Sraaintnu-Smith aud Messier 239

DESIGN CONCEPTS FOR INTEGRATION OF OPEN OCEANAQUACULTURE AND OSPREY" TECHNOLOGY

Bnan Braginton-SmithThe Conservation Consortium

4380 Main Street

Yartnouthport, MA 02675e- mail:consort I capecod.net

and

Richard H. Messier

University of MameDepartment of Mechanical Engineering

Orono, ME 04469e-mail:messier@maine.maine.edu

ABSTRACT

A unique opportunity exists to develop a rnulu-benefit, cninmercial ocean enterprise off the coast of NewEngland, with potential sites reaching from Nantucket, Massachusetts, to Eastport, 5/lxi no. This enterprise coutdgenerate electric power, provide a base for installation of open ocean aquaculture facilities. help revitalizedepleted fisheries, recycle discarded materials, and enhance economic de ve lo pment in several coastal industries,including shipbuilding and tourism. The concept is centeted on the Ocean Swell Powered Renewable Energy OSPREY! technology device developed by Applied Research dc Technology ART! of inverness, Scotland. TheOSPREY is a hybrid wind/wave energy generation system wherein wave energy is harnessed by means of snoscillating water column within a collector chamber anchored to the ocean floor by large, permanently insudledballast uutks, fbe OSPREY forms the central element in a multi-use ocean structure. Successful establishmentof aquaculture facihties in the high energy environment off the New England coast will require solutions to anumber of engineering challenges including s~ integrity, security, operability, maintainability, and affordabledesign. The concept of design integration of aquaculture net pens into the OSPREY provides the opportunity tomee a number of these challenges in a cost~ ffective manner. Concepts for integration of submersible and floatingnet pen structures and their operation into the OSPREY technology must be advanced, potentiat sites must bestudied, and benefits to the aquaculture industry determined.

INTRODUCTION

The purpose for this paper is to presentand discuss ideas for an existing technology whichmay provide a viable technical and commercialpartner for offshore aquaculture facilities in thefuture. It is clear, from research conducted by thepresent authors and many others, that theestablishment of a viable offshore aquacultureindustry in the Northeast United States will requiremeeting numerous technical and economicchallenges.

An offshore location for aquaculturefacilities will require structural design forsurvivability in the severe weather, which is

prevalent during the fall and winter seasons in theseareas. Large, wind-driven waves and strongcurrents are common in these latitudes, even

relatively close to the coastline. Permanentlymoored net pen structures must be designed tomaintain structural integrity and net integrity itlconditions approaching sea state seven perhapshigher sea state during hurricane season!, andcurrents up to 3 to 4 knots.

Thc offshore aquaculture facilities mustbe designed to provide for logistic support fromshoreside facilities through the use of servicevessels. The service vessels must be able to come

alongside, dock, and offload personnel, supplies,and equipment, Furthermore, products will be

Flgare 1. Modniar floating net pen,

harvested and delivered to shoreside facilities forprocessing by the same service vessels. Theaquaculture facility must provide for effectiveharvesting and net handling,

One of the major concerns voiced by theoperator conununity has been associated withsecurity of such offshore facilities. Thesestructures will represent potentially large capitalinvestment in net pen structures and finfish stock.Access to these facilities will be limited and/orimpossible during extended periods of had weather.This is in contrast to the existing operatingconditions inshore, where daily access and visualinspection are possible during all weatherconditions. Potential security concerns includeaccidental collisions by commercial shipping andoffshore fishing vessels, intrusion by marinemammals, human intrusion, and detection ofstructural degradation.

The economic challenges associated withestablishment of a viable offshore aquacultureutdustry are substantiaI. The market conditionsfor finflsh products in the United States areextremely competitive today. As finfishquaculture expands in developing countries,

ugNtt Teehaleel ttepaet No. 26

market competitiveness is expected to increase.The cost for purchase, tnaintenance, and operationof offshore facilities will be higher than such costsfor today's inshore facilities. These trends areclearly in conflict. Future. offshore aquacultureoperators will be required to explore new and noveltechniques for reducing cost and increasingproductivity in order to remain competitive.

Several net pen architectures are currentlyin use or are under consideration for offshorefacilities, Figures l through 4 illustrate floating,modular net pens, two types of individual floatingnet pens, and a submersible net pen conceptadvanced by the Ocean Engineering Departmentat the University of New Hampshire. Each ofthese architectures provides relative advantagesand disadvantages. Each meets the projectedrequirements with varying degrees of success,

Notional Technical RequiretneatsIn order to visualize the potential

advantages to integration of aquaculture net penswith OSPREY technology, it is useful to revie wspecific notional engineering technical requirementsfor offshore aquaculture. It is expected that these

Struetumlit! SupportedTensioned Cttge ME@i>!!!t! ttutl!!s

[e!lc4N!tt teu!!!! L @lit!ke3

res! e

Figure 2. Individual rigid floating net pen.

Figure 3. Individual flexible floating net pen.

The structure must retain integrity duringperiods of severe weather. As describedearlier, these periods would be primarily duringthe fall and winter seasons However, briefperiods of severe weather may occur duringspring and sutnmer seasons as well.The facility tnust provide a stable platform forpersonnel to perform operation andmaintenance tasks during periods ofoccupation. Walkways and enclosures are

facilities must meet the following operational andtechnical requirements:~ The facility must have the capability for

independent operation without humanintervention for extended periods. Theseperiods would be primarily due to weatherconditions. This operational need is distinctfrom today's practice of daily humanintervention which is, in most cases, continuousduring daylight hours,

Sraginton-Sntith and Messier 24l

242 t JAR Technical Repnri lSo. 26

? TA OkmA??t??

Figure 4. Pull-up pen PUP!, submersible net pen,

needed. Personnel safety must be ensured.Also, stability of the platform may be an issuefor certain species of finfish envisioned foroffshore culture.

Provision for alongside operations by servicevessels is required. This consists of featuresfor tie-up, fending, loading and unloading ofcargo and personnel, and conduct of nethandling operations. Successful performanceof these evolutions in open water will requirecareful engineering design and careful planningat time of execution.

The facility must include sheltered storagespace for feed, tools, spare parts, lines, nets,and other miscellaneous equipment.The facility should provide habitability spacefor short overnight visits by personnel duringperiods of settled weather and high activity

aboard.

~ The facility must provide sheltered spaces withsuitable environment for electrical and

electronic equipment, Such equipment mayinclude sensors and monitoring equipment forintrusion detection and alarming, netcontainlnent brcach, structural failure, weather

COnditiOnS, autOlnated feeding Cquipment,navigational aids, telemetry electronics,actuators for surfacing and submerging ofsubmersible net pens, materials handlingequipment such as cranes and hoists, electricitygeneration, and others.

~ The facility must provide security monitoringand alarming, Security includes humanintrusion, predation, structural integrity, and netcontainment integrity.The facility must provide an on-board electricalpower source for sensors, monitoringequipment, processors, navigational aids,telemetry electronics, materials handling,autornatcd feeding, and actuators.

Through consideration of the operation andmaintenance of a future offshore aquaculturefacility, it becomes clear that the design of such afacility must be very carefully considered, withparticipation by experienced operators along withmechanical, electrical, ocean engineers, and marinebiologists. A successful design will require aninterdisciplinary approach by a dedicated designteam.

In considering a relatively maturetechnology for electrical power generation usingwave energy, known commercially as Ocean SwellPowered Renewable EnergY OSPREY !, itbecame clear to the authors that an opportunityfor strong synergy between renewable powergeneration and aquaculture off the New Englandcoast exists. Design of an aquaculture facility forintegration with an OSPREY~ array offers thepotential to satisfy tnany if not all of the engineeringtechnical requirements for aquaculture describedabove. In addition, business arrangements may befeasible between the aquaculture operator and thepower generation commercial entity such as lease!which greatly reduce the cost of operation andmaintenance of the aquaculture facility, In the nextsection, we provide a brief overview of theOSPREY" system and notional concepts for

Figure 5. Dimensional 3-D drawing of OSPREY.

integration of nct pcn designs. Thc rcadcr isencouraged to consider the potcntia] advantagesfor structural integrity, protection from wave action,housing, storage, and electrical power which mayaccrue from such intcgratcd design,

OSPREY" system description and conceptsfor integration with aquaculture net pendesigns

The concept of utilizing ocean wave actionas an oscillating water column for energygcncration is an accepted technology and is utilizedin numerous applications around the globe. Mostof these installations are based upon coastalgeology and therefore offer poor replicabi lity on agcncral scale. The ability to fabricate such a deviceinto a deployable configuration would have far-reaching impact on renewable ocean energyutilization and sustainable-yield aquaculturedevelopment. This proven technology was realizedthrough the development of OSPREY by AppliedResearch &Technology of Inverness, Scotland. TheOSPREY unit is fabricated of a closed rear

bulkhead catamaran design. Each unit wouldconsist of 800 tons of steel or concrete and is

Bragiuton-Smith and Messier 243

estimated to cost $5 million US to build, includingan NEG Micon I-Mw wind generator. Figures 5through 7 depict OSPREY units in various settings.

