The Coal-Waste Artificial ReefProgram (C-WARP): A New Resource

Potential for Fishing Reef Construction

PETER M. J. WOODHEAD, JEFFREY H. PARKER, and IVER W. DUEDALL

Introduction

Artificial reefs undoubtedly work:They form a settlement base for bio­logical colonization and growth, andtheir crevices and surfaces provide coverand habitat for many organisms includinghshes, crabs, and lobsters. They haveproven success in attracting marine life,and in enhancing the local marine en­vironment to improve recreational hshingsignificantly.

Artificial reefs are popular with sporthshermen: angler's clubs and civicgroups have been active in reef con­struction, frequently with cooperationfrom local and state agencies.

While it is well known that reefs pro­vide benehts to recreational hshing, theyalso provide more direct economic bene­hts. A recent study by the South CarolinaDivision of Marine Resources indicated

ABSTRACT-Thefeasibility ofusing solidblocks of waste materialfrom coal:fired powerplantslor underwater construction. includingbuilding artificial fishing reefs. is being tested.On 12 September 1980, a SOD-ton demonstra­tion reef consisting of 15.000 solid blocks atstabilized jly ash and flue-gas desulfurization(scrubber) sludge from coal-burning powerstations. was constructed in the AtlanticOcean offLong Island. N. Y Biological settle­ment and epifaunal colonization are alreadywell established. Fishes inhabit the reet athigh population densities. and crabs andlobsters have begun to immiwate. Laboratoryand sea experiments over the past 5 yearssuggest that stabilized coal waste blocks maybe environmentally acceptable in the ocean.

16

that recreational hshing on the SouthCarolina artihcial reefs in 1977 ac­counted for local expenditures of about$5 million in the coastal communities.although through "multiplier effects" thetotal expenditures within the State wereestimated at about $10 million. Reefbuilding may therefore be a desirableactivity for marine habitat improvement,which provides tangible biological, rec­reational. and economic benefits to localcommunities.

Unfortunately. funding for reef con­struction is currently an important ob­stacle. Although materials for reef con­struction are frequently donated. thecosts are high for labor and for hiringcranes and barges to place the materialsin the ocean. Because the benefits froma reef are distributed widely in the com­munity no single group may wish to fundthe project. At the same time there istaxpayer resistance to spending publicfunds for privately enjoyed recreationalactivities. In recent years the lack ofadequate funds has prohibited new reefbuilding in important candidate areassuch as the New York Bight, which aresubject to intense sport hshing and wouldbenefit from habitat improvement (Jen­sen. 1975).

A potentially important new resourcefor the construction of fishing reefs maybe provided from by-products of coalcombustion, as electricity generating

Peter M. J. Woodhead. Jeffrey H. Parker. andIver W. Duedall are with the Marine SciencesResearch Center. State University of New Yorkat Stony Brook. Stony Brook, NY 11794.

stations increasingly convert from burn­ing oil to coal (Woodhead et aI., 1981).The waste materials from coal combus­tion, produced in large volumes daily,consist of a fl ue- gas desulfurization(FGD) sludge and fly ash, both of whichrequire disposal. For power plants nearthe coast. marine disposal might be anoption, but uncontrolled dumping ofuntreated scrubber sludge or fly ash inthe sea would have deleterious environ­mental effects. However. industry hasdeveloped a system to treat these wasteswith additives and enable cementitiousreactions to occur. The mix becomes astable material that can be formed intoblocks and cured to hard solids. Thestabilization reactions which take placeduring hard block formation are verysimilar to pozzolanic reactions whichoccur in curing of concrete.

We are assessing the feasibility of usingsuch stabilized, solid blocks of coal com­bustion by- products as potential con­struction material for artificial fishingreef building. If the blocks prove suitableand have no adverse effects on the ma­rine environment, the major expense ofreef construction - handling and trans­portation - may be encumbered in thewaste disposal costs.

