FISH SPECIES BIO: Summer Flounder (Paralichthys dentatus)

By Peter J. Park 

The summer flounder (Paralichthys dentatus), also called “fluke” by NY anglers, belongs to the Family Paralichthyidae (Large-tooth Flounders). Flatfish can be categorized by the side on which both eyes are located. In Paralichthyids, the eyes and camouflaged exterior are on the left side of the body; these fish lie on their right side. This family is distinct from Family Pleuronectidae (Righteye flounders), which have their eyes on the right side of the body and lay on their left side. Pleuronectids include the Winter Flounder (Pleuronectes americanus) and Atlantic Halibut (Hippoglossus hippoglossus).

The summer flounder occur along the entire northeast coast (Maine to Florida). From spring to autumn, they move from offshore breeding (and overwintering) grounds to inshore waters where they feed. In the spring, large schools of summer flounder can be found in shallow water (less than 10ft) with sandy bottom. During summer months, many move into deeper areas (over 30ft) near reefs and wrecks. Larger individuals usually occupy deep channels, ridges, and sandbars.

The summer flounder is a sit-and-wait, ambush predator. It is able to lie still on the bottom until approached by unsuspecting prey. The numerous pigment cells and spots (chromatophores) on the flounder’s skin allow it to camouflage itself by matching the color of its surroundings.

Despite its benthic (bottom-dwelling) orientation, the summer flounder is a voracious and aggressive predator, capable of rapid speed bursts. Prey may include vertebrates (e.g., fishes) and invertebrates (e.g., squid, shrimp, clams).

When hidden in sand, the summer flounder will flap its dorsal and anal fins
to draw sand up over its body to present a more convincing camouflage.

Breeding occurs during the autumn offshore migration. Spawning activity reaches its peak from September to November at depths of 50-150ft. The most productive breeding grounds are located off the coasts of NY and NJ. Generally, males and females become sexually mature at age 3. Males rarely survive past age 7 (3-5lbs), while females may reach up to 37in (25+lbs). Clutch size (i.e., number of eggs produced) depends on age and size of the female, and it often increases exponentially with age. A newly mature 3 year-old female (about 12-14in) will produce ~ 450,000 eggs in a season while a trophy-sized female (about 27+in) may produce over ~ 4,000,000 eggs in one season. After the eggs are fertilized, they become suspended in the water column and hatch after a few days.

Larvae are born looking much like a “normal” fish with one eye on either side of the head. Within a few weeks, these larvae undergo a drastic metamorphosis, but the precise timing of settlement depends on several factors including moon phase, tide stage, salinity, water temperature, substrate type, presence of predators, and type of predators.

Summer flounder are famous for their delicious taste. Their soft, flaky white meat makes this fish a seafood delight.

Anglers typically target summer flounder using bucktail jigging or drifting bait. These fish are known for their remarkable fighting ability. For the angler, targeting 10+lb “doormats” may become a lifelong pursuit. The most thrilling aspect of hooking a summer flounder may be the violent head shakes that ensue or the first sight of the brown body as the fish makes its way to the surface on the last few turns of your reel. Some anglers even claim that only the striped bass rivals the summer flounder as the Northeast US #1 saltwater gamefish.

The late Charles Nappi, a former charter captain from Long Island, caught the current world record summer flounder on Sept. 15, 1975 out of Montauk, NY. It weighed 22lb 7oz.

Nappi’s record has remained elusive, and in recent years, it seemed insurmountable. Unlike with the striped bass where a trophy fish weighing close to the record is caught several times a year, a summer flounder that teases Nappi’s record is rarely caught… well, until the summer of 2007.

Photo from http://www.nj.com/news/index.ssf/2007/09...orld.html

On Friday August 17, 2007, Monica Oswald, resident of Neptune, NJ and nurse at Riverview Hospital in Red Bank, N.J., caught a 24.3lbs (38 ¼in) summer flounder in 60ft of water. This summer flounder engulfed a squid-tipped 4oz Spro bucktail (Glo-color) with a stinger hook. The main line used was 65-pound braided nylon. However, this fish will not be remembered as the “new” world record. The International Gamefish Association (IGFA) world records coordinator Rebecca Wright summarized the story behind this fish as follows: “The tackle, the line, the leader and the [fishing] method were fine, but the rules specifically state you can't rest the rod” (Judy Peet, nj.com) - information which Oswald disclosed voluntarily. The act of resting the rod cost her the record and possibly thousands of dollars in potential endorsements.

After news of the catch, official pictures were immediately circulated on the internet. This had the unfortunate outcome of setting off a storm of harsh discussions on several forums - some of which may be ongoing. Anonymous individuals even suggested that Oswald cheated or that she did not catch the fish herself. As a result, Oswald volunteered to take a lie detector test, which she passed.

