Southern Flounder (Paralychthys lethostigma)
Anne Henderson
"We've got 'em, lots of 'em. It's one of the places on the Gulf where you can come and target flounder and catch them."
- Joe Brown |
Taxonomy
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Pleuronectiformes Family: Paralichthyidae Genus: Paralichthys Species: lethostigma |
The Southern flounder is found here in South Carolina and surrounding states. Southern flounder are flatfishes that live on the bottom of the ocean floor. They ambush prey by camouflage and lying sideways flat on the ocean floor. These fish are now considered over-fished and concern for their survival has increased. Flounder are caught by trawls and a lot of the time are a victim of bycatch. By creating awareness of regulations and laws concerning the flounder, people can begin to help their numbers increase over time.
The Southern flounder is a benthic fish, meaning it lives on the bottom of the ocean. They are often known as flatfishes because they lie on one side of their body for their entire life. They are the most abundant species of the Paralicthys genus. This particular flounder is a left-eye species so both eyes are located on the left side of the head and this side is the side that is facing up. They have large mouths with sheathed teeth. Their body color varies from a light to dark brown with dark spots. The bottom side of its body is all white [2]. Males will usually group up to 12 inches, while females can grow up to 25 inches and weigh as much as 17 lbs. They can be found from North Carolina down to Florida, and as far west as Texas. They prefer soft sandy or muddy bottoms so they can easily blend in with their surroundings. They live in estuary habitats, and migrate to offshore waters for reproduction [2].
After adult flounders lay their eggs in offshore waters, they will return to their estuaries. The eggs hatch and will begin their larval stage. In this stage these fish will swim like all other fish around them, and will have eyes on each side of their head. When the flounder are reaching the end of this stage they will migrate to the bottom of the seafloor and begin to morph. In the beginning of the juvenile stage the flounder’s skeleton begins to change, the nervous system and muscle tissue will rearrange, which will allow the fish to be able to live sideways on the bottom of the sea. During this same stage the fish’s right eye will begin to move to the left side of the head. Following all these changes the top part of the body’s skin will begin to darken. By this time the flounder have migrated back to the estuaries, usually the same ones that their parents are located [3].
A juvenile flounder diet consists of eating copepods, amphipods, shrimp, polychaete worms, and small fish. Adult flounder will eat the same things but are able to also eat crustaceans, and fish like anchovies, and striped mullet. They are ambush predators. They will camouflage themselves and wait for prey to come along and then surprise the prey and catch and eat them [5].
The flounder possesses many different evolutionary adaptions that make them successful predators. One is the movement of the eyes to the same side of the head. This allows the flounder to have sight of what is above it at all times, which protects them from predators and allows them to see prey coming [2]. Another adaption is the color pigmentation in its skin. This pigmentation allows the fish to change colors, so it can camouflage itself more effectively to match their surroundings. A third adaption is how the fish can bury itself into the sand to help with camouflage. The flounder can bend its dorsal and back fins which creates a depression allowing it to bury itself into the sand or mud. The flounder can also tolerate a wide range of salinity. This is what allows them to live in estuaries since estuaries are not as salty as other parts of the ocean [5].
After adult flounders lay their eggs in offshore waters, they will return to their estuaries. The eggs hatch and will begin their larval stage. In this stage these fish will swim like all other fish around them, and will have eyes on each side of their head. When the flounder are reaching the end of this stage they will migrate to the bottom of the seafloor and begin to morph. In the beginning of the juvenile stage the flounder’s skeleton begins to change, the nervous system and muscle tissue will rearrange, which will allow the fish to be able to live sideways on the bottom of the sea. During this same stage the fish’s right eye will begin to move to the left side of the head. Following all these changes the top part of the body’s skin will begin to darken. By this time the flounder have migrated back to the estuaries, usually the same ones that their parents are located [3].
