From Divers Who Contacted DAN on Both the Einergency and Non

DANANALYSIS OF RECREATIONALDIVE ACCIDENTS FOR 1988

P. B. Bennett J A. Dovenbarger C. J. Wachhok K S. Corson Divers Alert Network Hyperbaric Center Duke UniversityMedical Center Durham,NORTH CAROLINA 27701U. S.A.

TheDivers Alert ¹tN orkisapproaching theend ofits first decade ofservice tothe SCUBAdiving public and medi cine community. One of DAN's primary goals is thecollection of SCUBAinj ury statistics. The kist few years have seen increased effortsto collect more information onthe causes ofinj ury.

METHODS In 1988,SS3 diving accidents were reported from hyperbaric treatment facilities and fromdivers who contacted DAN on both the einergency andnon-emergency lines.Accident ReportForms are filled out by the injured divers and by hyperbaric facility staff. Hyperbaric staffprovide information ontreatment while the divers provide information concerning the diveprofile and personal data such as medical history. For clarification andconfirmation, personnelatDAN central contact the treatment facilities and divers byletter and telephone. ByJune of 1989,419 Accident Reports were received. Ofthe 419 cases received, 111were not recreational and40 were incomplete. Thus, 268recreational dive accident cases were analyzed.

DIVER AGE Themean age of an accident victim was 34 years with the range being 11-61 years. Table 1 givesa frequencyof agedistribution. Divingfor Science...1990

%bte1. Distrtbotionol' Age of DiveAccideat Victims

10-14 2 4 0.7 15-19 13 20-24 27 10.1 25-29 62 23.1 30-34 64 23.9 35-39 39 14.6 40-44 35 13.1 45-49 19 7,1 50-54 11 4.1 55-59 2 0,7

TOTAL 100.0

SEX

Menwere involved in divingaccidents more than three timesas often aswomen. This probablyindicates a largermale diving population but it could reflecthigher risk divinghabits for men. Table2 givesthe sexof the accidentvictim.

'ttabk 2. Sex of the occtdeat victim

Female divers 21.6

100,0

CERTIFICATION/EXPERIENCE

Forty-ninepercent 31 of 268! of the injured diverswere beginninglevel basicor openwater! SCUBAcertified. The majority 0 of 78! of new diver divers with one yearor lessexperience! injuries occurred in themore serious severity codes, indicating central nervous systemDCS and/or gas embolism. New diver profiles indicate 75 k dived20 timesor less,61% werediving at or deeperthan 80 feet, 50% were diving repetitively, 41% had a rapidascent and 31% were outside the USN dive tables. Bennett er aL Recreational Dive Accidents for 1988

Inthe 78 divers who had been diving one year or less there were 25 gas embolisms. Of the25 new diver embolisms, 16had rapid ascents. These 25 cases represent 32% of all new divers8! butit represents69% of all embolisrn cases 6! analyzedwhich could suggest that lack of experiencemay contribute to the risk of AGE.

CASE BREA%MOWN Ofthe 268 analyzed cases,46 were AGE, 60 were DCS Type I,and 162 were DCS Type

CONCLUSIONS Accidentsdonot just happen, The 500-600 dive injuries which occur each year can be attributedto nospecific cause, but they are frequently a productof a seriesof events.While theseevents can be differentfor eachdiver, similarities do exist.Certain conditions or behaviors,inparticular, are associated with injury, these include: fatigue, inexperience, and/or drinkingalcohol on the preceding night. Deep diving and repetitive diving are also strongly linkedto decompressionsickness. Inexperience is a majorpredisposing factor for both decompressionsickness and air embolism. New divers are less knowledgeable aboutdiving safetyand may have a tendencytogo along with more experienced divers doing higher risk diving. CHARACTERISTICSAND ASSESSMENTOF DREDGERELATED MECHANICALIMPACT TO HARD-BOTTOMREEF AREAS OFF NORTHERN DADE COUNTY, FLORIDA

StephenM. Blair Brian S.Flynn SusanMarkley Restorationand EnhancementSection Metro-DadeDepartment of Environmental ResourcesManagement 111 NW First Street Miami, FLORIDA 33128 U. S. A.

Beacherosion control measures have become a necessity along the south Florida coastdue to thecontinued erosional loss of protective beach and dune areas. The pnrruuymethodtodate, for beach reconstructionin southFloridainvolves dredging of sandfrom anoffshore "borrow area" and pumping the sand to theshoreline. Althoughthe method results in a "new"beach with greatly enhanced erosion protectionand recreatiorral use, it is oftennot without impacts both unavoidable andavoidableirnpacts! tothe environment. Inthe summer of1988, Dade County sponsoreda beach erosion control project to renourisha 2.5 mile segment of northernDade County shoreline. ¹ar thetime of completion ofthe project, areas ofmechanicalimpacts tothe reef adj acent to the borrow area were discovered. The physicalcharactenstics ofthe impact indicatedit wasassociated withthe dredging operations.A subsequent survey ofthe reefs bordering theborro~ area identified ninesites of impact. At eachsite physical evidence was found consistent with the dredgrngequipment making contact with and scraping thereef. Two of the nine locationsexhibited substantial i e., orders ofmagnitude greater in size! and severe impact.These sites were chosen for detailedassessment. Theassessment involved mappingthe extent and magnitude oftheimpacted area via evenly spaced transects whichwere evaluated bybiologists using scuba 7he assessed impact at the two siteswas spread over an area of 2.2acres. Appraxirnately 1.5acres of benthic hard-bottomcommunities withinthe impacted areawere destroyed destruction of 75-100%ofthe benthic organisms!. It was estimated that over 25,000 hard coral coloru'es,24,000 soft coral colonies andover 2,000 barrel sporrges wereamong the organismsdestroyed bythe dredging equipment. 77us destruction represents a significan~tract to the hard-bottom comrrutnity within the region byreducing habitatquality, density of organrsms,reefstructural complexity and the overall productivityof the area. Divingfor Science...19Ã

INTRODUCTION DadeCounty, Florida has approximately 21miles of ocean shoreline. Severe erosion alongthe shoreline, hasresulted inreduced storm protection and loss of a recreationaland economicresource. Metropolitan DadeCounty iscommitted toenhancing, restoring and revitalizingthecoastal beach and dune systems, to provide enhanced storm protection for barrierisland residents andrecreational opportunities forcounty residents and visitors. The County'sbeach projects are administered through the Department ofEnvironinental Resour- cesManageinent DC-DERM!. Todate, 15.4 miles of eroded beach front have been restored. Unfortunately,therestoration ofthe County's beaches hasnot been without impact tothe nearshorehabitats Marszalek 1981,Goldberg 1989!. Ofspecific concern tothis report isthe impactcaused byphysical contact ofdredging equipinent withthe hard-bottom live-bottom! reefareas adjacent tothe dredging site e.g., borrow area!. Although other modes ofimpact canoccur and can be of equivalentor greater concern, only the effects of themechanical impactswill be discussedhere.

Duringthe summer June through early October! of 1988DC-DERM served as the localsponsor fora federallyfunded beach restoration project along 2.5 miles of shoreline in SunnyIsles Figure 1!.The dredging inethod employed utilizes a "hopper dredge". This type ofdredge has arms mounted onthe sides ofthe dredge. The dredging end of the arm is lowered tothe bottom where the material i.e., sand! issuctioned upthe arm and into the "hoppers" onthe dredge. Theship moves along within the borrow area, dragging thesuction arin or "drag head"on the bottom Figure 2!. On August W, 1988, DC-DERM personnel noted mechanical impacttoa portionofthe third reef, adjacent to the borrow area. The location and charac- teristicsofthe impact indicated thatit hadbeen caused bythe contact ofthe hopper dredge's HopperDredge LONG ISLP&D! drag head with s! the reef. Subsequently, a surveyof the reefssurrounding theborrow area was conducted byDC-DERM biologists todetermine the extentand degree ofthe impact. Nine separate areasof impact were identified. This report detailsthelocation ofthe areas, characteristics ofthe impact and method used toquantify the areaof hardbottom impacted at twoof thenine locations. Thegeneral geological and biological features ofthe reefs found off the southeastern coastofFlorida have been described byGoldberg 973!, Jaap 984! and Shinn 988!. The geologicalandbiological features ofthe reefs off northeastern DadeCounty are siinilar to thosedescribed bythe above cited authors, butdiffer with respect tothe depth offormations, and,toa lesserdegree, withthe biotic components ofthe reef. A brief suminary ofthe specific featuresfound off Sunny Isles ispresented here,outlining thepertinent topographic features and biotic communities.

Qgg4Cy.Three distinct reef platforms, or terraces, are foundbetween 0.5 and 2.0 milesoff the Dade County coast Figure 1!. The reefs are formed ofpleistocene reefrock witha "cap",upto eight feet thick, of geologically recent coral reef Shinn 1988!. Shoreward ofthe first westernmost! reefis a largesand area with scattered patch reefs. The first reef is a lowprofile, non-continuous reefbelieved tobe formed bythe convergent growth ofsmaller patchreefs Goldberg 1973!. The second reefis relatively narrow 25-200 m wide!,andcrests Blairet al Hard-BottomReef Breeze Off M DadeCo.,FL

at11 to 13 m. The western edge ofthe second reef shows a mild relief of 1 to1.5 in, rising out of'a sandplain at a depthof14 to 15 m. The eastern edge shows a greater andsteeper relief dropping1 to 3.5 in to a depthof17 m ontoa sand plain which makes upthe borrow area. The westernedge of the third reef, adjacent tothe borrow area, has a reliefof1.5 to 3 in,rising frombetween 18and 19 m toapproximately 16.5m. The eastern edge of the third reef forms theouter reef slope, sloping to + 60m Figure3!,

A diverseand abundant assemblage of benthic plants, hardcorals, soft corals, sponges and fish is foundon theoffshore reefs in northernDade County.These communities havebeen, inpart, described byBlair and Flynn 989!. The communitiesonthe second and third reefs are of specific concern asthey are the reefs that sustainedmechanical itnpact from the dredge's drag head. The most abundant organisms are thesoft corals i.e., Ecmicea spp., Pseudopterogoqja spp.,Plexaura spp.! with numerous massive hardcoral colonies i.e., Dichocoenia stokesii, Siderastrea siderea, Agaricia spp., Montastrea spp.,Stephanocoenia michelini!ranging insize from 2 cmto 1.5 m indiameter. Goldberg 973!categorized thiscommunity asthe "Offshore Reef Platform" assemblage. Informationcollected from DC-DERM biological monitoring stations located around theborrow area show 28 species ofhard corals and over 130 species ofpelagic fish exist inthe immediateregion. Also, numerous species of sponges i.e., Xestosporigia muta[barrel sponge],Cliona spp. [boring sponge], Callyspongia spp.[tube and vase sponges], Ircinia spp. [tubeand cannonball sponges], Haliclona spp. [finger sponges]!, anemones i.e.,Polythoa canbbea,Bartholomea annulata, Ricordia florida! and algae i.e., Halimeda spp.,Dictyota spp., Sargavsumspp., Peyssorirtelia spp.,Hydrolithon spp.! cover the bot tom.

METHODS Betweenthe reef terraces found off the northern Dade County com- munityofSunny Isles are deposits afcarbonate sand. Specific regions ofthe sand deposits havebeen identified as"borrow areas" bythe U.S. Army Corps ofEngineers! foruse in beach renourishmentorrestoration projects. The borrow area used for the 1988 sutnmer project SunnyIsles Beach Renourishment Project!was located between thesecond andthird reefs, between2700and 3000 meters 9000 and 10000 feet! offshore, withapproximate bordering latitudesandlongitudes of25 57.50'N, 8005.75'W and25 5525'N, 8005.25' W! Figure1!. Theareas ofmechanical impact are located onthe eastern edge of the second reef and the western edge of the third reef.

O' O' examinedforsigns of impact i.e., denuded area of the bottom; overturned, broken or loose hardcorals, soft corals orsponges; areas ofrubble orlarge overturned boulders! byDC- DERMbiologists, using scuba. The survey began onthe eastern edge of the second reef and continuedonthe western edge of the third reef, until the entire reef edge adjacent tothe perimeterofthe borrow area had been examined. Swimming side-by-side andapproximately Divingfor Science...1990

3 to5 metersabove the bottom,two diverswere able to scana 20to 30 ineter pathof the reef. Whenan areaof possibleimpact was noted, the diversdescended and examinedthe bottom for indicationsof contactby the dredge'sdrag head with thereef. If the areashowed markings characteristicof suchimpact, the areawas marked with a buoyand the positionnoted. Impact locationswere noted with coinbinationsof "line-ups" alignmentof fixed shorepoints! and fathoineterprofiles.

3 3«2 dpp 3 3 3 * d deterinine the area impactedand destroyed. Theseareas were chosen due to the size minimallytwo ordersof magnitudelarger than the coinbinedareas of the reinainingsites!. At eachsite, using a compassand followingthe bearingof the impactpath, a meteredtape or a 10-meterline, was stretched along the bottom within an impacttract. At 10-meterintervals -meter intervalsfor impactsite 2!, a secondmetered line wasextended perpendicular to the first, from the westernmost point of impactto the edgeof the reef. The secondline was, therefore,perpendicular to the impacttracts. A DC-DERM diver then swamalong the perpendiculartransect line noting,on anunder water slate, the beginningand endpoints i.e., width! of anyimpact tracts and the relativedegree of impactwithin eachtract. Destruction wascategorized into oneof five levels:0% no impact!,0-25% slight!, 25 50% moderate!, 50-75% heavy!, 75-100% severe impact!.

