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O U s A N I I a i**afc SfKl pt ull / .ii Louisiana Conservationist (ISSN 0024-6778) Volume 45, No. 3 Baton Rouge, LA 70808 Edwin W. Edwards, Governor Joe L. Herring, Secretary Clyde W. Kimball, Deputy Secretary Fredrick Prejean, Undersecretary J. L.G. "Lee" Caubarreaux, Asst. Secretary William S. "Corky" Perret, Asst. Secretary JoeL.Herring,Secretary notherfiscalyearisdrawingtoacloseandit'stimetotakeacloserlookat Wildlife and Fisheries Commissioners yourDepartmentofWildlifeandFisheriesandthenecessityforchange. Bert Jones, Ruston, Chairman Ifweconsiderdirectandindirectimpacts,thisdepartmenttouchesthe Peter Vujnovich, New Orleans, Vice Chairman livesofmorecitizensthananyotheragency.Theimpactisunquestionably Joseph B. Cormier, Lafayette posiWtievedeaanldnobtenoenflicyiwail.thconservingandreplenishingfishandwildliferesources,but Perry Gisclair, Golden Meadow Jimmy Jenkins, Baton Rouge withprovidingvariedopportunitiesfornourishingoutdoorexperiences.Thisarea Tee John Mialjevich, Belle Chase ctaonuocehress,acraamppiedrlsy,sbwierldlwiantgcphoerrtsi,onnaotfuroaulrisctist,iazenndryt.hIotuisnaclnuddseosfhfiakmeirlsi,epshaontdogirnadpihveirdsu,- John F. Schneider, Ponchatoula alswhosimplyenjoyawholesome,outdoorenvironment. Traditionally,thedepartmenthasfocusedonthreeareas.Wehaveahalf-million Division Administrators huntersandalmostamillionrecreationalfishermeninLouisiana.Wehave300,000 Hugh Bateman, Wildlife registeredmotorboats,whichextrapolatestowelloveramillioncitizenswhoenjoy Bob Dennie, Information/Education boatingactivities.Finally,wehavethousandsofcitizenswhoderivelivelihoodsfrom Bennie Fontenot, Inland Fisheries commercialactivitiesineithersaltorfreshwaterenvirons. John Roussel, Acting, Marine Fisheries I believe, and the record substantiates, that we have done well meeting our Johnnie Tarver, Fur/Refuge responsibilities to maintain resources and provide services to an ever increasing Winton Vidrine, Enforcement constituency.Buttimeschange,andthechangeshavebeenabruptandsevere.The cost of maintaining our level of services has risen sharply. At the same time, the Magazine Staff demand for increased and expanded services has soared. Ranks of hunters and Bob Dennie, Editor fishermen haveincreased slightlyas thepopulationhasexpanded,buta new and Marianne Marsh, Associate Editor rapidly growing "usergroup" must be accommodated. These areso-called "non- Maurice Cockerham, Information Manager consumptive" usersofoutdoorfacilitiesand resources...hikers,campers,canoers, Clifton Coles, Staff Writer birdwatchersandamateurnaturalists.Theyhaveneverbeenrequiredtofinancially Andy Crawford, Staff Writer supportdepartmentoperations.Theyhadnolicensestobuy,norfeestopaytoutilize Juanita Garden, Circulation Manager departmentlands,watersorfacilities,nortobenefitfromsuccessesinourfishand Wayne Miller, Art Director wildlifemanagementprograms. Thetimehascome,undeniably,whenthegeneralpublicmustbegintopayapart of the costs if the department is to meet demands for these services. This is not Copyright1993bytheLouisianaDepartmentof unreasonable. Our overall mission has advanced far beyond providing public WildlifeandFisheries.Thispublicationisnot huntinggrounds,controllingwaterhyacinths,stockingfishandsettingcommercial responsibleforunsolicitedmanuscripts,photographsor shrimping seasons. We are challenged to provide increased "urban fishing pro- otheTrhmeatLeoruiiaslis.anaConservationistispublished grams,"naturetrails,publiceducationprograms,andothernon-traditionaloutdoor- bimonthlybytheLouisianaDepartmentofWildlifeand orientedprograms.Allofthesecostmoney. Fisheries,2000QuailDrive,BatonRouge,LA70808. skieBrosaatsrwaelmlpsasafnidshaeqrumaetni.cWwMeeAdscoanntdrorlefpurgoegsrparmosvipdreovniadteuraecctreasisls,fobricradnwoaetrcshianngd, pTmoaesiltleaipgnhegonpoefafiindcueasmt.bBeParotsoitsnm(aR5so0tu4eg)re:7,6SL5eo-nu2di9s1ai8da.dnraeSseascnocdnhdaa-dncdglieatssisotnoal photographyopportunities,andcamping facilitiesaswellashuntingand fishing. LouisianaConservationist,P.O.Box98000,Baton Researchandmanagementprogramsenhancehabitatfornon-gameaswellasgame Rouge,LA70898. species. Records and surveys clearly reveal the large numbers of citizens using stricRtelgyuplraothiiobnistuofnltahwefUu.lS.diDsecrpiamritnmaetniotnoifntheInterior