mfc stock assessment presentation.ppt - ncdmf.net stock assessment presentation.pdfflounder...
TRANSCRIPT
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N.C. Division of Marine FisheriesStock Assessment OverviewStock Assessment Overview
Trip Ticket ProgramRecreational Fishery Data Collection
Dependent Sampling ProgramI d d t S li PIndependent Sampling Program
Stock Assessments
Marine Fisheries Commission MeetingDec. 3, 2009,
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Trip Ticket ProgramTrip Ticket Program
Alan BianchiAlan BianchiTrip Ticket Coordinator
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What is the Trip Ticket Program?
A self reporting system through which dealers report every fish they purchase from fishermen for everyevery fish they purchase from fishermen for every commercial fishing trip that is made.Approximately 150,000 to 250,000 Trip Tickets are pp y , , pprocessed annually
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Example Trip Ticket
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Trip Ticket Software ExampleTrip Ticket Software Example
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Quality AssuranceQuality Assuranceand Compliance
Marine PatrolPort AgentRigorous data quality system
• Double Key Entry• Port Agent Review• Warning and Edits
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Comparison to Other States• Includes all fisheries from all coastal waters• Second oldest on East Coast
SC GA RI d ME T i Ti k t P• SC, GA, RI and ME Trip Ticket Programs are patterned after NC’s
• Extremely rigorous data quality control programExtremely rigorous data quality control program• Trip ticket analysts are very sensitive to
discrepancies and confidentiality
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T f A l iTypes of AnalysisEconomic Aid ProgramsEconomic Aid Programs
• Hurricane Floyd• ShrimpShrimp• Crab
Smooth Dogfish Trip Limit AnalysisEconomic AnalysisFederal Data Workshops
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Analysis Continued
More detailed analysis can also be completed• Poundage ranges by trip or fishermenPoundage ranges by trip or fishermen• Can be combined with license data• Multispecies analysis can be conductedp y
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Recreational FisheryyData Collection
Doug MumfordDoug MumfordMarine Recreational Statistics Coordinator
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Marine Recreationala e ec eat o aInformation Program (MRIP)
Two types of statistical survey design:
Eff SEffort SurveysCoastal Household TelephoneAngler Directory Telephone g y pFor-Hire Survey
Angler SurveysAngler SurveysAccess Point Intercept Surveys
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Methodology for Effortgy(Angler Trips)
Coastal Household Telephone Survey• Random calls to coastal residents
Accounts for exemptions in license frame• Accounts for exemptions in license frame
Angler License Directory Survey • Much more efficient• Still suffers from exemptions
For Hire Survey• Frame from blanket license and permit
10% C i ll d h k• 10% Captains called each week
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Effort Surveys yProvide Estimates of Overall Angler Trips
Coastal Household Telephone• > 15,000 calls annually• Every two months• Every two months
Angler License Directory• > 4,000 calls annually• Every two months
For Hire• > 3 000 calls annually• > 3,000 calls annually• Weekly
No catch data on phonep
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Effort Estimates
For Hire Telephone Survey
Angler LicenseDirectory
Total Angler Trips AdjustedDirectory
Telephone SurveyAdjusted
for Exemptions
Coastal HouseholdTelephone
Household SurveyHousehold Survey
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Intercept Survey• Comprehensive list of public sites• Random surveys at access sitesy• Interview anglers at end of trip • > 15,000 angler interviews annually • 27 interviewers statewide
• Data collected includes:
• 27 interviewers statewide
• Data collected includes:– Area fished, type of fishing,
tournament activity, artificial reef usage hours fished otherusage, hours fished, other
• Biological data collected includes:– Species observed and
reported, disposition,lengths, weights
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Sampler Distribution 2010#
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MRIP Pilot
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MRIP Catch Estimation
Effort Surveys Access Point Intercept Survey
Total X
AverageC t h = Total
Angler Trips
X CatchPer Trip
= Catch
Trip
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What Makes Good Data?What Makes Good Data?
PrecisionPrecision
•Mathematical analysis
Standards•Standards
Validation
Adj t t f b d•Adjustment for bad memories
•Ensure procedures followedEnsure procedures followed
•Cross-checking
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What Makes N C Data Better?What Makes N.C. Data Better?
