Marine Habitat Enhancement andUrban Recreational Fishing in Washington

RAYMOND M BUCKLEY

Introdm·tion

In 1974 the Washington Departmentof Fisheries began a marine fish enhance­ment program designed to establish ma­rine hahitat enhancement (artificial reefs)and puhlic fishing piers as acr.ept(;d fOtmsof fishery technology for improving urban recreational fishing in the PugetSound region (Fig. J). Both artificial reefsand fishing piers have heen used exten­sively for many years in some of theAtlantic and Gulf Coast States and inCalifornia to improve recreational fisherycatches and access in previously unpro­ductive fishing locations (Steimle andStone. 1973: Rickards. 19n; Fable andSaloman. 1(74). In contrast. Washing­ton's pier fJshing facilities were limitedto a few access areas on commercedocks. and earlier arlifJcial reef effortswere small-scale projects designed toprovide underwater recreation areas forscuba divers. None of these projects wereprimarily for shore fishing access orurban fishery enhancement.

Recreational fJshing in Pacific North-

ABSFRACT- A marine lish enhanccmentpmgram staned in 1974 has emphasized theuse 0/ habitat enhancement structures (urti­licia/r{:e!'s), hoth in coniunctiun with pu/JIiclishing piers and to create fishing reel~"/orbu(/{ anglers. tn impruve urban recreationalfishing in Puget Sound. Fhl? enhanced areaswere designed and sited to del'elnp hinlogi·calli' into replicates 0/ natural rockv reelcommunities ill order to promote productil'efishNies.

The site selectinn proc"ss was b£lI'ed (In

28

west marine waters has been synony­mous with fishing for Pacific salmon(Oncorh.l'nchu,\ sp.) from small boats.and this axiom has pervaded from an­glers. through fishery managers. to thefunding sources. Consequently. a newprogram directed at enhancement of(.tlier marine fish spt'cies-- using locallyunproven techniques. and partially tar­geling these fish for an essentially unrec­ognized clit'ntele--was met initially withfeelings ranging from skepticism to en­thusiasm. Fortunately. a significantamount of the enthusiasm to try habitatenhancement and public flshing pierswas generated with the State governmentfunding sources (i.e .. the legislature andthe Interagency Committee for OutdoorRecrC'ation). the fishery clientele. and

Ra)lllund M. Buckley is Chief. Marine Fish~~nhancelllent Division. Washington Departmentof Fisheries. 115 General Admlllistration Build­ing. Olympia. WA <)1;504. Views or opinionsexpressed or implied are those of the author anddo not ncccssarily retlecr the position of theNatiunal Macine Fisheries Service. NOAA.

indexes o/the macrobiota assemblages onrocky reel control areas in the same regionand on consideration a/potential impacts onlisheries and commerce. Experimental designstlIltegies/or hoth the entire hahitat enhance­ment area and the individual enhancementstructures were used to determine the npti­mum balance hetween aggregation and pro­dUClion u/ target species and management/01' sustained. quality Ii.\heries. Maiorstruc­tured design elemcnts ""ere/ound to be hori­cOl1/al and vertical relie( and numbers and

local government agencies and serviceorganizations. This provided the broadbase of public awareness and supportwhich resulted in rapid funding of theinitial projects.

During the first 7 years, the conceptsof the marine fish enhancement programhave been well received by the fisheryclientele and have proven relevant tofJshery management in Washington. Bio­logically. habitat enhancement structuresplaced in open. relatively unproductivemarine locations successfully increasethe areas' density and biomass of biotacommon to productive natural rockyreefs. Sociologically. public fishing piershave become extremely popular accesslocations for shore anglers previouslydenied use of the marine resources. andoffshore "fishing reefs" near metropolitanareas have created valuable recreationalbenefits which are easily accessible toall boat anglers. Economically, habitatenhancement projects and public fishingpiers compete very favorably with otherforms of outdoor recreation for the pub­lic funds dedicated to recreational use.

sizes or interstitial spaces. Abundant anddiverse algal growth on the enhancementstructures increases habitat complexity andheterogeneity. and may well be the mostimportant clement in the transition fromintroduced materials tn rqllicates o/produc­tive natural ree/s. Successional developmentollish communities appears to proceed/roma principal(v aggregated species base duringinitia( colonization to a )orager-aggregater"communitv stnlcture as food items developon the enhancement structures.

