The Gulf flounder (Paralichthys albiguttata) is a species of saltwater flounder.
The Gulf flounder is a flatfish that swims on its side. Their two eyes look upward when swimming. They have sharp teeth, two eyes on one side, and have a white side. Paralichthys albigutta is widely distributed in the western North Atlantic. Adults are found in a variety of habitats, but generally prefer hard, sandy bottoms; juveniles settle in high salinity seagrass beds. Longevity is 7–10 years and females reach maturity between 1–2 years. It is commercially and recreationally exploited. The center of abundance of Paralichthys albigutta in the Gulf of Mexico is along the northeastern coast of Florida. West of the Mississippi River delta, it occurs in very low numbers. It appears to naturally occur in low abundance in seagrass beds. It is common in museum collections (660 lots). Many species of fishes, including P. albigutta, have experienced declines in abundance in the Northern Gulf of Mexico from 1970-2000; although Fodrie et al. (2010),(This needs to be challenged, as in coastal Western Louisiana, the flounder have not been as plentiful in 50 years, as of 2018), attributed this at least in part to the effects of global rises in sea temperature, there are also a number of other factors (e.g., bycatch in trawl fisheries, increased recreational landings: T. Munroe pers. comm. 2015) that may contribute to these declines. Gill netting has been implicated in the decline of flounder stocks in North Carolina due to targeting of non-reproductive juveniles; however, the population-level effects of this method of harvest on P. albigutta are unknown 
This demersal species occurs in shallow depths within estuaries and coastal environments; it is most commonly found on the continental shelf at depths of 18–92 m, but has been collected to about 130 m. It is found in a variety of habitats, including seagrass beds, coastal lagoons, flat hard-bottom and limestone ledges. It prefers hard, sandy bottoms. Juveniles utilize vegetation for habitat or are found adjacent to vegetation in estuaries. Juveniles inhabit high salinity seagrass beds and older adults occur offshore in deeper depths. It undergoes ontogenetic shifts in dietary preference, feeding on amphipods and small crustaceans at small sizes, and feeding primarily on fishes as adults. Adults spend most of the year in bays and estuaries, migrating into deeper offshore waters to spawn during fall and winter (peaking between late October-mid-December). Specimens with ripe gonads have been collected at depths of 20–40 m in the eastern Gulf of Mexico. Larvae migrate inshore during January–February. The age at maturity for females is 1 year (FWRI 2010) with all mature by 2 years and size at 50% maturity is 35–38 cm TL. Males reach maturity between 30–35 cm TL. Females grow faster and larger than males. Longevity for males is 8–11 years and females is 7 years (Munroe 2002).
They are a common sport fish that can be readily caught with dead fish (such as mullet), live bait, or even artificial or frozen baits such as shrimp or clams. A common way of catching this flounder is by spearfishing or jigging. The recreational daily bag limit for this species is 10 and the minimum size is 12 inches (established in 1996). Commercial fishermen are permitted to take up to 50 lbs of flounder species as by-catch per trip. The Gulf States Marine Fisheries Commission is currently conducting stock assessments for gulf and southern flounder populations in the Gulf of Mexico, which will inform the development of a fishery management plan. This species is commercially and recreationally exploited as a foodfish. It is caught using trawl, gill net, gig, hook-and-line, and trammel net. As with P. lethostigma, this species is harvested using gill nets in estuaries.
Gulf flounder appear to prefer the ocean floor and camouflage against areas to stealthily strike their prey. This demersal species occurs in shallow depths within estuaries and coastal environments; it is most commonly found on the continental shelf at depths of 18–92 m, but has been collected to about 130 m.
This is a commercially and recreationally important species, particularly in Florida. It is also taken as by-catch in commercial trawl fisheries, particularly the penaeid shrimp fishery. Seagrass beds have experienced historical declines off Florida, especially in Florida Bay. The large seagrass die-off in Florida Bay between 1987-1995 was likely caused by salinity stress, turbidity, and algal blooms. Over that decade, the standing crop of Thalassia testudinum declined by 28%, Halodule wrightii by 92%, and Syringodium filiforme by 88%. Since then, the decline has slowed, but die-off continues to occur. Between 1995-2003, turtle and shoal grass abundance increased with improved water clarity and has remained generally stable. Tampa Bay and Sarasota Bay also experienced significant seagrass declines in the 1980s, but has since recovered following the improvement of waste water management. It has been recorded in the diet of the invasive Lionfish, which occurs throughout the entire depth range of P. albigutta.