First in nation in state participationFirst in nation in state participation Joined in 1987, nine other states have followed our lead
Conducted more than 400,000 angler interviewsConducted more than 400,000 angler interviews
Addressed limitations of MRFSSIncreased sample sizeIncreased sample size
Developed Catch Card Program, Ocean Striped Bass Catch Card, Upper Estuarine and Anadromous Sampling
MRIP ParticipationMRIP Pilot Programs
Coastal Angling Program (CRFL funded)
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Why is MRIP Important?yAvoid duplication
Take advantage of NOAA funding
Recognize need for regional database
Collective input for improvements
•Pilot programs underway nationwide p g y
•Magnuson reauthorization
NOAA must fix recreational data collection–NOAA must fix recreational data collection
–Over fishing must end in all areas by 2011
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Atlantic Coast Trips and Intercept
18 000
Sampling 2008
10,000,000
12,000,000
14,000
16,000
18,000
ts
Number of Intercepts
Number of
6,000,000
8,000,000
8,000
10,000
12,000
mbe
r of Trip
s
er of Intercep Trips
2,000,000
4,000,000
2 000
4,000
6,000
,
Num
Num
be
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2,000
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What Will the Future Bring?g
North Carolina Coastal Angler Program
•Staged for implementation in 2010
•Immediate increase in samples (5,000)
•Internet e-reporting
– Angler diaryg y
– Optional reporting
•Private accessPrivate access
•Flounder gigging and other nighttime fisheries
•Recreational shellfishRecreational shellfish
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Dependent Sampling ProgramsDependent Sampling Programs
Clark GrayClark GrayDMF Biologist
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What is Dependent Sampling?
The collection, recording and processing of data from commercial and recreational fishingdata from commercial and recreational fishing for use in management of the fisheries stocks.
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Predominant Fisheries Sampled: O ill t• Ocean gill net
• Estuarine gill net• Long haul seine/swipe net• Long haul seine/swipe net• Winter trawl• Pound netPound net• Beach seine/stop net• Crab pots
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Dependent Sampling Programs p p g g• Commercial fish house sampling program • Observer programObserver program
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H W S lHow We SampleFish houses are selected for sampling based on theirFish houses are selected for sampling based on their broad representation of fisheries and fishermen.
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Fish Houses Sampled
• Northern 31• Central 37Central 37• Southern 15
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Why We SampleT d t i i d i iti fTo determine size, age, sex and species composition of fish taken in commercial gears.
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Biological Data Collection • From a representative subsample of the catch
– Species/bycatch identificationL th– Lengths
– Weights• From the total catch• From the total catch
– Total weight – Species observedp– Specific gear, effort, and location information
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Sampling SummarySampling Summary2008
T i N mber of fish/ L th/M t iFishery Trips sampled
Number of fish/ crabs measured
Length/Metric Ton
Estuarine gill nets 1,053 49,630 18
Winter trawls 122 47,520 14
Sink nets 225 21,827 8
Pound nets 119 18 414 31Pound nets 119 18,414 31
Crab pots 486 24,514 2
Long haul seines 47 16,331 55
Other 461 16,031
Total 2,513 194,267
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Aging SamplesAging Samples2008
Number of Samples Southern flounder 892 Atlantic croaker 669
Bluefish 552 Spotted sea trout 538
Red drum 450 Weakfish 417
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Comparison of Dependent DataComparison of Dependent Data Collection in Other States
Required # lengths Completed # lengths North Carolina 474 6,343
Virginia 1,104 2,827 New Jersey 438 1,046 D l 66 409Delaware 66 409 Maryland 48 242 New York 234 213New York 234 213
Rhode Island 54 14
ASMFC FMP biological sampling of weakfish
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Ob D t C ll tiObserver Data Collection• Subsample catch (count, measure and weigh p ( , g
target/bycatch species)• Document time and location• Characterize gear• Record interactions with protected species
Collect environmental conditions• Collect environmental conditions
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A t 07 M h 09
Observer Summary
August 07- March 09
425 Trips19 532 M t19,532 Measurements
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Data Uses
• Coast wide assessments• Annual compliance reportsp p• Length-at-age keys• Catch-at-age matrices
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Benefits
• Provides timely and accurate data • Allows evaluation of effectiveness of current management• Continues development of long-term databases in North
Carolina and the Atlantic coast • Give opportunity for public outreach/input• Give opportunity for public outreach/input
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I d d t S li PIndependent Sampling Programs
Lee ParamoreLee ParamoreBiologist
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What Is Independent Sampling?What Is Independent Sampling?Information collected by biologists that does not y ginvolve the commercial or recreational harvest of fish.
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Why Do We Need It?
Fishery dependent data is biased. Fishermen use certain types of gear and employ fishing methods designed to target select species.
Fishery independent data is unbiased. Biologists use s e y depe de t data s u b ased o og sts useconsistent methods with the same gear for the duration of a survey.
