Harmful Algal Blooms Habs! in the United States
WHOI-T-00-002 C2
WHOI-2000-11
gp,N oGgg
0 Oo0
1930 WoodsHole
Estimated Annual EconomicImpacts from Harmful Algal Blooms HABs! in the United States
Donald M. Anderso'ri' Porter Hoagland Woods Hole Oceanographic Institution Woods Hole, MA 02543
Yoshi Kaortj Nanzan University...::;::::,'. Nagoya, lapan
Alan W. White MassachusettsMaritime Academy BuzzardsBay, MA 02532
September 2000
Technical Report
Fundingwas provided by the National Oceanicand Atmospheric Administration under Crants No. NA46RC0470 and NA90AA-D-SC480, the National Science Foundation under Grant No. OCE-9321244, and the Johnson Endowment of the Marine Policy Center, Approvedfor publicrelease; distribution unlimited. WHOI-2000-11
Estimated Annual Economic Impacts from Harmful Algal Blooms HABs! in the United States
by
Donald M. Anderson, Porter Hoagland Woods Hole Oceanographic Institution Woods Hole, MA 02543
Yoshi Kaoru Nanzan University Nagoya, Japan
AIan W. White Massachusetts Maritixne Academy Buzzards Bay, MA 02532
September 2000
Technical Report
Funding was provided by the National Oceanic and Atmospheric Administration under Grants No. NA46RG0470 and NA90AA-D-SG480, the National Science Foundation under Grant No. OCK-932I244, and the Johnson Endowment of the Marine Policy Center. Reproductionin whole or in part is permittedfor any purposeof the United States Government. This report should be cited as Woods Hole Oceanog.Inst. Tech. Rept., %'HOI-2000-l l.
Approvedfor public release;distribution unlimited.
Approved for Distribution:
Laurence P. Madin, Chair
Department of Biology EconomicImpact of HABsin the U.S.
ACKNOWLEDGE1VlKNTS
We extendspecial thanks to the followingpeople for theirassistance in providinginformation for this report: D. Baden Universityof Miami!; D, Blythe University of Miami!; J. Burkholder NorthCarolina State University!; R. Conn City of Sarasota,Florida!; L. Fleming University of Miami!; W, Foster Departmentof Marine Resources,State of Maine!; R, Haddock Guam Departmentof Public Health!;Y. Hokama University of Hawaii!; R. Horner University of Washington!;J. Hurst Departmentof Marine Resources,State of Maine!; C. Lobban University of Guam!; K. Lynch North CarolinaDepartment of Environment,Health and NaturalResources!; V. Paul University of Guam!; R. RaLonde University of Alaska!; W. Roihenbach City of Sarasota,Florida!; E. Todd Departmentof Healthand Welfare, Canada!; T. Tosteson University of PuertoRico!; K. Wtute Departmentof Fisheriesand Oceans, Canada!; and R. Weisrnan Florida PoisonInforination Center!.
We alsothank the following peoplefor information which they provided during the initial stages of thisproject: C. Allison AK!; S.Barker ME!; R. Barrett AK!; B. Barss OR!;T. Beardsley AK!; R. Reeker LA!; T. Bettinger AK!; E. Buskey TX!; D. Cannon OR!; K. Canty MA!; P. Chapman WA!; R. Collins CA!; E. Cosper NY!; E. Cox TX!; R. D'Arnica NY!; C. Dequillseldt NY!; B. Dewey WA!; P. DiPietro MA!; W, Donaldson AK!; B. Eisley NJ!; J. Finger CA!; A. Freudenthal NY!; J. Garrett FL!; B. Halgren NJ!; R, Hanowell WA!; D, Heil FL!; Y, Hokama HI!; R. Horner WA!; J. Hunt FL!; J. Hurst ME!; T. Johnson CA!; J. Johnson OR!; S. Kennedy FL!; G. Langlois CA!; R. Lewis ME!; R. Madiack NJ!; J. Mahoney NJ!; H. Marshall VA!; M. McCallum WA!; M. McNair AK!; J. Nelson NH!; C. Newell ME!; R, Nuzzi NY!; P. Olsen NJ!; M. Ostasz AK!; J, Paeth OR!; PierceAssociates MA!; R. Pierce FL!; H. Radtke OR!; P. Raiche NH!; T. Reisingor TX!; J. Rensel WA!; B, Roberts FL!; L. Robinson TX!; M. Ross CA!; P. Rubec TX!; ShoreAppraisals MA!; D. Simons WA!; T. Smith WA!; K. Spiller TX!; G. Stater OR!; K.Steidinger FL!; M. Street NC!; C. Strong NY!; W. Tatum AL!; P. Tester NC!; R. Usher MA!; J. Volk CT!; C. Weise AK!; T. Whitledge TX!; D. Whittaker MA!; S. Wilk NJ!; and G. Woods MA!.
We thankMs. Ellen Gately for typographicalassistance with this manuscript,and Ms. Judy Kleindinst and Ms, Kristin Gribble for their editorial efforts. This research was supported in part by NOAA NationalSea Grani CollegeProgram Office, Departmentof Commerce,under Grants No. NA46RG0470 and NA90AA-D-SG480, Woods Hole Oceanographic Institution Sea Grant ProjectsNo. R/8-150-PT and R/S-24,by NSF Grant OCE-9321244,and by the Johnson Endowtneni of the WHOI Marine Policy Center. Economic itnpact of HABs in the U.S,
EXECUTIVE SUMPclARY
Blooms of toxic or harmful microalgae,commonly called "red tides," representa significant and expandingthreat to humanhealth and fisheries resources throughout the United Statesand the world. These phenomenatake inany forms, rangIngfrom massiveaccumulations of cells that discolor the water to dilute, inconspicuous,but highly toxic populations, Ecological,aesthetic, andpublic health impacts include: mass mortalities of wild andfarmed fish andshellfish; human intoxication and death from the consumptionof contaminatedshellfish or Gsh; alterations of marine food webs through adverseeffects on larvaeand other life history stagesof commercial fish species;the noxious smell and appearanceof algaeaccumulated in nearshorewaters or depositedon beaches;and mass mortalities of marinemainmals, seabirds, and other animals.
Many harmful algal blooms HABs! havesignificant economic impacts. Shellfishclosures, wild or farmed fish mortalities, and scared consumers who avoid seafood are well-recognized impacts of major HABs, While adversehealth effects and lost sales of fish and shellfish products are direct costs, constraineddevelopment or investmentdecisions in coastalaquaculture due to the threat &om outbreaksof toxic algaeare examplesof poorly understood or poorly quantified indirect or hidden costs. Lost marinerecreational opportunities also are a significant cost of harmful algal bloom incidents.