Marine Fisheries Review

Figure J. - Locations of habitat enhancement areas in Puget Sound, Wash.

@ Public fishing pier

o Fishing reef

facets of the recreational fishery providedthe greatest benefits to the public.

The objective of habitat enhancement,used either in conjunction with fishing

Program Design and Methodology

piers or to create "fishing reefs" for boatanglers, was to establish enhanced areasthat developed biologically into repli­cates of productive, natural rocky reefcommunities. with resilient populationsof target species of fish which couldwithstand frequent fishing. The bio­logical investigations related to habitatenhancement have been designed tounderstand and utilize the artificial reefsfrom the perspective that the only "arti­ficial factor" in the reef is the originalplacement of the inert base materialaround and upon which the living, natu­ral reef community evolves. An under­standing of the factors influencing thisdevelopment enables construction ofhabitat enhancement complexes com­patible with environmental and biologi­cal constraints.

The increasing demands for improve­ments in urban recreational fishing op­portunities that were being recognizedon a national level in the mid-1970'swere also developing in the metropolitanareas of Puget Sound (pNRBC, 1970;BOR, 1977; Stroud. 1977l. This emphasison urban recreation offered the mostpotentially productive situations whereapplications of marine habitat enhance­ment would demonstrate the value ofthis technology in modern fishery man­agement.

Many target fishing locations for rockyreef-oriented fishes adjacent to the met­ropolitan centers of Puget Sound beganreceiving more frequent use in the middleto late 1970's. This resulted from in­creasing interest in these previously lesspopular fishes. caused, in part, by cur­tailments in the fisheries for Pacific salm­on dictated by the 1974 Boldt Decision(Williams and Neubrech, 1977) on treatyIndian fishing rights and, in part, bydramatic increases in energy (fuel) coststo reach more distant fishing grounds.

Many of these rocky reef sites werelimited in area and habitat diversity and,therefore, supported vulnerable popu­lations of the resident demersal fishesneeded for a continuous fishery. Catchesbegan decreasing in many of the morepopular and accessible locations, andanglers either invested the additional

::.jj

..... Everett

i20

mil esNautical, I

o 10::I: Olympia

This progress justifies application ofenhancement technology to "real"' fish­ery management problems, in whichsolutions maximizing accessibility to all

June-July 1982. 44(6-7) 29

Figure 2. - The Edmonds Public Fishing Pier.

costs to travel to more productive loca­tions, modified their criteria for pro­ductive catches. or withdrew from thefishery. Strong public sentiments devel­oped for more productive urban fishinglocations accessible (economically) to abroad spectrum of recreational anglers.The use of marine habitat enhancementto create productive nearshore fishingsites was an obvious and timely solutionto this problem.

The introduction in 1975 of largepublic fishing piers (Fig. 2) to the urbanrecreational fishery scene in Washingtonpresented an excellent "vehicle to gainvisibility" for marine habitat enhance­ment in an essentially risk-free manner.Metropolitan areas in Puget Sound hadthe potential for developing a large pierfishing clientele, but there were no avail­able facilities designed and sited specif­ically for recreational f]shing. Most ofthe metropolitan centers bordered ma­rine waters with good biological pro­duction potential and excellent fishingdepths (from -27 to -55 m MLLWImean lower low water j). This new urbanfishery was virtually guaranteed to pro-

30

vide popular. accessible. and affordableparticipation in marine recreationalfishing for all anglers. regardless of ageor physical ability (Buckley and Walton.1981 ).

The public fishing piers in PugetSound created intense. concentratedfisheries that could not enjoy sustainedcatches without dramatically increasedaggregation and production of importantspecies of fish in the pier areas. Theconstruction of large habitat enhance­ment complexes around the piers in­creased the areas' prnJuction of residentand semiresident species, and providedfeeding and orientation sites for aggre­gation of transient species- both im­portant in sustaining quality catches in acontinuous fishery situation. This com­bination of fishing piers and habitatenhancement brought the concepts andbenefits of habitat enhancement intocontact with the maximum number ofanglers in a "high profile" fishery at thestart of the marine fish enhancementprogram.