It is recognizedthat this methodologycan have multiple sources of error. For example, the subjectiveplacement of a regionwith 25%impact into the 0-25%or the 25-50%category can vary between individuals conducting the assessmentand the perception of the degree of impactcan vary. Further,the diver'sfamiliarity with the specificarea or habitatcan affect how he mayperceive the degreeof impact. Stepswere taken to ininimize thesesources of error. All the assessmentswere conducted by two DC-DERM biologists with extensive experience with coral reef conununities. Specifically,the biologistsconducting the assessmentsare responsiblefor conductingthe biologicalmonitoring programs associated with beachrestoration and renourishmentprojects includingthe SunnyIsles project! and are familiar with the areasin question.The specificdiver's ability to deternunelevels of iinpact wasverified using photogrammetrictechniques. As a matterof procedure,areas showing borderline levelsof impact i.e.,25, 50 or 75%iinpact! were placed into the lowerof thepossible categories. Areas wereassessed as mechanical impact attributable to the draghead only if characteristicscrapes or gouges, described below, were present. Specific areas adjacent to heavily or severely impactedareas may havebeen assessed a slightimpact level %25%! due to the iinpact of rubble,generated by the scrapingaction of the draghead on the benthicorganisms.

RESULTS AND DISCUSSION

A total of nine areas of impact were identified on the reefs. Two sites were on the easternedge of the secondreef, and sevensites on the westernedge of the t}urd reef. The most severelyimpacted sites were sites2 and 3, on the eastside of the secondreef. The approximatelocation of the impact sitesrelative to the borrowarea are shown in Figure 4. Blair et al: Hard-BotlorriReef Areas Off N. DadeCo,,FL

: At eacharea of impact,DERM diversnoted marks, scrapes,or tractsindicative of thedredge's drag head coming in contactwith the reefs. Gouges werecharacterized by smoothed, compressed, flat areasapproximately 8 to 10 crn wide which cutvertically 0.5 to 5.0cm into thecarbonate rock. The gouged, compressed areas were often seenside-by-side Figure 5! andcorrespond precisely to thesize and placement of metal"wear pads" steel plates placed on theedges of thewear head to preventwearing away of themetal draghead via abrasion!on the undersideof thedredge's drag head. Scraped areas appeared as flattenedsurfaces on the higherpoints of the reef alonga impactedtract. The scraped surfacesalso showed obvious compression, reflecting the considerableweight of theobject creatingthe impact. In themore severely impacted areas i.e., sites 2 and3!, swathes multiple tracts!of impactcould be seentraversing the reef. Thefull widthof a singletract i.e.,one passof the drag headover the reef! measured2.5 to 3 m, whichis equivalentto the width of the dredge'sdrag head. At sites2 and3, dueto repeatedincidences of thedrag head being pulled acrossthe reef, the width of the impacttract wasas wide as20 m. Within the areasof multiplepasses, virtually all benthic organisms i.e., soft corals, hard corals, sponges and algae! were destroyed Figure 6!. Along specifictracts within impactsite 2 and3, all sedimentand rubblewere removed from the crevassesand gullies within the impacttract, indicating the bargewas actively dredging while pulling the draghead across the reef.

In slightlyand moderately impacted areas e.g., sites 1,4-9!, the impactwas intermittent andlimited to the highestpoints of the reef. In theseareas it appearedas though the drag headof thedredge was suspended, or partiallyraised, and held at a constantdepth in thewater column. The drag head,therefore, only madecontact with the portionsof the reef thatwere shallowerthan the depthat whichthe draghead was held. Althoughthese areas of iinpact were not as apparentas the severelyimpacted areas, the characteristicscrape marks were presentindicating that the destructionwas caused by the draghead. In the areasof partial impact,fractured live bottom,coral heads, injured soft coralsand sponges were often found Figures 7 and 8!.

i Brief descriptionsof the locationand the impactat the sitesare given below, followed by the quantitativeassessments of Sites 2 and3.

Site+ Thefirst impact site was found on the western edge of thethird reef and crossed overDC-DERM's biological inonitoring station "H". The damageis alongtwo converging paths,indicating multiple incidences of contact.The tracts are 50-75 m longand involve slight -25%! destructionof thehard bottom. At thisspecific site, two large Monrastrea annularis coral headswere destroyed Figure 10!, alongwith a numberof smallercolonies of Dichocoenia stokesii and Mearidrina rneandrites. The heading of thetracts were approxintately 35 M/170-180 .

. Impactsite 2 islocated on the eastern edge of thesecond reef, approximately 50rn north of DC-DERM'sbiological monitoring station "I". Numeroustracts of impact were found,causing considerable destruction. The dainage is detailedlater in thisreport see Divingfor Science...1990

Site 3 is locatedon the easternedge of secondreef, where the reef projects eastwardtowards the borrowarea, forming an irregularityor notchin the generalrectangular shapeof the borrow area Figure 4!. As at site 2, the impact at this location consistedof numeroustracts of impact.This site had the greatest magnitude of impactedarea and degree d* f .Phd phd'd«'U'

~ The fourth area of impact is located on the western shore of the third reef adjacentto the northeasternmost point of the borrowarea Figure4!. This is the regionwhere the dredgeturned out of on northerlypasses! or into on southerlypasses! the borrow area. A singleimpact tract waspresent, approximately 2.5 to 3 rnwide and20 m long,within which anestimated 50 to 75%of thebenthic organisms were destroyed. Bearing of theimpact path wasapproximately 45/225 .

Site 5 ison the westernedge of the third reef, southeastof the "elbow"in the north endof the borrowarea Figure4!. Four tractsof impactwere observed, each 0.5 to 2.5 rnwide and 20 to 30m long.An estimated25 to 50%of thebenthic organisms were destroyed within the impacttracts. The bearingof the impactwas approximately 3545/215-225 .

~hh''g«*dh**dg*f«hfd f Figure4!. Eacharea consisted ofa singleimpact tract, 0.5 to 2.5m wideand 20 to 30m long, withinwhich 0 to25% or 25 to 50%of theorganisms were destroyed. The bearings of the impacttracts were 350-0/170-180 .

«h*f p '* ..U...g d .U» p seenat sites2 and3 wasof greaterseverity mostly 50-75% or 75-100%%uo! andinvolved a much largerarea. The width of specific portions of theimpacted area indicated that the drag head waspulled over the reef numerous times Figure 9 !. Thebottom was severely scraped and fractured,producing considerable amounts of rubble.Only very small organisms, that had settledin varioussmall depressions, survived.

An areaof 1,466m 2 5,7802 ft ! wassurveyed at site2. Impactwas documented alonga 115m path.Within that area destruction varied between 0 and75 100%,with the latterbeing most common. Impact to the reef, attributable to thedrag head, was found as far awayas 23.8 m fromthe eastern edge of the reef. The areas of slightor noimpact represent eithersandy areas, low lying areas or regionsof irregularcontour, which limited the contact of thedrag head with the reef. Furrows in the sand adjacent tothe reef, caused by dredging action,could be followedout of the sandand onto the reef.

Withinsite2atotalareaof938m2 0,096ft2 ! wasimpacted,ofwhich663.1m2 ,1373 ft2 ! wasdestroyed. This is believed to bea conservativeestimate of thearea of destruction, asthe regions assessed at75 100%damage were most often completely denuded ofepiben- thic,cryptic and endolithic organisms. The true percentage of destruction was 100 %. Wi& theprocedures used, however, the relative assessed loss would be calculated at a levelof 87.5% .875;Table 1!. Thisprocedure, in light of thedegree and extent of impact,errs on the conservativesidefor the estimates ofarea destroyed. Figure 9 isa mosaic,generated frora

10 Blairer aL Hard-Bottom Reef Areas Off N. Dade Co.,FL

thecalculated areasof impact and associated degree ofdestruction. It isapparent fromthe widthof the area, numerous incidences ofpulling the drag head over the reef had to have occurredto causethe amount and pattern of impactdocutnented. ~ Site 3 showedthelargest amount ofimpact. Anarea of 11,997 m229,135 ft ! wassurveyed atthis site. Varying levels ofimpact were documented alonga total length of 580m. The impact tract was interrupted atthe 470 meter mark by a largesand area. The tract continuedapproximately 150m southof thepoint of interruption,and continued foran additional110m e.g.,a total of580 m!. The total area impacted atsite 3 was7,979 m 85,885 ft ! withinwhich 5,343.0 m 7,511.6 ft ! was destroyed. Alongthe main path ofdamage, impactedareaswere documented onthe reef as far as 47 m fromtheedge ofthe reef Figure 10!.It isobvious from the extent and intensity of the datnage represented inFigure 10,that repeatedincidences ofpulling the dredge's drag head overs! the reef occurred inthis area. Further,some of the damage tracts had all rubble and sand removed from the crevices inthe bottom.This indicates thatthe barge was actively dredging while pulling the drag head over thereef and not merely holding the drag head atan inappropriate depth. lbble1. ZIie decimal equivalents ol'tbe mean values l'orthe percent impact categories.

0 25 .125 25 50 275 50 75 .625 75 -100 875

! AreaImpacted = Width Of Damage Patb X DistanceBehveen Assessments. ! AreaDestroyed = Area Impacted X Decimal Equivalent ofDamage. Thetotal area impacted atsites 2 and3 was8,917 m 95,982ft ! or2.203 acres. Of thatimpacted area, 6,006.1 m2 4,649.1 ft ! or1A84 acres was destroyed. It should be reiteratedthatthese values donot include theimpact associated withsites 1,4, 5, 6, 7, 8 and 9.A summary ofthe unpact documented atsites 2 and3 isgiven inTable 2. lbMeZ. Summaryofthe area extent ofimpact and impact ntsites 2 nnrt3.

Unit Kmhl&tth

m! 1,466 938 663.1 ft ! 15,780 10,096 7, 1375 acres! 0.362 0.232 0.164

Continued!

11 Diving for Science...1990

lkbte Z ConttaneL Unit htttbalcata

I! 11,997 7,979 5+3.0 ft ! 129,i.35 &5,885 7/11.6 acres! 2,965 1,972 1.320

13,463 8,917 6,006.1 TOTALS tt'! 144,915 95,982 64,649.1 acres! 3327 2 203 1.484

POLICY IMPLICATIONS

Althoughsmaller in scalethan the impacts reported here, other instances of mechanical or physicalimpact to reefs havebeen docutnentedduring beach restoration activitiesin southeastFlorida Britt and A~ciates, 1979,Marszalek, 1981, Barry et al. 1989!. The cumulative effect of these occurrences,as well asother secondary stressesplaced on the reef systemsduring these projects, inay ultimately change the developmentand implementation of long-termbeach restoration policies in Florida.

The mostimnediate changes in projectplanning and implementation may be affected throughthe regulatoryprocess and the criteriaused in permittingbeach nourishment projects. Numeroussafeguards intended to protectreef areas frotn direct andindirect dredging impacts are presentlyincorporated into State permitsand contractspecifications issued for beach nourishmentactivities. Theseconditions address such factors as maintaining minimal buffer zonesbetween reef and dredgingareas, monitoring the water quality and the physicaland biologicaleffects of the dredgingactivities. A patternof continuedreef impactsassociated with beachnourishment projects, despite specific safeguards to preventthem, could lead to policydecisions involving modification of permittingcriteria. The modificationcould result in more stringentpertnit conditions,requirements for mitigation, utilization of alternative sandsources or shorelinestabilization technology, and delays or possibledenial of permitsfor projectswhere a probability,or history,of significantresource impacts exist.

In manyareas even minor changesin the permittingrequirements could havea major effecton the decisionto implementlarge-scale beach nourishment programs. An increasein theminimal buffer zone, for example,from the current150 to 200feet, to a moreconservative 400 feet would greatly reduceboth the siltationeffects on surroundingreef areasand the likelihoodof mechanicalimpacts to the reef. The needto provide a widebuffer zoneon each side of an alreadynarrow borrow site, however,may greatly reduce, or eliminate the sand quantityavailable for a project. Changesof this typewill greatly affect the economicsand viability of nourishmentprojects as the increasedcosts of using limited offshore,or more

12 Blair et aL Hard-BottomReef Areas Off M DadeCo.,FL

expensiveoff-site i.e.,Bahamian aragonite or uplandsources! materials are weighed against alternative shore protection measures.

Withinthe last decade, increased governmental and public awareness of the sensitivity and fragility of our reef habitatshas greatly reducedthe attitude of acceptanceof natural resourceimpacts and resulted in a more aggressivemovement toward prosecutionand subsequentrecovery of damagesfor theseimpacts. Pastdamages awards have often been associatedwith "high profile" areasor habitatsand shippingaccidents i.e., groundingof the freighter WELLWOOD,Key Largo National MarineSanctuary, Florida, August 1988; groundingand oil spill of the EXXON VALDEZ, Prince William Sound,Alaska, March 1989-damagesnot yet determined!.Recent awards, however, have involved reef impacts associatedwith dredgingactivities in hard bottom habitats. Damagesof $1.0million, for example,were recently agreed upon in responseto a jointsuit filed by the FloridaDepartment of EnvironmentalRegulation and the DadeCounty Department of EnvironmentalResources Manageinentagainst the contractorresponsible for the reef impactsdescribed in this report. The funds will be usedby the State and County to restore and enhancethe impactedreef resources.A similar,though smaller, suit brought an equivalent on a permeter-square basis! settlementof damagesfor reef impactssustained during a 1988beach restoration in a Boca Raton,Florida. The precedentestablished by thesesettlements will certainlybe considered by contractorswhen contemplatingbidding on projects utilizing borrow sites in close proximity to reef areas.