HABs have increasedsteadily in both speciescomplexity and geographicalextent over the last severaldecades. In turn, the rangeof hmnfuI eKectsand the magnitudeof economiccosts have also widened. This report providesthe first comprehensiveestimate of the economicimpacts of HABs in the United States,focusing on both direct and indirect costs.
We estimatethe economicimpacts of HABs for events where such impacts were measurable with a fair degreeof confidenceduring the six-year interval of 1987-92 Table ES.1!. Due to reporting limitations, the selectedevents are a subset of all outbreaksthat occurred during the 1987-92 study period, and thus our ~ate economic impact underestimates the true impacts, "Economic unpact" is definedbroadly to meaneither lost grossrevenues in the relevantproduct or factor markets,expenditures for environmentalmonitoring and management, or other costs that would not have been incurred in the absenceof HABs, In general, this measure is consistent with published estimatesmade for other natural catastrophes,such as hurricanesor earthquakes, Economicmultipliers, often usedto approximatethe full ramificationsof costs or lossesas they are transferred through a local economy, are not used here. The calculation of economic multipliers in the absenceof detaileddata on market structure and interactionscan be misleading, as multipliers canbe sensitiveto local market structure characteristicsand to the quality of data that describe interactions among market sectors. Developing a description of local and regional marketsfor specific HAB eventswas beyondthe scopeof this project. Economic Impact of HABs in the U.S.
~C & N8
O CO Cl «! COK 0 O
tC gLs 'O0 Q
Ch C
00 Ch ~ Q4 O a5 Cg C
'a4J C Economicimpact of HABs in the U.S.
Economic impacts are grouped into four basic categories; ! public health impacts; ! commercialfishery impacts; ! recreation and tourism impacts; and ! monitoring and managementcosts. Unless otherwise indicated, all estimatesare reported in 2000U.S. dollars.
Public Health Im acts
Human sicknessand death from eating tainted seafoodresults in lost wages and work days. Costs of medicaltreatment and investigationalso are an important part of the economicimpact causedby suchevents. Cases of sicknessand death from shellfishtoxins are probably the most clearlydocumented among the different types of HAB impacts,since these cases are recorded by public healthagencies in individual statesas well as at the federallevel.
Forthe 1987-92period, the averagepublic healthimpact due to shellfishpoisoning from HABs wasapproximately $1 miUionper year causedby paralytic,neurotoxic and amnesicshellfish poisoning,or PSP,NSP, and ASP respective1y!.This total is low becauseof highly effective state monitoring programs that detect toxic sheNish and keep contaminatedproducts off the market, Another problem causedby toxic algaeis the fish poisoning syndromecalled ciguatera, causedby dinoflagellatetoxins that move through the tropical food chain to the larger fish that then poisonhuman consumers. Ciguatera affects predominantly the residentsof, and visitors to, Florida, Hawaii, PuertoRico, the U.S. Virgin Islands, Guam, and the Marshall Islands. Over the study interval, the economicimpact of ciguaterapoisoning varied from $18 million to more than $24 million per year,averaging $21 million, Theseestimates are low since ciguaterapoisoning has occurredoutside the tropical areaslisted above due to exports of fish to other jurisdictions, Further, some seafood companies purchase insurance to cover potential ciguatera-caused liabilities, andthere are court costs associatedwith ciguatera-relatedlitigation neither of which we were able to quantify for the study interval.
The total public healthimpacts &om HABs rangedfrom a low of $18million to a highof $25 million,averaging $22 million overthe six-yearinterval. Thesefigures represent approximately 45'loof the total economicimpacts from all causes.
Commercial Fishe Im acts
Commercialfishery impactsfrom HABs includewild harvest and aquaculturelosses of fish and shellfishresources due to NSP, PSP,ASP, ciguatera,and brown tides. Annual impactsvary &om $13 to $25 million with averageannual impacts of $18 million. These figures clearly are underestimatesbecause they do not includelosses from PSPclosures in several~tes where it was not possible to documentthe ~e closed or the value of the resourcethat was not harvested.The estimationof commercialfishery impacts is complicatedfurther by the transfer of shellfishingeffort from closedareas to areasthat remainedopen and by fishermenswitching to other fishing activities. In addition,the estimatesdo not include the value of wild fish kills or of lost opportunities for harvestingsome untapped shellfish resources. Measuring the economic impactsof wild fish kills is problematicbecause many involveso-called "trash" fish that, by Economic Impact of HABs in the U,S. definition, have no market value. Also, the ultimate causesof fish kills often are unclear. For example,fish kills causedby the dinofiagellatePPesteria undoubtedly occurred in North Carolina during the six-year study interval, but stateofficials could not indicate which events were caused by Pfiesteriaand which were due to othercauses, such as low dissolvedoxygen,
Another issue is that some currently untapped fishery "resources" have values that could be realized in the absence of HAB events, but such estimates are not included here. Examples include some shellfish resources of coastal Alaska, which are permanently quarantined due to persistent PSP toxicity and the logisticsof samplingdistant or remote resources. However, in order for such"lost opportunities" to be countedlegitimately as economicimpacts in this study, these fisheries must be demonstrated to be commercially viable. A plausible alternative reason for non-exploitationis that they are not profitable fisheriesbecause there is insid5cient demand or becauseharvesting is uneconomical, The annual economicimpact estimatespresented here include losses from these untapped resources only in certain special cases e.g., surf clams in Alaskaand on GeorgesBank!.
Recreation and Tourism Im acts
In 1991, a federal study esbrnated that expenditures by recreational fishermen for travel, food, lodging and equipment were 67 percent greater than expenditures for commercial fish landings. Although many expertsargue that the impactsof HABs on.recreation and tourism are important andpotentially large, there are few availabledata describing the size of the impacts. Clearly, the economicimpacts of HABs on recreationaland tourism activities deservesubstantially more attention than they have been given to date. In Fiorich, for example, recurrent red tides have been estimatedto causeover $20 million in tourism-relatedlosses every year. These impacts, as well as similar losses in Texas and other areas, are not well documented and thus are reduced to much lower levels in this study. The total annualestimates for recreationand tourism are, onceagain, underestimates,Efforts to measurerecreation. and tourism impacts inust be undertakenat the local level because local environmental and socioeconomic conditions are critical deternuiiants of changesin recreational benefits.
Estimatesof economicimpacts on recreationand tourism during the 1987-92period rangefrom zeroto $29 tnillion. The annualaverage is $7 million.