Each unit will bc constructed in a local

shipyard and launched, towed or thrustcd to thcdeployment site where it is scuttled and ballastedto thc bottom, then interconnected to the grid viasubmarine cable. Each unit will be designed forlocal wave resource optimization. When deployed,each unit will displace in excess of 8000 tons, Thisformidable structure, when deployed in arrays offive to ien units, will be able to enhance the wave

capture resource and the aquaculture resourceyield can be increased substantial ly,

LIMPET Locally Installed Marine-PoweredEnergy Transformer! coastal harbordeployment unit

Where practicable, structures could bedeployed along coastal harbors, improving harbordefense against ocean wave action whilegenerating clean renewable energy. We haveidentified our oceans as an important new frontier;we will need a platform to develop our coastalmarine technologies a.nd OSPREY is ideal, An

244 UJNR Technical Report Nn. 26

Figure 6. Rocky coastal harbor unit,

Figure 7. Ocean energy unit in storm conditions.

array of ten OSPREY could provide offshoreresearch opportunities for a better understandingof our coastal ocean resources, The structurecould provide sheltered facilities for the support ofocean ranching as suggested in the open oceancage culture section of this paper. The structurewould petfortn well as a structure for tneteorologicalarrays, remotely operated vehicle ROV!deploytnent, aquacul ture, and cage culture as wellas offshore laboratory deployment.

Eaelt site will determine structure designThe variability of the ocean wave resource

makes the specific design of the wave capturechainber and ancillary design criteria such as thoseoutlined previously very site-specific. It is thereforenecessary to understand the resource from aregional coastal perspective with energetic resourcesites given a priority development focus. Coastalresources, demand characteristics, anddetnographics will detertnine the final econonucpotential of each deployment opportunity,

The authors believe that the overall

economic resource represented in the developtnentof regional OSPREY centers will be substantial,The aquaculture conununiry is in general agreementthat offshore cage culture will become an importantcomponent of the future for sustainable-yieldaquaculture developmenL The OSPREY unitpresents the opportunity for a myriad of inarinetechnology applications as well. A detailed oceanenergy resource assessment should be conducted.This study wilt determine the wave resourcepotential and unit design criteria for a pre-designatedarea, ideally, from Florida, USA, throughNewfoundland, Canada.

Recommendations for future work

Future offshore aquaculture facihties tnustbe designed to meet challenging engineering andtechnical requiretnents. Potential for meeting theserequirements may be substantially improvedtough integration of these facilities into the designof OSPREY" offshore power generationstructures, The OSPREY~ technology isrelatively mature and commercially available.Potential exists for attractive commercialarrangements between the aquaculture operatorsand the power generation business entity which

inay increase the cost competitiveness of finfishculture. Furthermore, the integration of aquaculturestructures into the OSPREY" design cou!dprobably be accomplished wiih minimal impact tothe OSPREY mission,

The first step must bc to fully evaluate thepotential market detnand for commercial powergeneration with the OSPREY~' system off theNortheast coast of the United States. h must bc

shown that OSPREY"~ can generate power atsignificant levels at a competitive cost with fossilor nuclear sources. I should be noted that with

the on-going deregulation of the power generationindustry in the Northeast, several states areconsidering mandatory use of renewable energysources at a percentage of the total energy usage.It must be shown that OSPREY can competewith wind and hydropower sources.

A systems engineering study is requiredto integrate net pen concepts with the OSPREY"structute, Concepts for aquaculture inechanicaland electrical systems, aquaculture primarystructure for alternative atchitectures, and conceptsfor operation of both the OSPREY system andthe associated aquaculture facility must bedeveloped and evaluated. An important elementof this systems engineering effort must be costesti mates for acquisition, construction, and operationof the integrated facility.

A final element of this early work inust bethe examination of the range of commercialarrangements which may be possible between theaquaculture operators and energy generationoperator. The objective of this systeins engineeringeffort will be to establish the technical andcommercial feasibility of the integration ofaquaculture with OSPREY power generation forsites off the Northeast coast of the United States.

Tati ay an atti 247

WATER QUALITV GUIDELINES FDR AQUACULTURE:AN EXAMPLE IN JAPAN

Kazuf'urni Takay anagiNational Research Institute of Aquaculture

Nansei, Mie 516-0193, JAPANe-mail:kazufumi@nria.affrc.go.jp

ABSTRACT

The basis for setting up water quality criteria WQC! for the protection of aquatic living resources set by thejapan Fisheries Resource Conservation Association �FRCA! is that good water quality is needed to provide forthe healthy growth of fish and shellfish and to maintain their high economic values. Eleven parasneters areestablished to mainuun optimal conditions. The p~s are dissolved oxygen DO!, chemical oxygen demand COD!, pH, suspended particulate matter SPM!, total phosphorus TP!, total nitrogen Thl!, amount ofcoliform bacteria, Escheri chia cali, petroleuro hydrocarbons, temperature, toxic chemicals, and sediments.

INTRODUCTION

In the 1960s, water pollution was anepidemic in Japan and many fears concerningcontamination of fish and shellfish were

widespread. In response to those public concerns,in 1965, the Japan Fisheri es Resource ConservationAssociation JFRCA! had established WaterQuality Criteria WQC! for the Protection ofAquatic Living Resources. The WQC have beenrevised several times, and a inajor revision wasmade in 1995 JFRCA 1995! reflecting the renewalof the Environmental Quality Standards for WaterPollution EQSWP! set by the EnvironmentAgency of Japan EAJ! These WQC in the tnarincenvironment are presented and the strategy fordetermining WQC values is discussed in this report.

Basis f' or Water Quality CriteriaThe ideal situation in a good marine

environment for fish and shellfish often is one

without any anthropogenic perturbation. But, thatis almost impossible and it is not practical to setWQC based on no huinan impact. Therefore, weneed to seek a way to reconcile human activitieswith preservation of a good marme environment.Under these circumstances, good water quality isthe water condition which produces normal andsafe-to-eat fish. Harvested fish also need to be

economically high in value so that fishermen canearn enough money for a living, These basic ideasshould also be applicable to aquaculture. Humanimpacts are actually larger in aqusL~lture as it isnormally operated in semi-enclosed waters wherewater quality tends to get worse even withoutanthropogenic perturbation.

Items Related to Living EnvironmentEleven items are listed in Table 1. These

were made by reviewing existing data and alsoconsidering the environmental quality legislation Environmental Quality Standards and its relatedlegislation! issued by EAJ. Each item is discussedbelow.

Dissolved oxygen DO!Normal environmental water contains

oxygen close to its saturation depending ontemperature and sa!inity. But the concentrationmay fluctuate significantly in a short period of timeand it is difficult to maintain at a steady level. Onlya few studies have been reported for DOrequireinents for saltwater fish. An excellentreview by Davis �975! indicates that an oxygensaturation level less than 60% may inducephysiological changes in sonM: marine species suchas pile perch, dogfish, and dragonet. Saunders�963! even reported that any reduction in ambient

SPM

0.05

pH

ti3NR Teebtticul Report No. 26

~i t. Water Quality Criteria for tire protection of aquaticI;�;ttg resources; itetns related io living environtrtent by9FRCA!.

oxygen level produces a risc in ventilatory waterflow in Atlantic cod.

For common Japanese cornrnercial fishsuch as jack mackerel, sandfish, yellowtail, blackseabream, red seabream, stingfish and puffer, theincipient lethal level of DO ranges from 0.2 to 1,5rnI/L JFRCA l989! Chiba �983! reported, basedon his laboratory studies, that the 60% oxygensaturation level is necessary for the healthy gruwthof silver bteam. Field surveys of benthic organismsin the Seto Inland Sea by Imabayastu �983! showthat a decrease in DO causes a decrease in thespecies diversity. Moreover, the number of benthic%'mtsms exponentially decreases with decreasing

and below the DO concentration 2 mI/L theirsurvival becomes very low. Similar studies inOmumura Bay by Mori et al. �973! indicate that

benthic organisms such as goby, shrimp, and crabcan apparently swim away from Iow oxygen waters � rnI/L!. By considering all these facts, JFRCAjudged the critical concentration level to induce aphysiological change in saltwater fish to be 3,0 tnl/L = 4,3 mg/L!. Considered as a safe factor,JFRCA recommends 6 mg/L as WQC.

