NASGC-G-92-005 C2 a Seseanh Center SEA GRANT EXTENSIQN
CECUM ANR4S MAKP9 14K StephenT. Ssedhnayer ZAevim lihenm%mFisherks ~ist Flatfishare a widespreadgroupof fishes that are hund from cold boreal habitats to warm, tropical enviionments.Atlantic halibut is a mld- water flatfish, and Mexican Flounder is found in warm water. Flatfishes have developedspe- cial featureshr living on the bottom, the most interestingof which is that both of their eyesare on one side of the head. %hen positioned flat on the bottom of the water column, Qatfish can still seewith both eyes.If you can ixnaginehav- ing both of your eyeson the left sideof your nose as you lie on your right side, you have the cor- mct orientation of a left-eyedflatfish. Some of the other peciiliar characteristics of flatfish include: ~ Adults are not bila~ symmetricaL ~ The body is highly comp~. ~ Dorsal and anal fms are usually long. ~ Adults do not have a swim bladder. ~ Flatfish canchancy the colorand intensity of their skin coloration. This last trait of most flatfishes taxies advan- tage of an existenceon the bo5am. Thus, flat- fishescan match their badqpmnd or sometimes bury in the sediment and lie in wait for un- suspectingprey. Gimxnon names for Qatfishes include Qounder,halibut, sole, plaice, dab, and turbot, names which often apply to speciesin difkmnt hmiTies. Many speciesare important in commercial fisheries an are valued as a food sate. About 52Gdifferent speciesaxe &end in 6 families. TheBatfishes also have a widerange in max- imumsize. An Atlantichalibut Higegtassus hip pog~ weighedmore than 660 pounds, and a Pacifichalibut H. sknolepisJ, 460 pounds. The smallestis pmbably the pygmy tonguefish Sym- phtcnnpem4, which reachesits maximum size at 3 inches. MostmmmerciaUy and recreationally impor- tantflatfishes that occursouth of CapeHatter' through the Gulf of Mexico are membersof the familyParalichthyidae. This groupincludes the two most commonlycaught fjatfish in the north- ern Gulf of Mexico: the southern flounder or "mud flounder" Amlichtkys ktIuefjymcr!and the Gulf flounder P.uSigulttr!. These two species look very similar, except the Gulf flounder has threedistinct "bullseye" spots in a triarigularpat- tern Figure 1!. 'Bm other Batfish families that are common in the northern Gulf are the soles family Soleidae! and tonguefish family Cynoglosidae!.The solesare right~ Batfish and r3rely seenby the recreationalfisherman,
Fgure 't. GuNfhunder, Fbrabchtys afbigurra. Figure 2. Lined sole, Achirvs lineetvs.
Table 1. Current Records Of Southern Flounder Paralichthys lethosttgma],The Record Sam FIadda Is Also The WarM Record. State Slee nate Ghat 13 lb. 1976 H. Endioott Louisiana 12 lb. 2 oz, 1969 C, Craig Mississippi 9 lb 15 oz. 1986 R. Sheldon Alabama 13 lb. 3 m, 1978 P. Melech Florida 20 lb. 9 oz, l983 L, Mungin but soles axe frequently caught in commercial or bait trawls. The lined sole Ambme line's!, is sometimessold in aquarium storesas "fresh- water flounder" becauseof its ability to tolerate fresh or salt water Figure 2!. The tonguefishare also left~ flatfish but bear little resemblance to the Paxalichthyidae.They axelong, thin fish with one continuous fin amund the whole fish east the head.An munple Ofa tonguefishthat is oommon along the northeastern Gulf is the blackcheek tonguefish 9ymp uncs phrgigm; Figure 3!. Little is known about tonguefishand even the identification of adults has not been completely worked out. Alongthe northernGulf of Mexicothe southernflounder is foundin waterof lesser averagedepth compared tothe Gulf flounder, and thesouthern flounder frequently occurs in