Monitorin and Mana ement Costs
It is often the casethat water monitoring tasks, including shellfish testing for PSP, NSP, and ASP, are spreadacross different divisions of state government,making it difficult to collect data on costs. Further, monitoring activities for both HABs and other water quality testing, such as shellfish sanitation, often are conducted by the same personnel. As a result, it is difficult to factor out those costs related specifically to HAB monitoring and management, Given this qualification, annual average monitoring and management costs for HARs are estimated at $2 million, distributed among twelve states: Alaska, California, Connecticut, Florida, Maine, EconottticImpact of HABs in the U.S.
Massachusetts,New Hampshire,North Carolina,New Jersey,New York Oregon, and Washington.These costs include the routine operation of shellfishtoxin monitoring programs, planktonmonitoring, and other management activities.
Conclusions
TableES-1 presents the annual aggregate economic impacts in millionsof 2000dollars! of HABs Ui the United Statesduring the 1987-92period. The total costsaverage $49 million per year, rangingfrom $34 million to $82million. Overthe lastseveral decades, the cumulativeimpacts thusapproach $1 billion. Publichealth impacts are the largestcomponent, representing more than45 percentof total averageimpacts. Commercialfisheries impacts are the nextlargest component,representing 37 percentof the total. Recreation/tourismimpacts account for 13 percentof the total, and monitoring/nianagementimpacts represent the remaining4 percent. Further,it is importantto notethat expendituresmade to improvemonitoring and management likely resultedin decreasesin impactsin the othercategories.
Theseestimates are highly conservativeand reflect the difhcultiesin compilingand assessing the impactsof phenomenafor which economicstudies are rare.The totals in TableES-1 do not includethe effectsof economicmultipliers, which would increasethe estimatesseveral-fold. They alsodo not includethe valueof untappedor unexploitedresources, such as someof the extensiveshellfish populationsalong Alaska's 30,000-milecoastline, presently closed to harvestingdue to PSPtoxicity. Likewise,the effectsof delayedharvesting, as with temporary beachclosures due to PSP,could not be estimatedwith any precisionand thus are not included.
We note also that outbreaksof certainblooms may causesevere economic impacts that equalor exceedthe annual averages for the selectedstudy interval, For example,a 1976New Jerseyred tide causedlosses estimated at morethan $1 billion in 2000 dollars, Similarly, the 1997 PPesteria outbreakin the ChesapeakeBay is estimatedto havecost the seafoodindustry $46 million, Thesesingle events exceed the annual average of HAB impactsfor theentire nation.
The difficultiesencountered in our efforts to generatea nationalestimate of HAB economic impactsunderscore the needto modify the mannerin which HABs are reported. At present, information on HAB events is &agmentaryand inconsistentwith respect to the level of detail provided.The duration, affected acreage or shorelinelength, average toxicity levels, and values of affectedcoastal resources should be documentedfor eachbloom in order to describethe overall economicsignificance of the incident. In addition,local and stategovernments should place muchhigher emphasis on quantificationof economicimpacts. Until local governmentsbecome capableof supplying site-specificimpact information for each bloom incident, truly comprehensiveand detailednational level aggregationof such impacts cannot be realized. Furthermore,the causesof economicimpacts and the degreeof their uncertainty should be includedin any reportsof economicimpacts. EconomicImpact of HABs in the U.S.
Overall, the economic impacts kom HABs are diverse and large within the United States. Even with the highly conservativetreatment given the impacts in this study, the annual costs are significant. Perhapsmore importantly, many are recurrent,and show signs of increasingas the number of toxic and harmful algal species grows and as our reliance on the coastal zone for aquaculture, commerce and recreation expands. Prudent investment in research and monitoring can do much to reversethis trend and to reducethe annualimpacts. Economic Impact of HABs in the U.S.
TABLE OF CONTENTS
I NTRODVCTIONeeeoeee.r ~ ~ o~ ~92 re92or eeeeeoeoeer ~ ~ corereoee92oeeeeeeee ~ ~ eeeeee~ o 1 3
METHODS .16
2.1 Definition of Economic Impacts 16 2.2 Economic Impacts are not an Ideal Measureof Social Costs. 17 2.3 Ex Ante vs. Ex Post Impacts. 19 2.4 Nonmalleable Factors 19 2.5 Other Types of Impacts. 19 2.6 Distribution of Impacts. 2.7 Usefulness of the Economic Impact Measure ...... 20 2.8 Study Interval 20 2.9 Data. 21
P VBLIC HEALTH IMPACTS e r ~ oeooeroooeeoeooeoeeoooeeeoeoeeeroeeoeroooeeeeeeeeeoc~ ~ o eoeoeoeeooree22 3.1 PSP, NSP, and ASP Illnesses. 3.1.1 Illness Costs. 22 3.1.2 Unreported Illnesses. 25 32 Ciguatera. 26
4 COMMKRCIAL FISHERY IMPACTS 28 4.1 WiM Harvest and Aquaculture Losses 28 4.1.1 Brown Tide Impactson Bay ScallopHarvests in New York 28 4.1.2 ASP Impactson RazorClam Harvestsin Washingtonand Oregon...... 31 4.1.3 Alaskan Shellfish Resources. 32 4.1.4 CiguateraImpacts on Salesof RecreationalFish in Hawaii 32 4.1.5 West Coast Harvesting Delays 32 4,1,6 InconclusiveImpacts on Shellfish Harvestsin Maine and Massachusetts 33 4.1.7 Impacts from the Application of Health Standards. 34. 4,1.8 Impactsof Wild Fish Kills. 34 4.1.9 Inconclusive Evidence of SeagrassDieoffs in Florida. 36 4.2 Untapped Fisheries, 36 4.2.1 Alaska's UntappedShellfish Resources 37 4.2.2 Georges Bank Surf Clam Fishery, 42 4.2.3 GeorgesBank Roe-OnScallop Fishery, 42 4.3 Major HAH Eventsin OtherYears. 43
RECREATION AND TOURISM IMPACTS...... 44
5.1 The 1987 North Carolina Red Tide Event 45 52 The 1991-92 Washington and Oregon ASP Event.. .45 EconomicImpact of HABs in theU.S.