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Independent SamplingIndependent SamplingDesign and Standardization
• Stratified random or fixed station design• Standardized gear construction and sampling techniques• Standardized gear construction and sampling techniques • Designed to encompass occurrence by season and area• Not dependent on skill of sampler but can be replicatedNot dependent on skill of sampler, but can be replicated
following set protocol• Value of survey increases with time
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Juvenile Trawl SurveyJuvenile Trawl SurveyPurposep
• Produce annual recruitment indices• Identify nursery areas for fish and shellfish
Methods• May and June after 1989 (monthly back to 1978)May and June after 1989 (monthly back to 1978)• Statewide fixed stations (105 core stations every year)• Two seam 10.5’ otter trawl, 1/8 inch bag, 1-minute tow• Environmental and bottom type data• Count and measure captured species
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Program 120 core stationsgJuvenile Trawl Survey
FIXED STATIONS
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Juvenile Trawl SurveyJuvenile Trawl Survey• One of longest running fishery-independent surveys on east
t (1978)
Juvenile Trawl SurveyJuvenile Trawl Survey
coast (1978)• Used in identification of critical habitat for key species (i.e.
primary and secondary nursery areas)primary and secondary nursery areas)• Fixed stations and long time series allow for evaluation of
development and other factors influencing habitat use over itime
• Provides index of abundance for key juvenile species including: blue crab southern flounder spot Atlanticincluding: blue crab, southern flounder, spot, Atlantic croaker, and brown shrimp
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Pamlico SoundIndependent Gill Net Survey
• Purpose• Purpose– Produce annual abundance indices by age-class– Characterize habitat useCharacterize habitat use
• Methods– February to December (64 samples per month)– Stratified Random (OBX, Hyde Co Bays, Neuse and
Pamlico/Pungo; shallow & deep)G f ill t 30 d h 3 t 6 ½ b ½ i h (240– Gang of gill nets 30 yards each, 3 to 6 ½ by ½ inch (240 yard/sample)
– Environmental and bottom type dataEnvironmental and bottom type data– Determine condition, count, measure
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NC Independent Gill Net Survey
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Pamlico SoundPamlico SoundIndependent Gill Net Survey
• Provides age-specific relative abundance indices• Used as a tuning index in stock assessments for southern
fl d d d kfi h tt d t tflounder, red drum, weakfish, spotted seatrout• Provides baseline data to identify changes in stock abundance
that can result from fishing regulations or environmentalthat can result from fishing regulations or environmental changes
• Provides data to evaluate habitat use patterns for key t i iestuarine species
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Examples of more NC Independent Surveys• Pamlico Sound Trawl Survey (1987 – on)
• Albemarle Sound Independent Gill Net Survey (1990 – on)
• Juvenile Anadromous Survey (1972 – on)
A t f Fi h P l ti i th C F (1997 )• Assessment of Fish Population in the Cape Fear (1997 - on)
• Red Drum Seine Survey (1992 – on)
• Red Drum Longline Survey (2007 – on)
• Striped Mullet Electroshock (2003 on)• Striped Mullet Electroshock (2003 – on)
• Shrimp Sampling in Estuarine Areas (1970’s – on)
• Tagging Programs (1980’s - on)
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SummarySummaryNorth Carolina has a wide range of independent surveys that provide indices of relative abundance on various life history stages of key species
Independent surveys provide critical data for both monitoring trends in relative abundance and for evaluating critical habitat needs
S i tifi ll d i d d li th dSurveys are scientifically designed and sampling methods are standardized to minimize sampling bias
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How It All Fits TogetherHow It All Fits TogetherStock Assessment Reference Points,
M d l d P j tiModels and Projections
Louis DanielLouis DanielDMF Director
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What Is a Stock Assessment?
A stock assessment is a compilation of what is known about a stock that tells a logical story explaining about a stock that tells a logical story explaining historic trends and predicting future trends.
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What Does aWhat Does a Stock Assessment Do?
Provides past and present stock status - Is the stock getting bigger or smaller?
Makes predictions on a stock’ s response to management optionsmanagement options
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R i N l M liRecruits
‘Births’
Natural Mortality
‘Deaths’
THE STOCK
G th Fishing MortalityGrowth
‘Weight/Maturity’
Fishing Mortality
‘Death by Misadventure’
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What DoWhat DoStock Assessments Use?