The implicationof pastreef impactsand associateddamages can be nuinerous.There may be a highercost, for example,for nourishmentprojects with borrow areasadjacent to valuable or sensitiveresources; pernutting agenciesmay initiate irnplernentationof more stringentenvironmental safeguards or require mitigationcommitment i.e., mitigationbond! through the regulatoryprocess; water quality standardswhich do not appearto adequately protect living resourcesmay be reassessedor revised;and there maybe reevaluationof beach nourishmentas the preferred beachprotection strategy. The resultant changes in beach nourishmentpermitting and implementation will not necessarilyall be negative.The in- creasedemphasis on protectingthese resources inay accelerate the developmentof alternative sandsources and/or technologies which will reducethe frequency of renourishmentepisodes or will allowbeach nourishment activities to occurin anenvironmentally compatible manner.

SUMMARY

Nineareas of mechanicalimpact by the hopperdredge's drag head were identified on thereefs adjacent to theborrow area. Seven impact sites , 4,5, 6, 7, 8 and9!, showed slight to moderateimpact -25% or 25-50%!paths, which were short in lengthand involved one usually!tofour incidences ofthe drag head contactin~ thereef. Two sites and 3!had large areasof severeimpact. A totalof 8 917m 95,982ft !, or 2.203acres of impactedarea was documentedatsites 2 and3 938m [10,096ft2] atsite 2 and7,979 m [85,885ft2 ] atsite 3!. A totalof 6,006.1m 2 4,649.12 ft !, or 1.484acres, of theimpacted area was destroyed 63 1 in2[7,137.5 ft ] atsite 2 and5,343.0 rn [57,511.6ft ] atsite 3!. Damageto thereef was found

13 Divingfor Science...1990 asfar awayas 23.8 m 8 ft! atsite 2 and47 rn 54 ft! at site3, from the edgeof the reef. The magnitudeof impact documentedcould only haveresulted froin repeatedlypulling the drag head s!of the hopperdredge across the reef. Thislevel of destructionrepresents a signiTicant unpactto the hard-bottomcoinmunity within the regionby reducinghabitat quality,density of organisms,reef structuralcomplexity and the overall productivityof the area. Possible ramificationsof theseimpacts are increasedcost of future beachnourishment projects in regionswith sensitivehabitats in closeproximity; more stringent regulationsfor beach nourishmentprojects; and renewed intensity forward finding alternativemethods of beach nourishment and stabilization.

LITERATURE CITED

Barry,J.J., C. Vare,P. Davis and R. Clinger. 1989.Reef restoration off BocaRaton, Florida. Proceed. Fla. Shore and Beach Preserv. Assn. 1988. Gainesville, Florida.

Blair, S. M., and B. F, Flynn. 1989. Biological monitoring of hard bottom reef communities offDade County Florida: Community Description. pp. 9-24. IN: Lang and Jaap eds.! Diving for Science...1989.Proceedings of the American Academyof Underwater Sciencesninth annualscientific diving symposium. Costa Mesa, CA. 341pp.

Goldberg,W. M. 1989. Biologicaleffects of beachrestoration in southFlorida: The good, the bad and the ugly. Proc. Fla. Shore and Beach Preserv. Assn. 1988. Gainesville, Florida.

1973. The ecology of the coral-octocoral communities off the southeast Floridacoast: Geomorphology,species composition and zonation.Bulletin of Marine Science,23.'465-487.

Jaap,W. 1984.The ecologyof the southFlorida coralreefs: A cominunityprofile. U.S.Fish Wild. Serv.FWS/OBS 82/08. 138 pp.

Marszalek,D. S. 1981.Impact of dredgingon a subtropicalreef coinrnunity,southeast Florida, U.SA, Proc.Fourth Inter. Coral Reef Symp.Vol 1: 147-153.

Shim, E.A. 1988.The geologyof the Florida Keys. Oceanus,31: 47-53.

14 Blair et aL Hard-BottomReef Areas Off N. Dade Co.,FL

Figure i. Itegioaalmap sbowiug area of DadeCouaty where the project took ploce,and the relative locatlou of the borrow area to the offshore reef terraces.

Figure2. Schematicofa hopperbaqy: illustratiag how such a dredgeoperates. The drag head"is locatedat tbeead of the'Drag Arm'.

15 Divingfor Science...1990

~ 4

l44

4. ~ l, ~ l.4 444yl44l. 4IL4 ~ 04444014

Figure3. Nearsborebottom proSe fouad oil' Northera Dade County.

Figure 4. ~tloas ot the hopaet areasaroaod the borTo4rarea L-9! and the biological taoaltoriag statioas A, H, i!.

16 Blair et aL Hard-Bottom ReefAreas Off N. Dade Co.,FL

Figure5. Fnralietscrape marks left bythe wear pads of thedrag head. Notethe vertical gougingof the rock

Figure6. As impactcorridor produced by multiple inctdences ofthe drag bead being putted acrossthe reef- Notethe normal gronth ot softcorais andsponges to the rightof thecorridor.

17 Divingfor Science,.1990

Figaro7. h CractnredNonfsstma onnrdoris cond head adjacent to biological moaitoring station H. 'lbe whiteareas sa therodr. are alas ot the condhead ldlied by tbe impactand snbseqaent inversion.

Fignreg. h Xcsaupongiumala barrelsponge cat by thedrag head. 'gabe sponge remained attachedatter tbe impact.

18 Blair ef aL'Hard-Bottom Reef Areas Off N. Dade Co.,FL

0 ~000 ~ 00 LCVEL !. 0 0 II2 4-00 Q 00-1 ~

1 0 g 7 ~ 100

100 N ST 00 ~

NSTANCE ALONG PATH ligate 9. A mosaicof the impactat site2 geaeratedhorn tbe measumd areas of impact aad tbeh ~ted degreeaf destructiaa.

19 Divingfor Science...

SII333N D DDE ~~ ~ ~ OLBQtiVi@0 0

20 MECHANISMS OF OUTER CONTINENTAL SHELF OCS! OIL AND GAS PLATFORMS AS ARTIFICIAL REEFS IN THE GULF OF MEXICO

A. ScarboroughBull J J. Kendall, Jr. MineralsManagement Service Gulf of Mexico OCS Region Office of Leasingand Environment412! 120' E]inwood Park Boulevard New Orleans, LOUISIANA 70123-2394 U.S.A.

A studyof thefish and biofoulingcominunities at twoartificial reef sites was conductedin the Gulf of Mexico.South Tirnbalier Block 128 Platform A ST 128-A!had beendetonated and toppledin place nine monthspreviously. South TimbalierBlock 86 Platform A ST86-A!had been blown over during a hurricane fouryears previously. The predominance ofimmature fish and the paucity of adults of thosesame species on ST128-A indicate that this artificial reef has acted as a recruitmentsite for reef-dependentspecies. Observations on ST86-Aindicate that themajonty of structure-related fish species were full-grown adults. F'infish surveil- ktnce,observation of invertebrates,and thepresence of two scleractiniancoral speciesat ST86-A, and not at ST128-A, suggest that the biotic communities may bemore diverse and extensive at ST86-A. Thesedifferences could be due to the mannerby whicheach structure was toppled and orpossibly due to thelength of time each has remai ned undisturbed.

INTRGDUCAGN

Thereare approxiinately 3,700 oil andgas production platforms in Federalwaters of theGulf of Mexico.Production platforms are set in placeby driving steel support legs deep intothe seafloor. Working machinery and personnel sit above the water supported by a steel networkthat is intentionallyoverbuilt and remarkably secure Gallaway and Lewbel, 1982!. However,offshore structures are not intended to be permanent. Whenproduction ceases, the company operating the structure must then deterinine themeans of itsdisposal. The platform may be relocated for use in theindustry, removed and scrapped,or used as an artificial reef. In thelast few years the practice of convertingobsolete offshoreplatforms to artificialreefs has gathered broad public and private interest. For example,both Louisiana and Texas have legislated State programs toconvert obsolete offshore productionplatforms to artificial reefs.

21 Diving for Science...1990

Despitethe ratherextensive use of dedicatedartificial reefson the southeasternUnited StatesOCS, opinions regarding their useand effects remain divided Do artificial reefsresult in an actualbiomass increase, or dothey simply redistribute fish populations in thoseareas wherethey are established?If artificialreefs serve mainly as aggregators,concentrating otherwisenaturally dispersed fish stocks, extensive reef deployment coupled with uninanaged fishing could lower fisheriesproduction. However,if artificial reefs serve as habitat in space-limitedsituations, extensive reef development could stabilizeand/or increasefisheries production.

It is likely that the platformsin the north-centralGulf of Mexico are in somemanner influencingfishery resources in the Gulf. However,inforination and understanding are woefullyinadequate asto theextent of theinfluence, its nature, and whether it isnegative or positive,or both. Conclusiveevidence and quantitative data are scant. Since there are few naturalreefs in thenorth-central Gulf of Mexico,the controversy regarding natural versus artificialreefs may not be germane tothe issue. However, basic knowledge isalso lacking on the mechanismsof standing platforms as de facto reefs or on obsoleteplatforms used as artificialreef materials, and little is knownconcerning interactive effects of platformsas artificial reefsand anynearby natural reef communities.

The over3,7OO platforms of variousages, at variouslocations in the north-centralGulf ofMexico, present nuinerous, repetitive opportunities forstudy. Many platforms are operated byresponsible companies willing to assistin researchefforts. All platformshave electrical power,refuge from weather, a stabledeck, an established supply network, and are secure both aboveand below the surface Bull, 1989!.

It wouldrequire decades and billions of dollars to establish the study opportunities now presentinthe north- central Gulf of Mexico. To our knowledge, there is but one study planned toacquire basic information concerning standing platforms asde facto reefs. It ishoped the studywillbegin by 1991 and will last two to three years. Until quantitative studies ofrepetitive regularityare performed, information regarding communities associated with any platforms or artificialreefs will beof a qualitativenature, reporting observed phenomena but unable to quantifywhat is observed. That is the case with the present paper. Overa 2-dayperiod in August1989, we had the opportunity to observeand record the fishand biofouling communities inthe Gulf of Mexico at two sites approxiinately seven miles apartin distanceand four yearsapart in submergence.Both structures included the entire above-and below-water sections ofpreviously standing production platforms. These sub- mergedplatforms, now accepted asdedicated artificial reefs by the Louisiana Artificial Reef Program LARP!, had quite different histories inbecoming reefs Figure 1!.

In September1988, after 2O years of activeproduction, South Timbalier Block 128 PlatformA ST128-A! was retired, severed byuse of explosives 16ft belowthe seafloor, and toppledin place.In lateOctober 1985, completely shut down during the 20th year of active production,South Timbalier Block 86 Platform A ST86-A! was knocked over during Bulland Kendall; Oil 4 GasPlatformsirt the Gulf

HurricaneJuan. The objective of thisstudy was to comparethe fish and biofouling communities at the two sites.

METHODS

A qualitativestudy of the fishand biofouling communities at ST 128-Aand PI' 86-A wasconducted using a stationaryvisual census technique for fish Bohnsackand Bannerot, 1986!and macrophotography for invertebrates. Fish surveying was performed with thediver remainingstationary while listing and then counting the fish within a clearhorizontal range of vision.Additional information noted during fish identification included depth, teinperature, approximatelifestage, and behavior. The macrophotographysetup consistedof a Nikonos IV-A underwatercamera and 35 rnmlens, an OceanicModel 2000 underwater strobe, and a 1:2extension tube complete with framer Figure2!.

Data concerningfish and invertebratedistributions, densities, and diversitieswere gatheredduring two dives made at thissite. Duringthe first dive, a qualitativesurvey of fish wasperformed around the deck area and from the deck area to thebottom of theplatforin Figure3!. Duringthe seconddive, a concertedeffort was made to surveyfish and inver- tebratesalong the entirelength of a singleinner leg of theplatform reef. Thiswas the first attemptto observeand record the biota on thisartificial reef since it wastoppled in place.

Twodives were made at thissite. Recording of fishand hydrographic information was minimalon the firstdive due to the needto recordstructural measurements Figure 4!. However,macrophotography anda qualitativesurvey of thefish were performed during the second dive.

RESULTS AND DISCUSSION

Fishand biofouling coinmunities were present for 20 years prior to the designation of thesestructures asartificial reefs. While both fish and biofouling coinmunities were undoub- tedlybeyond the initial phases of recruitmentand colonization when the structures where last standing,the coinmunities were likely in vastlydifferent conditions when the platforms were designatedas reefs. Dgvbgfor Science...1990

In the caseof ST 128-A,the useof explosivesfatally concussedmost of the adult fish andcertainly all of the demersalspecies associated with the platform Figure 5!. Vjbratioii from theblasts ran upward through the supportlegs and was sufficient to dislodgemost of the biofoulingand sessile organisms as well David Bull, pers.comm.!. In the caseof ST 86-A, sinkingfrotn the force of a hurricanewas no doubtdisturbing, but it wasalso relatively slow andnot massivelydestructive.

Thebiofouling conununities typical of offshorestructures in the Gulf of Mexicohave beendescribed by Gallawayet aL 979!. In the coastalwaters -100 ft! of Louisiana,they are dominatedfram the surfaceto a depth of about 24 ft small acorn barnacles i%danas amphitriteand B. inrprovisus!.This almost continuousmat of barnaclesis then, in turn, coveredby a "secondary"mat of raacroalga,hydroids, bryozoans, and encrus ting sponges.The actualspecies composition of this secondarymat dependslargely upon turbidity and the season.At deeperdepths >24 ft!, andoften more turbid waters,hydroids dominate Gal- laway,1981!.