departmentfacilitiesforpurposesotherthanhuntingorfishing. departmentalfederallyassistedprogramsonthebasisof We feel certain the people of Louisiana will support the changes necessary to race,color,nationalorigin,ageorhandicap. Any assure that the Department of Wildlife and Fisheries can continue to meet the personwhobelievesheorshehasbeendiscriminated challengesanddemandsofourfuture.Weneedyourhelp. aagraeicnisptieinntaonfyfepdreorgarlaams,siascttainvcietyshorouflacdiwlirtiyteopteor:atedby Director,OfficeforEqualOpportunity,U.S. DepartmentoftheInterior, Washington,D.C.20240 2 LouisianaConservationist LOUISIANA PublishedbytheDepartmentofWildlifeandFisheriesintheinterestofconservationofLouisiananaturalresources. NutrientEnrichment:TooMuchofaGoodThing? By Robert Fritchey Hownutrients can make life flourish ormake life impossible. Louisiana's Electric Fishes ByRobertL.Ancelet,ClarenceLuquet&ChuckMancuso A lookatsome ofourstate fishes'shockingattributes. Rebirth by Fire By Sara Ann Harris Howcontrolledburningcan restore forests. Fishing Lake Concordia By Edwin A. Vice Angling one ofthestate's Trophy Lakes. How to Get into La/s Fish Record Book By Edwin A. Vice Tips forrecording thatonce-in-a-lifetime catch. Whitetails and Minerals By David Moreland Whyand when deerneedminerals. QueenBessIsland:AVictoryOverWetlandsLoss! By Charles W. Frank An example ofperseverancepaying off. Reptiles and Amphibians in Louisiana By Clifton Coles &ur. Harold A. Dundee A lookatupcoming regulations ofa multi-million dollarindustry. Education Corner: Environmental Ethics & By Lyle Soniat EleanorAbrams Law Lines By Capt. Keith LaCaze Safety withpersonal watercraft. Conservation Notes WildlifeandFisheries news briefs. Funny Side Up By Glynn Hams Bayou Kitchen By WayneMiller Making thebestofgrouper, amberjackanddrum. Front Cover Back Cover By Bob Dennie LDWFfile photo Sunsetat Lake Verret Louisiana's state bird May/June1993 The Gulfof Mexico receives Toomuchofagoodthing? drainagefrom nearly 60 percent ofthe BY ROBERT FRITCHEY continental United States. Phytoplanktonaretiny,single-celled plantsthatcolorLouisiana'ssaltywatersthemurky Nearly halfof green that timid bathers hate and that fishermen love. Phytoplankton help make these waters productive. Menhaden, forinstance, feed on phytoplankton: commercial fisher- the country's men land more than one billion pounds of pogies each year. The wriggling larvae of population mosquitoesstrainthewaterforphytoplankton;minnowsinthemarshliveonmosquitolarvae. lives in the Shrimp feed on small organisms that feed on phytoplankton; the state's shrimp harvest is the drainage area. largest in the nation. Finfish such as redfish, spotted seatrout and Spanish mackerel feed on menhaden, minnows and shrimp. The Gulf's Like other plants phytoplankton need nutrients to grow. But sometimes you can have too drainage basin much of a good thing. Draining into the Gulfare far more nutrients than it needs. includes three- Therearemorethanadozennutrientsessentialtoalllifeformsrangingfrombacteriatoman. fourths of the Nitrogenand phosphorusaretwoofthese.Theyareneeded tomaintaintheGulf'sproductivity farms and offish,shrimp,crabsandothereconomicallyimportantaquaticorganisms-buttheyareneeded ranches and inlesseramountsthantheestimated891,974tonsofnitrogenandthe221,526tonsofphosphorus that enter the Gulfeach year. almost 80 Too many nutrients may lead to the depletion ofoxygen in the water, either killing marine percent ofthe organisms outright or, at the least, reducing the area of suitable fishery habitat. The most cropland. dramaticmanifestationofnutrientenrichmentintheGulfisthe"deadzone,"anareaofoxygen- 4 LouisianaConservationist depletedbottomwaterthatoccursseasonally overlays the heavier,saltierwateron thebot- The satellite image offtheLouisiana and Texascoasts. Though it tom. With bacteria using up oxygen faster below shows the changes in location and size, the dead zone than itcanbereplaced from thesurfacelayer, discharge of the remains extensive, covering up to 3,000 or normally productive bottom becomes a bar- Mississippi and 4,000 square miles. Extending from the Mis- ren wasteland. Atchafalaya rivers sissippi Riverdelta westward intoTexas wa- TheGulfand riverwatersremainstratified within the 100 meter ters, the low oxygen conditions persist from through the summer and into the fall, when bathymetric con- JunethroughAugustbutcanoccurasearlyas