Later use of habitat enhancement tocreate "fishing reefs" for the boat fishing

clientele was the first application of thistechnology to benefit an establishedrecreational fishery in Washington.These "boat angler reefs" were sitedevery 18- 28 km along the 185 km cruis­ing route from southern Puget Soundnorth to the San Juan Islands. and werealso accessible from major recreationalfishing boat launch facilities. This pro­vided the opportunity both to occasional"yachting anglers" and avid small- boatanglers, representing the bulk of therecreational fishing effort on PugetSound, to utilize habitat-enhanced fish­ing locations.

The base of interest and support forthe marine fish enhancement programthat developed in the public sector wascomplemented by the very importantacceptance of the same concepts withinthe relevant scientific community. Thisresulted primarily from the promotionand use of marine habitat enhancementas a fishery management tool whichsecondarily had the capacity to recyclespecific types of solid wastes under eco­logically acceptable conditions. Thereis some evidence that earlier local (and

Marine Fisheries Review

national) emphasis on relating artiucialreef construction to deposition of a vari­ety of solid waste materials in the marineenvironment resulted in waste disposaloften being perceived and promoted asthe primary justincation for reef con­struction. A further consequence of thismisconception was the trend that artifi­cial reef projects had to be minimalbudget operations supported by dona­tions of materials and volunteer labor.which led to the traditional corollarythat artificial reef projects did not requirepublic funds and. therefore, had littleintrinsic value. In contrast, the represen­tation of marine habitat enhancementas a valid fishery management techniqueworthy of investment, the same as fresh­water fish-producing facilities (and lack­ing anything synonymous with the term"artificial"), utilized this traditional viewin a positive manner and supported theinvestment of public funds through theuse of donated materials. when appro­priate.

The Washington Department of Fish­eries receives construction funds formarine fish enhancement projects as partof the State legislative biennial appro­priations for the agency's Capital Out­door Recreation Budget. The source ofthese appropriations is a 50 percent StateGovernment/50 percent Federal Gov­ernment matching fund administeredthrough the State's Interagency Com­mittee for Outdoor Recreation. TheState's share of the fund is obtained fromvoter-approved Referendum Bonds forrecreation. The Land and Water Con­servation Fund. administered by theHeritage. Conservation. and RecreationService (absorbed by the National ParkService in June 1981) of the Departmentof Interior. supplies the Federal matchingfunds. The implementation of thesecapital appropriations, and the researchsupporting the marine ush enhancementprogram, are funded by the biennialOperational Budget of the Marine FishProgram.

Since the inception of the marine ushenhancement program in 1974, $3.2million in capital funds have been ap­propriated for marine habitat enhance­ment and public fishing pier projects.The 1981-83 Capital Budget included$2.5 million for 14 habitat enhancement

June-July 1982. 44(6-7)

projects, three associated with publicfishing piers. An additional $1.2 millionis scheduled for appropriation for an­other fishing pier project in 1983. Thisfunding base. which has established twopublic fishing piers and two "boat anglernshing reefs" and has one fishing pierand eight fishing reefs under construc­tion. is only as stable as its two fundingsources. Anticipated Federal reductionsand delays in the Land and Water Con­servation Fund appropriations to thestates in 1982 will cause severely cur­tailed construction schedules. and havecreated interest in establishing a 50 per­cent Federal Government/50 percentlocal government matching fund ap­proach for some projects. This releaseof State Government funds would enable100 percent State funding of some proj­ects. if current economic inflation factorsdo not prohibit continued sale of recre­ation bonds.

Site Selection, FacilityDesign, and Fishery Management

Successful biological development ofhabitat enhancement projects in marinewaters is a key prerequisite to productivefisheries on the enhancement structures.To maximize the potential for biologicaldevelopment, a site-selection processwas used which relied heavily on a biotaindexing comparison system developed

Figure 3. - Auto- tire artifact on sand substrate.

for the Puget Sound region (Hueckeland Buckley'). This system was basedon indexes of the macrobiota assem­blages on three natural rocky reef controlareas which had stable. diverse commu­nities of algae. invertebrates. and fishes,and were productive recreational fisherysites. Biota common to all three areaswere assumed to typify those that wouldoccur on habitat enhancement structuresplaced in areas with the environmentalparameters conducive to productivebiological development.