5.3 Recreational Impacts - Large but Uncertain. 5.4 Laguna Madre Brown Tide .. ..., ., 47 5.5 Property Value and Recreational Impacts of Macroalgae...... 47
6 MONITORING AND MANAGEMENT COSTS boaee eo ee 49
7 CONCLUSIONS AND FUTURE RESEARCH NEEDS...... 51
7.1 Annual Aggregate Economic Impacts. 51 72 Reasons Why Our Estimates are Conservative...... 51 7.3 Information Needs. 7.4 Overview. 55
8 RKFKRRNCKS.
AP PENDIX A. ~ eoeeeaeeaeoeeaooaeeaaeaeooeoooeoaeooooeeoeooooaeooeeeooeoeeeeooeeeeeeoooeeeeeeeaeooeoeeeeeeeeeeeeeoeooaeeeeeeee61
APPENDIX 8. .S9
10 Economic Impact of HABs in the V.S.
LIST OF FIGURES Page
Figure2.1. Economiccosts of'a HAB eventin a commercialfishery 17
Figure2.2. Economiccosts of a HABevent in a recreationalfishery
11 EconomicImpact of HABs in the U.S.
LIST OF TABLES Page
Table 3.1. Illness due to natural seafood toxins in the United States 23
Table 3.2. Shellfish poisoning impacts from harnifui algal blooms
Table 3.3. Public health impacts of ciguatera 27
Table 4.1. Commercial fishery impacts 29
Table 4.2. New York commercial bay scallop landings 980-84! 31
Table 4.3. Landed values in she116shin Maine 988 and 1992! 33
Table 4 4. Massachusetts state PSP testing results 35
Table 4.5. Status of Alaskan molluscan shellfish resources 38
Table 4.6. Estimated "net" gross revenues arising Born opening the Alaskan 41 and Georges Bank surf clam fisheries
Table 5.1. Recreation and tourism impacts
Table 5.2. Washington state recreational shellfishing trips for razor clams 46
Table 6.1, Arinual average monitoring and managementcosts 50
Table 7.1. Estimated annual economic impacts from harmful algal blooms 52 in the United States
12 EconomicImpact of HABs in the U.S.
1 INTRODUCTION
Oceanwaters are home to thousandsof speciesof microscopicalgae which together comprise the baseof the marinefood web. Most of thesespecies are harmless, and in fact arecritical to the ocean'secology and to theproduction of biomassat all levelsof themarine food web. Thereare, however,a fewdozen algal species which are associated with adverseimpacts of manydifferent types.The term "harmful algal bloom" or HAB is nowused to describethe destructive and often visible"blooms" of thesealgae that kill fish,make shellfish poisonous, and cause numerous other problemsin marinecoastal waters, The one feature uniting these diverse phenomena is that they causeharm. In thepast, the terin "red tide" wasused to describemany of thesephenomena, but theterm is potentiallymisleading and does not adequatelydescribe the many different types of harmfuloutbreaks. Some algal species produce potent toxins which accumulate in shellfishthat feedon thosealgae, resulting in poisoningsyndromes in humanconsumers called paralytic, diarrhetic,amnesic, and neurotoxic shellfish poisoning PSP, DSP, ASP, and NSP respectively!. A relatedphenomenon called ciguatera fish poisoning CFP! occurs when toxic algaeliving on coral reef seaweedsare consumedby herbivorous fish, which pass the toxins on to larger predatorswhich then deliver the neurotoxins to humanconsumers. All of thesetoxins can also altermarine ecosystem ~cture andfunction as they aretransferred through the food web, affectingfecundity and survival at multiple levels in waysthat are still largelyunquantified.
Sometoxic blooms kill wild and farmedfish populations. Others are associatedwith irritating andtoxic aerosols,due to the transportof toxinsin seaspray. Evennon-toxic algal species can causeproblems through biomass effects - shadingof submergedvegetation, disruption of food webdynamics and structure, and oxygen depletion as the blooms decay. Traditionally, the term HAB hasreferred to inicroscopicalgae, but its interpretationhas now beenbroadened to include bloomsof macroscopicalgae seaweeds!which displaceindigenous species, destroy habitat, causeoxygen depletion, and even alter biogeochemicalcycles. The causesand effects of macroalgalblooms are similar in manyways to thoseassociated with harrrifuimicroscopic phytoplankton species.
Duringthe past several decades, HAB eventshave occurred in morelocations than ever before throughoutthe UnitedStates and the world Anderson1989; Smayda 1990; Hailegraeff 1993!. Thenumber of algalspecies involved in suchevents has increased, there are more known toxins, more fisheriesresources are affected,and the economicimpacts of HAB outbreaksare larger as well. Whetheror not this globalincrease in HABs is takingplace because of enhancednutrient andpollutant loadings from anthropogenic sources has been a topicof debatewithin the scientific community e.g.,Anderson 1989; Smayda 1990!. Whateverthe reasons,virtually all coastal regionsof theUnited States are now subject to anunprecedented variety and frequency of HAH events. The United States is not alone in this respect, as nations throughout the world are increasinglyfaced with a bewilderingand disturbing array of toxic or harmfulspecies and impacts.
13 Economic Impact of HABs in the U.S,
In the United States, the inost significant economic and public health problems related to harrrdul algae during the 1987-92 interval that is the focus of this study were:
~ Paralyticshellfish poisoning PSP!,which occursin all coastalNew Englandstates as well as New York and along much of the west coast &om Alaska to California. This problemhas also extendedto offshoreareas in the Northeast,notably GeorgesBank.
~ Neurotoxicshellfish poisoning NSP!, and fish and marinemanimal mortalities in the Gulf of Mexico and, more recently, extending northward to the coast of the Carolinas.
Mortalities of farmed salmonids in the Pacific Northwest.
~ Recurrentbrown fides, causingmortalities of musselpopulations, massive recruitment failure of scallops,and reductionof eelgrassbeds around Long Island.
~ Ciguaterafish poisoning CFP!, a malady associatedwith dinoflagellate toxins accumulatedin tropical fish flesh, occurringin virtually all sub-tropical to tropical United Stateswaters, includingFlorida, Hawaii, Guam,United StatesVirgin Islands, Puerto Rico, and many Pacific Territories.
Amnesic shellfish poisoning ASP!, a sometimes fatal illness so named becauseone of its most severesymptoms is the permanentloss of short-terin memory. The ASP toxin, domoic acid, has been detectedin shellfish from both the West and East Coasts of the United States, and toxic Pseudo-nitzschia multiseries cells have been isolated from Gulf of Mexico water.
~ Diarrhetic shellfish poisonmg DSP! which some consider the most serious and globally widespread phytoplankton-related seafood illness, The first confirmed incidence of DSP in North America occurred in 1990 and 1992 in Canada. DSP- producingspecies of phytoplanktonsuch as Diriophysisacumiriata and Prorocentrum lima occurthroughout all temperatecoastal waters of the United States,though no outbreaks of DSP have yet been confirmed.
