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Published byJulian James Modified over 10 years ago
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(Western) Channel Fisheries UK Finlay Scott, Trevor Hutton, Alyson Little, Aaron Hatcher cemare
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Introduction Case study (Beam trawlers – English; sole and others) VIIe (assessment, projections)(TAC + X) SeaFish (two fleets, UK = 0.43) Profit (both fleets combined) MFA: enforcement (relationship estimated) –Enforcement effort (and cost) and X Shadow value of biomass (numerical approx) Social Benefit computed
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Data collection General setting ( ) Technical characteristics ( ) Biological characteristics ( ) Socio-economic characteristics ( ) Management ( ~ ) Enforcement (~)
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Area of study: boundaries General setting
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Landings Sole (VIIe) General setting
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Landings Monk Megrim Plaice (VIIe&d) General setting
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Effort
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Estimates of F General setting
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Landing per unit of effort
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Spawning stock Biological characteristics
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Long –term maximum yield (0.24) Biological characteristics ~ O.26
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Stock recruitment relationship Biological characteristics
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Management and Enforcement issue (X) Over quota (evidence of cod, sole) Declaring Sole (VIIe) as sole landed in VIId() Is what is in the hold or quay the same as the paper work
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Model: structure Stock(s) Fleets Effort VIIe Sole Catch Revenue Fishing costs Profit and incomes Outside VIIe Revenue Stocks in VIIe Recruitment, growth, natural mortality Effort VIIe Fish prices Other Catch (outside VIIe) F ~ TAC + x
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English Fleets data > 221 Kw 221 Kw >30m (Seafish economic data) Logbook data Average and Total GT, KW, no of boats - cross checked Partial catch for each fleet - adjusted for misreporting Effort over time in VIIe and outside - hours and days Compute partial F, then estimate catchability per fleet (q=F/E) Revenue of other stocks in VIIe Revenue outside VIIe (assumed to stay constant)
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Fleet economic info in the model Cost information based on survey returns from SEAFISH report Cost information checked Scaled for latest decommissioning Cost structures (2005) –Annual costs (£/vessel average) –fuel costs (per year), other running costs (convert to £/day for variable costs) –Crew shares (%), –Capital costs No depreciation No interest (presented) Quota values
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UK beam >221kw ( 221kw (<30m) Technical characteristics
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UK beam >221kw (>30m) Technical characteristics
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UK beam >221kw ( 221kw (<30m) Added up all variable costs And all fixed costs Economic characteristics
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UK beam >221kw (>30m) Added up all variable costs And all fixed costs Economic characteristics
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Estimates of profit 221 Kw 221 Kw >30m Total Revenue = Revenue VIIe (sole[model] + other in VIIe) + Rev(outside VIIe) Cost of effort in VIIe = partial F of sole each fleet / catchability (Catchability = F/E thus E = F/q) Total Variable costs = Cost of Effort in VIIe ( f (sole F) + outside variable costs Total Costs = Total Variable + Total Fixed + 0.25*Tot Rev (crew share) Profit = Total Revenue – Total Costs All estimated from 2005 data – the base year
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Enforcement MFA report (2006) Enforcement characteristics
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Enforcement - activity MFA report (2006)
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Consider: area with total - estimate costs for case study (requested information) Therefore – awaiting CASE specific data for VIIe Sole and SW-beam trawl fleet (for 2-3 years?)
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ASSUMED Enforcement relationships X = difference between reported and assumed (the mis-reported) Standardised enforcement effort(~?) Total £11m, assumed fishery max is £2m 01Prob of sanction X 0.6 step 1 step 2 step 3
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SSB over time (projections from assessment)
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Catch over time (vary F: TAC + X) Catch (tonnes)
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Social value versus cost of effort In this case difference in social value see Memo 8 Memo 8 this is termed the social value
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Social value versus enforcement effort Same again except plotted against enforcement effort
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Social Benefit versus enforcement effort
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Are we correct(?) Harvest (tonnes) Euros per tonne V is social value We vary (e) thus x, And compute v and V NOTE SB is a partial SB (SB of our fleets). A proxy for total SB assuming Others do the same
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Next steps MFA data required (to be released) Include penalty (f) Check assumptions and equations Sensitivity tests (assumptions about revenue of other stocks and F of other fleets [French and Belgium]) Uncertainty (recruitment only)
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Possible f values(?) Estimate expected f as a function of over-quota landings
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Summary Completed model Compute indicators Update and check all values Summarise results
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