Transects conducted on potentialhabitat enhancement sites qualitativelyassessed the biota in relation to prevailingsubstrate characteristics. Artifacts andsubstrate anomalies on the site (such asatypically large rocks. logs, and man­made debris, Fig. 3) were examinedcarefully. Their attached and relatedbiota were representative of the biotathat would develop on the site with theaddition of stable material to increasethe diversity and relief of the substrate.A high percent overlap between thecontrol site and enhancement site biotawas indicative of a good habitat enhance­ment site. although the opposite rela­tionship was not necessarily true. espe-

'Hueckel. G. J.. and R. M. Buckley. Site selec­tion procedures for marine habitat enhance­ment in Puget Sound. Washington. In prep.

Figure 4.-Scrap concrete used for habitat enhancement construction.

cially if rocky reef simulating substrateswere not available.

The site-selection process also con­sidered several other factors relevant toensuring that the habitat enhancementstructures attracted desirable biota andfishery utilization, and not unwantedsediments or commercial fishery nets.Conflicts with existing and future fish­eries were analyzed to avoid overlappingutilization of the area, if possible, or todetermine the most beneficial use of thesite. Conflicts with commercial vesseltraffic were avoided, both in relation tovessel draft restrictions caused by theenhancement structures and to surfacecongestion caused by fishing boats. Theproximity of the enhanced site to recre­ational access locations was also impor­tant to facilitate utilization and. there­fore. maximum public benefits.

Various design strategies for both theentire habitat enhancement areas andthe individual enhancement structureswere used to determine the optimumbalance between aggregation and pro­duction of target species and manage­ment for sustained, quality fisheries.These experimental design considera­tions required habitat enhancementconstruction techniques that went farbeyond the "random dump and hope"methods used in earlier artificial reefprojects, occasionally involving under­water construction and placement ofenhancement structures by scuba divers.

The habitat enhancement complexessurrounding public fishing piers coverfrom 1.5 to 2.0 hectares, which are farlarger areas than can be fished from the

32

piers. This design strategy makes 20-30percent of each pier's enhanced areaaccessible to pier angler's gear. andallows the bulk of the enhancementstructures to build reserve populationsof resident and semiresident fishes toreplenish removals by the pier fishery. Acompanion management strategy re­serves these populations for pier anglersby closing the enhancement areas to allother fisheries. The "extra large" en­hanced areas and the associated biotaalso serve as attractive target feedinglocations for transient (often pelagic)species of fish. holding them within reachof the pier fisheries for ex tended periods.

Individual habitat enhancement struc­tures are located either under the pier oroutside of a 2:\- 30 m perimeter surround­ing the pier. This creates an "open zone"around the pier to minimize gear foulingon the enhancement structures andmakes both open sand- bottom and rockyreef fish species available to the pierfishery harvest. Conservative harvestmanagement regulations are being testedto provide recreational enjoyment atreduced levels of impact on these, usuallyresident. target species.

The habitat enhancement complexescreating fishing reefs [or boat anglersutilize up to 10 hectares of the bottombetween the -1:\ to - 27 m MLLWdepths. These rather extensive areasallow a design strategy that distributesand spaces both the enhancement ma­terial and the ensuing fishing effort.Research has shown that large peripheralopen feeding areas are important to somerocky reef [lshes during specific life

history stages (Hueckel and Stayton.19R2) and that aesthetic enjoyment in arecreational fishery can be increased byreducing crowding in the fishing area.An extensive enhanced area also enablesmanagement strategies that disperse orrelocate fishing effort to reduce the im­pacts on fish populations inhabitingspecific enhancement structures, suchas spawning aggregations, juvenile re­cruitment areas, or overfished targetlocations. This can often be accom­plished by utilizing the "magnetic buoyfactor" which results in recreational an­glers fishing only around the buoy thatmarks the fishing reef. Fishing effort canbe evenly distributed by periodicallymoving the buoy to different locationsthroughout the enhanced area.

Theoretically. a fishing reef for boatanglers is totally accessible (if totallylocatable), and it is not practical to offsetfishery removals through building reservepopulations of fish by closing a portiono[ the reef to fishing. The potential foroverfishing is, therefore, much greateron a boat angler's fishing reef than in anenhanced area associated with a fishingpier, and this factor must be consideredin the fishery management strategy. Con­servative harvest management regula­tions are usually inappropriate in thesesituations. as they would have to applyto large geographic areas surroundingthe fishing reef to be enforceable andwould unnecessarily restrict otherfisheries.