~ "Pfiesferia-like"dinoflagellates, affecting human health and fisheriesin estuariesof the southeasternUnited States,and in particular the Neuse-Pamlicoestuaries. Although Pfiesteriahad been discovered by 1992,economic impacts of fish kills causedby this organism are not included in this study becauseno data could be obtained on the fish kills conclusivelylinked to Pfiesferiaover the 1987-92interval, or of the value of the deadfish. In the laboratory,human exposure to aerosolsfrom toxic PPesteriacultures has beenlinked to short- and long-termneurotoxic symptoins. Fishermenand others working in or exposedto estuarinewaters have complainedof similar probleins,
14 Economic1mpact of HABs in the U.S.
exempli6edin the worst casesas a loss of neurocognitiveability. There are no estimatesof the economicimpacts of thesehuman health effects in this report, again because of a lack of data.
~ Bloomsof macroalgae seaweeds!, in responseto nutrientenrichment associated with coastaleutrophication. Opportunistic macroalgal species outcompete, overgrow, and replaceseagrass and coral reef ecosystems. Once established, the macroalgalblooms mayremain in anenvironment for decadesuntil nutrientsupplies decrease. Negative effects include reducedlight availability to seagrassesand reef systems, leading to lowerproductivity, habitat loss from hypoxia/anoxia,and eventual die-off of sensitive species.
In thisreport, we providea nationalestimate of the economicimpacts of HABs from eventsfor whichsuch impacts were measurable with a fairdegree of confidenceduring the interval1987-92. Unlessotherwise indicated, all estimatesare reported in 2000U.S. dollars.! Due to inadequate reporting,the eventsincluded here are onlya subsetof the HAB outbreaksthat occurred duringthe six year studyperiod. For this reasonand others discussedbelow! we believe that our aggregateeconomic impact estimates significantly underestimate the true impacts.We acknowledge that "economic impact" is notan ideal measure of economicloss, but we employthe conceptin this study becauseit is the predominantform in which damagesare reportedby coastalmanagers and by scientistsin thepublished literature. We group economic impactsinto four basiccategories: 1! public healthimpacts; 2! commercialfishery impacts;3! recreationand tourism impacts; and 4! monitoringand management costs. This is the first effort to estimateeconomic costs of HABs at the national level, so it is perhaps not surprising that in the courseof this analysis,we encounteredmany unknownsand uncertaintieswith respectto quantifying impacts.These problems are discussedbelow.
15 EconomicImpact of HA3s in the U.S.
2 METHODS
The following economic impact analysis is based mainly on a survey of experts &om individual coastal states and the literature. Formal letters requestingeconoxnic impact information were mailed in August 1992 and February 1994 to individuals in certain heavily impacted states who were either knowledgeable about HAB ixnpacts or who were likely to know others who could be contacted for more specific details. In tota1, more than 170 people were contacted by letter and by telephoneto elicit economicimpact information and to uncoverdetails about individual HAB events. After a preliminary evaluationand synthesis of thesedata, topics requiring further data or analysiswere identified. Thesewere addressedthrough a new seriesof telephone calls and correspondencein 1997-99. We havesummarized these data in the body of the report.
2.1 Definition of Econoxnic Impacts
We define"economic ixnpacts" broadly to meaneither lost grossrevenues in the relevantproduct or factor markets,expenditures for environmentalxnonitoring and management, or other coststhat would not have been incurred in the absenceof HABs. In general, this measure is consistent with published estixnatesmade for other kinds of natural catastrophes, such as hurricanes or earthquakes e.g. Pielke and Landsea 1997; Pielke and Pielke 1997!. As such, the estimates reported here representa preliminary, but admittedly rough, approximation of the economic coststo the United States&om the occurrenceof HABs. Readersshould keep the limitations of economicimpact analysis in mind, realizing that it was developed as a purely descriptive technique. Its original purpose was to describe the economic structure of a region, to help understand economic interactions and linkages axnongsectors. In particular, it is not a form of benefit-cost analysis, and it should not be used to justify normative decisions Propst and Gavrilis 1987!.
Another considerationis that we do not apply "multipliers" in this report to capture the full ramifications of economicimpacts. Multipiiers can be sensitive to local market structure characteristicsand to the quality of data that describeinteractions among market sectors Archer 1995; Propst and Gavrilis 1987!. Developing a description of local and regional markets for specific HAB eventswas beyond the scope of this project. We haveidentified somestudies of HAB impacts in which mu1tipliers have been estimated and used, such as Maine's economic ixnpactcalculation for shellfishingclosure of September1980, and we recognizethat it is possible to calculate multipliers for this kind of application Loomis 1993!. However, we believe that the calculation of economic multipliers in the absence of detailed data on market structure and interactionscan be potentiallymisleading, creating a perceptionof exaggeratedeconomic costs of HAH events e.g. Hunter 1989!. Furthermore,the occasionalxnisuse of econoxnicimpact analysis to make riormabvedecisions to justify investments,for example,is made aII the worse when impacts are xnultiplied, EconomicImpact of HABs in the U.S.
2.2 Economic Impacts are not an Ideal Measure of Social Costs
Economicimpacts as defined here are not an ideal measureof the costs of HABs to society. Under ideal circumstances, we would like to obtain a measure of lost consumer and producer surpluses in the relevant markets due, say, to shifts in demand or supply curves. We demonstratethis point in Figure2.1, which depicts supply and demandin a commercialfishery duringone season', Assume that we areconsidering the costs associatedwith the closureof a fishery due to a HAB event. In a typical case,this can be representedby a shift of the supply curve,which itself is the horizontal sum of marginalcost schedulesfor individual firms, from So to Sl. The effect is a reduction in the supply of fish to the market, from Fo to F I, and an increase in the price of fish, from Ptito Pl. Prior to the closure,the net benefits flowing from the fishery are the sum of producers' surplus E+F+G! and consumers'surplus A+8+C+D!. After the closure, producers' surplus now becomes area B+E and consumers' surplus is reduced to area A. The net economic loss associated with the closure is therefore C+D+F+G. Compare this theoreticallycorrect, but often more dificult to obtain,measure with lost grossrevenues from the closure G+I!. It should be clear that the latter is not a very close approximation of "true" economic losses. In particular, although G is a true economic loss, I represents resources that can be productivelyinvested or utilized elsewherein the economy.
Pl
Pp
Fl FP Fish Figure 2.1. Economic costsof a HAB event in a commercial fishery.
I we examine the case of the lower section of the traditional backward bending supply curve, This exampie is relevant to the case of a fishery managed to maximize economic yield.
17 EconomicImpact of HABs in the U.S.
P
DFl DF0 Days Fished
Figure 2.2 Economiccosts of a HAH eventin a recreationalfishery.