What now? Tom Schlichter of NY Newsday writes the following in an article on August 21, 2007:
"I had the pleasure of fishing for fluke at Debbs Inlet with Nappi a couple of years before he passed away. At the time, I inquired how long he thought his fluke record might stand?
'I don't know,' he said in a reflective tone. 'That 22-pounder, that's a big fish.'
He paused for several seconds, lowered his bait to the bottom and then, with a chuckle, added: 'Twenty-five or 30 years would be nice.' "

Whether Oswald’s fish will be remembered as beating Nappi’s record or not, Capt. Nappi still got his wish.

Economic Value and Historical Impact:
- Summer flounder are managed by an interstate fishery management plan (IFMP) that is developed by the Atlantic States Marine Fisheries Commission (ASMFC). The IFMP assigns each state a fishing quota every year for all gamefish species. New York is a member of the ASMFC. The Federal Marine Recreational Fisheries Statistics Survey uses dock and telephone interviews from randomly selected fishermen to estimate the state’s total recreational harvest for that year. Each year, a projected state harvest is estimated based on the assumption that regulations and harvest patterns do not change. In 2003, it was estimated that NY recreational anglers exceeded their seasonal summer flounder quota by ~50% (the largest in years). Surprisingly, a comparable spike was not reported in Connecticut or New Jersey that year. To my understanding, 2004 was the first year that size restrictions and bag limits (a bag limit is the number of legally-sized fish allowed per angler per day) for the summer flounder differed substantially among states: New York (17in minimum length, 3 fish), Connecticut (17in minimum length, 6 fish), New Jersey (16.5in minimum length, 8 fish). Were these measures too extreme for NY anglers? John Mantione, president of the NY Fishing Tackle Trade Association, answered this question by saying, “You never make up what you lose.” (Albin, 2004).

In hindsight, the 2004 measures seem appropriate because the next two years told much of the same story. As expected, this was followed by stricter regulations on limits and further concern. 2007 was a memorable year. That year, the limit was 19.5” minimum length and 4 fish per day. Unfortunately, the quota was exceeded earlier than expected and the NY summer flounder fishing season was closed abruptly (Sept. 17, 2007) to remain in compliance with the ASMFC quota. [Last Updated: Feb 2011]

- Several flounder species that are closely related to the summer flounder are found in all coastal marine waters in Asia.

Olive Flounder or Bastard Halibut (Paralichthys
olivaceus), a popular gamefish in South Korea.

The light, rich texture of a filleted summer flounder resembles these species in both taste and appeal, making the American summer flounder a popular raw fish dish (sashimi or sushi) in sushi restaurants across the country.

- At first glance, a flatfish’s bottom-dwelling lifestyle may seem inefficient because the animal is limited to food only around its immediate surroundings. However, flatfish can be extremely successful predators. Some flatfish species can achieve enormous sizes. In fact, they grow larger than most other species of bony fish alive today. Although the summer flounder may only reach up to 25lbs, some flatfish of the Family Pleuronectidae, such as the Pacific Halibut (Hippoglossus stenolepis), can easily reach sizes of up to 550lbs! The quantity of meat in a large halibut is so substantial that they harvest only a few of these fish per year can sustain many rural native Alaskan villages and communities (e.g., Eskimo, Aleut) annually.

Author with a 100lb “barndoor” Pacific Halibut caught
summer 2007 in Seward, AK. Photo taken by Gary Garcia.

References and Further Reading:
Albin, S. 2004 (May 30). Fluke limits shrink, boat captain wails. NY Newsday (online). http://query.nytimes.com/gst/fullpage.ht...wanted=all

Comprehensive NJ news resource website: http://www.nj.com/news/index.ssf/2007/09...world.html

Gavlik, S. and Specker, J. L. 2004. Metamorphosis in summer flounder: manipulation of rearing salinity to synchronize settling behavior, growth and development. Aquaculture 240 (1-4): 543-559.

Martinez, G.M., and Bolker, J.A. 2003. Embryonic and larval staging of Summer Flounder (Paralichthys dentatus). Journal of Morphology 255: 162-176.

NY Department of Environmental Conservation: http://www.dec.ny.gov

Ristori, A. 2002. Complete Guide to Saltwater Fishing. Woods N' Water, Inc: USA.Schlichter, T. 2007 (August 21).  Big doormat for the ages. NY Newsday (online).  http://www.newsday.com/sports/columnists...655.column

U. S. Department of Commerce. 1999 (September). Essential Fish Habitat Source Document: Summer Flounder, Paralichthys dentatus, Life History and Habitat Characteristics. NOAA Technical Memorandum NMFS-NE-151.