A juvenile flounder diet consists of eating copepods, amphipods, shrimp, polychaete worms, and small fish. Adult flounder will eat the same things but are able to also eat crustaceans, and fish like anchovies, and striped mullet. They are ambush predators. They will camouflage themselves and wait for prey to come along and then surprise the prey and catch and eat them [5].
The flounder possesses many different evolutionary adaptions that make them successful predators. One is the movement of the eyes to the same side of the head. This allows the flounder to have sight of what is above it at all times, which protects them from predators and allows them to see prey coming [2]. Another adaption is the color pigmentation in its skin. This pigmentation allows the fish to change colors, so it can camouflage itself more effectively to match their surroundings. A third adaption is how the fish can bury itself into the sand to help with camouflage. The flounder can bend its dorsal and back fins which creates a depression allowing it to bury itself into the sand or mud. The flounder can also tolerate a wide range of salinity. This is what allows them to live in estuaries since estuaries are not as salty as other parts of the ocean [5].
In the 1980’s it was reported that the commercial catch of Southern flounder had declined by 20,000 metric tons and then people began to take notice of over fishing In response to these issues, a fishery management plan for the Southern flounder was developed and part of it was implemented in 2005 to achieve sustainable harvest in recreational and commercial fisheries [1]. Regulations are that the fish most be 14 inches or longer, there is a closed season from December 1 to the 31st, and a 100 lb. trip limit unless the individual has a License to Land flounder. There are also gear regulations to help prevent the younger flounder from being caught. For recreational fishing which is usually with a rod and reel, has a minimum of 15 inches that the fish must be in order to keep it. The harvest season for commercial fishing is January through November with peak catches in September through November. Recreational fishing is year round with peak catches from July through October. In 2010 the average commercial value was almost 4 million dollars, with almost 2 million flounder landed [1].
Southern flounder are commercially caught by bottom trawls. Trawling is when a fishing net called a trawl is pulled behind a boat and catches whatever on the bottom [2]. Trawling is the main and just about only way commercially these fish are caught. Recreationally, there are several different techniques fishermen use to catch these flatfishes. Another less known type of fishing is gig fishing. With this method, fishermen fish at night in shallow draft boats equipped with lights mounted on the bow. The lights are directed at the bottom of the water. One individual will have a spear. When the flounder is made visible because of the light the fisherman will spear the flounder, and then bring it into the boat [4]. Because this method is occurs at night in remote areas there isn’t much information on the number of fish harvested.
Southern flounder are commercially caught by bottom trawls. Trawling is when a fishing net called a trawl is pulled behind a boat and catches whatever on the bottom [2]. Trawling is the main and just about only way commercially these fish are caught. Recreationally, there are several different techniques fishermen use to catch these flatfishes. Another less known type of fishing is gig fishing. With this method, fishermen fish at night in shallow draft boats equipped with lights mounted on the bow. The lights are directed at the bottom of the water. One individual will have a spear. When the flounder is made visible because of the light the fisherman will spear the flounder, and then bring it into the boat [4]. Because this method is occurs at night in remote areas there isn’t much information on the number of fish harvested.
The Southern flounder is a fast-growing and is relatively short-lived species. The females in this species grow significantly faster than the males. Females are thought to be mature after the age of 3, and are about 28 inches at this age. So because of this fisheries will mainly try to target the females [1]. The main ways that they are caught is by gill nets and pound nets. In North Carolina, the spring and summer months are when the fish are targeted the most commercially and recreationally. In 2002, 3.5 million pounds of Southern flounder were landed commercially, which the 4th highest volume of finfish was landed. The increase in fishing for Southern flounder came about because there was a major decrease in the Summer flounder catch, and there began to be a high need for flounder in the sushi and sashimi market [1]. According to the Division of Marine Fisheries, from 2000-2009 the average commercial landings amount was 2, 605, 716, and then in 2009 specifically the commercial landing was 2, 395,385 pounds [2]. Estuarine gill nets harvest approximately 92 percent of the yearly commercial harvest in North Carolina [3]. As you can see in the graph the number of flounder is steadily on a decreasing pattern. The laws now protecting the flounder and the regulations on the amount and size a person can catch has helped the flounder to not have a sharper decrease but they are in fact still decreasing regardless [3]. In the Gulf States, another issue that emerges is the flounder getting caught by shrimp trawls as by catch. This means that fishermen, who are pulling nets to catch fish, incidentally catch many other things and flounder is usually one of the main organisms. Depending on the state’s regulations, if the flounder is of marketable size then it can be retained.