The caseof a recreationalfishery is representedin Figure 2.2. In the present study, we have estimatedeconomic impacts as the product of lost days fished, e.g., due to a fishery closure, times averagedaily recreationalexpenditures. Note that somerecreational fisheries may have a commercialcomponent, complicating the analysis.! However,this measuredoes not representa true economiccost of a HAB event because,when expendituresare not made, individual recreationalfishermen incur no costs. Nevertheless,there may be consumersurplus losses, which represent true economic costs. Assume that there exists a recreational market" demand curve M! along which fishing success i.e., catch rate! is assumedto be constant Anderson 1986!.Prior to a HAB event,gross benefits are equalto areaA+B+C+D+E and expendituresare equalto areaC+D+E. Net benefits are therefore equalto areaA+B. Now assumethat an alyQ bloom resultsin the closureof somefishing areas,causing reduced catch rates in areasthat remain open,say, due to increasedfishing pressurein the latter. Becausefishing successdeclines, aiba closureswill resultin the contractionof recreationalmarket demand for eachlevel of aggregate daysfished. for example,Mo shifts down to Mt. At the current level of fishing expendituresof
2 Other scenarios are certainly possible. For example, a bloom evetit may result in the closure of an entire recreational fishery. Closurescould be temporal,instead of spatial,limiting the total daysfished. Analysesof other scenariosshould be straightforward.
18 Economic Impact of HABETin the U.S.
P, a new equilibrium of DFI aggregatedays fished is established. Following the logic described above,net benefits at the new level of days fishe are equal to areaB. The loss in consumer surplusfrom theclosure is equalto areaA. Notethat there is no explicitmarket for daysfished. Thedemand for daysfished is a "non-market"demand. Estimation of this demand,and therefore lossesto a recreationalfishery f'rom a HAB event, requiresthe applicationof specialized economic methods.
2.3 Kx Ante vs. Ex Post Impacts
Thepoint in timeat whichimpacts are measured also must be considered.When a commercialor recreationalfishery is closedex ante, then the appropriate measure of economiceffects is the sum of lost consumerand producer surpluses, as describedin the previousparagraphs. However, if commercialfish have been harvestedalready and the product subsequentlyprevented from reachingthe market becausetoxicity exceedssafe levels, then it is appropriate to add harvest costs areaI in Figure 2.1! to the measureof economiclosses. Harvest costs are includedbecause theyare a measureof resourcesthat have been utilized to no productiveeffect. Anotherexample is the occurrenceof a HAB that affects an operating coastal aquaculturefacility that must subsequentlyincur additional depurationcosts or disposeof tainted product. In both examples, there may be additional costs, such as higher tipping fees, associatedwith the disposal of the tainted seafood.
2.4 Nonmalleable Factors
Another source of economic costs relates to the ease with which capital or labor can be transferredto other productive activities. In the economicmodels described above, we assume thatfishing vessels, processing plants, fishermen, etc. will immediatelyand costlessly switch to their next best alternative activity. In other words, capital and labor are assumedperfectly "malleable." However, when exnnining specific cases,we may find that this assumptionis not valid. Good examplesinclude empty botel rooms or slowed restaurant trade resulting kom reducedcoastal tourism during a HAB event. As anotherexample, it may be costly for fishermeii to re-rigtheir boatsor steamto anotherfishing ground when a HAB closurehas beendeclared. Often, economicimpact studieswill assumethat capitaland labor is completelynonmalleable. In this report,where feasible, we point out anymalleability assumptions m thestudies that we cite.
2.5 Other Types of Impacts
We havecollected data on other types of impacts. The economicunpacts that we measurein the form of hospitalization costs or monitoring and managementcosts are true economiccosts. These activities represent the allocation of scarce medical and managementresources that otherwise would be devoted to other health problems or public goals. Interestingly, these activities help to mitigate the larger "potential" costs of HAB events. For example, monitoring
19 Economic Impact of HABs in the U,S.
might prevent the consumption of toxic seafood, and hospitalization might reduce inortality from seafoodconsumption. As a result, there may be net benefits &om undertakingthese activities. The existence of net benefits will depend upon a comparison of the total costs and total benefits of these activities.! Our econoinicimpact analysis does not account for the benefits of these types of mitigating activities.
2.6 Distribution of Impacts
Note that some firms in the relevant market actually may benefit &om a HAB event. For example, if a fishing location is closed becauseof a HAB event, a firm fishing for the same species in a location that remainsopen may actually seean increasein price for its product, Although there is a clear net loss at the market level, local net gains or net losses may occur, and the distribution of gains and losses may not be uniforin across all localities. Unless demand is perfectly elastic with respect to price, consumerswill unambiguouslylose becauseof price increaseswhen supplyis reducedas a consequenceof a HAH event. Somewill even be unwilling to purchase the Ash or shellfish at the new higher price.
2.7 Usefulnessof the Economic Impact Measure
Even though our measure of economic impacts is not theoretically correct, it can still be useful. First, this measureis very easyto collate and calculate. To our knowledge,there are few studies that haveexainined the true econoiniccosts of HAB events,but inany have estimatedeconomic iinpacts. Second,this approachcan give an ideaof the scaleof the problem. If economicimpacts are found to be large in any particular instaiice, it indicates that we need to take a closer look at the true economic losses. Third, the geographiclocation of economic impacts can give an estimateof where local lossesoccur, and the type of iinpact can help us identify the relevant market. When combinedwith an understandingof the relevantproduct or factor market, we may be able to predict where local net gainsmight occur. Thus, economicimpact analysis can give a feel for the distributional effects of a HAB event.
2.8 Study Interval
We exaininea "window" of impactsresulting from eventsduring the six-yearperiod irom 1987to 1992 to develop an estimate of "annual" economicimpacts. There is still a great deal of uncertainty about the frequencyand spatial distribution of HAB occurrences. Becauseof this uncertainty, the choice of a shorter period could result in either under- or over-estimates of economiciinpacts, depending upon when and where HAB eventsoccurred. The six-year period was the longest period for which we could collect a consistent set of data within the constraints of the project, Although our choicesabout the timing and duration of the study period are somewhatarbitrary, we believe that it gives us a reasonableinterval within which to develop cretlibk estiinaies of the annual economic impacts of HAB events at the national level.
20 Economic Impact of HABETin the U.S.
2.9 Data
Although we madean effort to gathereconomic iinpact dataas comprehensivelyas possible, both the type and amount of available data were limited, Most coastal states have neither conducted economic analyses of HABs nor collected data that can be used to generate reliable quantitativeeconomic impact estimates. In manycases, the complexphysical and ecologicalcharacteristics of the coastalenvironment make it dif6cult to determinewhether an algalbloom is the immediateand relevantcause of certaincoastal phenomena such as fish kills, oxygendepletion, or seagrassdieoffs. Moreover, local expertsoften differ substantially in their opinions aboutthe magnitudeof economicimpacts from HABs.