Experimentation with the design ofthe individual habitat structures is beingexamined as a method to control therate of fishery removals over a longperiod of time, especially for the residentand semiresident species which utilizethe structures for productive habitat.Enhancement structures constructedfrom large, angular material (such aslong, flat concrete planks, Fig. 4) createlarge cave-like habitats which have ahigh refuge potential from anglers' gear.This reduces (or controls) the fishabilityof the enhancement complex throughphysically preventing frequent contactbetween fish and fishing gear, but stillallows harvest of those fish on the pe­riphery of the structures. This construc­tion technique also appears to minimizegear fouling on the structures.

Marine Fisheries Review

Figure 5. - Rockfish (Sebastes sp.) utilizing small habitats on an auto- tire module.

Habitat Design, Colonization,and Ecosystem Development

The design of the marine habitat en­hancement program in Puget Sound isbased on directing the biota developmenton. and in close association with. thehabitat structures toward a multispeciesand multilife- history stage community.This follows the premise that biota diver­sity will lead to productive, relativelystable communities of organisms whichhave the resiliency to respond to fisheryremovals throughout development. How­ever. it is apparent from other researchthat this premise may be flawed. Indiscussing a general hypothesis of speciesdiversity, Huston (1979) pointed out thatdiversity has been both positively andnegatively correlated with productivityby many authors. Sale and Dybdahl(1975) found that communities of coralreef fishes are likely to demonstrate onlyweak stability and that the equation"diversity = stability" has questionablevalidity. A saving (or modifying) factormay be that most of this work relates totropical patch- reef situations and maynot be totally applicable to temperaterocky reefs. Sale and Dybdahl (1975)also pointed out that a fuller under­standing of community structure (andresponses?) will urgently require fargreater information on the biology ofthe species involved.

The work carried out to date in Wash­ington's marine habitat enhancementprogram has shown that the design andrelative spacing of enhancement struc­tures influence ecosystem developmentin the enhanced area, from initial place­ment of the structures throughout theirlong- term development. Major structuraldesign elements are 1) horizontal andvertical relief and 2) numbers and sizesof interstitial spaces. The latter elementdirectly affects the sizes of the morecryptic fishes that colonize the structuresand may also influence the species offish and the sizes of some invertebrates.The spacing and sizes of the habitatstructures affect the amount of interfacewith the surrounding pelagic and benthicenvironments, which has, as yet, an in­completely understood effect on inter­structure relationships. It has beendemonstrated that maintaining open

June-July /982, 44(6-7)

zones within the enhancement areas isbeneficial to both reef species (Hueckeland Stayton, 1982) and nonreef species(Walton, 1979).

Current literature on reef colonizationsupports the view that determination ofthe actual factors controlling this processis a continuing question. especially intemperate regions (Fager. 1972; Talbotet al.. 1979; Stephens and Zerba. 1981;and others). Brock et al. (1979) examinedrecolonization in coral reef communitiesand found that "the structure of reef fJshcommunities may be the result of amosaic of deterministic patterns andstochastic processes that occur duringinitial colonization and continue throughtime." This fInding supports the generalconsensus in the literature that the var­ious resource-partitioning, space­limited. predator-limited, lottery­hypothesis. resource-sharing viewpointsall have their own areas of credibility asmechanisms which influence coloniza­tion, diversity, and stability in reef fishcommunities. For example, Russell etal. (1974, in Brock et aI., 1979) workingon the Great Barrier Reef, noted thatthe physical structure of artifIcial reefhabitats was relatively unimportant indetermining early colonization com­munity structure, and Nolan (1975, inBrock et aI., 1979), working in the Mar-

shall Islands. could not find any obviouscorrelation between artificial reef sub­strate complexity and fish species diver­sity. However, Walton (1979), workingin the Pacific orthwest, found that thestructural design and physicaJ placementof artifIcial reef modules affected thedensity and biomass of associated fIshpopulations.