Chemical oxygen dentand COD!Thc COD is an amount of oxygen

molecules equi valent to organic rnatter consumedby oxidizing chemical reagents. There are severalmethods for the determination of COD, JapaneseIndustrial Standards JIS! has listed three methods Japanese Industrial Standatd 1993!. Among them,the dichroinate reflex method is inost widely usedfor COD CODst,!. But, this inethod is iriterferedby chloride ion and suffers reproducibility. Sincethe chloride ion is the major component of seawater,this method is not suited for seawater analysis. Therecommended procedure is alkaline oxidation usingpotassium permanganate CODoH!.

'&e COD is considered an indicator ofeutrophication. A high load of nutrients and organicrnatter froin land disrupts the materiaI cyclings incoastal environinents and pruduces nutrient-richconditions and eutrophication Fig. 1!. The targetvalue of CODott is not an anthropogenicperturbation level. ln the marine environment,reported values of COD during a pre-highlyinduslrialized period in Japan between 1931 and1940 are less than I mg/L. However, some coastalspecies such as mullet, sea bass, and sardine areknown to be caught in higher COD waters Satomi1985!. Therefore, JFRCA recommends I mg/Las WQC for open waters and 2 mg/L for coastalwaters.

An event of acid rain leads the public toan increasing awareness of a pH change in aquaticenvironments, especially in the freshwater system.A suitable pH range for organisms is 6 5 - 8.5. ApH change may induce a physiological disturbance.It may also promote a higher toxic effect ofchemicals dissolved in water to aquatic organisms.However, in the marine environtnent, the effectof acid rain is minimal due to the buffering capacityof seawater. JFRCA recommends natural levels

Takay an a gi 249

Figure 1. Material cycling in coastal environments modified after JFRCA!.

of pH, 7.8-8,4 for seawater, as WQC.

Suspended particulate matter SPM!In general, aquatic organistns, especially

bottom-dwelling fish, can adapt to highconcentrations of chemically non-reactive SPM.However, pelagic fish may show an escapemovement from muddy waters. Furthermore, 5mg/L of SPM can be fatal to juvenile stripedknifejaw Oplegnathus fasciarus!, Naturalpopulation of phytoplankton can also be consideredas SPM since SPM is defined as any substancestrapped on a filter. Therefore, JFRCArecommends the man-induced SPM such as fromsewage and industrial effluents! of 2 mg/L forseawater as WQC.

Total phosphorus TP! and total nitrogen TN!These are also used as indicators for

eutrophication, However, it is difficult to determine

the baseline concentration and to set a WQC,especially in coastal waters. Coastal waters arealways influence by land runoff and offshorecurrents. Nutrients are continuously supplied bylands and diluted with open-ocean seawater.Furthermore, natural causes such as upwelling canbring nutrient-rich waters to the surface.

The TP and TN are closely related to CODin seawater, and they are a sum of inorganic andorganic forms of phosphorus and nitrogen,respectively. Living organisms such asphytoplankton are included in these fractions. Bydefinition, these living organisins are also part ofCOD. Therefore, TN, TP, and COD are necessaryfor good environtnental conditions for fisheries.There needs to be adequate levels of TP and TNto support good fisheries. After all, phosphorusand nitrogen are the nutrients for primary producers Fig, 2!.

Since the input of these nutrients and CODs

from lands is tightly regulated by the water pollutioncontrol legislation, TN, TP, and COD in seawaterarc mainly thc results of organic production byprimary producers, especially in nonpolluted areas.However, in a semi-enclosed water body wherewater circulation is restricted, TP and TN may bcaccumulated in the water column and they maytrigger undesirable plankton bloom rcd tide!. Aneventual collapse of the bloom can lead to theconsumption of DO and higher COD values.Therefore, wc need to seek desirable TP and TNlevels to sustain primary producers, but not toomuch to produce high COD values such as a

Figure 2, Nutrient levels and fisheries.

25ti t;JNR Teehnicttl Report No. 26

production of rcd tide!.Satomi and Takayanagi �987! reviewed

the existing data of TN, TP, and COD in unpollutedcoastal waters in Japan and recommended that0.022 mg/L for TP and 0.32 mg/L for TN to meetthe EQSWP COD value. Satomi �983! alsoreported that higher populations of manycommercially available marine spccics are toundin the water having TP 0,03 mg/L arid TN 0,3mg/L. On thc other hand, high populations ofcoastal fish such as mullet, sca bass, and sardine

arc found in thc water having TP > 0.1 mg/L andTN ! 1.0 mg/L Satomi 1985!.

'rakayanagi 251

Figure 3. Cycling of toxic substances in coastal environments modified after JFRCA!.

By considering these reviews, JFRCAdivides water bodies into three categories, andrecommends TP values of 0.03, 0.05, and 0.09 rng/L and TN values of 0.3, 0.6, and 1.0 mg/L foropen waters, coastal waters and nearshore waters,respecti vely.

Coliform bacteria, Escherichia coliThe main concern is for oyster aquaculture.

The WQC needs to be detertnined based on thesafe cating of uncooked oysters, The value of 70/100 ml is set by the food hygiene legislation foroyster aquaculture. Therefore, JFRCA adaptedthis value for oyster aquaculture, and recommendsl 000/100 ml.

n-Hexane extracts

Remnants of oil spills and tar balls areincluded as n-Hexane extracts. Toxic effects of

n-Hexane extracts may not be clear, but fish canaccumulate odor-producing substances Motohiro1973!. Bad smell certainly reduces the economicvalue. Recommended concentration is less than

0.001 mg/L, which is currently the detection limit.

Sediment parametersBiogeochemical processes occurring in the

sediments can affect the water quality. Sedimentmay act as a secondary source of contaminationand may worsen all thc water quality parametersdescribed above. Therefore, WQC is also

considered for sediments. Sulfide, COD, and n-

252 UJNR Technical Report No. 26

'Ishle 2. Water quality criteria for metais in seawater by JFRCA and EAJ.

I Japtm Fisheries Resources Conservation Association~~ Environment Agency of Jape

Table 3. Water Quality Criteria for synthetic organic substances in seawater by JFRCA and EAJ.

~Japan Fisheries Resources Conservation Association*~Ettvironrnent Agency of Japan

Chiba,

Davis,

Japan

Japan

<JNa yqchaicai Report No. 26

Hexane extracts have been chosen as iheBy reviewing the existing data.,

JFRCA recommends 0.2 mg/g, 20 mug, and 0. 1 %for sulfide, COD, and n-Hexane extracts as WQC,respectively.

Toxic chemicislsCycling of toxic chemicals entering the

marine environment is shown in Figure 3. Sincethere arc two passages of these chemicals tomarine organisms, through water and through food,toxic effects by both waterborne and foodcontaminants need to be considered, The WQCfor heavy metals and selected organic chemicalsare listed in Tables 2 and 3, respectively. TheseWQC values «re based on the no-effectconcentration level. By comparing the reportedtoxiciry values &om chronic toxicity test, early-lifestage toxicity test, and acute ioxicity lest, the lowestvalue was taken as WQC. Environmental QualityStandards for Water Pollution for health items are

also listed in Tables 2 and 3 for comparison.

ACKNOWLEDGMENTS

Thanks are due to Mr, H, Tamori of

JFRCA for his encouragement and constructivecomments on the manuscript. Thanks are also dueto Dr. H Yamada for reading the manuscript andto Ms. M. Kurihara for drawing the figures.

I-ITKRATURE CITED

K. 1983. The effect of dissolved oxygenonthegrowthof young silver bream, Bull.Jpn. Soc. Sci. Fish. 49: 601-610.J. D. 1975, Minimal dissolved oxygenrequirements of aquatic life with emphasison Canadian species; a review. J. Fish.Res. Board Can. 32: 2295-2332.Fisheries Resource ConservationAssociation. 1989. Finalreportof 5-yearcarrying capacity project, Japan FisheriesResource Conservation Association,Tokyo. 1003 p, [in Japanese!Fisheries Resource ConservationAssociation, 1995, Water qualityguidelines for livmg resources in aquatic

ents. Japan Fisheries Resource

Conservation Association, Tokyo, 68 p.[in Japanese]

Japanese Industrial Standard, 1993. Testingmethods for industrial wastewater. JIS K0102-1993, Japanese StandardsAssociation, Tokyo, 327 p. [in Japanese]

Imabayashi, H. 1983, Effects of oxygen deficientwater on the benthic corninunities. Bull,Jpn. Soc. Sci, Fish. 49: 7-15 [in Japanese].

Mori, I., T. Tokunaga, M. Kuwaoka, and T. Fujiki.l973. Distribution of bottoin fishes in

relation to oxygen contents in the bottomwater of Omura Bay. Bull. Jpn. Soc. Sci.Fish. 39 �!; 753-758 [in Japanese!.

