Demystifying Creek Shrimp: A Complete Guide to These Sweet, Succulent Crustaceans

Shrimp are Americas most valuable and most popular seafood. There are three kinds of penaeid shrimp that live in South Carolina. They are the brown shrimp (Farfantepenaeus aztecus), the white shrimp (Litopenaeus setiferus), and the pink shrimp (Litopenaeus duorarum). Brown and white shrimp are more common than pink shrimp. All three taste the same.

In the water around South Carolina, grass shrimp and other small shrimp species are often mistaken for penaeid shrimp juveniles, but they are not useful for fishing or hunting. Rock shrimp are found in the offshore waters of South Carolina and are fished for food off the East Coast of Florida. Their name comes from their thick, hard shells. The mantis shrimp (not a true shrimp) is a flattened, inshore crustacean sometimes incorrectly called “rock shrimp. ” Mantis shrimp can be eaten, but have little meat of poor quality.

Identification of Shrimp Species

The three types of shrimp that can be eaten look a lot alike, but if you look closely, you can tell them apart. White shrimp has a lighter color than brown or pink shrimp. White shrimp have tail flippers, which are called uropods. They are black near the base and bright yellow and green around the edges. Brown shrimp tails are red, dark green, and occasionally light blue in color. Pink shrimp have a light blue-purple tail and a dark red spot on the side of their abdomen most of the time. There are grooves on the top middle part of the head and the top middle part of the lower abdomen of brown and pink shrimp. The grooves on pink shrimp are slightly narrower than those of brown shrimp. White shrimp do not have grooves and typically have much longer antennae and a long rostrum (horn).

Brown, white, and pink shrimps have similar life cycles. Spawning usually occurs in the ocean, ranging from near the beaches to several miles offshore. A single female produces between 500,000 and 1,000,000 eggs and may spawn several times. Brown shrimp spawn during October and November, and occasionally later. White shrimp typically spawn in the spring and early summer. The exact timing of the spawning period depends on water temperature.

During mating, the male transfers a packet of sperm, called a spermatophore, to the female. Brown and pink shrimp mate when the females exoskeleton is soft, immediately after molting. The spermatophore is covered by two “plates” that hold it in place. Females may spawn days later. White shrimp mate between molts when the exoskeleton is hard. The spermatophore is glued to the underside of the female, and spawning occurs almost immediately. When eggs from both species are thrown past the spermatophore, they get fertilized and sink to the bottom of the ocean. After about 12 to 24 hours, they hatch into tiny larvae that rise into the water column.

The shrimp goes through about 10 stages of larvae before it reaches the post-larval stage, which takes about two weeks. During the first stage, the larvae look like tiny mites. Postlarvae look like miniature adult shrimp. Brown shrimp postlarvae remain in the ocean bottom sediments during the winter. The postlarvae become active when the ocean warms up in late February and early March. They ride the currents of the tides into the estuaries. About two weeks after spawning, in late May or early June, white shrimp postlarvae move into estuaries. With each high tide, they move further in. For shrimp larvae and juveniles, death rates are very high; only 1% to 2% of eggs that are laid become adults.

Postlarval shrimp settle out in the shallow waters in the upper ends of salt marsh tidal creeks. Shrimp stay in this “nursery habitat” for about two or three months, growing to about four inches long. During high tide, juveniles move into the marsh grass to feed and escape predators. At low tide, when the water level is below the salt marsh grass, shrimp gather in creek beds. The smallest shrimp stay close to the creek bank while larger juveniles prefer deeper water. In unusually clear water, shrimp seek the deepest areas available to avoid predatory birds, fish, and crabs.

Both brown and white shrimp prefer muddy bottom, but pink shrimp do best on a sand/shell bottom. Pink shrimp larvae and juveniles are hard to find in South Carolina’s mostly muddy estuaries, but post-larvae are pretty common.

Young shrimp grow quickly, up to 2. 5 inches per month, molting their exoskeleton as they grow. Small shrimp molt several times per week, but molting slows as they become larger. Shrimp can tolerate a wide range of salinities. For white shrimp, the best place to grow up is in saltwater that is 25 to 40 percent seawater and 35 to 65 percent seawater for brown shrimp. But shrimp can do well in water that is close to 100% saltwater, like in Murrells Inlet, or in water that is 10% saltwater, like in the Cooper River near Charleston.

Shrimp move three different ways, using either their walking legs, swimming legs, or with a sudden tail snap. Shrimp can walk short distances, but when they’re moving long distances, they swim up to two to five miles every day. When a shrimp wants to get away from an animal that wants to eat it, it tightens its abdominal muscles. This makes its tail snap, which moves the shrimp backwards. White shrimp commonly use this method to jump from the water.