The structure of temperate reef fIshcommunities in Puget Sound may beheavily influenced by chance factors onthe species level, as long as suitably sizedhabitats are available to meet the needsof the life history stages (sizes) of thespecies recruiting to the reef (somewhatdeterministic biological patterns'!).RockfIsh (Sebasles sp.) colonization ofthe auto-tire module and rubble rockenhancement structures associated withthe Edmonds Public Fishing Pier fol­lowed a defInite pattern of associationbetween fIsh size and habitat selection.Small interstitial spaces formed by rubblerock were utilized by small rockfIsh upto 15 cm in length, and tire modules(triads) with large cave-like openings andsmall crevices showed rockfIsh distribu­tions based directly on habitat size (Fig.5.6). This same pattern was observed inthe initial colonization of scrap concreteenhancement structures at Gedney Is­land by hoth juvenile and adult rockfJsh,

]3

Figure 6.-Rockfish ISebasles sp.1 utilizing a large habitat on an aUla-tire module. Figure 7.-Juvenile rockfish (Sebasles sp.) uti­lizing a narrow protective habitat.

where (protective?) habitat selection wasstrongly size- related and the area ap­peared to be habitat-limited for juveniles(Fig. 7).

The suitability of the habitats formedby enhancement structures has also beenobserved to affect initial colonization bysuch diverse biota as 8 cm shrimp and100 em predatory fish. Protective habitatfor the coon-striped shrimp, Pandalusdanae. a major food item for many fishes,consisted of the smaller interstitial spacesand often included the same crevicesused by juvenile rockfish which wouldlater become shrimp predators. Spawn­ing territories for lingcod, Ophiodol1elongatus, were established at sites withthe appropriate semiexposed crevicehabitats suitable for retaining large eggmasses (up to 0.5 m diameter). whichsolidify to the shape of the crevice to

34

prevent dislodging when washed by tidalcurrents (Fig. 8).

Selection of construction materialsand techniques which allow optimumvertical and horizontal distribution of avariety of interstitial spaces provides thebest potential base for successful habitatenhancement in local marine waters.Equally important. however, are thelong- term physical and chemical stabilityof the construction materials and theamount of photic-zone exposure of theenhancement structures, hath of whichinfluence algal community development.Scrap concrete. auto tires. and quarryrock are all acceptable substrate mate­rials. offering firm. textured surfaces,although concrete is currently the mostcost-effective, durable. and structurallydesirable for local marine habitat en­hancement.

Abundant and diverse algal growthon the enhancement structures signifi­cantly adds to habitat complexity andheterogeneity. allowing more species andmore organisms to coexist in the en­hanced areas. This may well be the mostimportant element in the transitionfrom introduced materials to productivenatural reef replicates with stable com­munities. Sessile algae are major contrib­utors to the physical structure of com­munities in the marine environment(Fager. 1972). and the microhabitatscreated by their holdfasts and upperstructures are used extensively by avariety of invertebrates that are potentialfood organisms (Hueckel. 1980). Theincreased predator- prey interactionsavailed by the increased production offood items provide greater choices forenergy transfer through the food web in

Marine Fisheries Review

Figure 8. - Male lingcod. 0. elongGtu5. guarding an egg mass.

the community, and the number of linksin the food web is a measure of thestability of the community (Odum, J953in MacArthur. J955).

The successional development ofalgae and invertebrates on substratesintroduced into the marine environmenthas been well documented for manyregions (Coe and Allen, 1937; Tsudaand Kami, 1973; Saito et aI., 1976).Hueckel (1980) studied colonization ofauto tire habitat enhancement structuresat the Edmonds Public Fishing Pier for24 months (1977-79) and found that algaldevelopment was very important to sub­sequent invertebrate colonization: "Priorto algal colonization, only Ithe crevice­related I coon-striped shrimp (Pandalusdanae), two species of starfIsh (Pycni­podia helianthoides and Evasteriastroscheli), acorn barnacles (Balanus

June-July /982, 44(6-7)

glandula), and a sea anemone (Metridi­urn senile) had been observed on thetires. After the development of algae onthe tires, large numbers of gammaridamphipods, caprellid amphipods, har­pacticoid copepods and hippolytidshrimp were observed associating withthe algae .... Platytharnnion pectinaturnwas the dominant red algae IRhodophy­ceae I species on the artifIcial reefthroughout the study. The fIlamentousstructure and profuse branching of thisspecies provided refuge for most of themicroinvertebrates on the artifIcial reeL"Walton (1979), studying the same en­hancement structures, found that thespecies and numbers of fish increasedwith the age (increased development) ofthe habitats, the same pattern of devel­opment noted on nearshore artificialreefs in California and related to increas-

ingly available food and shelter (Turneret aI., 1969).