low salinityor evenfresh water. The Gulf flounder rarelyenters waters ofreduced salinities, and it isusuaHy caught outside Mobile Bay. The life historyof the Gulf flounderis unknown,but thegeneral aspects have been workedout for the southernflounder. Adult southernflounder migrate out of the bays and estuariesin the hll Fgure4!. An abrupt cold snapcan trigger a massivemqpation. In a more gradualcooling the seaward migration isslower. Southernflounder begin tospawn either during thismigration asthey move out of the passes or fartherout in the Gulf; the exact timing and lo- cationsare not fully understood. Research indi- catesthat both southern and Gulf flounders at- tlin sexualmaturity at 2 yearsof age,The spawningtakes place in thewater column with
Figure3. 8tackcheektonguefieh, Symphvrus pAhgtuee. several females and a single attending male. beginsto warm up in the sprmg,young Qsh grow Fecundityaverages 40,000 eggs per femalein rapidlyas they take advantage of the abundant the 2- to 6-poundrange. Southern and Gulf food scrurrxsavailable. Fish reach about 8 inches flounderare external spawners with eggsand at the end of this first year Figure 5!. Whether spermreleased into the water cohmn. Fertilized or not these yearlingsparticipate in the hll eggsfloat quickly to thesurhce. Eggs hatch in spawningmigration is the subjectof current about2 days,and young yolk-sac larvae are ex- res eRfl91. tmnely vulnerableto predationand starvation. How large a particular species grows is Somehow,it is not yet knownhow, a smallper- usuallyof interestto anglers.The bestway to centagesurvive and make their wayback to the answer this for southern flounder is to examine estuary.Duiiilg theseearly ~ flounder have state and world records ghble 1!. The cunt the normalfish appearance, that is,with oneeye world record of 2Gpounds, 9 ounces has held on each side of the head, and they swim in the since 1983,so we think that southern flounder normalupright position. It isonly after they reach donot gpm muchbigger.Records have not been the estuarythat the eyesmigrate to oneside of keptfor otherspecies, probably because they do the head,the flounder drop out of the water not reach very large sizes.Currently there are column,turn on their sides,and assumea bot- no restrictions on the recreational catch of tom existence.This shower/ardmigration oocuxs southern flounder in Alabama federal or state betweenDecember and April. Oncethe estuary waters, but Florida has an 11-inchsize hmit.
t/st' Gulf
1/F' Gulf
Estuary Gulf 1/4" Gulf
I I 1/2" / Tranaitio
Figure4. Life historyof southernflounder, Fbmb'ehthys/ethosr/pma. NATIONl Sfl c ' "'%TEARY PELLUBRA " ''JG URI NARRAGANS' " ',,AMPULE 4ARRAGNtSEiP '<2 20
15 1004 28 612 141016 1820 Age yeel3! Figule5. Age arid growthof southernflounder, Rsnshchfhya/ethoe5yme.
CIRCULAR ANR~ MASGP-9!%20 Auburn Unhreraity Marine Extension gI Refeareh Center 4170 CommandersDrive, Mobile, AL 36615 05! 438-5690 Coopesu8ng Agencies Alabama CooperativeExtension Service A!abamaSea Grant ExteruuonProgram AlabamaAgricultural Experiment Station AuburnUniversig College of Agriculture Departmentof Fisbertesand AlVied Aquacultures 'L hastT. , Jhfen. ttoorkJs y a result Ohh, 06sce of Ssa rant, Depart- Grant No. Nh16RG015501, Isoaodlafartbmoaca of~vo Rdtottshawar b ia~ aad borna oco. aamtaaACta Of Stay S aadJtma SS, l9 IO, la ~ Witb tboUB nsparbrsatt at~ %O AlabamaCSropamdtra rttaadtm Ssrotae, Aabora ~, Aaa K ~ nbsatar,OIIOm Sdoaodaaol prasrama Sad ~ tO aspotuda wltbaotraptrd m rOOO,Oabrr, Oaaaaot misbt, Oss, aSO, Or baataaap Sad b oaotpod apportttatty~. UPS,SM06, ASS, AMISSS