Early Studies

The coal- waste artificial reef program(C- WARP) began in 1976 with variouslaboratory studies of the interactions oftest blocks made from coal waste mate­rials in seawater systems. Special atten­tion was given to the leaching of major

Marine Fisheries Review

chemical components and of heavymetals from the blocks (Seligman andDuedall, 1979). Bioassays of seawaterelutriates were made with cultures of asensitive marine diatom, Thalassiosirapseudonana. to determine whether therewere any toxic effects. Assay methodsrecommended by the U.S. Environmen­tal Protection Agency and the U.S. ArmyCorps of Engineers were followed. Sig­nincant leaching of potentially toxicelements did not occur and inhibitoryeffects on plant growth and photosyn­thesis were not observed in the elutriates.Physical tests showed that the blocks didnot bread down in seawater but remainedsolid, dense, and strong.

Following the positive results of thelaboratory investigations, small-scaleneld investigations were conductedduring 1977- 78 and 1978-79 with arraysof blocks of stabilized materials set outon the bottom of a shallow embaymentof Long Island Sound. The results ofthese early series of field investigationsalso suggested that the coal combustionwaste materials, when stabilized intosolid blocks, are acceptable in the marineenvironment (Roethel et aI., 1980). Wesaw no adverse environmental effects.The physical integrity of the blocks wasmaintained over exposure periods of 1and 2 years at sea and some increases inblock strength during exposure weremeasured. The materials were found toprovide suitable substrates for biologicalcolonization and overgrowth by encrust­ing marine organisms which are charac­teristic of artificial reefs. Fishes becameassociated with these early arrays of testblocks - toadfish, Opsanus tau, soonspawned and attached their eggs to theblock surfaces, some fish species fedupon the encrusting epifaunal growths,and others took up residence in the nooksand crannies between blocks.

Blocks and Reef Building

The next phase of the C- WARP wasto build a demonstration, pilot-scale reefof waste blocks in the Atlantic Ocean.The program required that the demon­stration reef would be studied for 3 yearsby a multidisciplinary team of oceanog­raphers, fishery biologists, and engineersto provide data to assess its biological,

June-July 1982, 44(6-7)

physical, and chemical interactions withthe marine environment.

Our initial laboratory and neld studieshad been mainly made on stabilizedwastes formed into small numbers ofcubic- foot blocks which were individu­ally mixed and formed by hand. For thedemonstration reef. which requiredthousands of blocks, such laborious, slowfabrication methods were unacceptableas well as expensive and new methodshad to be adopted. In collaboration withthe Besser Compan/, Alpena, Mich.,we developed techniques to processpower plant wastes with the machinesand equipment used by the concreteindustry. The new techniques were suc­cessfully transferred to a commercialconcrete block factory and 500 tons ofpower plant FGD scrubber sludge andfly ash were used to manufacture largenumbers of solid blocks of the stabilizedmaterials, 20 X 20 X 40 cm (8 X 8 X 16inches). The blocks were formed out oftwo coal waste mixes from differentsources, having fly ash to scrubber sludgeratios of 4: 1 and 1: 1, respectively. Con­crete blocks of the same size were usedfor controls.

The 500 tons of factory fabricatedblocks were cured in kilns to achievecompressive strengths of about 500 psi,which allowed stacking for transport.They were trucked to a terminal on theHudson River estuary and loaded on abarge ntted with bottom opening doors(Fig. 1). On 12 September 1980 the bargereleased the blocks at the project site(Fig. 2,3) to build the Atlantic demon­stration reef consisting of more than15,000 blocks of stabilized coal waste.

Our field studies on this demonstrationreef and its interactions with the oceanare in their second year and prospectsfor utilizing coal waste materials as aresource for reef construction continueto look promising. We are also makingcomparisons between the populationsof colonizing invertebrates and of nsheson our reef, and the populations that wefind on the long established Fire Islandartincial reef system, described by Jensen(1975), which is nearby.

'Mention of trade names or commercial firmsdoes. not .imply endorsement by the ationalManne Flshenes Service, NOAA.

Study Area Description

The demonstration coal waste blockreef is located south of Long Island, N.Y.,at long. n013'W, lat. 40035.8'N; 5.8miles ESE of Fire Island Inlet. The15,000 blocks lie on a sandy seabed at20 m depth, and form one continuousstructure approximately 77 m (250 feet)long, 14-18 m (45-70 feet) wide, andI to 2 m (3-6 feet) high. The seabedsediments in the vicinity consist generallyof medium to coarse light brown quartzsand with grains from 0.1 to 2 mm diam­eter; there are also overlying patches ofdark gray mud up to 1cm thick scatteredin the area. The macrobenthic infaunahas been sampled frequently and is char­acteristic of the general inshore regionof the New York Bight.