Acorn barnacles colonized the Ed­monds enhancement structures in highnumbers during the first spring, followedby rapid mortalities over a 4-month pe­riod, and never regained the initial highconcentrations (Fig. 9). There is goodevidence that this decrease was directlyrelated to grazing by starfish (F. helian­thoides and E. troschelt) and surfperch(Embiotoca lateralis and Rhacochilusvacca). Subsequent algal colonizationoccurred on the basal plates left aftergrazing and may have inhibited barnaclerepopulation by preventing the larvae(cypris) from setting on the solid sub­strate. Red algae dominated the en­hancement structures (approximately 95percent coverage by F. pectinatum, and5 percent by Callophyllus spp. and Poly-

]5

Figure 10. - Percent coverage of algae on habitat enhancement structures at theEdmonds Public Fishing Pier (from Hueckel, 1980).

Jan1979

Jan1979

Oct

Oct

Sampling deplhs

0--0 = 10 m•..... = 12 mrr---A = 15 m

Jan1978

S8JT'4*lg deplhs

<>--<> = 10 m..... =12 m6----6 = 15 m

.'.

Jan1978

-.

•., l..•..,? \, .•

. . ."Lf,'

0--0-""" ..

Oct

Oct

·, .· .· ,... \

"\....•----~,. \,

.. ~. '-

.All

"T.~·\. . .

100

Figure 9.- Percent coverage of the acorn barnacle. Balanus glandula, on habitatenhancement structures at the Edmonds Public Fishing Pier (from Hueckel. 1980).

80 .' .•<»Cl.. 60Q;>00

C<»~ 40<»"- .

""·.· ,· .20 · ,

. · \,.' \ "

:

0

Apr ~I

1977

lOll

80

&e 80<»>00

i0 40~"-

20

neura latissima) and commenced to showthe expected seasonal abundance cycle(Fig. 10).

This enriched habitat on the enhance­ment structures supplied microinverte­brate prey organisms «2.5 cm in length)in concentrations up to 400/m2

, andmacroinvertebrate prey organisms (in­cluding coon-striped shrimp) in con­centrations up to 371m2 (Hueckel, 19S0).Combined with additonal prey organismsoccurring naturally in the surroundingsand substrate (Table 1), the entire en­hanced area adjacent to the EdmondsPublic Fishing Pier provided a productivefeeding location for many species of fish(Hueckel and Stayton, 1982).

It is interesting to speculate (and pos­sibly worth future consideration) whetherecosystem development on habitat en­hancement structures could be con­trolled, or periodically altered. to in­crease the abundance and types of preyorganisms. For example, would the in­troduction of large numbers of her­bivores on some of the enhancementstructures at Edmonds graze down thealgae and allow recolonization by acornbarnacles? Could this be carried outimmediately adjacent to the fishing pierto pr.ovide a prime feeding site for surf­perch, which would be removed by thepier ushery before they could heavilyimpact the barnacle population. leavingan abundant food source to attract moresurfperch (baited-trap equilibrium?)?Sale (1977) expressed the view that thediversity of coral reef fish communitieswas directly correlated with the rate ofsmall-scale, unpredictable disturbancesto the supply of living space, and thatthis could be tested experimentally bymanipulating the rate of disturbancethrough increased predation (spear ush­ing). It seems equally plausible to ex­perimentally control sessile and motile

Table 1.-Prey organisms identified in benthic cores,benthic plankton-net tows, and successional develop­ment studies in the habitat enhanced area at the Ed·monds Public Fishing Pier, August 1977-December1978.

Percent

Habitat enhancement SandPrey organisms structures substrate

Microinvertebrates' 80 46Caridean shrimp 20Polychaete annelids 33Bivalve mollusks 15Nematodes 6

'Less than 2.5 em in length.

invertebrate populations on island-likeenhancement structures.