Biological information (independent and dependent)• Monitoring surveysg y• Age and growth • Environmental conditions
Fishing activity (commercial and recreational) • Landings and discards
G• Gear• Effort
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What Methods Are Used?• Trends AnalysisLOW
• CPUE• Catch Curve Data Needs
• Biomass & Production• Catch Survey AnalysisComplexity
• Virtual Population Analysis• Mark-Recapture, Tag Return
Informationp g
• Statistical Catch-at-Age• Multi-species
HIGHp
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Length at Age FlounderLength at Age Flounder
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Flounder Estuarine GillnetFlounder Estuarine Gillnet
30
35
25
30
ency
15
20
cen
t F
req
ue
5
10
Per
c
0
Size Class (in.)( )
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Flounder Estuarine GillnetFlounder Estuarine Gillnet400,000
300,000
350,000
200,000
250,000
PO
UN
DS
100,000
150,000
-
50,000
0 1 2 3 4 5 6 7 8 9AGEAGE
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Flounder Independent Gill Net 0.45
0 30
0.35
0.40
n
0.20
0.25
0.30
rop
ort
ion
0.05
0.10
0.15P
0.00
0 1 2 3 4 5 6 7 8 9
AgeAge
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What does age structure tell us?
• At what age the fish are harvested• How long the fish live• How many of what age make up the stock
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Hypothetical Human ypPopulation
Unstressed20
Unstressed
14
16
18
s)
10
12
atio
n (m
illio
ns
4
6
8
Pop
ula
0
2
Age
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Stressed18
20
12
14
16
ns)
6
8
10
ulat
ion
(mill
ion
0
2
4
Pop
u
Age
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At War
161820
s)
8101214
atio
n (m
illio
ns
2468
Pop
ula
0
AgeAge
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What Is Mortality?What Is Mortality?
Rate that fish dieRate that fish die• Fishing mortality = death from fishing
– LandingsLandings– Discards
• Natural mortality = any other death – Predation– Disease– Environmental– Old age
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How Do We Determine Mortality?How Do We Determine Mortality?1200
Fished Unfished
800
1000
ions
)
600
800
Fish
(in
mill
200
400
Num
ber o
f F
00 2 4 6 8 10 12 14 16 18 20
Ageg
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Speckled TroutSpeckled Trout Spawning Stock Biomass
400
s (l
b)
2003-2008 (SPR 8%) Threshold (SPR 20%) Unfished (SPR 100%)
150
200
250
300
350
Sto
ck B
iom
ass
050
100
150
0 1 2
Sp
awn
ing
S
0 1 2 3 4 5 6+
Age
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The Final Step: Using Results
Biological Reference Points• Targets• Thresholds
ProjectionsU i th lt d b i d l k• Using the results and same basic models, work forward to predict what might happen under management alternatives
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Biological Reference PointsBi l i l f i t i di t th h t kBiological reference points indicate the chosen stock state and mark the boundary of undesirable stock conditionsProvides guidance in determining• If the population is too small• If F is too high
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Choosing Reference Points
Begin with a management goal• Sustainable harvest• Preserve the parent stock• Rebuild the parent stock
Q tif th t lQuantify that goal• Yield- based points• Spawning stock biomass per recruitSpawning stock biomass per recruit• Maximum sustainable yield
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Fishing Mortality withR f P i tReference Points
1.40001.60001.8000
ity
0 60000.80001.00001.2000
ing
Mor
tal
FThreshold
0 00000.20000.40000.6000
Fish
FTarget
Threshold
0.0000
Year
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Spawning Stock Biomass with Reference Points
7,000,0008,000,0009,000,000 SSBTarget
SSB
4,000,0005,000,0006,000,000
emal
e SS
B SSBThreshold
01,000,0002,000,0003,000,000Fe
0
YearYear
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Sustainable ResourceSustainable Resource $50 Monthly Light Bill
$1,000 Principal (SSB)
5% Interest(F)
$50 Earnings(Sustainable Harvest)
$800 Principal(Red Tide)
5% Interest $40 Earnings
$790 Principal
$800 Principal 8% Interest $64 Earnings$800 Principal 8% InterestF Rebuilding
$64 Earnings
$814 P i i l$814 Principal
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Projections Are Used To:E ti t t k t t i th tEstimate stock responses to management scenarios that end overfishing and rebuild the stock
Answer ‘what if’ questions
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ProjectionsProjections90000006,000,000
6000000
7000000
8000000
4 000 000
5,000,000
omas
s
Target SSB(Sustainable harvest)
4000000
5000000
6000000
3,000,000
4,000,000
g St
ock
Bio
Threshold SSB(No longer overfished)
1000000
2000000
3000000
1,000,000
2,000,000
Spaw
ning
0
1000000
01 2 3 4 5 6 7 8
Year
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U t i t i D t P j tiUncertainty in Data Projections
Arises from many sources• Input data• Model assumptions• Environmental Influences
M d l Li it ti• Model Limitations
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Uncertainty
Assessments and projections should show, as best they can, the levels of uncertainty in the results
Knowledge of this uncertainly helps managers make informed decisionsinformed decisions
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