tropical storms or hurricanes mix the water tour. The brighter April and last as late as October. columnandre-aeratethebottomwaters.Later bluetones represent During this time, the dissolved oxygen in the year, similar mixing results from ther- higher concentra- content of bottom waters becomes so de- mal cooling of the water column and winds tionsof suspended pleted that organisms either leave or die. In generated from cold fronts. sediment. some cases, the oxygen-deficient water may Though nutrient enrichment is primarily causelargefish kills, such as theone that put responsible for oxygen depletion, there are thousands of dead fish on beaches along the other factors. Rabalais, who studies how the southeastern coast of Louisiana in the sum- water quality of the Mississippi River has mer of 1990. been changing over the years, notes that the "What probably happened," says Nancy amountofsedimenthasdecreased,primarily Rabalais, associate professor at Louisiana asa result ofdamsand reservoirsbuilt in the Universities MarineConsortium in Chauvin, upper regions of the watershed and of farm- "is that a mass of oxygen-depleted water, ing practices that reduce erosion. Clearer combined withhydrogensulfide, gotpushed waters allow more sunshine to penetrate the inshore, trapping a lot of organisms." The depths, enhancing phytoplankton growth in dead zone, adds Rabalais, "sloshes around, the nearshore Gulf, she says. movinginshoreandoffshoreaccordingtothe Excess levels ofnitrogen, phosphorus and wind and currents." other nutrients come from city sewage treat- The combined flows from the Mississippi ment plants, failed individual septic tanks, andtheAtchafalaya riverscarrymorethan70 industrialoperations,over-fertilizationofgolf percent ofthe total nitrogen and phosphorus courses, homeowners' use of phosphate de- that enter the Gulf from all U.S. sources. As tergents and over-fertilization of lawns and ImageprovidedbyLouisianaStateUniversity currents carry this nutrient-richriverwaterwest- ward along the Louisi- ana and Texas continen- 9 Mar 89 1851 Z Turbidity W tal shelf, phytoplankton Coastal Studies Institute growth explodes. As these microscopic plants die, they sink to the bottom. Slightly larger organisms, "zooplankton," T graze on the blooming phytoplankton. As they 1 £ * feedtheyreleasefecalpel- fk lets that sink to the bottom.Whenthezooplank- ! ton die, they too sink. As these organic ma- terialsaccumulateonthe bottom,theyarefedupon bybacteriathatconsume oxygen in the process. During the relatively calm summer months, -100- little mixing occurs between the layer of fresh, lessdenseriverwaterthat May/June1993 gardens. Primarily, though, nutrients come from farmlands, says Dugan Sabins, who is with the Office of Water Resources at the LouisianaDepartmentofEnvironmentalQual- ity (DEQ). The culprits are the application of excessive fertilizer to crops or runoff from operations where animals are concentrated, suchaspoultryfarms,dairyandswineherds, feed lots and even the huge catfish aquacul- ture operations in the Yazoo delta. Sources of nitrates and phosphorus from agricultural runoff in the Mississippi River watershed have increased with the growing useofinorganicfertilizersintheUnitedStates since 1950. Nitrate concentrations in theMis- sissippiaredoublethelevelsmeasured inthe 1950s. Phosphorusconcentrationsintheriver Ninety percent ofthe freshwater inflow into the Gulf comes from as farwest as also have increased. Colorado, as far north as Canada and as far east as Maryland. Nutrients notonly stimulatethegrowthof phytoplankton, producing fodder for oxygen-consuming bacteria; they may also con- tribute to blooms of noxious algae, some of which are more commonly known as red or brown tides. Toxic red tides have led to fish kills in the Gulf. They also affect the market- abilityand,onoccasion,thehealthofoysters. In addition to killing marine organisms outright, noxious algal blooms may also de- stroy fishery habitat by killing submerged aquatic vegetation. Because seagrasses need sunlight to grow, water clouded by noxious algal blooms can shade grass beds until they die.Excessivenutrientsalsomaycauseblooms ofanepiphyticalgaethatgrowsontheseagrass itself, also shading it out. According toRabalais,thereisnotenough Thesatellite imageabovewastakeneightdaysafterthe imageonpage5. Notice historical data to