When shrimp get bigger, they leave the nursery area and move toward the ocean with the tide, especially at night. Shrimp move from the shallow estuary creeks into coastal rivers when they are about four inches long. As they move into the lower parts of sounds, bays, and river mouths, where they gather just before going into the ocean, they keep getting bigger.

When white shrimp are in the staging areas, they feed in nearby shallow areas at night. Brown shrimp, on the other hand, prefer to stay in deeper waters at night. When there are lots of shrimp, they move into the ocean when they are four to five inches long. When the population is smaller, however, shrimp may be six inches or more before they leave the estuaries. Shrimp growth rates slow down in tidal creeks where there are a lot of them because they have to compete for food and spend more time protecting their space instead of eating. Low salinities due to heavy rainfall cause juvenile shrimp to leave nursery areas early, reducing growth and survival.

When it rains a lot, most white shrimp move into the ocean in August, which is about a month early. This can make it hard to catch shrimp with bait and for commercial trawlers in October, which is usually one of the best months for shrimp fishing. Charleston Harbor and Winyah Bay, which get a lot of water from upstate rivers, are the areas most badly affected.

If there isn’t a lot of rain or river flow in the fall, white shrimp stay in the estuaries until the water cools to between 60 and 65 degrees. Migration into the ocean occurs during the large tides associated with new and full moons.

Shrimp seldom live more than eight or nine months. In July 1979, a commercial shrimper caught a white shrimp that was just over ten inches long. It was the world’s largest white shrimp. That shrimp was probably about 14 months old.

Shrimp are bottom-feeding omnivores, eating most organic materials – animal or plant – they encounter at the bottom. Smaller shrimp eat things that are in the sediment, while bigger shrimp eat polychaete worms, amphipods, nematodes, crustacean larvae, isopods, copepods, small fish, grass shrimp, fiddler crabs, and squareback crabs. Shrimp also eat other shrimp.

Several diseases affect shrimp. One of the most common, cotton disease, is caused by a single cell protozoan parasite called a microspordian. These tiny animals invade various tissues of the shrimp, turning the affected areas grey or white. Cotton disease can affect only the head or the reproductive system, but most of the time it affects the whole muscular system of the shrimp. Large white shrimp are most likely to get cotton disease, but small white shrimp and other species can also get it. At times, up to 15 percent of the population of white shrimp has cotton disease. Seventy to eighty percent of white shrimp may have a minor infection, which looks like small spots of diseased tissue. These spots are usually only on the head. Large individuals with cotton disease often have a dark blue or black band across the abdomen. Eating shrimp that have cotton disease won’t hurt you, but it will change the texture and taste of the meat.

Another disease that is common along the Atlantic coast is called black gill or brown gill disease. It was first seen in 1999. This disease is caused by another single celled protozoan known as apostome.

This parasite’s swarming stage, which is called a tomite, seems to stick to and enter the shrimp’s gills, turning them brown or black. It hurts the shrimp until it molts and sheds its old shell, which covers the gills on the outside.

Black gill disease usually begins in mid August, peaks in September, and slowly disappears in October. The disease doesn’t kill the shrimp directly, but it makes them less able to breathe, which makes them more vulnerable to predators and changes in temperature. The parasite is not a danger to humans.

A lot of shrimp died in mariculture farm ponds around the world in the 1980s. This helped scientists learn more about how viruses affect shrimp. These viruses are relatively common and can cause mortalities in intensive shrimp farming operations. Shrimp viruses pose no danger to humans and have not negatively affected wild shrimp in South Carolina. However, DNR requires that live shrimp imported for shrimp farming be certified as free of diseases.

Shimmering shrimp leave the salty water as they get bigger and move slowly toward the saltier ocean water. Most shrimp probably leave the marsh creeks during ebb tides and this may be more pronounced at night. Shrimp usually begin moving into coastal rivers when they reach about 4 inches in length. More fish grow in the rivers until the shrimp are ready to move into the lower parts of bays, sounds, and river mouths. Some biologists call these lower areas “staging areas” because they are where shrimp gather right before they go out to sea. After the white shrimp have staged, many of them will move to the shallow edges to feed at night. Brown shrimp don’t seem to do this as much as white shrimp do; at night, they prefer to stay in deeper water. When there are a lot of shrimp, they may move into the ocean when they are about 4 to 5 inches long. But when there aren’t many shrimp around, the average size may be 6 inches or more before they leave the estuaries. The size difference between years with lots of stocks and years with few stocks seems to be linked to something called densitydependent growth. When large concentrations of shrimp are in the tidal creeks, growth rates are reduced. This could be because there is a lot of competition for food, or each shrimp could be protecting its own space more than eating. Heavy rainfall, resulting in very low salinities, can force juvenile shrimp from nursery areas. When forced into open-water areas that aren’t good for them, growth and survival rates are lower because there is less food and better places to live.