The most conspicuouscomponent of both the ST 128-A and ST 86-A biofouling corrununitieswas barnacles Figure 6!; however,a significantproportion of thesewere dead. While the causeof the mortalitycan only be speculated,the clearanceof ST 128-Aand ST 86-Awas 54 and41 ft, respectively.These depths are somewhatgreater than that suggested for a conununitydominated by barnacles Gallaway et al., 1979!.As such,the historiesof these structuressuggest the "drowned"remnants of barnaclecommunities growing at shallower depthswhen the structureswere intact. Theseremnant barnacle communities now function asshelters for manysrnaH, motile or semimotileanimals living on or within them Figure7!. Manymotile e.g.,blennies! and semimotile e.g.,sea urchins! animalsdepend upon these refugesfor protectionfrom strong currents, protection from predators,and for reliable areas wheredetritus and other food materials may settle out Gallawayand Lewbel, 1982!.

Barnaclesare also an importantfood source. Gal!awayand Martin 980! identified barnaclemolts as a dominantfood sourceof the crestedblenny, Hypleorochilus geminatus. Barnaclesmay also become available when bits of fleshare left attached to the crushedplates asa resultof the feedingof largegrazers Gallaway and Lewbel, 1982!.

The biofouling communitiesof ST 128-A and ST 86-A can be discussedin terms of the sequencesof reef development Schuhmacher, 1977!. The encrustationsof barnacles, bryozoans,colonial tunicates, and filamentousalgae found in abundanceon both structures may be consideredremnants of the initial stagesof reef development: the rapid and homogeneouscolonization by predominantlynoncalcareous fouling organisms.The second stageof reefdevelopinent is the settlingof mollusks,calcareous red algae,and foraminiferans not affectedby grazingorganisms, which often largelyconsume the initial settlersand sub- sequentlyattaching larvae. The colonizingorganisms may includeoysters, calcareous algae, andforaminiferans. Atlantic winged oysters, iberia colymbus, were observed at ST 128-A Table1!, and calcareous algae were widely abundant at both ST128-A and ST 86-A.

24 Bull and Kendall: Oil k Gas Platfovns in the Gulf

The growth of scleractinianand hydro-coralson the remainsof attachedshells, or on other places often inaccessible to grazers, characterizes the third stage in this sequence. Colonies of the flower coral, Eusmi1iafastigiata Figure 8!, and the orange tube coral, 7ttbastrea coccinea, were found at ST 86-A. T. coccinea is known to colonize and thrive in "shady"areas Kaplan,1982!. This behavioris partiallythe resultof their lack,or independence from, zooxanthellae,the endosyrnbioticdinoflagellate algae upon which hermatypic reef- building! corals depend.

What maybe consideredthe dominantorganism associated with this third develop- mentalstage at ST 128-Aand ST 86-A are coloniesof the "soft corals,"Telesto riisei Figure 9!. While the order Telestaceais of minor importancein comparisonto the five ! other orders of the Octocorallia,T. riisei may haveparticular significancein the Gulf of Mexico becausecolonies may reach over 12in Colin, 1978!.Colonies as large as 12in wereobserved at both structures, particularly at ST 86-A.

The final stageof reef developmentis characterizedby deadcoral colonies overgrown by calcareousforanuniferans, algae, and bryozoansconsolidating the corallinestructures by their deposits. These are often followed by the recruitmentand growth of more massive hermatypiccoral species. While hermatypiccorals e.g.,brain corals!have been documented growingon offshorestructures, particularly on the outer shelf David Bull, pers.comm.!, the waterquality of coastalLouisiana, which includes the SouthTimbalier area, is not conducive to their developinent.This areais heavilyinfluenced by the dischargeof the MississippiRiver, resultingin highprimary productivityand high zooplanktonconsumption, frequent periods of high turbidity, and even fluctuations of the physicochemicalparameters.

Coralsare relatively sensitive to manyenvironmental perturbations Jaap,1979; Loya and Rinkevich, 1980!. The effects of turbidity have been widely studied and have been implicatedas a prime causeof decreasedgrowth e.g.,Aller and Dodge, 1974;Loya, 1976; Kendallet al., 1985;and others!. However,in the Caribbean,the octocoralT. nisei is known to grow readily on pilings in many harbor areasand may be the only octocoral of any significanceas a fouling organism. Where it is foundgrowing on reefs,it is usuallyin more turbid environments Colin, 1978!. Theseconditions are not unlike thoseencountered at ST 128-A and ST 86-A.

The skeletonof the octocoralT. riisei is a ratherrigid structurecomposed of spicules of calciuincarbonate imbedded in a hornymaterial. Thisskeleton is then often colonizedby a varietyof other organisms.This additionalrelief canthen be utilized ashabitat by a hostof other organismsas was clearly evident at both ST 128-Aand ST 86-A. Theseother organisms includedseveral varieties of Caribbeantropical fishessuch as cocoa damselflish lbntacentnrs variabilis!,spotfin butterflyfish Chaetodonocellatus!, angelfishes e.g., Pomacanthus p~!, severalspecies of blennies e.g.,Hypsobknnius invetnar and Hypkuroch2usgeminatttt'!, and a diverseassemblage of invertebratessuch as seaurchins Arbaciasp.!, arrow crabs Stenor- hynchussp.!, and sponges IIaliclona sp.! Figure 10!. Divingfor Science...1990

Theorganisms associated with the skeletonof T.re'hei may be involvedin variousbiotic interactionssimilar to thosereported for coral reef environments. While this analogymay seemextreme to some,it is a convenientstarting point for analyzingthe communitycornposi- tion and interactionsoccurring on theseartificial reef structures. For example,the estab- lishmentof algal patchesby damselfish,at the expenseof hermatypiccorals, is a commori occurrenceon coral reefs Kendall and Bright, 1989,and referencestherein!. The lush commurutiesof algaeare believed to suppressthe growth of corals through a reductioniri availablefree space for recruitmentand expansion. Coral mortality within thesealgal patches mayalso result from algalovergrowth, increased sedimentation, and a persistentbiting bythe resident damseKsh Fotts, 1977!.

Themost striking observation was that the majority of the fish at ST 128-Awere young of the year YOY!, immatures,or youngadults Tables1 and2!. Except for immaturecocoa damselsand blennies, which were present at both ST 128-Aand ST 86-A, all fish observed duringdives at ST 86-Awere adult. ST 128-Awas exceptional in that numerousimmature grouper and snapperwere present. In addition, of those adult finfish observed on ST 128-A, no immaturesof the samespecies were observed with the exceptionof blennies.

At leastone pair of adult cocoadamsels was observed on ST 86-A. Adult cocoadamsels requirea minimumterritorial space that contains attached, small rnacroalgae. While damsel- fishterritories may develop at the expense of otherorganisms notably corals!, they do function as centersof primaryproductivity Brawleyand Adey, 1977!. They also provide infaunal organismssafe refuge and protection from carnivores. The diversityand abundance of small motileinvertebrates have been found to besigniflcantly greater in suchpatches than in nearby nonalgalareas Lobel, 1980,and references therein!, At the sametime, however,the con- surnptionof noncalcareousalgae by grazers,such as the darnselfish,butterflyfish, and sea urchins,have been implicated in thesuccessful recruitment of coralto newsubstrata Dart, 1972;Potts, 1977; Sammarco, 1982!.

Blenniesbrood their eggs inside barnacle shells in the latespring and protect their youngfor a shortperiod after hatching. It is noteworthythat fewer immature blennies were observedat ST86-A than at Sl' 128-A.It wasunexpected, that on ST 128-A,barnacles and blennieswould be living at depths of 55-58 ft whenthey normally occupy the top 20 ft under a standingplatform Gallawayet aL, 1979!.

Thereare several factors that are important for artificialreefs to successfullyattract fishand/or increase local flsheiy biomass. It is well known that fish have an innate, positive attractionto underwaterstructures thigmotropism!. Reef-dependent species e.g., snapper, grouper,damseKsh! recruited toartificial reefs wiH become residents. Ocean pelagic species e.g.,amberjack, cobia, mackerel! use the vertical relief of artificialreefs as a visualcue for theirtransient movements Gallaway and Lewbel, 1982! Figure 11!.

26 Bull andKendall: Oil & GasPlatfonmin the Gadf

Bohnsack989! concludedthat the presenceof artificialreefs is moreimportant for reef-dependentspecies in locationsmore isolatedfrom naturalreef habitats. Both ST 128-A andST 86-A are over 100miles from naturalreef habitats.However, they are not far from standingplatforms that are likely actingas establishedartificial reefs Scarborough-Bull, 1989!.

Stoneet al. 979! deternunedthat an artificial reef in closeproximity to anestablished reefinitially attracts only the juveniles of reef-dependentspecies from the nearby established reef. Further, theyobserved that transientspecies begin to key on an artificial reef assoon as the artificial structureis emplaced.They concluded that artificial reefsdid not diminish the residentpopulation of nearbynatural reefs by attractingadult reef-dependent species to the new habitat.

CGNCLVSIONS

Conclusionsare basedon very little data and are thus qualitative. The observations anddata that were collected, however, suggest that continued monitoring of bothstructures on a regularbasis could yield quantitativedata concerning artificial reefs.

ST 128-Awas set in placein 1968and toppledin place20 yearslater by multiple explosivecharges that severedall but two legs. It is assumedthat the topplingactivity and explosivesremoved most of the adult fish. It is knownfrom real-timevideo surveys that blenniesoriginally within 20 ft of thesurface were alive after the platform was toppled David Bull, pers. comm.!. Whether those saineblennies continued to live or remain on ST 128-A is unknown.

The presenceof a inixtureof species,the predominanceof immaturefish of those species,and the paucityof adultsof thosesame species lead to the conclusionthat ST 128-A hasacted as a recruitmentsite for reef-dependentrelated species. In addition,the presence of severalviable finfish nestsand gastropodegg cases indicates that this artificialreef is providing acceptable conditions that will increase biomass.

ST 86-Awas set in placein 1965then knocked over during Hurricane Juan 20 years later. ST 86-Ahad been down nearly four yearsat thetime of thesurvey. To the associated marinecommunity, being blown over by a hurricanemust have been a greatdisturbance at the time. However,the eventwas certainly no moredestructive than the explosivesused at ST 128-A.Qualitative observations indicate that the structure-relatedspecies were full-grown adults. Manyof the grouperspecies e.g., hinds, coneys! were as large or largerthan any individualsobserved during inany years of divingunder platforms in theGulf of Mexico.Since theplatforms were approximately the sameage, and the exact time of platformsubmergence

27 Divingfor Science...1%6 isknown, quantitative monitoring on a regularbasis may elucidate the carrying capacity of the structureand the turn-overrates of the populations.

Ultimately,whether or notthere will be furtherrecruitment to, anddevelopment of, thebiofouling communities of ST 128-Aand ST 86-A will dependupon a numberof environmental,biological, and chemical parameters acting synergistically. Site selection by the larvae, toleranceof theturbidity nepheloidlayer!, hypoxic events, susceptibility to predation,coin- petitionfor space,and resistance to biologicaldisturbances caused by grazingactivities and other biotic disturbances will have direct and indirect influences.

The abundanceof the soft coral T. rib ei and its associatedepifauna and infauna, damselfish,and a varietyof associatedfish and invertebrates,suggests similar biotic interac- tionsat ST 128-A andST 86-A. Studiesexamining the relationshipsbetween these coin- ponentsmay provide information invaluable in predictingthe developmentalstages, communitystructure, and possibly the productivity of thesebiofouling communities. A more detaileddiscussion of theresearch potential of offshoreplatforms maybe found in Bull 989!.

Whileboth ST 128-Aand ST86-A retained renmants of whatmay have been very similarbiofouling communities prior to submergence,subtle differences between their com- munitieswere evident. General observationsand the presenceof two scleractiniancoral speciesat ST 86-A,and not at ST 128-A,suggest that the bioticcommunities may be more diverseand extensive at ST86-A. As suggestedin the conclusions for fishcommunities, these differencescouM be due to the mannerin which eachstructure became an artificial reef andjor possiblydue to the lengthof time eachhad remained undisturbed.

ACKNOWLKDGEMENTS

The authorswish to acknowledgethe MineralsManagement Service MMS! Dive OBicer,Mr. Les Dauterive;the MMS Gulf of MexicoRegional Dive Master,Dr. Rik Anuskiewicz;the coordinatorfor the LouisianaArtificial ReefProgram LARP!, Mr. Rick Kasprzak;and the Friendsof LARP,Messrs. David Stanley and Joel Chalky for their diving support. The authors wish to thank Ms. Debbie Miller and Mr. Mike Dorner for their assistancein preparation of the manuscript.The contents do notnecessarily reflect the views andpolicies of the U.S.Department of theInterior, Minerals Management Service. Bulland Kendall; Oil k GasPlatforms in theGulf

LITERATURE CITED Aller,R. C. and R.E. Dodge. 1974. Animal-sediiiient relations ina tropicallagoon: Discovery Bay,Jamaica. J. Mar. Res. 32:209-232.

Bohnsack,J. A. 1989. Are highdensities of fishesat artificialreefs the resultof habitat limitationor behavioralpreference? Bull. Mar. Sci. 44!: 631-645. Bohnsack,J.A. andS. P. Bannerot. 1986. A stationaryvisual census technique forquantita- tivelyassessing community structure ofcoral reefs. NOAA Tech. Rept. NMFS 41: 1-15.

Brawley,S. H. andW. H Adey. 1977. Territorialbehavior of thethreespot damselfish Eupomacentruspkuufrons! increases reef algal biomass and productivity. Envir. Biol. Fish. 2!: 45-51.

Bull,D. 1989. Offshoreoil platforinsin the Gulf of Mexico,conversion to artiTicialreefs: an opportunityfor longterm biological studies. Pages 25-28. In: M. A. Langand W. C. Jaap eds.!,Diving for Science...I989,American Academy of UnderwaterSciences, CostaMesa, Calif. 341 pp.