prove a direct relationship the increase in suspended sediments. between noxious algal blooms and nutrient imbalancesintheGulf,yettheconnectionhas been observed in other bodies ofwater. Ninety percent of the freshwater inflow into the Gulf is from the Mississippi and Atchafalaya rivers; drainage to these rivers extends as far west as the top of the Rocky MountainsinColorado,asfarnorthasAlberta, Canada,andasfareastasCumberland,Mary- land. The Gulf's drainage basin includes nearly 60 percent of the land area of the continental UnitedStates.Nearlyhalfofthepopulationof the United States lives in the drainage area. Three-fourthsofthelandinfarmsandranches isinthedrainagebasinandalmost80percent of the cropland. Aeriai images are importantforcoastal studies. They provide clear information Alongwiththisextensiveagriculture,there m changesalongthecoastlineoveraperiodofyears.Theaboveimagewastaken arehundredsofcitiesandthousandsofindus- in January1992. tries. Allareputtingnutrientsintowaterthat 6 LouisianaConservationist eventually flows into the Gulf of Mexico. dairy workersand restaurant workers. Phos- Over enrichment is caused not only by phatesarealsoneeded in regions where min- activities along the coast but also by those of erals such as iron or magnesium make the Iowafarmers,Pennsylvaniasteelmills,urban water hard, which includes much of north residentsincitiessuchasIndianapolis,Louis- Louisiana. ville, St. Louis and Minneapolis, and subur- "In some areas where phosphates were ban homeowners in Indiana. In order to pro- banned, they had to add other chemicals to tect the Gulf, plans must be developed for killthebacteria," saysWilson. "Then theyget influencing their behavior. into the water, so you're really not gaining Large-scalewatermanagementplanshave anything. been devised for other parts of the U.S., such "Hopefully," adds Wilson, "our program as Long Island Sound, theGulfof Maine and will equip consumers with the knowledge the Chesapeake Bay. they need to enable them to decide which "We're working on an action plan, but detergents are both safe for the environment we're not as far along as Chesapeake Bay. and effectiveincleaning the family laundry." They've got at least ten years on us," says With grants from the Gulf of Mexico Pro- KennethBlan,SoilConservationService(SCS) gram and the Department of Environmental representativetotheGulfofMexicoProgram. Quality's Office of Water Resources, the Co- ThemultiagencyGulfofMexicoProgram,led operative Extension Service has produced by the Environmental Protection Agency, educational brochures as well as a video that should haveanaction plancompleted within isbeingshowninstoreswheredetergentsare the next year or two, according to Blan, who being sold. A longer educational video is is headquartered at the Stennis Space Center being used to train volunteers around the in Bay St. Louis, Mississippi. state. "Our home economist in each parish is "Wehaveidentifiedabout12specificnutri- training volunteers who then go out to edu- ent sources and established demonstration cate consumers," Wilson concluded. projects to address several of these. Not only Anotherdemonstrationproject,conducted does thisgiveus experiencein the real world bytheSCS,USDA,isevaluatingtheeffective- but, when the action plan is finalized, we'll ness of artificially constructed wetlands in have concrete solutions to point to," he says. reducing concentrations of nutrients in ani- Oneprojectunderway in Louisiana evalu- mal wastes. Animal waste fromconcentrated ates the effectiveness of a public education operations such as dairies, poultry houses, campaign regarding phosphate detergents. hogoperations,and feedlotsmayfinditsway The tri-parish pilot program, conducted by into the Gulf from sources far up river. theLouisianaCooperative ExtensionService, Waste from a dairy herd near Newton, LSU Agricultural Center, is taking place in Mississippi flows first into an anaerobic la- Lafourche,St.TammanyandCaddoparishes. goon,wherea certain percentageofnutrients First, volunteers from groups like the 4-H is removed by anaerobic bacteria. The waste Clubaretrained.Thentheygointothesuper- thenflowstoasecond,shallowerlagoonwhere marketswheretheystudyconsumers'buying aerobic bacteria remove more. While most of habits and count the number of phosphate thesolid wastesettles in theselagoons,waste detergents