Repeated oceanographic surveys havebeen made at and near the project siteto characterize the physical and chemicalproperties of the water column, nutrientconcentrations. suspended particulates,current speed and direction. etc. Seatemperatures range from maxima inAugust of 23°C at the surface and about14°C at the bottom, falling to a winterminimum of 0°-1°C in February, whenthe water column is completely mixed.Salinities are typical of the coastal seasand range from 30 to 34°/00, althoughperiodic low salinity inputs from GreatSouth Bay are not uncommon. Close tothe seabed, turbidity is relatively high.sighting distances often being only 1or 2m and after storms may be reduced tozero visibility. The results of the initialoceanographic surveys of the site havebeen published (Woodhead and Duedall1979) and further surveys have bee~completed to describe the seasonal cy­cles of oceanographic change.

Physical and Chemical Results

Long- term laboratory experimentshave connrmed several trends in thephysical effects of seawater immersionon test blocks. Block densities werefound to increase throughout continuedexposure to seawater. Block strengthsalso showed increases after immersion.Such extended nondestructive studieswere made possible by the use of ultra­sonic test procedures developed byengineers in the program. Positive cor-

17

Figure I. - Loading "pocket" bargewith eight compartments tiltedwith bottom opening doors.

Figure 2.-Barge tilled with 15,000blocks being maneuvered for release

at project site.

/8

• Concrete

• IPALCO

aS 0 N D1J F M A M J J A S-1980· 1981----

MONTHS

20

• Conesvi lie

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100

a:: 5'"m::E::>z

25

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E~m+ 15

~Vl

~ 10~Vl

ol:I60§

40<t

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Figure 3.-Blocks on sea bed. Bottom water at site characteristically containsparticulates and mucous strings.

Figure 4. - Progress of epifaunal colo­nization on reef blocks. Top, numberof colonizing species; bottom, areacovered.

relations were developed between thevelocity of sound transmitted throughthe blocks and compressive strength. Theultrasonic method is now used by diversat sea for nondestructive, repetitive test­ing of reef blocks in situ.

A variety of coal wastes which werescreened were analyzed by a number ofdifferent techniques for elemental com­position and mineralogy. The changeswhich occur with curing and duringprolonged exposure in the sea are nowbeing studied. Long term leaching ex­periments in seawater yielded leachingrates for major block components, suchas calcium and sulfate. These data havebeen used to construct a model for thediffusion with time of major componentsfrom the blocks into seawater (Duedallet aI., 1982). Such a model may beimportant in estimating the life of theblocks in the ocean, based on the ratesof loss of major components which we

measure in blocks which we periodicallybring back from the reeL

Epifaunal Colonization

Biological settlement and colonizationon the reef blocks have taken placecontinuously since the reef was firstestablished. Test blocks have been re­moved from the site every 4-6 weeks forlaboratory analysis, and a steady increasein the biological cover of block surfaceswas recorded. Due to low light penetra­tion at the site, plants did not settle andgrow but overgrowth by animals on thetop surfaces of the blocks after I year inthe sea was 51 percent and 41 percent ofthe surface area on the 4: 1 and 1:1 wasteblocks, respectively. Colonization onbottom surfaces was rather more dense(probably because the bottoms had pro­tection from sedimentation), the equiv­alent percent cover being75, 70, and 45,respectively (Fig. 4). Generally the de-

gree of settlement on the concrete andon the 4: 1 waste were similar during thefIrst year. but settlement on the 1: 1 coalwaste was slower or less successful. Con­crete surfaces were harder than eithercoal waste and the immediate surfIciallayer of the I: 1 mix in particular was softor slick. This probably influenced surfaceselection by some epibenthic larvae andmay also have effected the long- termadhesion of organisms with upright,branching growth forms, such as hy­droids and bryozoans.