Colin,P. I. 1978.A fieldguide to the invertebrates and plants occurring on coral reefs of the Caribbean,the Bahamasand Florida.T.F. H. Publications,Inc.Ltd., Neptune City, N. J. 512pp.

Dart, J. K. G. 1972. Echnioids,algal lawn and coral recolonization. Nature. 239: 49-50. Gallaway,B. J. 1981. An ecosystemanalysis of oil andgas development on theTexas- Louisianacontinental shelf. U.S. Fishand Wildlife Service, Office of Biological Services,Washington, D. C. FWS/OBS-81/27. 89pp. Gallaway,B.J., M. F. Johnson, R.L Howard,L R. Martin and G. S. Boland. 1979. A study ofthe effects ofBuccaneer oilfield structures andassociated effiuents onbiofouling communitiesand the Atlantic spadefish Chaetodipterus faber!. Annual report to NationalMarine Fisheries Service, Galveston, Tex. LGL Limited- U.S., Inc., Bryan, Tex. 126pp. Gallaway,B.J. and G. S.Lewbel. 1982. The ecology ofpetroleum platforms inthe Gulf of' Mexico:a communityprofile. U.S. Fish and Wildlife Service, Office of Biological Services,Washington, D. C. FWS/OBS-82/27. Bureau of Land Management, Gulf of MexicoOCS Regional Office, Open-File Report 82-03. xiv + 92pp. Gallaway,B.J. and L R. Martin.1980. Effect of gas and oil field structures and effiuents on pelagicand reef fishes, and demersal fish and tnacrocrustaceans. In: WB. Jacksonand E.P.Wilkens, eds.! Environmental Assessment of Buccaneer Gas and Oil Field in the NorthwesternGulfof Afeuco, I978-79. NOAA/NMFS Annual Report to EPA. NOAA Tech.Meino. NMFS-SEFC-37, Vol. III,49 pp. Jaap,W. C. 1979.Observations onzooxanthellae expulsions atMiddle Sambo Reef, Florida Keys.Bull. Mar. Sci. 29: 414- 422.

29 . A6ld~ide tocoral reefs, Caribbea andHorida. We Peterson Field an,E.H.GuideSeries.1982. HoughtonA ~ Mifo'i in Company, Boston. 289pp. ll,S.J.Connor, T.J. Bright, and C- E Zastrow1985 turbidityoncalcification 'fi ' dan tthe e free amino acidpool ofthe coral A, 0 Mar.Biol. 87:33-46. dT.J.B 'mt. 1989. An analysis ofbiotic interaction on GardenBank Gulf ofMexico! using short-term time-lapse photog MA,Lang and %C. Jaap eds.!, ~for ~~~ ofUndematr S'en~c t Me~Gal pp. '"o'yy~ifishand thetrrole in coral reef co~. BulLMar. Sci. 30: 273 289. e& ofwater turbidity and sedimentation on the co PuertoRican corals. Bull. Mar. Sci. 26: 450-466. Y. andB. Rinkevich. 1980. Effects of oil pollutionon coral reef cornmurut'eah4, Ecol.Prog. Ser. 3: 167-180. , D.C. 1977.Suppression of coral populations by filamentousalgae within damself5b territories.J.Exp. Mar. Biol. Ecol. 28 207-216. mmarco,P. W. 1982.Echinoid grazing as a structuringforce in coral communities:whole reefmanipulations.J. Exp. Mar. Biol. EcoL 61: 31-55. borough-Bull,A. 1989.Fish assemblages at oil andgas platforms, compared to nattnxl hard/livebottom areas in theGulf of Mexico.Proceedings of the Sixth SytnposiuntOs CoastalandOceanManagernent.Charleston, S.C. VoLI, pp 979-987- hmacher,H. 1977.Initial phases inreef development, studied at artificialreef types« Eilat RedSea!. Helgolander wiss. Meeresunters. 30: 400-411- e,R. BH.LPratt, R.O.Parker, Jrand G. E. Davis. 1979.A comparisonof> populationsonan artificial and natural reef in the Florida Keys. Mar. Fish. Rev. <1 1-11. Bull and Kendall; oil & Gas Platforms in the Gulf

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liable 1. Observationsperformed daring Curstdive otl ST 128-A..

31 Dr'vingfor Science...1990

0 IVE gc~ Seelgoof fill g to&a~ fl V'ESSKI4/5 rat ~ r C. ~ /lg/Og y 'IOOO pffft gf I IO gtl vetvr~ C

tovcg 56 lt SIV~ resaer ~ avlt C4ieo~ lag reap~ Og-OSP leva~ tr 1gt~ r~ ~c sc~ ~ Cvlt lg ale lalar lo Cla fsl foa 4 ~ll92c erevger TOTer 5 ~ ~ ataf lag elec t ~ ~ ravta6 gravitas I ~-5 ~ I ~ 5Srocpar Tgyer I a ~rr ~ Cvt~ ~ gelt I ~ ft, I alt ioagleg aroeag ~ Celtvv eetor~ I esa Ioc ~ iert~ tar act j ~I14111 fgf Cr I CO lar ~ sores Isc cro ~ leeI ~I ! ~ 4 ~Ie tie oreegasgeeloe ~At4 4I a~a g og tt evsat fy ~ I~ ~to i ~g 4I ~~ rove Ig It gate vary st r I II t lei c ~~ l sot tt '56 ~I ~ lace Cpeclea ctrl s scar I rge isracolas v IOT ar I lets ~ aell ~ rraveras ~ l44CS~ vo ~ lett ~ cioella ~ c loslag tarov~ i fecag ~ aed~ fI ~i t ret spettss taeag gl il la I ~ ec at r halte cpattea Ieeag Tg t f ~ gla oc i rcealee ~ Cia/groopol TOI er ~ ~ 5~ Tlag~ Iee ta gratti g areale ~ I ~ 4atl'op46 ~ C ~ ~ ar~ ecI ~ ~S boa areal' ~ eatlf I ~ lh earcarv~ 4~ ~1 ggea ~ sl~ I'I ~CL Tovag lg vcisallsg ae coles lag terovgl I rracCll ~ 5t ~I ~ Taearlog ~ Cier laeileg Iar f 446 56-60 cvceaCaoc ~ Ic TOT~ 46 I'se ~ verges~ re 4 Itrcetcr ~ vite ~ ts roots eeoc terri ter I ~I 55 aetsfI as facet la crevlea ID ~ itepaa~ cf ~ evlt~ 5 ~ I I I I a ~~ See t 'lI ~ st~ tl~ ~ @It of $4$leo I feedle ~ ea I ~Vvager eacrvatleg S ~ttarflf fl ~ i ~ pecg~

Thbie2. Observationsperformed during sef.'oad dive oa ST 128-A.

32 Bull and Kendall: Oil & Gas Platfovnsiver the Gulf

Figurei. Louisianaothhore artitlciaireef planaiugareas. South'Hmbalier, site 6, was the studylocation.

Ftg R. Recordingdata nt SV uS-a. I m ItutL

33 Divingfor Science...1990

Figure3. Scbetuatlcof toppled piatformST 128-A courtesyof CbevronUSA Iuc.!,

Figure4. Scbexauticof sunken phtform ST 86-A courtesyof ODECOOii nnd GasCo.!. Bull and Kendall:oil & GasPlatfonnsirt the Gulf

Figure5. Through this "window,"cut into a legof platform ST 128-A,explosive charges werv. lowered to 16 ft below the seaiioor before detonation. c! David Bull.

Figure6. ST 86-A areaof submergeddeck showing heavy growth of barnaclesand encrusting sponges. c! David Bull. 35 Divingfor Science...19Ã

Figure7. Dotalof dead~es ouST 128-A: home to a crestedbleuuy, Hypiettrochihts geminate,uud spoug tuuicate,Didrmnttn conchykatttm. c! JamesKeudail.

Figure8. DetaQofiiower coral, Zasmilia fastigiata, oaKI' 86-A. c! James Ken dali.

Figure9. Detail ofoctocoral, Tetesto nisei, ou ST 86-A. c! James KeudulL 36 Bull attdKendaH: Oil 4 GasPlatforms in the Gulf

Figure 10. Detail of communityassociated with octocoral;immature cocoa damseliish, Ponracentrusvariubitis, sponges, and seaurchin, Arbaciasp., on ST 1ZS-A. c! James Kendall.

Figure11. Oceanpelagics, cobia, Rachycentron canudran, above ST 128-A, c! DavidBuH.

37 "LIVE BOTTOMS" IN THE CONTINENTAL SHELF ECOSYSTEM: A MISCONCEPTION?

La~rence B. Cahoon DavidG. Lindquist IleanaE. Clavijo Departmentof BiologicalSciences Universityof NorthCarolina Wilmington,NORTH CAROLINA 28403 U.S.A.

Theterm "live bottom" has been used to denoteareas of hard bottom with broken reliefthat have large associated populations ofsessile invertebrates andfishes. "Livebottom" communities have been described in U.S. continental shelf waters primarilyfrom North Carolina to Texas."Live bottom" habitats are considered by severalfederal regulatory agencies tobe areas of biological importance. Wequestion theuse of the term "live bottom" because itsuggests thatother kinds of bottomhabitats, especially soft bottom habitats, are unproductive and uninteresting.Our research shows that soft bottoms support large, producti vepopulations of benthicmicroalgae, demersal zooplankton, andepi fauna. We have also found that fishesassociated with "live bottom" habitats frequently obtain a substantialportion oftheir diets from soft bottom habitats, either by off-reef foraging orimport ofsoft bottom-derivedfood items.

Wesuggest that the term "live bottom" be replacedby theterm "hard bottom community'.

INTRODUCTION Struhsaker969! first used the term "live bottom" to denote portions ofthe sea bottom insoutheastern U.S, continental shelf waters of broken relief with rich populations ofsessile invertebratesandrelatively dense aggregations ofcommercially exploitable fishes. He dif- ferentiated"live bottoms" from four other bottom types: coastal habitat, open shelf habitat, shelf-edgehabitat, and lower shelf habitat. Others have subsequently distinguished between "livebottoms" and coral reefs, e.g., Rezak et aL 985!. Furthermore, it isimportant tonote thatnot all hard bottom habi tats in continental shelf waters support "live bottom" communities Kirby-Smithand Ustach, 1986!.

Hardbottom areas in a broadarea of the U.S. continental shelf have been designated orreferred to as "live bottoms". The term has been used frequently inreference tohard bottom cominunitiesinthe South Atlantic Bight the continental shelf between Cape Hatteras and

39 Diving for Science...1990

CapeCanaveral; Struhsaker, 1969; Huntsman and Manooch,1978; Miller andRichards, 1979' Powlesand Barans,1980; Van Dolah and Burrel, 1981;Parker et al., 1983;Hales 1987!. bottom habitats that are not coral reefs have also been identified as "live bottoms" in Florida waters,particularly off the westcoast of Florida Gettleson,1981; Gettleson et al., 1983 MineralsManagement Service, 1986; Derrenbacker and Lewis, 1985!. "Live bottom hab'tats havealso been identified off the coastof Texas Bright, 1981;Rezak et al, 1985! Hardgroun off the California coasthave also been identifiedas "live bottoms" Lissner,1981!

Several distinct and well-known hard bottom areas have been termed "live bottom habitats.Gray's Reef off Georgia and the Flower GardenBanks off Texashave both been designatedor proposedas National Marine Sanctuaries,and are often referred to as "live bottom" areas Rezak et al., 1985;Fallon andHopkinson, 1986!. An areareferred to as'Ten FathomLedge" off CapeLookout, North Carolina,has been proposed as a NationalMaririe Sanctuary,and is alsofrequently identified asa "livebottom" area Mobil Oil Company,1989!. The Florida Middle Grounds,an area of hardbottoms in the westFlorida shelf with highrelief that is heavilyfished, also fits the conunondefinition of "live bottoin" habitat Parkeret al., 1983!.

"Live bottoms"are easily identified andbiologically significant habitats. The geological and biologicalarchitecture of thesehabitats confers on them a threedimensional character that is absentin other habitats,and which provides important shelter and substratefor numerousspecies of many taxa, "Livebottoms" support important commercial and recreational fisheriesfor reef fishesand other species e,g., spiny lobster!. Thehard substrate typical of "livebottoms" supports many species that requirefirm attachmentto resistnatural physical perturbations.Many of thesespecies are autotrophs,such as macroalgae or somecorals with symbioticzooxanthellae, while others are iinportant suspensionfeeders that trap and retain materials. Partly as a result of the physicalstability of thesecommunities through time numerousbiological interactions,such as symbioses,have evolved. Unfortunately,"live bottom"corrununities are particularlyvulnerable to suchhuman activities as dredging, spoil disposal,and accidental groundings.

The distinctivenessand apparentimportance of "livebottom" habitats has led to their identification as areasof specialconcern to governmentagencies with responsibilityfor managementof outer continental shelf OCS!resources and impacts resulting from exploita- tion of theseresources. The MineralsManagement Service MMS!, formerlythe Bureauof LandManage inent BLM!,is chargedwith managing development of OCS resources, and has commissionedseveral studies of the OCS environment that focus on "live bottom" habitats Centerfor NaturalAreas, 1979; Duke UniversityMarine Laboratory, 1982; Marine Resour- cesResearch Institute, 1982; Rezak et al., 1985!.The NationalOceanic and Atmospheric Administration NOAA!, throughits SanctuaryPrograms Division, has funded studies of "live bottom"habitats in NationalMarine Sanctuaries,such as Gray'sReef, e.g., Fallon and Hopkinson986!, ashas the National Marine Fisheries Service, e.g., Harris ]978a,b!, The EnvironmentalProtection Agency and the Corpsof Engineersalso use the term "livebottom" to distinguishproductive hard bottom habitats T. Nifong,pers. coinm.!. It mustbe noted, however,that the terin "live bottom" is not defined by statuteor in the Code of Federal

40 Cahoonet aL' "Live Bottoms" in ContinentalShelf

Regulations,and so is usedby theseagencies only as a descriptiveterin T.Nifong, pers. comm.!.