Motohirri, T. 1973. Water pollution by oil and somebiological considerations. Japan FisheriesResource Conservation Association,Tokyo. 82 p. [in Japanese]

Satomi, Y. 1985, Some problems on total nitrogenand phosphorus criteria. J. WaterWastewater Res. 27: 131-139 [inJapanese].

Satorni, Y. and k. Takayanagi, 1987. Water qualitycriteria for fisheries in Japan: totalphosphorus and total nitrogen. WaterQual. Bull. 12�!: 163-165.

Saunders, R. I. 1963. Respiration in the Atlanticcod. J. Fish. Res. Board Can. 20: 373-

386.

Baldwin nad Kraus 2S5

MARINE MAMMAL � GEAR INTERACTIONS: PROBLEMS,ACOUSTIC MITIGATION STRATEGIES, OPEN OCEAN

AQUACULTURE

Kenneth C. Baldwin

University of New HampshireCeriter for Ocean Engineering

Durham, NH 03824e-mail: kcb@christa,unh. edu

and

Scott D. Kraus

New England AquariumEdgerton Research Laboratory

Boston, MA 02110e-mail: sdkraus Cw neaq.org

ABSTRACT

Interactions between maritte mammals and fishing gear have changed as fishing technology and activity haveevolved. The interactions are wide rangi ng, and have included large seines for tuna with dolphins in the eastern uopicalPacific, cod traps and humpbacks in Ne wfouudland, harbor porpoise and gil inets all around the northern hemisphere,and seals and saltuon aquaculture pens. Many of the mid gation strategies have been active acoustic devices targetedat a single marine mammal species. Moving aquaculture offshore tu the open ocean piesenrs a situation where avariety of interactions could occur due to the many tnarine mammal species present. Resolving the interactions willrequite new approaches to the ruultiple species situation. Further. because offshore aquaculture may be moving intosignificant iuarine rnarnrnal areas, special precautions must be taken to ensure that any amflict mitigation does not leadto excluding a species from habitat critical for its survival.

INTRODUCTION

To meet the dcrnand for future grow-out space for finfish, aquaculture activities willhave to move offshore, especially in NewEngland. As offshore aquaculture activitybegins, there is a need to consider all the potentialsituations that can develop with regard to marinemammals, and to address them from thebeginning. This new level of aquaculture activitywill require placing large, fixed net-penstructures at offshore sites, It is essential that

these structures be designed to resist theweather and seas, to accornrnodate the fishadequately, and to avoid negative interactionswith marine mammals. This ncw initiative in

aquaculture should not be the victim of

shortsighted design that results in conflicts withmarine mammals, and hence a difficult start.

HISTORICAL OVERVIEWAs the demand for fish increased, the

fishing industry expanded to meet this demand,This required more gear in the water,Technology evolved to optimize the ability of asingle boat to haul more nets. For example, nettwine which was traditionally a hemp or cotton-based material became monofilament nylon.This enhanced the fishing operation, but createdproblems for marine mammals. Nylonmonofilament is virtually acoustically transparent Vicedomine 1991!, and its use led to marinematnmal entang le ments, damaging fishing gearand killing marine mammals,

256 UJNR Tcchnical Report 5a. 26

ln Newfoundland, Canada, this scenarioexisted in the inshore cod fish traps, Collisionswith humpbacks always occurred according tothe older fishermen. The collisions resulted in

gear damage to the cotton and hemp lines. Withthe advent of stronger lines, tnore collisionshappened with more whale entanglements. Overthe period from 1979-1990, Lien �994! reportedthat 30% of the marine mammals entangled infishing gear in Newfoundland were dead. Theresponse to this situation was to begin a programfocused on developing an acoustic alarm to warnmarine mammals about the presence of thefishing gear. A 4-kHz acoustic alarm resultedand was effective in reducing the marinemammal-fishing gear conflict.

A similar scenario exists with the gillnetfishery in the northern hemisphere with theentanglernent of harbor porpoise, The old twinenets had tninirnal problems with entanglements,but the nets when soaked were difficult to hauldue to the weight. The movement to syntheticmonofilament nets improved the haulingefficiency, but rendered the nets virtuallyacoustically transparent. En tanglements ofharbor porpoise became relativelycommonplace. The mitigation strategy was touse an acoustic pinger to warn the harborporpoise about the existence of the gilinets. Thisacoustic pinger has a fundamental frequency of10 kHz wi th harmonics up to the 100-kHz rangewith a source level of approximately 135 dB re1 liPa. The initial testing of this pinger, inexperiments with a valid statistical design,indicates that it is very effective at deterringharbor porpoises from gillnets Kraus et al.,1997!.

Presently, the primary conflict betweenmarine mammals and aquaculture gear is withthe salmon net pens. Seals are predators tothe fish in the net pens and the industry hasdeveloped the practice of using acousticharassment devices AHD! to scare the sealsaway from the pens. A commonly used AHDbroadcasts a IO-kHz signal at 210 dB re 1 @Pawith a 10% duty cycle every 4 sec This is aneffective deterrent for the seals, but the soundpropagates a long distance, and there is some

evidence that harbor porpoise in BritishColumbia, Canada, have been displaced dueto the sound Olesiuk et al. 1995!.

In the examples stated above, therewere a variety of interactions with marinemammals and fishing gear. The mitigationstrategies have all been acoustic, and have beena reactive fix to the problcin. The mittgationstrategy for one species interaction canpotentially lead to displacement or habitatexclusion of another species, To effectivelyaddress the potential for marine marnrnalinteractions and acoustic deterrcnts in openocean aquaculture, it is necessary to formulatea basic model of the acoustic propagation andhow marine tnamrnals fit into this environmentand interact acoustically. This acousticinteraction scenario will provide a basis forunderstanding mitigation strategies.

ACOUSTIC PROPAGATION MODELThe objective to developing a

propagation model is to have an understandingof how a sound that is generated at a sourcetravels a path and is received. Models can besimple and qualitative in which case they identifythe salient features such as source, path,receiver. Or they can be a very quantitativesonar model with all the complexities onedesires, The goal here is to present a simplemodel that explains qualitati vel y the propagationenvironment for marine mammals and fishinggear.

The basic propagation model has asource, path, and a receiver. This genericscenario is depicted in Figure 1, The source inthe aquaculture case could be the sound froin adeterrent device or sounds associated with theaquaculture activity. The former is meant tokeep marine manunals away, but the latter couldbe a curiosity enhancer.

The path is the ocean between the sourceand receiver. This path is most likely short whenconsidering the size of the oceans, but still itcan be cotnplicated due to local propaga«oneffects. Topography, temperature profiles, andambient noise are three factors that can readilyeffect the path. Figure 2 is a plot of the variouscotnponents of ambient noise, The spectral

Baldwin and Krnns 257

RECEIVER:

DETECTION,HEARING

SOURCE:

GENERATES

SOUND

PATH:

PROPAGATION

EFFECTS

Figure 1. Source � Pa h � Receiver Inodcl for defining basic acoustic parameters.

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content is presented as sound pressure level orsound pressure spectrum level. The latterpresentation is more readily accepted in practiceas the units !tP! 2/Hz infer frequencydependence. The basic trends show that thereis a higher level of ambient noise at lowerfrequencies with a steady decrease in level asfrequency increases. Shipping and industrialactivity typically have a frequency range from10 Hz to 10 kHz. Biological sounds cover awider range of the spectrum.

This basic model can provide insight intohow a sound is propagated and its sound pressurelevel, how loud it is, at range from the source.There are two basic concepts ta understand here:there is a zone of audibility and a zone ofinfluence Richardson et al. 19S9!.

The zone of audibility is determined bythe ambient noise level, As sound propagatesout from a source, its level is diminished due to

spreading losses geotnetric! and attenuation true energy loss!. These two loss mechanisms

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258 UJNR Technical Report No. 26

ZONE OF AUD IBILI'I'Y are defined as transmission loss in sonar

modeling. On a plot of sound pressure level vs,range, and a constant ambient noise level vs.range, the intersection of these two lines definesthc zone of potential audibility. When thereceived sound pressure level is greater thanthe constant ambient noise level, then the sound

can be heard. This occurs at shorter ranges,At longer ranges, the ambient noise is greaterthan the received sound pressure level; the soundis effectively inaudible. This concept is shownin Figure 3A.

The zone of influence is a modification

to thc above as it incorporates a responsethreshold. The response threshold is a soundpressure level above the atnbient noise that isrequired for a marine rnamrnal to determine thata specific sound is present. The effect of thisresponse threshold is to reduce the range atwhich thc two plots intersect. Hence, the zoneof potential influence is a shorter range fromthe source than the zone of potential audibility.This is shown in Figure 3B.