- Munroe, T. (2015). "Paralichthys albigutta". The IUCN Red List of Threatened Species. 2015: e.T190358A16510817. doi:10.2305/IUCN.UK.2015-4.RLTS.T190358A16510817.en. Downloaded on 20 March 2018.
- Nicolas Bailly (2011). Bailly N (ed.). "Paralichthys albigutta Jordan & Gilbert, 1882". FishBase. World Register of Marine Species. Retrieved April 16, 2012.
- Topp, R.W., Hoff, F.H. Jr., 1972. Flatfishes (Pleuronectiformes) . Memoirs of the Hourglass Cruises, pp. 135. Florida Department of Natural Resources, St. Petersburg.
- Matlock, G.C., 1982. By-catch of Southern Flounder and Gulf Flounder by commercial shrimp trawlers in Texas Bays. Management Data Series No. 31. Texas Parks and Wildlife Department.
- Crawford, C.R, Steele, P., McMillen-Jackson, A.L. and Bert, T.M. 2011. Effectiveness of bycatch-reduction devices in roller-frame trawls used in the Florida shrimp fishery. Fisheries Research 108: 248–257.
- Fodrie, J.F., Heck, K.L., Powers, S.P, Graham, W.M., Robinson, K.L. 2010. Climate-related, decadal-scale assemblage changes of seagrass-associated fishes in the northern Gulf of Mexico. Global Change Biology 16(1): 48–59.
- Gloeckner, D.R., Luczkovich, J.J. 2009. Experimental assessment of trophic impacts from a network model of a seagrass ecosystem: Direct and indirect effects of Gulf Flounder, Spot and Pinfish on benthic polychaetes. Journal of Experimental Marine Biology and Ecology 357: 109–120.
- Kendall, M.S., Bauer, L.J.,.; Jeffrey, C.F.G. 2009. Influence of hard bottom morphology on fish assemblages of the continental shelf off Georgia, southeastern USA . Bulletin of Marine Science 84(3): 265-286.
- Murphy, M.D., Muller, R.G., McLaughlin, B. 1994. A stock assessment of Southern Flounder and Gulf Flounder. Florida Marine Research Institute, St. Petersburg, Florida.
- Thorpe, T., Beresoff, D. and Cannady, K. 2001. Gillnet bycatch potential, discard mortality, and condition of red drum (Sciaenops ocellatus) in southeastern North Carolina. Final Report: North Carolina Marine Fisheries Commission. Fishery Resource Grant Program: 00-FEG-14.
- Robblee, M. B., T. R. Barber, P. R. Carlson, M. J. Durako, J. W. Fourqurean, L. K. Muehlstein, D. Porter, L. A. Yarbro, R. T. Zieman, and J. C. Zieman. 1991. Mass Mortality of the Tropical Seagrass Thalassia-Testudinum in Florida Bay (USA). Marine Ecology Progress Series 71(3): 297-99.
- Zieman, J. C., Fourqurean, J. W., & Frankovich, T. A. 1999. Seagrass die-off in Florida Bay: Long-term trends in abundance and growth of turtle grass, Thalassia testudinum. Estuaries 22(2): 460-470.
- Hall, M.O., Durako, M.J., Fourqurean, J.W. and Zieman, J.C. 1999. Decadal changes in seagrass distribution and abundance in Florida Bay. Estuaries 22(2B): 445-459.
- Hall, M.O, Madley, K., Durako, M.J., Zieman, J.C., and Robblee, M.B. 2007. Florida Bay. In: Handley, L., Altsman, D., and DeMay, R. (eds), Seagrass Status and Trends in the Northern Gulf of Mexico: 1940-2002 U.S. Geological Survey Scientific Investigations Report . U.S. Geological Survey and the U.S. Environmental Protection Agency, Reston, VA.
- Tomasko, D. A., Corbett, C. A., Greening, H. S., & Raulerson, G. E. 2005. Spatial and temporal variation in seagrass coverage in Southwest Florida: assessing the relative effects of anthropogenic nutrient load reductions and rainfall in four contiguous estuaries. Marine Pollution Bulletin 50(8): 797-805.
- Dahl, K.A. and Patterson III, W.F. 2014. Habitat-Specific Density and Diet of Rapidly Expanding Invasive Red Lionfish, Pterois volitans, Populations in the Northern Gulf of Mexico. PLOS ONE 9(8): e105852.
- Photos of Gulf flounder on Sealife Collection