Designationby federal agencies of "livebottoms" as areas of specialbiological interest hasled to specialconsideration of thesehabitats iii environmentalimpact statements and relatedassessments of environmental effects of exploration/exploitationproposals byOCS leaseholders T. Nifong,pers. comm.!. Furthermore, "live bottom"habitats are accorded specialprotection under MMS regulations and lease rules. Thus, the "live bottom" concept has acquiredat least semi-legal status and is used practically in thecontext of OCSdevelopment.

The term live bottom"suggests that other substratesare "deadbottoms" that are unproductiveand biologically as well asphysically separate. The absenceof "live bottom" habitatsin someareas where developtnent activities are underway or proposed isbeginning to beused as justification for claimsthat no harmto hvingresources will occuras a resultof theseactivities. The results of ourresearch, and that of others,lead us to questionthis attitude and the use of the term "live bottom".

Soft BottomProductivity

A keydistinguishing feature of "livebottom" communities is their apparently high productivity,supposedly in marked contrast to thatof otherbottoin types. This high productivity is manifestedas high standingcrops of macroalgae,sessile invertebrates, and/or associatedfishes. However, it is importantto realizethat these organisins are easily detected andquantified by the two principaltechniques used in seabottom surveys, still andvideo photography,e.g., Parker et al. 983!, anddredge and trawl sampling methods, e.g., Cerame- Vivasand Grey 966!, Schneider976!. Thesemethods are biased toward sampling macro- fiora and macrofauna.

A substantialbody of evidencenow existsto showthat soft bottom habitatsare also quiteproductive. However, the organisms responsible for this productivity are generally small anddiKcult to sampleby the methodsnamed above. Furthermore, soft bottom habitats are easilyand frequently disturbed by physical processes, often preventing the establishment of highstanding crops of eventhe more obvious soft bottom flora andfauna. Nevertheless, small or crypticpopulations in thishabitat type are still quiteproductive.

Benthicrnicroalgal biotnass and production have been measured in softbottom habitats onthe North Carolina continental shelf Cahoon,1987, 1989; Cahoon et al.,in press!.Benthic inicroalgaeassociated with the siliceoussands of theCarolina shelf are priinarily pennate diatoms;other forins of benthicmicroalgae, perhaps cyanobacteria, dominate the carbonate sandsof shelfhabitats off southernFlorida Cahoon,pers. obs.!. The bioinassof benthic inicroalgaein shelf sediments can equal or exceedphytoplankton biomass integrated through theoverlying water column in continentalshelf waters For example, mean benthic microaigal biomassmeasured in 1984and 1985 at 17stations in OnslowBay, N.C. was 20.4 mg ch4l m

41 Divingfor Science...1990

s.e.= 2.77!,and mean integrated phytoplankton biomass at the samestations was 5.92 mg chipm s.e. = 0.70! Cahoonet al.,unpublished!.

Microalgalbiomass accumulates at the sediment-water interface as a resultof produc- tionia ~ Measurementsof benthicmicroalgal production in shelfhabitats show that productionat thesediment-water interface can approach integrated phytoplankton prod«- tion in shelfwaters. For example,benthic primary production measured at sevensites in OnslowBay,North Carolina from1985-1989 averaged 23.3mg C mh s.e.= 3.08>n =26!. andwater column primary production measured concurrently averaged 27.6 mg C m h s e- = 5.26,n =15! Cahoon,1987, 1989, unpublished data!. Thus, soft bottom habitats support substantialprimary production that is concentratedat the sediment-waterinterface. Softbottoms harbor a diverseconununity of smallanimals including interstitial meiofaunaresident among sediment particles, and demersal zooplankton, which alternately enterand leave the substrate. Although these are distinct groups, their memberships overlap somewhat;both groups appear to bedominated by harpacticoid copepods and nematodes Coull, 1971;Schwinghammer, 1981; Tronzo, 1989!. Studies of the abundanceof demersal zooplanktonassociated with soft bottom sediments in continentalshelf waters by Tronzo 989! and Cahoonand Bonzo989! haveshown that densitiesof theseanimals can reach 20,000and 33,000 individuals m in siliceousand carbonate sediments, respectively. Mesc densitiescan equal or exceedthe densities of zooplanktonin the overlying water column gtonzo, 1989;Table 1!.

Table1. Comparison of average total water column zooplankton collected by vertical haulswith a 150um net, 0.5 m diam!vs. average total demersal zooplankton collected by reentrytrapping! inOnslow Bay, North Carolina. Five most abundant taxa listed in decreasing order of frequency Gonzo, 1989!.

WaterColumn Zooplankton DemersalZooplankton animalsm ! animalsm !

17,705 20,364

Calanoida Harpacticoida Cyclopoida Nematoda Appendicularia Amphiams Chaetognatha Cyclopoida nauplii! Cumacea

Softbottoms also support substantial populations oflarger epifauna, including several specieswith commercial value. The latter include calico scallops, flounders, andpenaeid shrimps Schwartz andPorter, 1977; Kruczynski, 1974!. Other epifaunal organisms found in

42 Cahoonet al: "LiveBottoms" in ContinentalShelf softbottoin habitats include a varietyof demersalfishes, echinoderms, bivalves, gastropods, and numerouscrabs and shrimps authors,pers. obs.!.

Imported Materiais Manyof the organisins typical of "live bottoin" communities areplanktivorous. Sponges, bryozoans,tunicates, and many tube-dwelling polychaetes feed on verysmall suspended particles,primarily phytoplankton, while hydrozoans, anthozoans, and planktivorous fish e.g., Hales,1987! associated with "live bottoins" consume zooplankton. Some of thisplanktonic foodis probablyderived from nearby soft bottoms as suspended benthic microalgae and deinersalzooplankton carried by currents into "live bottom" habitats. All of theseplanktonic formsrepresent food imported to the "livebottom" community from other communities.

Off-reef Foraging

Studiesof reef-associatedfishes have shown that manyof the smallerfishes that feed oninvertebrates as opposed to theprimarily piscivorous game fishes! are obtaining a major fractionof theirdiets from soft bottoin habitats. Bolden 990! foundthat tomtate Haemulon aurolineatum!,a coinmon reef-associated fish, move over soft bottoms at night,presumably to feed.Approximately 80 and 20%%uo asdry weight! of thediets of tomtatesassociated with an artificialreef and a nearbynatural ledge in OnslowBay, North Carolina, respectively, were softbottom organisms. Although tomtates consumed some inacroalgae, their gut contents did not includethe sessileinvertebrates characteristic of "live bottom" habitats, i.e., sponges, tunicates,and coral polyps. Burk 990! foundthat black sea bass Centropristis striata! associatedwith the samereefs included various crabs, shrimps, peracaridan crustaceans, and molluscstypical of softbottom habitats in theirdiets. Black sea bass also did not appear to consumesponges or corals.Harris 979! found that cubbyu Parequesumbrosus! are associatedwith hard substrate habitats, but include many soft bottom species in theirdiets, a findingconfirmed by Lindquistet al. inpreparation!. Studies of reef-associatedfishes by Steimleand Ogren 982! andSedberry 985, 1988!also show that these fishes obtain food from soft bottom habi tats.

CommunityHeterotrophy

Fallonand Hopkinson 986! measuredbenthic respiratory and photosynthetic rates at Gray'sReef National Marine Sanctuary, a "live bottom" habitat off thecoast of Georgia. Theyshowed that respiration exceeded production by 32%, and inferred that this "live bottom" communitywas heterotrophic, that is,it dependson importedorganic material to sustainit. Ourstudies of anotherhard bottom community 3-mile rock! in OnslowBay, North Carolina, similarlysuggest that the biomass and productivity of rnacroalgaeon thehard substrate are inadequateto supportthe reef-associatedconsumer community we quantified authors, unpubl.data!.

43 Divingfor Science...1990

CONCLUSIONS

Our objectionsto the term "livebottom" center around two points.First, we haveshown that other bottom types,particularly soft bottoms,are productiveand support importaiit populationsof organismsthat directlyand indirectly support species of economicvalue. Much of the productivityof softbottoms, however, is that of microscopicor slightlylarger organisms, which conventionalsampling techniques have overlooked. Second, we haveshown that "live bottom" commututiesmust be linked trophicallywith other bottom types,and are not self suNicient.Thus, a "livebottom" community depends on the surroundinghabitats; its productivity andeconomic value are partly a functionof this externalsubsidy.

The unfortunate connotation of the term "live bottom", that other areas are "not live", hashelped to focusattention awayfrom biologicallyproductive, but visuallyunimpressive habitats, and has focusedthe attention of industry and regulatoryagencies involved in developingOCS resources on "live bottoms",even when this attentionis not appropriate.As a recentexample, the MMS hasdirected Mobil Oil Companyto includeconsideration of "live bottom" habitats in its environmental assessmentof an area of the continental slope off Cape Hatteras, North Carolina, in which Mobil and other companiespropose to explore for natural gas0 CFR 250.33 b!2!; LeaseOCS-A 0236, Stipulation No.2!. As part of its claimthat no significant biological damagewill result from this exploration, Mobil has stated that no "live bottom" habitatswere found in this area,even though Mobil's surveydid find very large populationsof soft bottomorganisms at the site Mobil Oil Company,1989!.

We advocate the replacement of the term "live bottom" with the term "hard bottom community". The latter term connotesthe essentialgeological and biological features used to definethe former term, but doesnot imply that other habitatsor bottomtypes are unproductive, uninteresting, or not worth protecting.

ACKNOWLEDGEM ENTS

We would like to acknowledgesupport from UNC SeaGrant RjMRR-88-1!, the National UnderseaResearch Center at UNCW, and the Center for Marine ScienceResearch at UNCW for this work. Wethank S. Bolden, S. Burk, J. Cooke,J. Finlay,M. Samples,and M. Wessel for their assistance.This is contribution 4019 of the Center for Marine Science Research at UNCW.

LITERATURE CITED

Bolden,S.K. 1990.Abundance, diet andforaging migrations of the tomtate Haemulon auroEineatccm!on an artificial and naturalreef in OnslowBay, North Carolina. Un- publishedM.S. thesis, UNC Wilmington,Wilmington, N.C. Cahoonet aL."Live Bottoms"in ContinentalShelf

Bright, TJ. 1981. Biotic conununities of hard-banks in the northwestern Gulf of Mexico. Estuaries 4:304.

Burk, S.W. 1990.Migration anddietof blacksea bass Centropristisstriata! on an artificial and natural reef in Onslow Bay, North Carolina. UnpublishedM.S. thesis,UNC Wil- mington, Wilrnington, N.C.

Cahoon, LB. 1987.The role of sediment-water column interactions in the continental shelf ecosystem,pp. 171-180,in C. Mitchell, ed., Diving for Science....1986,American Academy of Underwater Sciences,La Jolla, CA.

Cahoon,LB. 1989.A cotnparison of phytoplanktonand benthic microalgalproduction in North Carolina continental shelf waters, pp. 175-186,in George, R.Y. and A.W. Hulbert, eds.,NOAA-NURP Report89-2.

Cahoon,LB., and C.R. Tronzo. 1989,A comparisonof demersalzooplankton collected at Alligator Reef, Florida,using emergence and reentry traps.Fish. Bull. 86:838-845.

Cahoon,L,B., R.S. Redman,and C.R. Tronzo.n.d. Benthicmicroalgal biomass in sediments of OnslowBay, North Carolina.In press,Est., Coastal Shelf Sci..

Centerfor NaturalAreas. 1979.A summaryand analysisof environmentalinformation on the continentalshelf and Blake Plateaufrom CapeHatteras to CapeCanaveral, Volume I Book2, Chap. VIII-XIII. Dept.of Interior,Bureau of LandManagement, Washington, D.C, ContractAA550-CI7-39. 621 pp.

Cerame-Vivas,MJ., and I.E. Gray. 1966.The distributionalpattern of benthicinvertebrates of the continental shelf off North Carolina. Ecol. 47.260-270.

Coull, B.C. 1971.Meiobenthic harpacticoida Crustacea, Copepoda! from the North Carolina continental shelf. Cah. Biol. Mar. 12:195-237.

Derrenbacker,J.A., Jr., andR.R. Lewis, III. 1985.Live bottom communities of TampaBay, pp. 385-392,in Treat, S.F.,J.L Simon, R.R. Lewis, III, and R.L Whitman, eds., Proceedings:Tampa Bay areascientific information symposium, Florida Sea Grant Program Rept. 465.

DukeUniversity Marine Laboratory. 1982. South Atlantic OCS area living marineresources studyyear II. VolumeII. An investigationof live-bottomhabitats off North Carolina. U.S. Dept. of Interior, MineralsManagement Service, Washington, D.C. Contract AA551-CT1-18.143 pp.

Fallon,R.D., and C.S. Hopkinson. 1986. Community metabolism and nutrient fluxes at Grays Reef National Marine Sanctuary.U,S. Departmentof Commerce,NOAA Technical Report SeriesOCRM/SPD. Washington, D.C. Contract PNA84AA-H-CZ027.61 pp. Gettleson,D.A. 1981.Biological assemblages live bottom!associated with hard bottom areas in the Georgiaembayment and easternGulf of Mexico. Estuaries4:304.