This basic model is useful in defining the

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Figure 3. Graphical definition~ of Zone of Audibility A!2nd Zone of Influence B! Richardson et al. l 989!

100

00

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Figure 4. Underwater audiograms of several odontocetes; A! white whale White et al. 1978; Awbry et al, 1988!; killer whale Halland Johnson 1972!; harbor porpoise anderson 1970a!; B! bottlenose dolphin Johnson 1968a; Ljunblad et al, 1982c!; Amozonriver dolphin or boutu Jacobs and Hall 1972!; false killer whale Thomas et al. 1978!, Richardson et al, 1989!

Baldwin and Kraus 259

4

04 4

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Figure 5. Underwater audiograms of several odontocetes: A! white whale White et al. 1978; Awbrey et al. 1988!; killer whale Halland Johnson 1972!; harbor porpoise Andersen 1970a!; {B! bottlenose dolphin Johnson 1968a; Ljungblad et al. 1982c!; Amazonriver dolphin or boutu {Jacobs and Hall 1972!; false killer whale {Thomas et al. 1978!. Richardon et al. 1989!

100

100

0010 10 10 10 10

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Figure 6. Underwater audiograms of several pinnipeds: California sea lion Schusterman et al. 1972!,' average of two fur seals Moore and Schusterman 1987!; harbor seal {Mnttht 19681!; average of two ringed seals Terhune and Ronald 1975a!; harp seal Tehrune and Ronald 1972!. Richardson et al. 1989!

above concepts. The limitation is thc usc of asingle number, constant level, for thc ambientnoise and the response threshold, As shownearlier, ambient noise has definite spectral

100

100

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characteristics. Upon close examination ofmarine mammal acoustics, it is apparent thatthey too have spectral characteristics to theiracoustic behavior,

260 UJNR Technics! Report No. 26

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Table 1. Characteristics of underwater sounds produced by Alaskan odontocetes whales, Richardson et aL, 1989!

MARINE MAMMAL ACOUSTICS

Marine mamtnals are the receiver in the

previous model. They have spectralcharacteristics associated with their receivingmechanisms, and also they have spectral contentassociated with various vocalization used for

cotnmunication, navigating, and foraging. Theeffect of ambient noise and noise generated fromaquaculture activities can potentially affect theintent of thc marine mammal vocalizations.

Audiograms are the method of definingthe spectral characteristics of hearing. Mostaudiograms have a band of frequencies overwhich the hearing is most sensitive. This bandvarieS fOr different marine marnlnals, as well as

the threshold or hearing sensitivity. Theaudiograms in Figures 4, 5, and 6 show typicalresults for a variety of marine marnrnals, bothodontocetes and pinnipeds. There is a differencein the basic structure of these audiogratns. The

odontocctes are typically more sensttive between10 and 108 kHz, while pinnipeds are moresensitive between 5 and 40 kHz. Also, the actualthreshold for the odontocetes is in the 40-60 db

area while thc threshold for thc pinnipeds is inthe 60-80 db area,

The other aspect of marine mammalacoustics is their vocalizations. This activity hasboth spectral and source level characteristics.From Table 1, it is scen that a variety of type ofsounds are produced. These sounds havedifferent dominant frequencies, bandwidths, andsource levels. The functions of the sounds are

short and long distance communication,echolocation, and reproductive displays.

Introducing other sounds into the watercolumn, on a continual basis, that can interfere

with these behaviors can have adverse effects

on the species. These "introduced sounds" canimpact the ability of an animal to hear the

behavioral sounds, thus potentially driving aspecies from a site. This is obviously the goalof acoustic deterrent devices. The key toeffective design of these devices is to target asingle species that is problematic to theaquaculture operation and minimize the effecton other species.

DISCUSSION AND SVMMARY

Historically, most fishing interactionshave been single species and a reactive fix hasbeen found. The key to an effective acousticfix is to assume that the initialization of oncspecies interaction is not exclusive for another.Alternatively, what deters one species couldeasily be the dinner-beB for another, A deterrentfor one species could effectively impact thevocalization responses for another. Long tennstudies on inarine mammal exclusion due todeterrent sounds have not been done yet. Whenconsidering an acoustic deterrent for aquaculturesites, specific local information about the ambientnoise, propagation path and marine marnrnalsneeds to be assimilated for an objective, focusedapproach for solving the problem.

To facilitate objective approaches tomarine mammal-aquaculture acousticinteractions, the following points needconsideration. The database for auditoryresponse of marine rnaintnals needs to beenhanced. Threshold levels where soundsproduce detriinental effects need to be clearlydefined, Developing a better understandingbetween species vocalizations, environmentalnoise, and deterrent sounds is critical toeffective use of sound as a warning/deterrent.These efforts will lead to a rational context fordesigning species specific acoustic alarms foruse in offshore aquaculture,

LITERATURE CITED

Kraus, S., A.D. ReaL, A. Solow, K. Baldwin,T. Spradlin, E. Anderson, and J.Williamson. 1997, Acoustic alarins

reduce porpoise mortality. Nature 388:525.

Lien, J, 1994, Entraprnents of large cetaceansin passive inshore fishing gear inNewfoundland and Labrador l979-1990!. Report of the InternationalWhaling Commission, Special Issue 15.

Olesiuk, P. F., L. M. Nichol, P, J. Sowden, andJ. K. B. Ford. 1995. Effects of sounds

generated by «n acoustic deterrent on theabundance of harbor porpoise Phocoenaphocoeira! in Retreat Passage, BritishColumbia. Department of Fisheries andOceans, paci fic Biological S t ati on,Nanaimo, B, C,

Richardson, W. John, J. P. Hickie, R. A. Davis,D. H. Thomson, and C. R. Greene, 1989.Effects of offshore petroleum operationson cold water inarine rnaminals; a

literature review. API Publ. No. 4485,American Petroleum Institute,

Was hingt.on DC.Vicedomine, J, 1991. Investigation of the

acoustic interaction between harbor

porpoise Phocoena phocnena! and Gulfof Maine cotnmercial gillnet fishing. MSthesis, Ocean Engineering Program,University of New Hampshire, Durham,NH.

Golds tetn 263

NORTH AMERICAN LOBSTER CULTURE HOMARUS AMERIC41VUS!,HATCHERY METHODS, AND TECHNIQUES:

A TOOL FOR MARINE STOCK ENHANCEMENT?

Jason S. Goldstein

New England AquariumEdgerton Research Laboratory

l Centra! Wharf, Boston, MA 02] 10e-mail:jsg olden eaq.org

ABSTRACT

The North American lobster Homarms aasericonstr Milne-Edwards! is fishedintensively throughout tts l 1,000-bn range resulting in only a fraction of these animals survi ving long enough ta reproduce. Success in marine stockenhancetnent programs suggest that enhancement may be possible for lobsters as well. Personnel at the lobsterrearing facility of the New England Aquarium are studying the methodologies used in the culture af larval andjuvemle iobsters, as well as explore the tnajor considerations involved for inibating and carrying out a producuveand effective lobster stock enhancement program.

INTRODUCTION

The American lobster is found naturallyalong the east coast of North America, from NorthCarsylina to Labrador, being tnost abundant fromNova Scotia to New York Herrick 1895!. Themajor population centers, and therefore inshorefisheries, are located within the Gulf of Maine andin the New Brunswick and Nova Scotian coastal

waters, where over 90% of the inshore landingsarc made Cobb and Phillips 1980!. During thelast decade, areal expansion of the lobster fisheryand the continued intense inshore fishery havefocused attention on the relationship betweenanimals in inshore and offshore areas. If consistent

recruitment in coastal areas depends on cggproduction from offshore, heavy exploitation ofoffshore populations could impact aII fisheries. TheNew England Fishery Management Council NEFMC! currently considers the Americanlobster resource overexploited. There is currentlyno commercial culture for the North Atnerican

lobster; however, these animals have long beenreared in pilot scale projects, and have received aconsiderable amount of attention froin

aquaculturists. The reason for the attention is clear.lobster is a very popular seafood with a high market

value. Lobster stock enhancement is not a new

concept. Efforts to rear and culture lobsters haveexisted since the early 1880s Addison andBannister 1994!. Lobster hatcheries originated inFrance and Norway over 130 yr ago, hatching andraising the European lobster Horrtartas garrvnartas Herrick 1909!. The first successful attempt athatching H, amert'cartus larvae was in 1885 at thenewly established laboratory of the U.S. FishCamrriission in Woods Hole, Massachusetts Rathbun 1886!. The world's f irst lobster culturefacility was completed at St. Andrews, NewBruns-wick, Canada, in 1974, The work done atSt. Andrews closed the lobster cycle from egg tobroodstock, Because the private sector was notprepared for the direct transfer of this technology,potential governmental and academic researchprograms stalled, The popular perception of lobsteraquaculture is that it is analogous to farming, inwhich lobsters produce eggs that are hatched,reared, and then sent to market. The other potentialapplication however, is in marine stock or resourceenhancement, whereby young of year lobsters arecultured and released to enhance natural stocks,To be able to move forward in this area of researchhowever, it is imporumt to disseminate the detailsof culturing such animals for these types of studies,

264 UJNtt Techrdcai Report No, 26

MATERIALS AND METHODS

i pprre pprapp~ «J

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Figure 1. The kteisel or circulating rearing tank, Modified frotn Schuur et al� t976, With permission.!

and relate what others have done to contrtbutc to

lobster stock enhancement.