on the shelves. When the educa- water is channeled through a series of plots tional campaign is completed, the volunteers thatareplantedwithwetlandvegetationsuch willreturntothesupermarketstoevaluateits as cattails or maiden cane. success. "It'sourcontentionthat most people "We know the concentrations as they en- willchosephosphate-freedetergentsoncethey ter," says Lon Strong, SCS Water Quality realizetheirbenefit. And publicbuying pres- Coordinator. "Bytestingthemastheyexit,we sure will force those that contain phosphates find that the plants are removing 70 to 90 off the shelves," says Kenneth Blan. percent oftheoxygen-depleting substances." Phosphate detergents have been banned At615,000squaremiles,theGulfofMexico outright in some states but, says program istheworld'sninthlargestbodyofwater. But director Dr. Evva Wilson, "We don't want to like the Mediterranean and other seas, it is dothatinLouisianabecausethisisanagricul- virtually an enclosed basin. Because of its turalstate."Notonlydophosphatesridcloth- limited exchange of water with the Atlantic, ing of many pesticides, they are effective in what drains into the Gulftends to stay there. cleaning garments thatcontain high levels of AnddrainingintotheGulfarefarmorenutri- bacteria, such as diapers and those worn by entsthanneeded. May/June1993 Tlie Gulfof BY ROBERT L. ANCELET, CLARENCE LUQUET & CHUCK MANCUSO Mexico offers Oneofthe many thrillsassociated with tion, mimicry, barbels, feeding adaptations, a variety of fishinginthemysteriouswatersofthe and...electricorgans.Althoughmanyofthese fish species for Gulf of Mexico is the constant poten- specializations appear in otheranimals, only the sportsman. tial of landing strange, and even ex- fishes are known to have organs capable of otic, forms of sea life. Identifying unusual generating an electric current sufficient in Those species catches can produce surprises ranging from magnitudetoaffecttheirimmediatesurround- includefive electric amusement to a real shock. ings.Thisuniquespecializationisutilized for fishes that are Modern fishes have developed into an ar- purposes of attack or defense as well as for caught off the ray of diverse species, some with rather re- navigation. These fishescanalsodeliberately coast of Louisiana. markable specializations. Fish are known to regulate the strength of the electric charge A havedevelopedvenomousspines, poisonous delivered. Weaker shocks serve to dissuade real shockfor flesh,poisonousskin,bonyarmor,lungs,bac- would-beattackers,whilestrongshocksinca- the unsuspecting terial luminescence, photophore lumines- pacitate or even kill prey or enemies. fisherman. cence, cryptic coloration, disruptive colora- The independent development of electric 8 LouisianaConservationist Vi Narcine bmsiliensis; the Atlantic torpedo, Tor- The Amazon pedo ndbiliana; the skates, Raja spp.; and the electric eel (photo at southernstargazer,Asfroscop!(si/-^rat'cw;H,pos- left) can generate a sesselectricorgans.Allofthesefisharefound shock of in the nearshore or offshore marine environ- more than 500 ment of the Gulf of Mexico. volts. This is Theelectricorgansarecomposed ofmodi- enough to fied striated muscle cells, electroplaques, ca- electrocute pable of producing, storing, and discharging a large fish or electricalpotential. Thesecellsoriginatefrom incapacitate differentpartsofthebodyindifferentspecies a man. - the upper body and tail musculature in the electric eel, hyobranchial muscles in theelec- tric rays, and eye muscles in the stargazers. This is an example of convergent evolution, where electric organs have evolved from muscles in different parts ofthebody among divergent groups of fishes. The electroplaque arrangements and generating mechanisms differ between the marine fishes and the freshwater Amazon electriceel,Electrophonts.Theshortbutnumerous vertical electroplaque columns of the marine electric fishes are arranged in parallel as op- posedtotheseriesarrangementofthenumer- ous electroplaques in the lengthy columns of the electric eel. The results of these arrangements are: high amperage in the marineelec- tric fishes, and high voltagein the freshwater electric eel. These mechanisms represent adaptations to different environments. High voltagenecessary toovercomethehigh resis- tanceoffreshwater,andhighamperageinthe lowerresistance ofsalt water. Theelectriceel