Southern Flounder Information

Southern flounder is the most recreationally popular and economically important of the three main flounder species found in South Carolina. (Photo: SCDNR)

Everything You Always Wanted to Know about Flounder
Dr. Mike Denson, director of the Marine Resources Research Institute 
from The Fishing Wire

Last month, SCDNR shared important information about the documented decline in southern flounder across our region, including a link to a public survey. Many thanks to the nearly 2,000 of you who have already taken the survey, which will remain open until January 31, 2020. Later this season, we’ll analyze and share the survey results. 

In the meantime, we wanted to let our biologists answer some of the most frequently asked questions on this topic. Pulling from recurring topics at fishing club talks, social media, and public presentations, we posed a series of questions to the SCDNR biologists most knowledgeable about flounder. Find their answers below – and if you’ve been wondering about something that isn’t answered below, please leave your question in the comments.

Why are we hearing about the flounder decline now? This first-ever regional evaluation of the health of southern flounder along the southern Atlantic coast (from NC through the east coast of FL) was completed, peer-reviewed, and published in 2019. Until this study, there was no complete picture of the status of this population upon which to accurately assess condition and consider necessary corrective actions to ensure the long-term health of the stock and sustainability of the fishery.– Mel Bell, director of the Office of Fisheries Management

How will North Carolina’s actions impact South Carolina’s flounder?North Carolina’s planned actions will likely have a positive effect on flounder in South Carolina, but since flounder are all part of the same population regionally, the effectiveness and timeframe of their recovery also depends on other states also taking action to reduce fishing pressure and allow the population to rebuild to sustainable levels.– Chris McDonough, fisheries biologist 

If the flounder population is in such bad shape, why did I have a good day/month fishing for flounder? 
There’s a reason why you may still have success even when the overall population is down. When a population is very healthy and there are lots of available fish, they will be spread out throughout the estuary and on lots of different types of habitat. Some habitats are very attractive to flounder and include features like current eddies, shell beds, a transition between mud and sand bottom, and lots of available baitfish and shrimp. There are other, barer areas that don’t have all of these fish-attracting features.

When the population is large, there will be fish on both the most attractive and the less attractive habitats, because space is at a premium. As the population decreases, fish tend to disappear first from the less attractive habitats, either because they were removed and not replaced or because more room became available on the most attractive habitats and they moved to those locations. The absolute best habitats tend to hold fish, even when the population is small. That means a skilled angler that is fishing or gigging on the most attractive habitats may have some success until the point at which the population crashes. – Matt Perkinson, biologist and saltwater angler outreach coordinator

What impact does the commercial industry have on South Carolina’s flounder population? In recent years, the total commercial landings of flounder (from trawling and gigging) have made up less than 1% of the flounder harvested in South Carolina. Changes in federal and state commercial fishery-related laws since have resulted in commercial flounder landings shrinking to less than 2,000 pounds per year, while recreational landings are in the neighborhood of 350,000 to 400,000 pounds annually. Another important question about commercial fishing that frequently comes up is the impact of the commercial shrimp trawl fishery and the bycatch of flounder. 

While southern flounder are frequently caught as a bycatch species in the shrimp fishery, the impact of that on the population is not likely as significant as some might perceive, for several reasons. First, South Carolina has not allowed commercial trawling in inshore estuarine waters (where > 90% of southern flounder occur) since 1988, and gill nets were banned from estuarine waters in 1990. Second, southern flounder occur primarily in estuarine waters and only move to nearshore and offshore habitats in the winter to spawn and escape colder estuarine waters. The general decline in southern flounder has occurred after commercial trawling was banned from inshore waters. Additionally, southern flounder are one of three flounder species from the same family commonly caught in South Carolina, the other two being gulf flounder and summer flounder.

  Both summer and gulf flounder are more common offshore. SCDNR surveys 0-3 miles offshore, where a majority of shrimp trawling occurs, have found that summer flounder make up the majority of the flounder (78.1%) followed by southern flounder (16.3%) and gulf flounder (5.6%). So, while there certainly is some southern flounder by-catch in the shrimp trawl fishery, the overall impact it has on the population has likely been a minor component of the overall decline in southern flounder.– Mel Bell, director of the Office of Fisheries Management, and Chris McDonough, fisheries biologist

What impact does gigging have on South Carolina’s flounder population? From past estimates, we believe that somewhere in the neighborhood of 15% of licensed saltwater fishermen may participate in flounder gigging in a given year. Surveys of flounder giggers have shown typically larger landings per person than are estimated for the average recreational hook and line flounder fishing trip. However, given the limited number of available days with the proper conditions for tide, moonlight, water clarity, current, etc. it is most likely that total recreational flounder gig landings are much less than total estimated recreational hook and line flounder landings. – Mel Bell, director of the Office of Fisheries Management

Can flounder be stocked to help the population?The SCDNR has grown flounder in captivity for a number of years to look at the potential of producing them for stock enhancement. Flounder have a very complex life history, making them very difficult to produce in large numbers. Flounder begin life like all other fish, with eyes on each side of their head. They then go through a physical change, called metamorphosis, where one eye migrates to the other side of the body and they begin to flatten out and drop out of the water column to live their lives on the bottom. During that time, they are very sensitive to changes in water temperature. 

If it’s not just the right water temperature, all the flounder become males, which means they don’t grow to a large size like the females and will not even make it to the minimum harvest size of 15 inches.In addition, flounder grown in captivity are very sensitive to having the right nutrients in their diets. If it’s not “just right,” not many will survive and a high percentage of those that do will be partially albinos that are easily picked off when released into the wild.  

We have conducted many experiments over the years but have not been able to produce enough fish that were exactly like wild fish – with the same coloration and the same ratio of males and females – to feel like we could make a contribution to the wild population.  Southern flounder (Photo: E. Weeks/SCDNR)What’s more, as we have learned about flounder life history through tag-recapture, most flounder that grow up in South Carolina leave to spawn before they reach legal size and are mostly recaptured in Georgia waters, making a flounder stocking program less a benefit for anglers in South Carolina.