A year-round culturing facility for thcAmerican lobster is located in the Harold E.

Edgcrton Research Laboratory of the New EnglandAquarium. The culturing facility incorporates twoseparate systems: a cold seawater system 8-lOoC! for holding gravid female lobsters, and awarm seawater system � goC! for the productionand growout of larvae and juvenile lobsters,

Broodstock system:Female lobsters obtained through the

Marine Research Station Vineyard Haven,Massachusetts!, New England Aquarium staffdivers, or other similar sources are put through astrict quarantine process before they are integratedinto the primary lobster recirculating system, Whenobtained, wild-caught females are first given aphysical checkup in which they are visually

inspected for lesions, infections, abnormalities, oranything cise which looks or appears suspicious.ln most cases, this procedure is often done off-siteprior to bringing animals into the facility so as notto introduce diseased or abnormal animals.

Animals then undergo a series of dips, swabs, andbrushes. They are sprayed lightly with distilledwater and large portions of thc shell and joint areasare swabbed and/or brushed with a 10ok solution

of betadine. A smail sample of eggs are removedand inspected microscopically for any severe casesof fungal or bacterial growth and are also analyzedfor their current embryonic developmental stageby applying the Perkins eye index formula Perkins1972!. In some cases, new lobsters are weighed,measured, and tagged as well. These lobstersremain in quarantine for up to 3 wk at which pointthey can be integrated into the rest of the system.

I.arval system:The larval rearing system consists of eight

circular tanks or "kreisels" with cross-section

conical bases Figs. 1 and 2! each of 40-L capacity.

'ntdstein 265

Figure 2. Planktonic kreisel. These 40-L tanks are ideal forlarval culture. Cannibalism can be avoided by keeping thewater moving and intensively feeding.

Water is pumped into the base of the tanks througha manifold with a series of offset holes producinga cyclonic upwelling water circulation. This isnecessary to keep larvae dispersed and hencereduce losses by cannibalism. Kreisels are typicallystocked with 2000 larvae each. Larvae are fed

frozen brine shrimp Arterrti a salina, frozen mysids,and live amphipods. Larvae are typically held for4 wk at 18-2PC during which they molt three times.Survival to the post-larval stage is variable, with10%-15% typically surviving.

Juvenile system:Once larvae have molted to the post-larval

stage stage IV!, when they normally would beready to assume a benthic existence in the wild,they are removed from the larval system and placedin individual holding trays or "condo trays" Fig.3!. These shallow seawater trays, perforated withholes, allow them to be flushed of uneaten foodand wastes and also allow for identification and

cataloguing of lobsters. Water exchange in thecubicles is achieved by continuous circulation ofwater along the trays. These animals are thenweaned off of the brine shrimp diet and introducedto a gelatin-bound diet called "Supergel" Figs, 4and 5!,

Figure 3. Juvenile holding tank tray. Probably one of themost unique attributes to lobster lab culture is the use ofindividual rearing compartments. Elevated and seated inshallow recirculating seawater trays, to flush out organicsand keep water circulating, compartmentalizing animalsallows for careful identification and cataloging of lobsters,as well as a tool for easy sorting and grading,

Life Support: The Key to a SuccessfulHatchery

To efficiently culture and produce animalsfor potential resource enhancement, a sound andwell-designed system should be used.Recirculating aquaculture systems RAS! offercomplete control over environmental growingconditions such as temperature, salinity, and waterquality, while eliminating conventional concernsabout weather and clitnatic conditions. Additionally,stock management and inventory control are greatlysimplified. A properly designed RAS can be placedalmost anywhere and used to produce a widevariety of aquatic animals. The following threecomponents are excellent additions to any lobsterhatchery setup.

Chiller units:

Continuous seed larval! supply requiresmanipulation of either or both the spawning orhatching cycles Waddy and Aiken 1992!.Temperature is the dominant regulator for thecontinuance of year-round larval lobsters. To assistin this challenge, having one or more chiller units

266 UJNR Technical Report Vo. 26

Figure 4. Aside from temperature, nutrition is the mostimportant parameter governing the survival and growthof cultured lobsters. Adult brine shrimp is the staple foodused here as well as enriched brine shrimp nauplii.Juvenile lobsters receive a gelatin-bound diet of brineshriinp, krill, kelp, spirulina, soy lecithin, bone meal, andcrabrneai all pictured here.

allows incubation periods which result in staggeredhatch-out periods. This application of temperaturegreatly increases the chances to regulate andsustain a year-round population of larval lobsters.

Ultroviolet disinfection:

Ultraviolet radiation in the 200-300 nm

range is extremely effective in killing mostmicroorganisms.

Protein skimnrer foam fractionator!:Foam fractionation is a cost-effective and

efficient means of removing fine suspended solids �0 Jtm in size! and dissolved organic rnatter,Foam fractionation is accomplished by bubbling airthrough water to trap fine solids and organics whichthen generates a foam Weeks et al. 1991!.

DISCUS SION

A lobster does not achieve its benthic

existence until some point in the fourth stage ofdevelopment Botero and Atema, 1987, Govind andPearce 1989!. Releasing these animals during

Figure 5. This I -month-old, 9-min H aniericanus is readylor transfer into the seawater condo tray system.

fourth stage still exposes them to heavy predation.One manageinent practice used in Europe is torear juvenile lobsters for up to 1 yr or more beforestocking them in appropriate benthic substrateswhich offer the proper habitat release component.

One excellent case study on lobster stockenhancement involves a comprehensive 6-yr studyin Cardigan Bay in the Northwestern Wales district,UK Cook 1995!, The stock enhancementexperiment carried out at Aberystwyth hasdemonstrated that releases of hatchery-rearedjuveniles onto carefully selected substrate can resultin a good rate of recapture by the commercialfishery, with peak returns occurring between 4-6yr after release. Differences are apparent betweenthe inshore and offshore release sites. The

Aberystwyth experiment failed to establish theoptimum release size for juvenile lobsters.Carapace lengths as low as 14 mm produced verygood returns, but the recapture rate of small lobsters 9 mm carapace length! was extremely poor Cook1995!. This is an important aspect of lobsterrestocking because post-larval lobsters would bevery inexpensive to produce in large numbers bymass rearing. It still seems inevitable that to rearjuveniles through several molts with acceptably lowmortality, individual compartments will benecessary to avoid cannibalism. The consequent

GoMstein xs7

satcrease in space required, and particularly inhusbandry and heating costs, ineans that the uni production cost of lobsters rises steeply the longerchey are kept. Advantages to later release meansa. greatly increased survival; the disadvantage is atm much greater cost. Thc long period of intensivecultivation prior to release raises. the potential stockenhancement cost considerably Factor 1995!.Wny future lobster stock enhancement programshould consider the f'ollowing factors: �! moredetailed and extensive surveys of potential areas~f suitable substrate within thc particular test sitemr area, �! an assessment of the natural~ruitment patterns and population structure oflobsters within these areas with a view to assessingtheir suitability for enhancement, �! a inorc~gorous investigation of the optimumrelease sizef' or lobsters, �! development of improved hatcherytechniques in order to reduce the unit cost of thej xivenile lobsters, and �! a detailed appraisal of thec=conamics of lobster stock enhanceinent.

ACKNOWLEDGMENTS

I ain grateful to the New Englandaquarium and the Edgerton Research Laboratoryf or providing the support and expertise of so tnanytatiented staff members, in particular Marianneharrington and Albert Barker, Also my gratitutcao W. Cook of the University of Lancaster, UK.Iffy thanks also go to continuous and past fundingas.gene ies, the National Science Foundation. Grass& oundation, and the National Institutes of Health,

X ITKRATURE CITED

addison, J.T. and R.C.A. Bannister. 1994. Re-stocking and enhancement of clawed lobsterstocks: a review. Crustaceana 67�!: l31-155.

X3otero, L. and J. Atema. 1987. Behavior andsubstrate selection during larval settling inthe lobster, Homarus americanus. J. Crust.

Biol. 2: 59-69.

cobb, J.S. and B,F. Phillips, Editors, 1980. TheBiology and Management of Lobsters, Vol,L Acadenuc Press, New York. 463 p.