The community of epifaunal organ­isms growing on the blocks after a year'sexposure at sea was diverse; the pre­dominant organisms were stalked cili­ates, polychaete worms, mussels, barna­cles, and feathery growths of hydroidsand bryozoans. In August 1981, 16 dif­ferent species were found on concreteblocks compared with 19 and 13 specieson the 4: 1 and 1: I mix experimental

June-Julv 1982, 44(6-7) 19

blocks. In the following month. Sep­tember, after completion of I year in thesea. there was a small reduction in thenumber of species recorded on the coalwaste mixes to 14 and 10 species, respec­tively, compared with 16 on the concretecontrols. The communities on all blockshad similar species composition althoughthe percentage representation of somespecies changed signitJcantly with blocktype. In particular, quite marked differ­ences were found consistently over mostof the year for the polychaete tube worm.Po/ydora socia/is. which occurred com­monly on the blocks of coal waste butwas only sparsely represented or absentfrom concrete. Polydora was able to boresuperncially into the outer layer of thecoal waste to build tubes, but not intothe concrete. which may account for itssuccess in becoming established on thecoal waste blocks.

Epifaunal colonization and over­growth of the blocks had been morerapid in the early tJeld experiments madein a shallow embayment of Long Island

Sound. with good light penetration. Ma­rine plants grew profusely on these shal­low blocks and within less than a yearepifaunal development on the differenttypes of blocks had converged so thatthe communities were not distinguish­able (Roethel et al.. 1980). The differ­ences which we have found at the At­lantic project site, particularly the lowerrate of colonization, may be attributedto the low levels of light penetration.Plants do not grow and the energy inputsto the fauna are probably less allowingonly slow growth and community devel­opment.

Toxic Potentials

These waste materials contain verysmall amounts of potentially harmfulelements such as cadmium. arsenic, lead.mercury, and selenium. Released intothe environment, these components ofcombustion wastes might be expectedto exert toxic effects. However. initiallaboratory bioassays made on seawaterelutriates from tJnely powdered block

material failed to demonstrate inhibitoryeffects on the growth and photosynthesisof a marine diatom, nor were the survivaland normal development of sensitive eggsand larvae of winter flounder, Pseudo­p/euronectes americanus. affected(Woodhead and Duedall, 1979).

Bioaccumulation of heavy metalsthrough marine foodwebs is an importantenvironmental concern and organismsexposed to these wastes for long periodshave therefore been analyzed for uptakeof heavy metals. A series of repeatedcollections of epifaunal biomass fromthe blocks in an embayment of LongIsland Sound was made on nve occasionsover 2 years. Analyses of acid digests ofthe biomass collections for copper, chro­mium. zinc, nickel, lead. cadmium.mercury, and selenium showed no evi­dence of elevated levels in the colonizingbiomass growing upon coal waste blocks,compared with that which was collectedat the same time from concrete blockcontrols (Roethel et aI., 1980).

Suspension feeding organisms whichtJlter particulates from large volumes ofsurrounding seawater would be espe­cially vulnerable to releases of blockcomponents. Tests for trace elementuptake were made by holding activelyfeeding blue mussels, Myti/us edu/is. for3 weeks in aquaria with different sedi­ment loadings of tJnely powdered coalwastes, which were kept in suspensionby slow agitation. The mussels were fedon phytoplankton and ingested the par­ticulates with their food; particulateswere subsequently found in their fecalpellets having passed through the gut.Microanalyses of digests of the soft tis­sues of experimental mussels for traceelements showed signitJcant elevationsof tissue iron concentrations, which arenot toxic. But no increases were foundin zinc, lead, nickel, manganese, or cad­mium. As this study continues, moreelements such as arsenic and mercuryare being included. But on the basis ofthe initial results, it does not appear thattJlter feeders had accumulated toxic ele­ments from the ingestion of coal wasteparticulates.

Habitation by Fish

Divers reported that tJshes had alreadybegun to move into the nooks and cran-

Figure S.-Cunner and blackfish at Fire Island Reef.

20 Marine Fisheries Review

Figure 6. - Black sea bass occur innumbers from June to October.

nies of the new reef by the time of theorst scuba survey. =" weeks after place­ment on the seabed. Cunner. TaUlo­golabrus adspersus, were the initial in­habitants and remained the most nu­merous Ilshes throughoul the (lrsl yearof surveys. It was also the most abundantspecies on nearby Fire Lsland Reef (Fig.=" l. Other species founo at the reef duringthe orst year's surveys were black seabass. Cenl merislis slriata: black (lsh.Tau/oRa onilis: conger eel, Conger oce­anicus: winter flounder; summer floun­der. Paralic/hI's denlatus: ocean pout.Macrozoarces americanlls: sea raven.HemiLri/1lerus americanus: and longhornsculpin. Ml'oxoceehalu:, oClodecemsl1i­nosus (Fig. 6l. Adult rock crahs. CanceriFromlus. were early migrants to the reefand toward the end of the orst yearduring summer. juvenile lobsters. Ho­manls americanus. 10- 25 cm in tOlallength, began to appear in increasingnumbers.

