which affects the texture and flavor of the receive relatively large amounts of meat. upstate river discharge. A second condition common If there is not significant rainfall along the Atlantic coast is called and/or river discharge during black gill or brown gill disease, fall, white shrimp remain in the first seen in 1999. This disease is estuaries until water temperature caused by another single celled Rock Shrimp falls to about 60-65 degrees. protozoan known as apostome. Migration into the ocean occurs The swarming stage of this parasite, less than 50 thousand pounds and that can be used for recreational called a tomite, apparently often zero. shrimping. attaches to and penetrates the The second season is for brown Changes in the Shrimp shrimp’s gills, turning them brown shrimp. This fishery usually begins Population Size or black. The shrimp is affected in June and ends in August, Shrimp populations experience until it molts and casts off its old although significant quantities of relatively dramatic fluctuations. shell, which includes the outer brown shrimp have been landed Annual commercial shrimp covering of the gill. in October during years when the landings have ranged from 1.3 Black gill disease usually population of brown shrimp was to 6.8 million pounds.