Winter flounder

Winter flounder
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Pleuronectiformes Family: Pleuronectidae Genus: Pseudopleuronectes Species: P. americanus
Binomial name
Pseudopleuronectes americanus (Walbaum, 1792)
Synonyms
Pleuronectes americanus

The winter flounder, Pseudopleuronectes americanus, (also known as black back) is a flatfish of the family Pleuronectidae. It is native to coastal waters of the western north Atlantic coast, from Labrador, Canada to Georgia, United States. In the waters from Newfoundland down through Massachusetts Bay it is the most common near-shore (shallow-water) flounder. It grows up to 64 cm in length and 3.6 kg in weight.

It spends the summer off shore in deeper waters, and winters in shallow coastal estuaries rivers and bays.

Winter flounders are highly regarded for their delicious white meat. They are sometimes called lemon sole in the U.S. .

They can be differentiated from summer flounder because they almost always have eyes on the right side of their bodies. They also do not have teeth. Summer flounder have their eyes on the left side of their bodies, and do have teeth.

Life Cycle

The name ‘winter’ flounder refers to its annual spawning migrations into nearshore waters in winter. Adult winter flounder migrations consist of two phases; an autumn estuarine immigration prior to spawning, and a late spring/summer movement to either deeper, cooler portions of estuaries or to offshore areas after spawning. This pattern of seasonal distribution may change in the colder waters of the northern extent of the flounder’s range where it migrates to shallow water in the summer and deeper waters in the winter. The annual spawning period for winter flounder varies over its geographic range. Although spawning periods overlap considerably, peak spawning times are earlier in southern locations.

During spawning, females release eggs whose properties facilitate retention within spawning grounds. A number of factors influence larval and juvenile growth and survival, including temperature, salinity, dissolved oxygen, and food availability. Nursery habitat for winter flounder larvae and juveniles is typically saltwater coves, coastal salt ponds, and estuaries although larvae and juveniles have also been found in open ocean areas. Larvae are predominantly found in the upper reaches of natal estuaries in early spring, moving into the lower estuary later in the season.

Sources of natural mortality for winter flounder include predation, parasites, disease, and competition. Predatory fish such as striped bass, bluefish, toadfish, and summer flounder, as well as birds, invertebrates, and marine mammals prey on larvae and juveniles. Atlantic cod, spiny dogfish, goosefish, and winter skate are the main predators of adult winter flounder. Little skate, smooth dogfish, hakes, sea raven, striped sea robin, striped bass, bluefish, and wrymouth also consume adult winter flounder in smaller amounts.

Winter flounder diet is limited by their small mouth size. Adults feed mostly on small invertebrates, shrimp, clams, and worms. Feeding occurs solely during the day because winter flounder depend on sight to locate prey, and intensifies during ebbing and flooding tides. At night, winter flounder lie flat with their eye turrets retracted until sunrise.^[1]

Management

Winter flounder population has been decreasing due to overfishing and habitat destruction. Management of the species is focused on regulations to minimize fishing mortality rate, economic impacts, social impacts, and dead discards.

References

1. ^ "Atlantic States Marine Fisheries Commission: Winter Flounder". http://www.asmfc.org/speciesDocuments/winterFlounder/winterFlounderProfile.pdf. Retrieved on 2009-07-02. 

• "Pseudopleuronectes americanus". FishBase. Ed. Ranier Froese and Daniel Pauly. May 2006 version. N.p.: FishBase, 2006.