~k, W. 1995. A lobster stock enhancementexperiment in Canligan Bay, North Western

and North Wales-Sea Fisheries Commits

Report, Uruv. Lancaster, 32 p.Factor, J,R., Editor!. 1995, Biology of the Lobster

Hontarus americanas, Academic Press,New York. 528 p.

Govind, C.K. and J. Pearcc, 1989, Critical periodfor determining claw asymmetry indeveloping lobsters. J. Exp. Zook 249: 31-35.

Herrick, F.H. 1895, The American lobster; astudy of its habits and development. Bull.U.S. Fish Comin. 15: 1-252,

Herrick, F.H. 1909. Natural history of theAmerican lobster, Bull. U.S. Bur, Fish, 29:

148-408+20 plates.Perkins, H.C. 1972. Developmental rates at

various temperatures of embryos of thenorthern lobster Homarus americanusMilne-Edwards!. Fish. Bull. 70: 95-99.

Rathbun, R. 1886. Notes on lobster culture. BulLU.S. Fish Conun. 6; l7-32,

Schuur, A., W,S. Fisher, J,C. Van 01st, J.M.Carlberg, J.T. Hughes, R.A. Shleser, andR.F. Ford. 1976. Hatchery methods forthe prnduction of juvenile lobsters Homarusamericanus, Sea Grant Pubk No. 48, Univ.California, Inst. Mar, Resour., La Jolla

Waddy, S,L and D.E. Aiken. 1992. Environmentalintervention in the reproducti ve process ofthe American lobster, Homarus

aneri carms lnvertebr Reprod, Dev. 22:1-3, 245-252.

Weeks, N.C., M.B. Tiininons, and S Chen. 1991.Feasibility of using foam fractionation for thcremovaJ of dissolved and suspended solidsfor fish culture. Aquaculture �7!: 101-106.

Klkuebi 2si9

gLUE MPSSELS IN THE DIET OF JUVENILE JA.IsANESE FLOUNDER

Kotaio Kikuchi

Central Research Institute of Electric Power IndustryAbiko Research Laboratory

Abiko, Chiba 270-1194, Japane-maikkikuchi@criepi.denken, or.jp

ABSTRACT

Blue mussels hfyrilus golloprovincialis were used in the diet of juvenile Japanese flounder. The control dietmainly consisted af white fish meal, potato starch. and pollack liver oil. and part of the control diet wasexchanged with freeze-dried meat, fresh meat, or fresh whale blue mussel in experimental <bets. Fish of about 5g in initial body weight were fed each diet to satiation, twice daily, fs daystwk i' or 8 wk at 2 PC, The final bodyweight and weight gain of fish fed diets containing freeze-dried and fresh bhie mussel meat were higher than thosefed the control diet p <0.05!, These ~rs in the whole blue mussel diet were comparable to ihe connokAddition of freeze-dried and fresh blue mussel meat to the diet did not affect the feed efficiency, while the feedefficiency of fish fed the whole blue mussel diet was lower than that of fish in the other reatrnents. Proteinefficiency ratio was in the same range among all dietary groups tested. There wae small differences in bodycomposition, or hematological and hernatochemical parameters, of thc cultured fish.

INTRODUCTION examined to develop techniques for practical useof the blue mussel in the diet of fish.

MATERIALS AND METHODS

Blue mussel s are a nuisance organism forelectric power plants located along the coast ofJapan. Excessive inussel growth along waterintake pipes constricts and iinpedes the inflow ofcooling water. Generally, they are collected onceor twice a year and buried in the landfill of theplant after incineration of organic matter. Theremoval and disposal require considerable cost;moreover, landfill space rapidly fills.

Several studies on the utilization of

collected mussels have been conducted to work

out the disposal problems; however, no effectiveways but as a source of fertilizer have beendeveloped, We previously reported that. the freeze-dried meat of blue tnussels My fi Jttsgalloprtsviitcialr's, predominant in power plants ofJapan, can effectively replace fish meal as a mainingredient in the diet of juvenile Japanese flounderParalicJtfhys olivaceus, In addition, blue musselmeat appears to stimulate the feeding behavior ofthe flounder Kikuchi and Sakaguchi ]997!. Inthis study, freeze-dried blue mussel meat, freshtitussel meat, and fresh whole mussel werc used,and effects on the growth of juvenile flounder were

EXPERIMENTAL DIET

The formulation and composition of theexperimental diets are shown in Table 1, Thecontrol diet basically consisted of 8].7% white fishtneal, 10. 8% potato starch, 3.0% inineral mixture,and 4.5% vitamin mixture. The basic ingredientsof the control diet were replaced with fresh bluemussel meat at a rate of 17 and 33% weighttweight! in diets 2 and 3, respectively. Five percentof the basic ingredients in the control diet werereplaced by freeze-dried mussel meat in diet 4, and20 and 30% with fresh whole mussel in diets 5 and

6, respectively. Live blue mussel s obtained fioiu afish market were used, ln diets 2, 3, 5, and 6,fresh blue mussel meat and whole blue mussels

were tninced and gmund into a liquid mostlywater!, and used as an ingredient in the diet.Freeze-dried mussel meat was prepared asdescribed previously Kikuchi and Sakaguchi 1997!.Blue mussels in diets 2 through 6 replaced fish mealsuch that the ratio of white fish meal protein to

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279 UJAR Techaiesl Repart No. 26

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RESULTS

'2Fr, DF"pm'�'Diet Average body weight g! Weight gain Survivalinitial Final �!

28.2 '2 9 7%bc

513525'

144 3.2149' 3. 3

4.64.6

2 1 1 �

97

3o.8~

31. 3'

27. 44

28. 8

l47 3.2

148 3.3

137 3. !

133'

569

573

498

520

4.5

4.6

4.5

4.6

2.1 97

2.1

2 2

98

98

aVerage value Of tripliCate fOr each dietary gZ~.Feed efficiency %, weight gain/feed

protein efficiency ratio weight gain/dietary protein intake!.Daily feed consveption � batty weight.! .

s Values in the same colustn having satae superscript are not significantly different !»0. 05

't!sbte 2. Growth data of Japanese !ovnder fed sir erpenrnental diets for 8wtt» '

blue tnussel protein was 98.7:1.3, 97.5:2.5,97.5;25,99,3:0.7, and 98.5:1.5, respecti vely. All feedstu ffs,except the pollack liver oil, were ground, minced,and formed into spheres of about 2 and 4 mm indiatneter using a twin extruder with additions oftap water. The formulated diets were dried in anair dryer at 2PC, and an equal amount of pollackliver oil was added to each diet. Diets were dried

again and stored at -35 "C until used.As shown in Table 1, the crude lipid

contents of' all diets were similar to each other,however, the crude protein of diet 6 was lowerthan that of the others.

EXPERIMENTAL PROCEDUREIn 3uly 1996, juvenile flounder of about 1

g in body weight were transported frotn the ChibaPrefectural Fisheries Experimental Station to ourlaboratory in Chiba Prefecture. Fish were rearedin 2000-L tanks at 2 FC with a commercial dietused for Japanese flounder Higashimaru FoodsInc.!, until the start of the feeding experiment. Thefeeding experiments were conducted for 8 wkbeginning in August 1996 in two 2000-L tanksequipped with a closed recirculating seawatersystem. The tanks werc placed in a room undernatural light conditions and the water temperaturewas kept at 20 i 1'C. At the start of the feeding

experiment, the fish were tran sferred into floatingnet cages �5 x 35 x 25 cm - W x L x H! within heaquarium, 20 fish/cage, with three replications perdietary treatment. Fish were fed to satiation twicedaily for 6 days/wk with each experimental diet.The body weight of each fish was measured at thebeginning and at the end of the study after the fishwere starved for 36 h, At the end of experiment,analyses of proximate composition of the wholebody and of hematological and hematochemicalparameters were conducted by the methodsdescribed previously Kikuchi et al, 1994a. b!.

Differences in proximate composition ofthe whole body, and the hematological andheinatocheinical parameters among treatmentswere tested for significance using the Mann-Whitney test Campbell 1983! Data on final bodyweight, weight gain, feed efficiency, and proteinefficiency ratio were analyzed for significance byDuncan's multiple range test {Duncan 1955!.

The growth and feed performance dataare shown in Table 2. All fish soon accepted theexperimental diets and fed actively for the durationof the experiment. Survival rates were high in alldietary groups and most of the mortality was from

UJNR Technical Report No. 26

Rmayh~ Hanal~t lax! bleed cell proteintg/10Qnt ! <~> MO'/heal! tg/It!Qat !