The Southern flounder is supposed to be landed whole/round form. Many surveys have shown that about half are sold whole, however it also shows that about 70 percent are sold fresh, and then the remaining are filleted and sold either fresh or frozen. There is also a huge Asian market that flounders are sold to. Because this fish closely resembles the Summer flounder and the Gulf flounder, identifying the different species becomes a major problem for researchers [1].
The Southern flounder is supposed to be landed whole/round form. Many surveys have shown that about half are sold whole, however it also shows that about 70 percent are sold fresh, and then the remaining are filleted and sold either fresh or frozen. There is also a huge Asian market that flounders are sold to. Because this fish closely resembles the Summer flounder and the Gulf flounder, identifying the different species becomes a major problem for researchers [1].
In 2005, in North Carolina the Southern flounder stock assessment was determined over-fished and that the over-fishing was still occurring. The Fishery Management Plan developed in 2005 has improved the over-fishing but then in 2009 the stock assessment showed that the fish were still being over fished So Amendment 1 was recommended to manage and restore North Carolina’s Southern flounder stock long term. Main factors in the amendment are to achieve sustainable harvest, solve by catch of under-sized flounder, and sustain environmental factors. These are all important things that each state needs to consider when dealing with sustaining these flounders. In North Carolina, the average flounder harvested decreased 75 percent from 1991 to 2007. Because the Southern flounder are the most economically important estuarine fin-fish species the need for the law and regulations are very important for their state. Another assessment by NCDMF concluded that the flounder were being over fished It also found the stock is largely dependent on incoming number of age 1 and age 2 flounder. Tagged flounder are recaptured and found very close to the place that they were tagged, and the tagging supports that the same fish come back to the same estuaries after spawning in offshore waters [2].
The need for flounder has increased because of the importance it has become for Japanese markets. In Japan, the flounder rank third in importance with annual production at approximately 7,000 MT [1].
The Southern flounder are being overfished but thanks to law and regulations by some of the states, they have plateaued and are not decreasing much more. Some assessments say that they are even improving while other research proves that they are still slightly decreasing. With the help of laws managing the fishing, the flounder are being given the opportunity to bounce back.
The need for flounder has increased because of the importance it has become for Japanese markets. In Japan, the flounder rank third in importance with annual production at approximately 7,000 MT [1].
The Southern flounder are being overfished but thanks to law and regulations by some of the states, they have plateaued and are not decreasing much more. Some assessments say that they are even improving while other research proves that they are still slightly decreasing. With the help of laws managing the fishing, the flounder are being given the opportunity to bounce back.
[1] Texas Park and Wildlife
www.tpwd.state.tx.us/huntwild/wild/species/flounder/
[2] South Carolina Department of Natural Resources
www.dnr.sc.gov/cwcs/pdf/Southernflounder.pdf
[3] SRAC Facts
http://srac.tamu.edu
[4] Alabama Department of Conservation and Wildlife
www.outdooralabama.com/fishing/fish/flounder
[5] North Carolina Department of Environment and Natural Resources
www.portal.ncdenr.org/web/mf/flounder_southern
www.tpwd.state.tx.us/huntwild/wild/species/flounder/
[2] South Carolina Department of Natural Resources
www.dnr.sc.gov/cwcs/pdf/Southernflounder.pdf
[3] SRAC Facts
http://srac.tamu.edu
[4] Alabama Department of Conservation and Wildlife
www.outdooralabama.com/fishing/fish/flounder
[5] North Carolina Department of Environment and Natural Resources
www.portal.ncdenr.org/web/mf/flounder_southern