In Appendix A, we summarizeHAB events reported informally by individual coastal state expertsto a "nationaloffice" of the ICES Centerfor the Exchangeof Information on Exceprional Plankton Blooms, located at the Woods Hole Oceanographic Institution. Although the data are rudimentary in nature,these are the only nationalcompilations of bloom data. In Appendix 8, we presentthe namesand aKiliations of the individualswith whom we corresponded. EconomicImpact of HABs in the U.S.
3 PUBLIC HEALTH IMPACTS
Human sicknessand death from eating tainted seafoodresults in lost wages and work days. Costs of inedicaltreatment and investigationalso are an important part of the economicimpact causedby such events. Individuals who are sick may also experiencepain and suffering. In theory, thesefeelings could be quantified in economicterms, but we makeno attempt to do so here. Casesof sicknessand deathfrom shellfishtoxins are probably the most clearly documented amongthe different types of HAB impacts. Becauseof the high level of public interest in seafoodsafety, these cases are recordedby public health agenciesin individual statesas well as at the federal level.
3.1 PSP, NSP, and ASP Illltesses
During 1978-87,paralytic shellfishpoisoning PSP! was a minor causeof seafood-borneillness in the United States,according to data on illness casesreported to the Center for DiseaseControl CDC! in Atlanta Table 3.1!. On1y two deathsdue to PSP were reported during this period. Nishitani and Chew 988! presentdata on reportedPSP cases during 1979-87in the four Pacific Coast states:Alaska, Washington,Oregon, and California. These data show that in the more recentyears there were far fewer PSPcases than in the earlieryears, especially in California. A separatereport &om the U.S.Food and Drug Administration identifies shellfish poisoning cases for the 1973-92period Rippey1994!. The reported number of PSPsiclmess cases varies widely acrossthese sources. For example,the CDC reports no PSP casesin 1987, but Nishitani and Chew 988! report seven PSP casesin Alaska in that year. Becausereports to CDC are voluntary, we believe that the CDC databaseunderestimates the number of PSP sickness cases in any year.
For the 1987-92period, we show in Table 3.2 our estimateof the public health impacts resulting from PSP,NSP, and ASP. Impactsranged from $11,098to $4.84million, with an averagecost of $1,02 million, The illness and death casespresented in Table 3.2 were compiled from the informationin AppendixA andthe tables in Nishitaniand Chew 988! andRippey 994!.
A few casesof respiratory complaintsand eye irritation are reported in Appendix A. Aerosolizedtoxins, such as those &om Gymnodiniumbreve in Florida, may well have caused someof thesecases, However, thesecomplaints are not included in Table 3.2 becauseof the difficulty in quantifyingthe numberof casesas well astheir impacts.
3.1.1 Illness Costs
We adoptthe estimatesused by Todd 995! for PSP illnesses C$1500 [1993 Canadiandollarsj per reported illness and C$1180 [1993 Canadiandollars] per unreported illness! to estimatethe costsof foodbornedisease due to PSP,NSP, and ASP in the United States.Unreported illnesses
22 EconomicImpact of HABs in the U.S.
Table 3.1: Illness Due to natural Seafood Toxins in the United States Reportedto the Center for DiseaseControl
NOTE: An outbreakis an incidentinvolving two or more sick individuals,and a caseis a single ill person. Source: F. E. Ahmed ed.!, 1991.Seafood Safety, p. 89.
23 Economic Impact of HABs in the U.S,
Table 3.2: Shellfish Poisoning Impacts from Harmful Algal Blooms
'Reportedillnesses are estimated to be 10percent of all illnessesdue to HAB events Todd, pers.comm., 1997!. Economic impacts are estimatedat $1,374 per reportedilhess, $1,0SI per unreportedillness,and $4.73 million per death 000 dollars!. Pleasesee the text for references.!Values in the tableare reported in 2000 dollars.
'Includes one mortality in Alaska.
Sources: Appendix A, Nishitani and Chew 988!, and Rippey 994!. EconomicImpact of HABs in the U.S. do not, by definition,incur medicaland transportationcosts. Illnesscosts includelost productivitydue to sick days,costs of medicaltreatinent and transportation,and costs associatedwith investigationsfor the causeof the sickness. The figureswe useare downward revisionsof earlierestimates published by Todd 989a, 1989b!.Because cost information is not availablespecifically for NSPor ASP illnesses,we apply the cost estimatesfor PSPcases to these illnesses. Duringthe study period, one person died &om PSP in Alaskain 1989. Our estimateof the economicimpact per deathis basedupon labor market studies of the implicit valueof life Viscusi1993!. Such studies have been used to developestimates of boththe value of life and thecosts of nonfatalillnesses from empirical data that relatewage premiums to job risks. These studiessuggest that thereis a rangeof the valueof life &om $3 to $7 milhon,and we use an estimate of $4 million for the one life lost in Alaska 993 dollars!.
3.1.2 Unreported IHnesses
We know that a substantialnumber of illnessescaused by HABs remainunreported. However, no reliablemethod has been proposed for extrapolating&om the reportedcases to estimatethe true numberof illnesses. Todd 989a! proposedmultiplying the numberof reported casesby a factor of ten to estimatethe total. Until betterinformation on unreportedillnesses is available,we believethat the most conservative way to reportour findingsis to providecost estimatesbased uponactual, reported poisoning episodes, using Todd's multiplier, without additionalarbitrary adjustments.
Our estimateof publichealth costs of unreportedillnesses is much lower than the annualPSP costsof $2.31million 000 U.S.dollars! estimated for the United Statesby Todd 989a!, who employedmuch larger estimates of costsper i11ness C$6000 in 1985Canadian dollars! during a differentperiod 978-82!. Todd'scalculation also accounts for the likelihoodthat unreported casesare very likely to be lessserious than reportedcases, implying that theremay be lower associatedmedical treatment and invesugationcosts. Following Todd's lead,we multiplied the numberof reportedcases during 1987-92 by 10,and weighted reported illnesses by the higher costper illness. Our annualaverage estimate of the publichealth impacts due to shellfish poisoningwas $1.02 million 000 U.S.dollars!, a valuethat is substantiallyless than Todd's 989a! estimate.
3 Labor market studieshave also been used to estimatethe implicit value of nonfatal injuries. These estimates fall in the rangeof $25to $50thousand Viscusi 1993!. Other methods for valuingmorbidity effects, such as survey techniques, resultin estimatesthat rangefrom $700to $3500,which aremore consistent with Todd's estimatesof illness costs e.g., Viscusi et al. !9S7!. Note, however, that survey methodsare very sensitive to perceptionsof risks.