27.1'.1

24.66.8

27.4' 4

23.Qt2.4'

25.ts4.d

3I.Qt2.8'

s.m.P

5.2tt!.P

5.7'.1

5.200.7

4.8�.4'

5.550.8

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3.m.5'

3.Is0. 1'

3.040.9

3.Qt0. I'

3. Iio. 5'

4.049.2

4.5tI. I'

3-5t0.1

3.5'!.l

3.5t0.8

7.6'.7' 11.583.5 136t7.7

7.720.6 11.5u!.6' 1342. ~

6.8t0.2 11.420.4 138t5.4

6.8t0.6 11.3t0.3' ~.8'

13.2'.5'

6. Bto.2 11.4' I 1$85.tf

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21.7i4.3'

22.Qt6.6'

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2e.2t6.9'

5!Qb?BS

6249235

34~7

73&fZPf

74~' Harm and ae axatttt ekiviaticna tbr five ~a Sac t2e 5xaxx:ee cf Table 2.

Thble 3. Hematological characteittucs ajid contents nf some ptasma cunuituents of Japanese flounder fed sixexperimen tat diets for 8 wk*'

DISCUSSIONfish that jumped out of the net cages. Final bodyweight and weight gain of fish fed diets 3 and 4were significantly higher than those in the control p <0.05!. These parameters in the otherexperimental groups were comparable to thecontrol. Feed efficiency was similar for diets 1 to4, and significantly higher than that of diets 5 and 6 p <0.05!. Some differences were observed inprotein efficiency ratio.' however, a significantlylower value vs, the control was obtained only indiet 5 p <0.05!, Final body weights aad weightgain of fish increased as blue mussel in the dietincreased diets 1 to 3!.

The hematological characteristics and theplasma constituents are shown in Table 3. Alldietary groups were identical in terms of red bloodcell counts. Although there were some fluctuationsin hemoglobin and hematocrit values, noexperitnental dietary groups werc significaritlydifferent fry!m those of the control. Plasma proteinin diets 3 and 4, and triglyceride in dict 4 wercsignificantly lower than those in the control;however, there were not any differences in theother parameters.

The whole body composition of theultured fish is shown in Table 4. No significant

differences were observed among dietary groupsn the basis p f crude protein, crude lipid, and crude

ash contents. The inoisture content of fish feddiet 6 was sig ficant]y higher than that of fish fedleis 1 and 3 p c0.05!.

Gltxxxau Rcsphate Ctlciua t3iio~tng/100at! tng/10Ctnl ! tag/IQthtt ! tng/IOQal!

Similar trends as shown in the previousreport Kikuchi and Sakaguchi 1997! � superiorgrowth, comparable feed efficiency, and proteinefficiency ratio to the control � were observed mdietary groups which contained blue mussel meat diets 2 to 4! in this study. Therefore, it is clearthat the inclusion of blue inussel meat in the dietpromotes feeding and growth of the flounder, evenif it is a very small amount �% on a dry basis!.Furthermore, the positive effect on growth wasnot different whether the mussel was fresh orfreeze-dried according to the results of this study diets 3 and 4, Table 2!.

Many studies have been coiiducted onstimulating the feexling behavior of fish with variouskinds of organistns, Soine amino acids such asglycine, alanine, and valine showed activity to fish,especially when two or three of them formcomplexes e.g�The Japanese Society of FisheriesScience 1981!, Ina and Higashi �978! and lna�986! reported that amino acid fractions of bluemussel s hf yiilas echdis stimulated feeding activityof red sea bream Chrysophrys major, There isno useful information on feeding attractants forJapanese flounder; however, it is considered thatamino acids in the mussel may contribute to thepromotion of feeding activity of the flounder.

The final body weight and weight gainof fish fed diets containiug whole blue mussel weresimilar to those in the control, although the feed

Klkucbi

Moisture Crude rotein Crude li id Crude aahDiet

74.410.2 11. 4i 1. 4

18.221.9

17.3a2.6'

16.5%1.1

17.211.5

17.712.1

4.2a0.6'

4.310.5

4.e*0.6

4.7%0.3

4. &0.3

4. 5i0. 7

3 410.2'

3.510.1

3.510.1'

3-4~0.1'

3.410.1'

3.390.1

74.520.9

74.4t0.5

74.3%0.8

75.1fl.l

75. 2%0. 4

* See the footnote of Table 3.

Table 4. Proxintate composition of the whole body of Japanese flounder fed six expetimental diets for 8 wk %! +

LITERATURE CITED

efficiency was lower due to higher crude ashcontent in the diet. This means that even whole

mussel can be used as an ingredient in the diet forthe flounder if the inclusion level is low up to 30%as fresh whole blue mussel!, because fish feedactively and compensate for the high ash contentof the diet as shown in increasing daily feedconsumption Table 2!. Whole blue mussels M,edtdis were used by Berge and Austreng �989!as substitute for fish argentine Argenrintts silas!in a moist pellet for rainbow trout Saba gaiIdneri.They showed that there was a tendency towardpoorer gmwth and feed efficiency with increasinglevel of the blue mussel in the diet; however,statistical difference were not observed amongdietary groups as shown in this study. They alsostated that the mussel meat may be a good proteinsource and has a favorable fatty acid composition.

On the other hand, Grave et al. �979!reported that rainbow trout fed frozen blue inusselM. edsdis meat showed much higher growth, feedefficiency, and protein efficiency than those fedcoinmercial trout pellets, when the daily rationlevels were in the same range. Kitamura et al�981! reported that the growth of red sea breamPagrus major fed inoist pellets containing apowder of freeze-dried blue mussel M.galloprovinc'ialis meat as a main ingredient wasalmost equal to that of fish fed commercial pelleteddiets when the moist pellets were supplementcxiwith Vitamin B l.

These studies and our previous work

show that blue mussel meat can be considered as

a replaceinent for fish meal in the diet for inanykinds of fish. However, considering the high marketprice of blue mussels, it is hard to say that musselscan be used as an economically attractive ingredientfor fish meal in the diet. Moreover, because manyof the rnussels obtained from power plants are shelland sometiines contain sludges and othercontaininants, acquiring a large amount of meat isnot considered to bc cost effective. Therefore,

from a practical point of view, it would be better toutilize its effect on feeding stimulation as an additivein the diet than as a inain ingredient, at least forjuvenile Japanese flounder.

ACKNOWLEDGMENTSThe author wishes to thank Dr H-

Daniels, Department of Zoology, North CarolinaState University, for his valuable ad»ce areading of the manuscript. ~ aMr T Furuta, Central Research In»tutepower industry, and Mr, T Sato, Tokyo Uni"e~i yof Fisheries, for their technical tts»sta"~.

Berge, G,M. and E, Austreng. 1989- Bluiil feed for rainbow trout. Aquacul&m81: 79-90,

Campbell, R.C 1983. Mann-Whitn y "" p '55-g9. Jn: Statistics for Biologists, 2nded. Baifukan Tokyo [ JaP

z74 UJNR Techmcsl Report No. zs

Duncan, D.B, 1955, Multiple range and F tests.Biometrics 11: 1-42,

grave, H., A. Schu ltz, and R. Van Thielen. 1979,The influence of blue mussel, Mytilasedulis, and krill, Euphausi o superba, ongrowth and proximate composition ofrainbow trout, Salmo gai rdnerr, pp. 575-586, ln: J.E.Halverand K. Tiews cds,!,Proceedings of the World Symposium onFinfish Nutrition and Fishfeed

Technology, Vol. 1. Heeneinann, Berlin.Ina, K, 1986. Artificial diet with plantprotein for

fish. Suisan no Kenkyu 5: 85-91. [InJapanese j

Ina, K. and K. Higashi. 1978. Surveys of feedingstimulants of the sea bream

Ch rysophrys maj or!l. Ni pponNogeikagaku Kaishi 52: 7-12. [InJapanese]

Kikuchi, K. and I. Sakaguchi.1997. Blue musselas an ingredient in the diet of juvenileJapanese flounder. Fish. Sci. 63: 837-838.

Kikuchi, K., T, Furuta, and H. Honda, 1994a,Utilization of feather meal as a proteinsource in the diet of juvenile Japaneseflounder Fish. Sci. 60: 203-206.

Kikuchi, K., T. Furuta, and H, Honda. 1994b,Utilization of soybean meal as a proteinsource in the diet of juvenile Japaneseflounder, Paralichrhys oli vaceus.Suisanzoshoku 42: 601-604.

Kitamura. H., H. Mizutani, and Y. Dotsu. 1981.Rearing experiment on young of samefishes and decapodid crustaceans fed onthe meat of the common mussel, Mytilusedrdis gallopmvincialis. Mar Foul 3:23-27. [In Japanesel

The Japanese Society of Fisheries Science. 1981.Chemical sense of fish and feedingstimulants. Koseisha Koseikaku, Tokyo.128 p. ]In Japanese!.