45 Divingfor Science...1990

Gettleson,D.A.,K.D. Spring, R.M.Hanuner, andR.E. Putt. 1983. Comparison ofgeophysi- callydefined hard bottom and visually detected livebottom inthe Charlotte Harbor areaof the Southwest Florida shelf. Proceedings Oceans '83: Effective use of the Sea: Anupdate, SanFrancisco, August29-September 1,1983. Volutrie 2:Technical Papers. Hales,LS., Jr. 1987. Distribution, abundance, reproduction, foodhabits, ageand growth of roundscad, Decaprerus puncratus, inthe South Atlantic Bight. Fish. Bull. 85:251-268. Harris,C.A. 1979. Resource partitioning infour species ofreef fishes inOnslow Bay,N.C. UnpublishedM.S.thesis, East Carolina Univ., Greenville, N.C.35 pp. Harris,C.D. 1978a. Location andexploration ofnatural reefs onGeorgia's continental shelf. Finalreport, Dingell-Johnson projectF-31, Georgia!. Ga.Dept. ofNat. Res., Coastal Res.Div., Brunswick, GA. 14 pp. Harris,C.D. 1978b. The fisheries resources onselected artificial and live bottom reefs on Georgia'scontinental shelf. Final report, Dingell-Johnson projectF-31, Georgia!. Ga. Dept.of Nat. Res., Coastal Res. Div., Brunswick, GA.55 pp. Huntsman,G.R.,and C.S. Manooch, III.1978. Coastal pelagic andreef fishes inthe South AtlanticBight, inH. Klepper, ed.,Marine Recreational Fisheries,No. 3 Proceedings ofthe Second Annual Marine Recreational Fisheries Symposium, Norfolk, Va.,March 29-30,1978. Sport Fishing Institute, Washington, D.C. Kirby-Smith,WW.,and J.Ustach. 1986.Resistance tohurricane disturbance ofan epifaunal communityonthe continental shelf off North Carolina. Est., Coastal and Shelf Sci. 23:433~2. Kruczynski,W.L1974. Areview ofthe oceanography andfishery ofOnslow Bay, North Carolina.N.C.Div, Comm. & Sports Fish., Dept. Nat. and Econ. Res. Infor. Ser. g6. 47 pp- Lissner,A.L1981. Biological andgeological reconnaissance surveyoftwo offshore southern Californiabanks. Estuaries 4:304. lVfineralsManagement Service, 1986. Proposed program: 5-Year outer continental shelfoil andgas leasing program forJanuary, 1987-December, 1991,detailed decision docu- rnents.U.S. Dept. af Interior,Washington, D.C. MarineResources ResearchInstitute, SouthCarolina Wildlife andMarine Resources Dept, 1982.Final report: South Atlantic OCSarea living marine resources studyyear II.An investigationoflive-bottom habitatsiti the South Atlantic Bight.U.S. Dept.of Interior, MineralsManagement Service, Washington, D.C.Contract AA551-CI'1-18. Three volumesand executive summary. Miller,G.C., and WL Richards. 1979.Reef fish habitat, faunal assemblages, andfactors determiningdistributions inthe South Atlantic Bight. Proc. Gulf Caribb. Fish. Inst. 32:114-130.

46 Cahoonetal: "Live Bottoms" in Continental Shelf

MobilOil Company. 1989. Draft exploration planManteo area Block 467 offshore Atlantic. Mobil Oil Coinpany.Two volumes. Parker,R.O., Jr., D.R. Colby, and TD. Willis. 1983. Estimated ainount ofreef habitat on a portionofthe U.S. South Atlantic and Gulf of Mexico coiitiiiental shelf. Bull. Mar. Sci. 33:935-940. Powles,H., and C.A. Barans. 1980. Groundfish monitoring insponge-coral areasoff the southeasternUnited States. Mar. Fish. Rev. 42:21-35. Rezak,R.,TR. Bright, and D.% McGraiL 1985. Reefs and banks ofthe northwestern Gulfof Mexico:Their geological, biological andphysical dynamics. JohnWiley and Sons, New York. 259pp. Schneider,C.W.1976. Spatial and temporal distributions ofbenthic marine algae on the continentalshelf of theCarolinas. Bull. Mar. Sci. 26:133-151. Schwartz,FJ.,and HL Porter. 1977. Fishes, macroinvertebrates, andecological interrelation- shipswith a calicoscallop bed off North Carolina. Fish. Bull. 75:427-446. Schwinghainmer,P.1981. Characteristic sizedistributions ofintegral benthic communities, Can.J. Fish.Aquat. Sci.38:1255-1263. Sedberry,R.G.1985. Food and feeding ofthe tomtate, Haernitlon aurolineatum Pisces: Haemulidae!,in the South Atlantic Bight. Fish. Bull. U.S. 83:461466. Sedberry,R.G. 1988. Food and feeding ofblack sea bass, Centropnstis striata,in live bottom habitatsinthe South Atlantic Bight. J. Elisha Mitchell Sci. Soc. 104:35-50. Steirnle,F W., Jr., and I Ogren.1982. Food offish collected onartificial reefs inthe New York Bightaiid off Charleston, South Carolina. Mar. Fish. Rev. 44:49-52. Struhsaker,P.1969. Demersal fish resources: Composition, distribution, andcommercial potentialofthe continental shelf stocks off southeastern United States. Fish. Ind. Res. 4:261-300. Tronzo,C.R. 1989. The ecology ofdemersal zooplaakton inOnslow Bay, North Carolina. UnpublishedM.S.thesis, UNC Wilmington, Wilmington, N.C.82 pp. VanDolah, R.F., and VG. Burrell, Jr.1981. South Atlantic OCS area living marine resources study.Estuaries 4:304.

47 BIOLOGICAL ASSESSMENTS OF DAMAGE TO CORAL REEFS FOLLOWING PHYSICAL IMPACTS RESULTING FROM VARIOUS SOURCES, INCLUDING BOAT AND SHIP GROUNDINGS

Billy D. Causey SanctuaryManager Looe KeyNational Marine Sanctuary Rt. 1, Box 782 BigPine Key, FLORIDA 33043U. S.A.

Wisemanagement of coral reef environments requires that all impacts andstresses to thecoral reef ecosystem be identified, and minimized whenever possible. The effectsof naturalenvironmental perturbations are more dificult toidentify and manu' thanthose impacts resulting from human activity. Obviously, thisincreases theneed for managersof coralreef habitats to recognize those forms of stressand impactsthat can be minimized through application of nuznagementstrategies.

Physicaldamage to coralreefs from boatand ship groundings has been identified asa majorimpactto thecoral reefs of thewy Qrrgoand Looe Key National Marine Sanctuaries. Sanctuaryregulations prohibit vesselsPom operatingin such a marineras to strikeor otherwisecause danqge to the naturalfeatures of the sanctuary.Currently, the primary deterrent for thissource of reefdanube has been throughcivil procedures and penalties for vesselgrounding cases. Litigation to recoverdamages to naturalresources is alsopursued in thecase of kugescale groundings.This legal process requires that thearea impacted, or damaged,be accuratelyassessed for bothbiological dantage and physical evidence to support thelitigation. Methods for conductingsuch assessments arepresentedin this paper, alongwith recommendations on what observations are considered important. A reviewof assessmenttechniques and application oftheinformation gathered dunng theassessment process are presented. Some of thecriteria used to establishcivil penaltiesfor damagesto thecoral reef resources are discussedin this paper.

INTRODUCTION Reportson the threats to coralreefs are continually appearing in popularperiodicals Lapointe,1989;Lapointe,1989; Shinn,1989; Bunkley-Williams and Williams,1990; Stone,1990;Hallock-Muller,1990; Cole,1990; and Ward,1990!. While some of thesereports emphasizeone form of stressas being more detrimental to the coralreef environmentthan

49 Divingfor Science...1990 others,the obviousconcern is that the healthof coralreefs is deterioratingthroughout the Caribbean,and possibly around the circum-tropicalbelt of the globe Stone,1990!.The specificcauses for thesedeclines are not known,but from all indications,man's activities appear ta be the major culprit. Aside from the human impacts,are the environmental perturbationsthat continuallyaffect the healthand success of coralreef environments.These formsof stresspresent the greatest challenge to scientistsand coral reef managers alike, in termsof quantifyingand qualifying their impact. On the other hand, the direct physical human impactsthat reefs receive are easier to quantify and qualify, thus serving to make litigation and mitigationuseful tools in coralreef rnanageinent.

DISCUSSION

Wisemanagement of coral reef resources requires that the resource inanagers identify asmany forms of naturaland humanly induced stress as possible, and eliminate or reducethose thatare within managements' capability of addressing.When an area first comesunder some managementprogram, the obvious strategy is to beginby addressing the mostconspicuous and harmfulimpacts, and then determine the other perturbations that are having a deleterious effecton theresources of thearea. Clearly, the goal for manageinentis to eliminateas many formsof stress as possible and see that the resources are enhanced, while not unduly restricting the activitiesof thosewho want to enjoyand use the area.

Thismanagement approach is usedat theLooe Key and Key Largo National Marine Sanctuaries LKNMS & KLNMS!in theFlorida Keyswhere regulations have been established thatprotect the coral reef resources from a widerange of physicalimpacts. Law enforcement surveillance,civil penalties,and the threatof naturalresource damage actions serve as deterrentsto sanctuaryviolations.

A speciTicregulation in thetwo sanctuaries among others! prohibits the "removalor damagingof distinctivenatural features." Although this regulation generally protects all of thenatural and historical resources ofthe sanctuaries from a widevariety of impacts,the regulationhas been most useful in prohibitingthe taking or harvestingof stonycorals and octocorals.Additionally, the sanctuaryregulations prohibit anchoring on coralin the Fore Reefat LKNMSand generally prohibit the anchoringon coralthroughout the KLNMS. Vesselsoperating in the sanctuariesshall not beoperated in sucha manneras to strike or otherwisecause dainage to thenatural features of thesanctuary 5CFR, 929.7, !, i! and 15CFR,937.6,!, iii!. Althoughboth sanctuaries have other regulations that help in their manageinent,the regulationsgiven above specifically serve to protectthe coral reef resources from directphysical impact.

Theenforcement program in theFlorida sanctuaries has made it possibleto use surveillanceand litigation as a deterrentto thepoaching, or takingof stonycorals and octocoralsbyvisitors to thearea. Certainly, education has also aided in reducingthis iinpact to the reefs.The installation of 180mooring buoys at LKNMSand KLNMS bas served to

50 Causey:Assessments of Damage ro Coral Reefs

reduce the amount of anchor damageto the coral reefs of both sanctuaries. Also, underwater patrols and surveillancehave been usedto enforcesanctuary regulations that prohibit the physicalcontact with corals by divers and snorkelers. All of these are but a few of the managementstrategies that havebeen used in the sanctuariesto reduceas much of the direct humanimpact as possible,while givingthe reefsan opportunityto combat the problemsof water degradationfrom excessivenutrients, sedimentation, pollution from run-off, and a varietyof other problems Lapointe, 1989;Shinn,1989; Ward,1990; and Cole,1990!.

The reefsof the FloridaKeys are already under a considerableamount of naturalstress simplybecause of their locationat the northernextent of their zoogeographicrange. For that reasonalone, it makeswise managementsense that coral reef managerseliminate as many physicalimpacts to coral reefs as possible,enabling them to be more capableof combating naturalforms of stress,as well as the stressbrought on by deterioratingwater quality.

VKSSEL GROUNMNGS

Smallboat and shipgroundings on the reefsof the Florida Keyshave been recognized as a major source of direct human iinpact to the coral reef resourcesfor a number of years Jaap,1984; Dustan and Halas, 1987;Tilmant, 1987;and Miller, 19SS!.Over 225 recorded vesselgroundings have occurredin the Key Largo N.M.S. since1980 and another33 have occurredat Looe Key N.M.S.since 1981.

Although mooring buoys have served to reduce the amount of anchor damage in the sanctuaries,and law enforcementefforts have been helpful in reducingthe incidenceof other resourcedepleting or damagingactivities, vessel groundings continue to adverselyaffect the coral reef resources Hudson and Diaz, 1988!. Regulationsin both of the sanctuariesstrictly prohibit this type of impact,yet they continue. For that reason,it has becomeincreasingly iinportant that this form of resourcedamage be firmly addressedby both coralreef resource managersand law enforcement staff alike.

SanctuaryOfficers investigateall reported and witnessedvessel groundings in the sanctuariesand enforce the regulationsthat prohibit damageto the natural featuresof the sanctuaries.Citations are written for boatsrunning aground in all habitats,including sea grass beds, fossilized rubble bottoin, hardbottom communities, and of course, coral reef communities. jn the earlier daysof the activeenforceinent programs at the two sites982-19S3! it wascommon to encountera captainthat had run aground,and who was surprised to receive a citation for the damagesthat his vesselhad done to the coral reef resources.This was probablybecause attention to boat groundingsin the past prior to sanctuaryenforcement! hadfocused on the unfortunatemishap for the captainand the resultantdamage to his vessel. Today,when Sanctuary Officers respond to groundings,visitor safety remains a toppriority, but attentionis focusedquickly on thedamages to the resourcesand the inethodsto getthe vesselfree of the reef without causingany additional, or unnecessarydamage to the resources.

51 Divingfn Science...1990

BIOLOGICAL DAMAGE ASSESSMENTS

With over 250recorded groundings in the sanctuariesin lessthan 10years, investiga- tionsof groundingcases has consumed a considerableamount of stafftime overthe years.Me extensivetime and effort spenton thesecases has resulted in an establishedprocedure by whichthe boat groundingcases are investigated by the sanctuarystaff. A majorportion of the investigationis an underwaterbiological assessment of damagesto the coral reef resources resultingfrom the incident i.e., boatand ship groundings!.