is capable of generating more than 500 volts, whilethegreaterelectricray,Torpedondbiliana, / *v%! can produce a current of 220 volts at 50 am- peres, enough to electrocute a large fish or incapacitate a man. The lesser electric ray, Narcine bmsiliensis, is capable of producing a current of 37 volts. PhotocourtesyofTheAudubonInstitute Theimpulsemechanismofanelectroplaque is similar to a typical nerve cell. The mem- organs in unrelated fishes was enigmatic to branesareselectivelypermeabletopotassium early observers. It was puzzling to observe ions and negative ions, while excluding so- electric species among the ancient cartilagi- diumionsand positiveions. Theinsideofthe nous fishes, Elasmobranchs, as well as the resting electroplaque's membrane is nega- modern bony fishes, Teleosts. Until recently, tive, while the outside is positive, thus creat- primitive, jawless Ostracoderms of the class ing an electrical potential. When stimulated, Cephalaspides were believed to have pos- thenerveimpulsechangesthepermeabilityof sessedelectricorgans. Today,thereareabout the membrane permitting the sodium ions 250 species of electric fishes that include the and positive ions to rush inside the following: skates and rays, ray-like torpedo electroplaque, depolarizing it and sending fishes, stargazers, the South American knife the impulse to the next electroplaque. Each fishesand electriceel,andtheAfricanelectric electroplaque of Torpedo, Narcine, and catfish. Astroscopus putsoutbetween 50and 80milli- In Louisiana waters: the lesserelectric ray, volts.Withtheelectroplaquesfacingthesame May/June1993 Southernst.1rg.1zer (Astroscopusy-graec LesserElectric Ray (Narcinebrasilieusis) Atlantictorpedo (Torpedo nobiliana) IllustrationsbyDuaneRaver, Jr. Although many of direction and the ventral side negative, the stingrayswithoutspinesarefoundfromdeep top surface ofthe organsare electro-positive. offshore waters to nearshore shallow waters the specializations The negative lower side of the organ repre- where they feed on fish and shellfish. appear in other sents the plus or anode pole of a multiple The electric rays are dorso-ventrally com- animals, only concentrationcell witha discharge from ven- pressed fisheswithrelativelylargetailswhen fishes are known tral to dorsal. compared tootherrays.Thelargeandpower- to have organs Skates, Rajaspp.,possessslendermassesof fulelectricorgans(onesixthofthetotalmass) various lengths and thicknesses along the are situated in the "wings" on either side of capable of sides of the tail that are modified into rudi- thedisc-likebody. Aspeciallobeofthebrain, generating an mentary electric organs. Some skates have "lobuselectricus" sendsout five largenerves electric current well-developed columns ofelectroplaques at thatbranchseveraltimes,eventuallyforming sufficient to affect rightanglestothelongitudinalaxisofthetail, fine fibrils that innervate the ventral connec- their immediate while others haveclub orcup-shaped organs tive tissue wall of each electric disc or withtail-likeprolongationsofvariouslengths. electroplaque. These discs, clear jelly-like surroundings. Shocksofapproximately .5voltspercentime- masses containing multinucleated cells enter oforgan length have been recorded. This closedwithinconnectivetissuecompartments weakshock,dischargedonlyaftergreatprovo- arrangedinverticalcolumns,formtheelectric cation, goes unnoticed by most fishermen. organs.Theseorganscancontainhundredsof Several species of skates are found in thousands of discs in the greaterelectric ray, Louisianaoffshorewaters.Theclearnoseskate, Torpedo nobiana. The electric organs, situated Raja eglanteria, common in the northeastern on either side of the head at the base of the Gulf, isknown topossesselectricorgans.The pectoral fins, form massesoflarge hexagonal spreadfin skate, Raja olseni, probably has cells visible through the skin of the lesser electricorganssimilartoitscloserelative, the electric ray, Narcine brasiliensis. The Atlantic barndoor skate, Raja laevis, of the Atlantic torpedo,T. nobiliana, isa largeray(tosixfeet) Coast. R. olseni is a small skate (20 inches), known from the northern Gulfat the edge of while the clearnose skate, R. eglanteria, can thecontinentalshelfofftheMississippiRiver reach three feet. These rays, resembling Delta, while the lesser electric ray, N. 10 LouisianaConservationist