25 EconomicImpact of HABs in the U.S.
3.2 Ciguatera
Another problem causedby toxic algaeis the syndrome called ciguaterafish poisoning CFP!, which is linked to dinoflagellatetoxins that move through the tropical food chain to the higher predators. Although ciguateratechnically is not a "blooin" phenomenon,we investigate it becauseit originateswith toxic microalgaeand has significanteconomic and public health costs e.g, Ragelis1984!. In Table 3,3, we report the number of human sicknessesdue to ciguatera poisoning in Florida Weisman, pers. comm., 1997!, Hawaii Hokama, pers. comm., 1994!, Puerto Rico Tosteson, pers. comm., 1997!, the U.S, Virgin Islands Tosteson, pers. comm., 1997!,Guam Haddock,pers. comm., 1997!,and the Marshall Islands RuQ' 1989!, We develop our own estimates of sicknessesin Palau, Micronesia, the Northern Mariana Islands, and AmericanSamoa based on the incidenceof ciguateraillnesses in the Marshall Islands. To be consistent across all regions, we adopt Todd's 995! estimate of the illness costs 993 Canadiandollars! due to ciguateraof C$1100 US$1,007 [2000 dollars]! per reported caseand C$750 US$687 [2000 dollars]! per unreported case. This may result in an overestiinateof ciguateracosts in Puerto Rico, as Tosteson pers. comm., 1997! thinks that the costs per reportedcase are lower in PuertoRico about US$532per reportedcase 000 dollars!.
Experts differ on the ratio of reported to unreportedillnesses in eachjurisdiction. We use the following ratios. 1.'4for Florida Weisman,pers.comm., 1997!; 1;10 for the Marshall Islands, Palau,Micronesia, the Northern MarianaIslands, and AmericanSamoa our own estimate!;and 1;100for Hawaii, Guam,Puerto Rico, and the U.S. Virgin Islands Tosteson, pers. comm., 1997 andour ownestimates!. The economicimpact varies from $17.72million to $24.28million per year,averaging $21.19 million on an annualbasis. It is clearthat the economicimpacts due to ciguaterapoisoning account for mostof the public healthimpacts &om toxic algae, Nevertheless, we may not be estimatingthe true scaleof the problem, Ragelis 984!, for exaxnple,notes that ciguaterapoisoning often occursoutside of tropical areasdue to exports of tropical fish to other jurisdictions. Further, someseafood companies now purchaseinsurance to cover potential ciguatera-causedliabilities, and there are also court costs associatedwith ciguatera-related litigation, which has becomequite common.We have no estimatesof thesecosts, so ~ our estimates are conservative.
4 We includethe MarshallIslands, Palau, and Micronesia in our U.S.estimate because all threenations have a "compactof free association"with the United States and all three are heavily dependent upon the United States for foreign aid. The Northern Mariana Islands is a Commonwealthin political union with the United States, much like Puerto Rico. American Samoa is a territory of the United States much like the U.S. Virgin Islands. EconomicImpact of HABs in the U.S,
dd dl cdd g.cd 4C~d 0 +Cdl O dd O 55 'O cp Ch C5 dl 05 ~ C5 OQ .55 ~OcdU '4 OCI 'o ~ 0 cc5cd I c5 cca gdl0 Ch 0 OCI cc5d5 P i 0 0Ccd I 0O e ccrc A. 0 dl I 'a dl 0 V Cd dd C5 C5 cd~ Q0dl 0d5 o~ Ch c5 C4 dJ a cI cd 0 0 O OD 55g Cd Si < O cc5 O O0 cd ~ cd cc5C5 d5 cd CI 'Q "Cl O NI cd C5 cd C5 C5 I dl m dl 8 Q m cd ccem dl 'aE Cl 55 cd 04l 8 ~O ~55 dl C4 Cl d5 dl NO 5566 ~ & 0 ~ 0 dl 65 I c C cd dl cd Q v Q C4 VJdl I 55 O .icddcdl cc555 cd PAm 'aaQ0 0H dl ocd O cd cd dl dl 55 550 cd cd dd Kdl dl g ~ Cc o I 05 O nl V 8 cd Ch Ch M 0cd t9 C5 C50Clc cdM 55 55~. O0 pO0 cleg- I V O O 4 k C5 cp 8 0 Q CI 0 O o C! p o O' cd D CV O |50 0 ~ ca O dl Q M cd O O WWZ Wi
C5 Cd vj
C5
27 Economic Impact of HABs in the U.S.
4 COMMERCIAL FISHERY IMPACTS
In Table 4.1, we present HAH events for which commercialfishery impact information was obtained. Most of these eventsare describedin further detail in Appendix A, Annual impacts vary from $13.82to $25.88million. Averageannual impacts are $18.95million 000 dollars!.
4.1 Wild Harvest and Aquaculture Losses
We estimate total commercial harvest lossesduring a November 1987 to February 1988 G. breve bloom in North Carolina Testeret al., 1991! to be $8,27 million. We estimatetotal impacts of $17.64million arisingfrom the deathsof farmedAtlantic salmonkilled by phytoplanktonblooms in Washingtonin 1987, 1989,and 1990by multiplying the market price of salmonby the weight of lost fish. Two commercialshellfishing interests, Taylor United and the Coast Oyster Company,estimate a combined$1.22 million loss incurred during a shellfish recall resulting Rom the detectionof PSPtoxins in WashingtonState shellfish, Severalother HAB eventsare further clarified in the following sections.
4.1.1 Brown Tide Impacts on Bay Scallop Harvests in New York
In 1985, a brown tide bloom first appearedin the Peconic Estuary, Long Island and has reappearedsince on a regularbasis. The most significanteconomic impact was the eradicationof the Peconic'snationally significant bay scallopstocks. The Suffolk County Departmentof Health Servicesestimates that the 1982 value of cornlnerciallandings of bay scallops from the PeconicEstuary was $12.55million SCDHS 1992!. A multiplier may have beenused to arrive at this estimate.! However, Tettelbachand Wenczel 993!, citing a report by Rose 987!, estimatethe value of commercialbay scallop landings &orn New York waters for the years precedingthe 1985 brown tide incident at a much lower level, averaging$2.60 million 000 dollars! Table 4.2!.' In theonly studywe areaware of that looksat lost surpluses instead of lost sales!fiom a HAB event, Kahn and Rockel 988! estimate annual total consumers'and producers'surplus losses from the elimination of bay scallop populations in Long Island waters at a verysimilar level of $3.27million 000 dollars!.
Landing values are measuredat the averageV.S, bay scallop price of $4,9I/lb. 984 dollars!. The average price was $4.46/1b.in 1985. Estimatesof lost output have been converted into 2000 dollars in the table. EconomicImpact of HABs in the V.S.
Table 4.1: Commercial Fishery Impacts*