Long.Term Fish Community Structure

The successional development of fishcommunities on habitat enhancementareas in Puget Sound appears to proceedfrom a principally aggregated speciesbase during initial colonization to a"forager-aggregater" community struc-

ture as food items develop on the en­hancement structures. A composite ofresearch information from several en­hancement areas shows that the earlycolonizing ushes represent 1) uve speciesof aggregaters, averaging 43 g each.which utilize the habitat structures fororientation and protection while feedingprimarily on organisms from the sur­rounding benthic and pelagic environ-

36 Marine Fisheries Review

Table 2.- Harvests at residenl (R), semi resident (S-R), and transienl-feeding (T-F) fishes fromthe Edmonds Public Fishing Pier.

Fishery year First qtr 1 Second qtr. Third qtr Fourth qtr Total

March 1979- R ' S-R 922 813 68 38.4 32.6March 1980 T-F 7.8 18.7 932 61.6 67.4

May 1980- R , S-R 83.5 22.5 496 65.8 401May 1981 T-F 16.5 77.5 50.4 342 59.9

'Quarters overlap only 1.5 months between fishery years.

ments, and 2) two species of (predatory)foragers, averaging 1.553 g each, whichutilize the habitat structures as a placeto feed on structure- related organisms(principally aggregated (lshes), Afterseveral years of biological development,the fish community structures change torepresent five species of aggregaters,averaging 545 g each, and eight speciesof foragers, averaging 364 g each, withat least 60 percent species overlap ineach group. These disparities in averagesizes of early colonizing fishes demon­strate that the aggregaters were primarilyjuveniles (seeking unoccupied habitat?)and the foragers were (wandering?) adultpredators, In comparison, the averagesizes in the developed fish communitiesdemonstrate a more balanced distribu­tion of all aggregater and forager lifehistory stages, This pattern of early col­onization of reef structures by mainlyjuveniles, with some (itinerant) adultfishes, has been reported by many re­searchers (Talbot et aI., 1979; Brock etaI., 1979; and Stone et aI., 1979),

Persistent aggregation of fishes byhabitat enhancement structures is veryimportant to continued fishery utilizationof the sites, Foragers represent many ofthe resident and semiresident species thatare limited in abundance by the amountof food and habitat (area) provided bythe enhancement structures. The aggre­gaters include the transient species thatutilize the enhanced areas as "patchy"feeding locations in rather broad geo­graphic regions. These large populationsoccur intermittently in the target fishinglocations, providing excellent catchesand reducing pressure on resident andsemi resident stocks, but are less vulner­able to overharvest. The first two fisheryyears on the Edmonds Public FishingPier produced harvests dominated bythe transient-feeding fishes (67.4 and59.9, respectively), but quarterly catchestimates demonstrated the equally im-

June-July 1982, 44(6-7;

Percent of harvest

portant role of the resident and semi­resident fishes in carrying the fisherythrough less productive periods (Table2).

Stone et al. (1979) are the most recentresearchers to show that marine habitatenhancement (an artificial reef) will in­crease carrying capacity and reef fishbiomass in the immediate vicinity of anatural coral reef, without diminishingthe resident population of the naturalreef through attraction to the new habi­tat. Similar results have been found tooccur in local temperate waters betweennew and old habitat enhancement struc­tures which simulate rocky reef-likehabitats. A quarry rock breakwater­rubble rock- covered pipeline habitatestablished in 1968-71, had fish densitiesaveraging 0,27 fish/m1 (quarterly, July1975 to June 1976) just prior to con­struction of an adjacent tire- moduleartificial reef (Walton, 1979). Five yearslater, fish densities on this habitat hadincreased to 0.44 fish/m 2 while the tiremodules had developed fish populationsof 1,77 fish/m1 (Washington Departmentof Fisheries survey data),

These examples of an absence of long­term detrimental effects between thenew and old habitats, and the apparentrelatively independent development ofassociated fish populations, support theidea that increasing the amount of reef­simulating habitat in the nearshore ma­rine environment increases fish produc­tion. Local marine waters do not (cur­rently) represent a nutrient-limited sys­tem that can be adversely affected by anexpanding habitat enhancement program;in fact, there is a closer representationof a habitat-limited system that respondsto increased habitat diversity with in­creased production of desirable biota.

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37