The biological damageassessment is preparedby the SanctuaryBiologist or other qualified person,and must attemptto quantify and qualify the damagesto the coral reef resourcesresulting from the incident.Additionally, the assessmeritmust serve to substantiate, or refute the descriptionof events or circumstances!as they were given to the investigating SanctuaryOfficer by theviolator. Therefore,the damageassessment is divided into a biological sectionand a physicalsection and the followinginformation is collected:

BIOLOGICAL SECTION

! A descriptionof the habitatimpacted i.e. coral reef, seagrasses, coral rubble, sand,etc.!.

! Dimensionsand calculations of the total extentof areaaffected i.e., length and width of grounding tract!.

! Calculationof the extentof resourcestotally destroyed.

! Calculationof the extentof resourcespartially destroyed.

! Calculationof the percentliving coralvs. dead fossilized coral in the impactedarea.

! Specieslist of the organismsaffected by the incident.

! Quantificationof biota damagedor destroyed,based partially on a surveyof the surroundingunaffected areas and partiallyon actualdamage observed inside the impacted area

PHYSICAL SECTION

! Courseof the vessel directionof travel! at the time of the impactas it canbe determinedfrom physicalevidence gathered at the groundingsite.

! Approximatespeed at whichthe vesselwas traveling when it ran aground.

52 Causey:Assessments of Damageto Coral Reefs

! Tidesat the time of the grounding.

! Depth at the forward-mostpoint of progressby the vessel;and depth at the stern restingposition of the vessel.

! Recordingand collection of anyphysical evidence i.e., bottom paint,wood, fiberglass,or other substantiatingmaterial! present at the groundingsite. This is particularlyimportant if the vesselhas left the scene,or wasnot observed agroundby the enforceinentstaff.

It is not within the scopeof this paperto specificallydescribe the variousmethods that are currentlyin usefor completingbiological damage assessments. Regardless of the method or techniqueused, the iinportant objectiveis to get the information necessaryto precisely describe and quantify the extent of damagesto the natural resourcesresulting from an unnaturalevent. Consistencyand repeatabilityare importantcomponents of anybiological damageassessment technique and are criteria that must not be compromised. The following is not an atteinpt to describeaB the varioustechniques, but simplya brief descriptionof the kind of information neededto successfullyprosecute an administrativepenalty case.

Initially, the biologicaldamage assessment inust includea descriptionof the habitat s! impactedby the grounding or othertype of impact.Sanctuary regulations state that "watercraft shall not be operatedin sucha manneras to strikeor otherwisecause damage to the natural featuresof the Sanctuary."Therefore, boat groundinginvestigations and biologicaldamage assessmentsare not limited to the coral reef habitat, but may include all of the major cominunitiesthat helpto comprisethe coral reefecosystein. Underwater photodocumentation of the impacted habitats and the unaffectedareas surrounding the groundingsite is an extremelyimportant part of thisphase of the assessment.The most cornmoitly used methods are35 nun photographsand underwatervideos.

The secondphase of the assessmentis to completelydetermine the extentof damaged area,and to accuratelysurvey the total areaiinpacted by the grounding or other formof physicalimpact!. The total lengthof the groundingtract andall the other dimensionsthat are necessaryto help calculatethe total sizeof the areaimpacted must be carefullymeasured and surveyed.Open-reel, fiberglass surveyor tapes are ideal for takingunderwater measuretnents and determiningdimensions. Copper-clad surveyor stakes are helpful in semi-permanently markingvarious points of importancealong the groundingtract i.e., begiriningand end of tract!. The final figure dimension!of areadamaged or impactedby the groundingthat is soughtby theassessor surveyor! should include the following: all areasscraped clean by the vessel;areas partially dainaged; areas buried by fall-outrubble debris from prop-wash; reef frameworkdamage Hudson and Diaz, 1988!; and any other discernable damage to thereef resourcesfrom the impact.Photodocumentation is an importanttool in thisphase of the biologicaldamage assessment. Afterthe extent of damages impact! has been calculated the next step is to determine howmuch of thecoral and coral related organisms have been totally 00%! destroyedby the

53 Divingfor Science...1990 grounding.NOAA's Office of GeneralCounsel determines a monetary penalty based on the extentof damageand whether the corals were completely or partiallydestroyed. Clearly, if the coralcolony is completelydestroyed, or fragmentedto thepoint that recovery is not possible,then the assessor declares it 100% destroyed. This assessinent isparticularly easy ta makein areasthat have been scraped clean of allbiota. Individual techniques for measuring, or estimatingthe size of thearea impacted vary, but generally, the use of 1 in,10 m, or larger quadratesis a standardmethod in makingthis kind of determination.The frequency at which thequadrates are deployed in anarea, and the methods of recordingthe dataobserved inside thequadrates may vary between assessors. However, the final figure of percentarea impacted andthe severity of theimpact is what needs to bedetermined for the assessing a civil penalty. Thecalculation of thearea of partialdamage is accomplishedin much the same manner.

Forpurposes of assessinga civil penalty, the percent of barrenfossil coral substrate is currentlycalculated in thevicinity of the grounding.The use of quadratesis onceagain the simplesttechnique for determining this figure. The reason for making this calculation isthat the areaof barrensubstrate % barrenor fossilsubstrate! is deletedfrom the total area impactedby thegrounding. Some argue that 100%of thesubstrate is covered with living organisms,whether it bealgae, diatoms, etc., and the percent barren substrate should not be deletedfrom the total calculation ofarea damaged. This poses a goodargument, and revisions to thepenalty assessment may be considered. However, to datethe biological assessments in thesanctuaries have continued the practice of subtractingthe amount of barrensubstrate from the total areadamaged.

A specieslist, and a quantificationof theorganisms affected by thegrounding, is compiledby the assessor. This list may be extensive in some biological zones, or verylimited in otherssuch as seagrass beds. Biological damage to corals and coral-related organisms are givenhigher assessed penalties than are impacts toseagrass orrubble habitats. Although the sanctuaryregulations address damage to all "naturalfeatures" ofthe sanctuary resulting front boatgroundings, relatively speaking, there has been a tendencytogive higher fines for damages to corals and coral-related organisms! than for damagesto otherreef inhabitants.

PENALTY ASSESSMENT Followingthe field investigation and biological assessment, theprocedure for process- inggrounding cases inthe National Marine Sanctuaries andassessing a penalty fine! begins withsubmitting the case to the NOAA Office of GeneralCounsel. The biological assessment includingall supporting evidence such as photographs andvideos!, issubmitted along with the investigativereport that is completedby a SanctuaryWw EnforcementOfficer. The SanctuaryOfficer's investigative report includes a coinpleteinvestigation and docurnentatiori of theincident, asper the procedures established byNOAA for successfully prosecuting ari administrativepenalty case.

54 Causey:Assessments of Damage to CoralReefs

The Office of the GeneralCounsel uses the informationfrom the SanctuaryOfficer' s investigativereport, combined with the biological resource! damage assessment, to establish a penaltyforthe infraction. The consistency bywhich these assessments havebeen conducted overthe years in theLooe Key and Key Largo National Marine Sanctuaries has resulted in a procedurebywhich the NOAA attorneys can establish a civil penalty for boat groundings with impressivecongruity. In summary,the information that is collectedby the assessor includes, but is not liinited to, the following:

! Estimateof biota affected area impacted! a! coral totally destroyed b! coral partially destroyed

! Estimateof percentcoral covervs. barren substrate ! Circumstancesof the violation [attenuating circumstances e.i., adverse weather!; negligence;etc]

Title III of the Marine Protection,Research, and Sanctuaries Act of 1972specifies that a civilpenalty of up to $50,000.00can be assessed per violation for eachday that sanctuary regulationsare violated. The civil penalty that is assessed forimpacts to thenatural resources of the sanctuaryresulting from boat groundingsis a fine for a violation s!of sanctuary regulationsasthey are published in 15 CFR, Part 929 KLNMS! and Part 937 LKNMS!. Theamount of thepenalty assessed for individualboat grounding cases varies sig- nificantlydepending on the extent of damagesto the natural resources and the circumstances surroundingthe incident. Sanctuary Officers issue citations for groundings asminor as boats striking,or bumpingbottom, to asdevastating asmajor ship groundings. The level of concern thatvessel groundings has posed for managementof the National Marine Sanctuaries in the FloridaKeys has led to a demandthat each incident be firmly addressed through litigation. It is difficult to determinehow much of a deterrentthis staunchapproach has had regarding boat groundingsin the sanctuaries. Although the number of casesseem to beon the rise in both sanctuaries,sois the increase in boating traffic. Also, the level of awareness hasbeen increased in theregular visitors charterboat captains! to thesanctuary regarding the sanctuary's concerii for boatgroundings and more incidents are being reported to the sanctuarystaff. It is anticipatedthat strict enforcement ofthe sanctuary regulations regarding boat ground ings will servein aneducational manner to pointout that this kind of unnecessaryimpact to thecoral reef resourcescan no longerbe tolerated.

CONCLUSIONS In recentyears there has been numerous assaults on coralreefs throughout south Horidaresulting inthousands ofsquare ineters of damage tocoral reef habitat. These physical impactson the coral reef inhabitants have not aH been the result of vesselgroundings. Off

55 Divingfor Science...1990

BocaRaton, Florida a steel cable scoured acres ofcoral reef habitat, and in the Miami area a dredge,involved ina beachrenourishment project,destroyed acres ofreef habitat. The frequentoccurrence ofthese kinds ofunnatural damages tocoral reefs has brought tothe attentionofscientists andresource managers atall levels ofmanagement, theneed to firmly addresstheseunnecessary formsofreef damage. Asa result, several individuals, representing a varietyofstate, county, andfederal agencies havebeen involved incompleting biological assessmentsondamages tocoral reefs, resulting from a varietyofphysical impacts tocoral reefhabitats. Byway ofthis paper, I am announcing a jointpublication thatwill be compiled bylValter Jaap and myself, thatwill deal with the specifics ofa wide variety ofbiological assessmentprojects that have been completed asa resultof thesevarious incidents. A completiondatehas not been projected, butsome ofthe preliminary discussions havetaken place,and several commitments tocontributions have been received. Amongtheobjectives ofthe "treatise" willbe to familiarize thescientific community andresource managers aroundthe world, with the techniques forconducting biological assessmentsofphysical impacts tocoral reef communities. It isanticipated thatthe project willbe completed within the next year.

ACKNGWLEDGEMEIVTS Severalindividuals whohave been involved inthe preparation ofthis manuscript deservespecial recognition. JoyTatgenhorst andGeorgette Carverof the Looe Key National MarineSanctuary staffwere both extremely helpfulin preparing various drafts ofthe paper. RalphLopez and Darlene Finch ofthe Marine andEstuarine Management Division ofNOAA deservea special thanksfor their critical review ofthe manuscript. Also,Bill Nielander, Staff Attorneyforthe Of5ce ofGeneral Counsel, NOAA, contributed considerably tothe review of this paper.

DISCLAIMER ! Theauthor ofthis paper isemployed bythe Florida Department ofNatural Resources,Division ofMarine Resources, Bureauof Sanctuaries andResearch Reserves and inno way, ormanner, isrepresenting theviews of the National Oceanic andAtmospheric Administration NOAA!. This is not an official NOAA publication andits contents arethe solethoughts and responsibility of the author. ! Thisarticle focuses solely onadministrative penalties asopposed tonatural resourcedamage actions filedin U.S. District Court. The article refers only to assessments relativetoadministrative penalties, asopposed tonatural resource damage action filed in U.S. DistrictCourts which are along withcivil forfeiture ofoffending vessels! authorized bythe MarineProtection, Research, and Sanctuaries Actof 1972.

56 Causey:Assessments of Damage to CoralReefs

Thebiological and physical assessments fornatural resource damage action may have a moredetailed focus than those assessments donesolely for thepurpose of administrative penalty.

LITERATURE CITED Bunkley-Williatns,L and E. H. Williams,Jr. 1990.Global Assault on Coral Reefs. Natural History. 4/90pp. 47-54. Cole,J. 1990.The State of Our Seas. Florida Keys Magazine. 13!. Pp.20-24. Dustan,P.and J. C. Halas. 1987. Changesin theReef-Coral Community ofCalysfort Reef, Key Largo,Florida I974-1982. Coral Reefs6: 91-106. Hallock-Muller,P. 1990.Coastal Pollution and Coral Communities. Underwater Naturalist. 19 !, Pp.15 18. Hudson,J.H. and R. Diaz. 1988. Dantage Survey andRestoration ofM/V Wellwood Grounding Site,Molasses Reef, Key Largo Aational Marine Sanctuary, Florida. Proceedings ofthe 6thInternational Coral Reef Symposium, Australia. 2. Pp,231 236. Jaap,W. C. 1984.?he Kcologyofthe South Rorida Coral Reefs: A Community Profde. Mineral ManagementService MMS 84-0038. Pp. 138. Miller,J. W. ed.!. 1988. Results ofA WorkshoponCoral Reef Research AndManagement In ?heRorida Keys: A BlueprintForAction. National Undersea Research Program Re- searchReport 88-5. Pp.49. Lapointe,B. 1989.Are We Killing the Reef. Florida Keys Magazine. 12!. Pp.19 28. Lapointe,B.E. 1989.Are 7hey Becoming Algal Reefs' Sea Frontiers. 35!. Pp.82-91. Shinn,E.A. 1989.What isReaDy Kdling the Corals. Sea Frontiers. 35!. Pp.72-81. Stone,A. 1990.Project ReefKeeper. Underwater Naturalist. 19!. Pp.8-11. Tiltnant,J.T. 1987.Human Impacts ofRecreational Activities onCoral Reefs: Facts and RecommendationsB.Salvat ed., Antenne Museum E.PH.E. French Polynesia: Pp. 195 209. Ward,F. 1990.Florida's Coral Reefs are Imperiled. National Geographic. 178!. Pp- 115-132.