A census of the Ilsh populations takingup habitation on the new reef was madeby regularly setting out Ilsh traps instandard arrays. both on the new reef ofwaste blocks and also on an outlyingsection of the old Fire Lsland Reef nearby.The traps are rectangular, made fromvinyl- coated 14 gauge wire and measure90 x 60 x 30 cm. and they have a singlenetting funnel about 60 cm long. The"soak" time is 2 days, two strings of trapsbeing oshed on the waste reef. with twoadditional strings oshed on Fire LslandReef at the same time. (Fig. 7l.

A storm wrecked much of the trappinggear the first time it was oshed afterplacing the reef, but after replacement,the gear subsequently worked weU, being

Figure 7. - Shooting a stringof Dsh traps over the stern of

SUNY research vessel Onmsi.

June-Jull' 1982. 4416-7) 2/

Leaching of major components into sea­water decreased exponentially with timeand trace elements appeared to remainabsorbed in the blocks. Different mea­sures of biological acceptability have in­dicated that the stabilized material isnot toxic to organisms in the sea. Thestudy should continue for 3 years beforeassessments are made but already itappears that the cured blocks are suitablefor biological colonization and over­growth by epifauna, and that fish areresident in the reef.

Zawacki (1969) has made the point:"The use of waste materials ... to con­struct artificial reefs may help solve someof the disposal problems of large citieswhile providing excellent fishing for theever-increasing angling public." Whileagreeing, Jensen (1975) cited the needfor caution and a systematic approach,to temper the zeal for building new reefswith due regard for regulatory require­ments and accepted environmental safe­guards.

The stabilization of coal waste intocured blocks for disposal may providejust such an example. If our extendedprogram of testing and oceanographicmonitoring continues to find the blocks

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Conclusions

Since J976, the C- WARP has made awide variety of studies of the reactionsof coal waste materials with seawatersystems, both on small scale in the labo­ratory and, more significantly. at sites inthe open sea. Our diverse data derivedfrom these investigations of the physical.chemical, and biological interactions ofdifferent stabilized coal waste mixes inmarine systems have so far all suggestedthat in the form of solid blocks, thematerial is compatible with the marineenvironment.

During some longer exposures, whereblocks have been in the sea from 1 to 4years, physical integrity has been main­tained and material strength increased.

16APR 29MAY 16JUL 16SEP 4NOV12AUG

MONTHS

Figure S,-Catches of cunner (cpuel at new reef and at FireIsland Reef ('rubble reef). Note that low catches in Septemberwere accompanieJ by highly turbid conditions which reducecatch,

OL-L.----L----I.----'---"---------'

The black sea bass in particular haveshown quite high lag returns - almostall coming from sport fishermen. Furthergrowth and development of the epifaunalcommunities on the reef blocks are antic­ipated in 1<')1'\2. We hope to determinethe extent to which this occurs andwhether epifaunal changes are matchedby changes in the composition and sizeof fish populations inhabiting the newreef.

fished throughout 1981. Average catchesof fish showed increases from Marchthrough summer (Fig. 8), with cunnerusually forming about 90 percent of thetrap catch. Larger male fish were pre­dominant among the early colonizers.but by summer small juveniles had re­cruited to the reef in numbers. Averagecatches on the Fire Island Reef wereabout twice as large but followed thesame seasonal cycle of change and had asimilar species composition.

The total area being fished at FireIsland Reef is not yet established but it islarger than the area of the new reef ofblocks. which may account for the largercatches made. The catching efficiencyof traps is influenced by temperatureand the low catches made in spring 19R1(when temperature was low) in bothsituations probably do not reflect thedensity of fish on the reefs when com­pared with summer catches at highertemperatures.