Extreme weather conditions, like droughts or unusually warm fall weather, can make it take longer for white shrimp to leave for the ocean. White shrimp with tags that were released into the coastal waters of South Carolina in September have been seen to stay in the estuaries for at least two months before moving out to sea. Heavy rain or river flow, along with drops in water salinity (the amount of salt in the water), has been known to push shrimp into the ocean before they should.

It’s possible for most of the white shrimp to move into the ocean in August if it rains a lot. Because of this, it would not be a good time to bait shrimp or catch shrimp with commercial trawlers in October, which is usually one of the best months for shrimp fishing. Charleston Harbor and Winyah Bay, which get a lot of water from upstate rivers, are usually the areas that are most badly affected.

If it doesn’t rain or flood a lot in the fall, white shrimp stay in the estuaries until the water temperature drops to between 60 and 65˺F. They then move to other areas, mostly during the big tides that happen when the moon is new or full. Some experienced shrimpers claim that the condition known as red legs is indicative of the onset of migration. This phenomenon has not been investigated scientifically.

Shrimp trawlers, boats that are 17 to 85 feet long, do most of the commercial fishing in South Carolina. Trawling can only be done in the ocean, but trawlers can work in the lower parts of Winyah and North Santee Bays for a short time in the fall. Most shrimpers trawl within three or four miles of the beach.

The commercial shrimp trawling fishery has three seasons. The first is the so-called roe shrimp season in May or June. The DNR declares this season open when they think there are enough eggs to make a good fall harvest. The roe shrimp season lasts for less than a month, and the number of landings (catches) depends on how bad the winter was the year before. Following mild winters, heads-off landings are often 400 to 600 thousand pounds. After severe winters, landings of roe shrimp are usually less than 50 thousand pounds and often zero.

The second season is for brown shrimp. Usually, this fishery starts in June and ends in August. However, big hauls of brown shrimp have been caught in October in years when the brown shrimp population was high. Good years for brown shrimp have landings of 1. 3 to 2. 0 million pounds (heads off).

The fall white shrimp season typically produces the largest catch. These shrimp are the offspring of the spring spawn. Once a year, in September and October, the commercial fleet brings in the most young white shrimp. The season usually lasts through December and sometimes into January.

The channel net or set net fishery occurs in Winyah and North Santee bays. This limited fishery usually starts in September and goes through December 15 if there are enough shrimp of the right size and number to make it worth the money. This fishery involves the use of anchored nets that are very similar to shrimp trawls. Long wooden poles hold the mouths open, and shrimp are caught as the tide carries them out to sea. In some years, this fishery can be very productive, with high catch rates and low costs to run.

Cast nets and seines are used to catch brown shrimp for fun in the state’s tidal creeks. This usually starts in early June. In late July or early August, white shrimp are first caught in the creeks. By late October, they have usually moved to the ocean. The law says that the shrimp baiting fishery for white shrimp can only last for 60 days. It starts at noon on the last Friday before September 15. People also use drop nets to catch shrimp for fun from docks and seawalls in the fall, when the bigger white shrimp are moving out to sea. Unlike seines and cast nets, drop nets require bait. See DNR regulations for the types of nets that can be used for recreational shrimping.

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FAQ

What is the best shrimp to eat?

What are creek shrimp in South Carolina?

Why is it called calabash shrimp?

Where do the best shrimp come from?

What kind of water do shrimp eat?

The smallest shrimp stay close to the creek bank while larger juveniles prefer deeper water. In unusually clear water, shrimp seek the deepest areas available to avoid predatory birds, fish, and crabs. Both brown and white shrimp prefer muddy bottom, but pink shrimp do best on a sand/shell bottom.

What is a brown shrimp?

Also known as “brownies,” brown shrimp are a warm water species (farfantepenaeus aztecus, via NOAA) that inhabit the waters off the Atlantic coast and the Gulf of Mexico. According to a study out of Texas A&M, the flavor of each of the major Gulf shrimp species — brown, pink, and white— varies according to their preferred habitat.

Are there shrimp in South Carolina?

In South Carolina waters, other small species of shrimp, such as grass shrimp, are easily confused with juveniles of penaeid shrimp but have no commercial or recreational value. Rock shrimp, named for their thick, hard shells, occur in South Carolina’s offshore waters and are commercially fished off Florida’s East Coast.

What is a white shrimp?

Western White shrimp is a slightly grayish shrimp with good flavor and texture and is highly regarded in the United States. Our Mexican Whites, also called Blue Shrimp because of their greenish-bluish tint, is found from the Baja to Peru, and is a major species on the Pacific Coast of Mexico.