Fish caught in the traps are in excellentcondition and several hundred have beentagged with both plastic "spaghetti" tagsand with Petersen buttons to provideinformation on the residence at the siteby different species and on their seasonalmovements. Perhaps more importantly.recaptures of tagged fish have been usedto make first estimates of the size of fishpopulations at the reef.

Due to their abundance, the best avail­able population estimate in the first yearis for the cunner. Using all the recaptureinformation from a sequence of taggedfish releases in 1981, two methods wereused to calculate population size from therelease- recapture experiments: Schna­bel's method and modified Schnabel(Ricker, 1975). The two estimates of thenumbers of adult cunner on the reefwere 3.735 and 3,856 fish. The area ofthe waste reef is approximately 1.230 m

2

and the mean density of adult cunner onthe reef in the first year was thereforeabout 3 fish per m

2• That density is

already as high as Stone's (197K) esti­mates for adult cunner on rough bottomsin the New York Bight.

The reliability of these estimates willbe reassessed in 1982. Population as­sessments will be extended to other fisheswhich have been tagged: Black sea bass,ocean pout, conger eel. and hlackfish.

22 Marine Fisheries Review

to be without adverse effects in the sea,an acceptable alternative may have beenfound to problems of disposal of coalcombustion wastes from power plants.That solution would also carry benefitsfor the marine recreational fishing com­munity through reef construction andmarine habitat improvement.

Acknowledgments

The C- WARP is funded by New YorkState Energy Research and DevelopmentAuthority (NYSERDAJ, the ElectricPower Research Institute, U.S. Depart­ment of Energy, the Power Authority ofthe State of New York, and Long IslandLighting Company. During fiscal year1979, the U.S. Environmental ProtectionAgency was also a sponsor.

For the initial program, blocks of sta­bilized waste were donated for testing

June-July 1982. 44(6-7)

by IU Conversion Systems. Inc.; fundingwas provided by NYSERDA. the LinkFoundation, and the New York Sea GrantInstitute. We are very grateful to all ofthese agencies for sponsorship and totheir program managers who providedadvice and support at critical times indevelopment of the project. Data for thesections concerning epibenthos, toxicity,and fishes were provided by Myrna E.Jacobson, Tim E. Cross, and Mark S.Alexander, respectively.

Literature Cited

Duedall.l. W.. J. S. Buyer. M. G. Heaton. S. A.Oakley, A. Okubo, R. Dayal, M. Tatro, F. J.Roethel. R. 1. Wilke, and P. J. Hershey. InPress. Diffusion of calcium and sulfate ions instabilized coal wastes. In I. W. Duedall, B. H.Ketchum, P. K. Park, and D. R. Kester (edi­tors), Industrial wastes in the ocean. Vol. I.Wiley Intersci., N.Y.

Jensen, A. C. 1975. Artilicial lishing reefs. In

C. L. Williams (editor), New York Bight atlas.MESA Program Monogr. 18.23 p.

Ricker, W. E. 1975. Computation and interpre­tation of biological statistics of lish popula­tions. Fish. Res. Board Can. Bull. 191,328 p.

Roelhel, F. 1., 1. W. Duedall, H. B. O'Connors,1. H. Parker, and P. M. J. Woodhead. 1980.The interactions of stabilized scrubber sludgeand By ash with the marine environment.J. Test. Eval. 8:250-254.

Seligman, 1. D.. and I. W. Duedall. 1979. Chem­ical and physical behavior of stabilized scrub­ber sludge and By ash in seawater. Environ.Sci. Technol. 13: 101:\2-1087.

Stone. R. B. 1978. Artilicial reefs and lisherymanagement. Fisheries (Bethesda) 3:2-4.

Woodhead, P. M. 1., and I. W. Duedall. 1979.Coal waste artilicial reef .program, Phase I.In N. F. Lansing (editor), Electric Power Res.1nst. Rep. EPRI FP-1252, Res. Proj. 1341-1.Interim Rep.. Nov. 1979,83 p.

_--::-::-_::- ' J. H. Parker, and I. W. Duedall.1981. Coal combustion products - new sub­strates for artilicial reef construction. /n D.Aska (editor), Artiflcial reefs: Conferenceproceedings. p. 219- 224. Fla. Sea Grant Coil.Rep. 41.

Zawacki, C. S. 1969. Long Island's artiliciallishing reefs. Conservationist 24(7):18-21.

2]