MANAGING NORTHERN BALTIC SALMON FISHERIES UNDER SOCIAL-ECOLOGICAL COMPLEXITY. Maatalous-metsätieteellinen tiedekunta

Koko: px

Aloita esitys sivulta:

Download "MANAGING NORTHERN BALTIC SALMON FISHERIES UNDER SOCIAL-ECOLOGICAL COMPLEXITY. Maatalous-metsätieteellinen tiedekunta"

Mari Uotila
6 vuotta sitten
Katselukertoja:

1 MANAGING NORTHERN BALTIC SALMON FISHERIES UNDER SOCIAL-ECOLOGICAL COMPLEXITY Atso Romakkaniemi 20/07/2016 1

2 CONTENTS Introduction to the conflict between sequential salmon fisheries Description of the bioeconomic model Ecological and economic implications of ignoring behavioral complexity of anglers Atso Romakkaniemi 20/07/2016 2

3 THE MIGRATION ROUTES AND FISHERIES OF RIVER TORNIONJOKI SALMON STOCK Migration routes Trap net fishery 3 Recreational fishery Longline fishery 20/07/2016

4 COMMERCIAL SALMON FISHERY IN DECLINE Finnish marine commercial salmon catch Atso Romakkaniemi 20/07/2016 4

5 SALMON ANGLING GAINS POPULARITY Source: Natural Resources Institute Finland Atso Romakkaniemi 20/07/2016 5

6 SALMON SPAWNING RUN Number of salmon Natural Resources Institute Finland Date Atso Romakkaniemi 20/07/2016 6

7 COASTAL VS. RECREATIONAL FISHERY How the optimal management of the commercial fishery depends on the recreational fishery? What are the implications of ignoring angling and the behavioral complexity of angling? 7 Atso Romakkaniemi 20/07/2016 7

8 THE BIOECONOMIC MODEL Direct effect: Commercial effort decreases the fish available for anglers Indirect effect: Angling effort decreases the number of spawners Atso Romakkaniemi 20/07/2016 8

MODEL SPECIFICATIONS Age-structured population model Leslie matrix

Optimized commercial trap-net fishery Commercial fishermen are profit

effort through time Recreational fishery Type-specific utilities based

based on the satisfaction of previous angling trip Socialization

9 MODEL SPECIFICATIONS Age-structured population model Leslie matrix model with 10 age-classes Beverton-Holt stock-recruitment relationship Optimized commercial trap-net fishery Commercial fishermen are profit maximizers Dynamic optimization is used to define the commercial effort through time Recreational fishery Type-specific utilities based on valuation studies Anglers decide whether to stay home or go fishing based on the satisfaction of previous angling trip Socialization defines the frequenzy of angler types through time Atso Romakkaniemi 20/07/2016 9

10 SOCIAL COMPLEXITY ATTRIBUTES OF 1. EFFORT ORIENTED ANGLERS - Enjoy the nature - Strong preference for solitude Effort oriented 2. CATCH ORIENTED ANGLERS - Prefer to catch something - Slight preference for solitude Catch oriented Atso Romakkaniemi 20/07/

11 SCENARIOS 1. No recreational fishing A hypothetical scenario to see what is the optimal level of commercial effort when there is no angling 2. Static recreational fishing A scenario that mimics the current ICES salmon assessment model, where recreational fishing is described by a constant mortality 3. Endogenous recreational fishing with angler behavioral complexity Recreational fishing effort is endogenously changing. Anglers change the frequency of angling trips, dependent on how satisfying each trip is. Atso Romakkaniemi 20/07/

12 8 x OPTIMAL COMMERCIAL TRAP NET EFFORT Effort in geardays No angling Static angling Endogenous angling Time Atso Romakkaniemi 20/07/

13 1 COMMERCIAL FISHERY: CATCH PER UNIT OF EFFORT Catch per unit of effort 0.9 CPUE Time No angling Static angling Endogenous angling Atso Romakkaniemi 20/07/

14 ENDOGENOUS ANGLING: HARVEST 8 x Number of fish Coastal trap net fishery Catch Effort oriented harvest Effort Catch oriented harvest Time Atso Romakkaniemi 20/07/

15 ENDOGENOUS ANGLING: NUMBER OF ANGLERS Effort oriented Catch oriented Number of anglers Time Atso Romakkaniemi 20/07/

16 ECONOMIC VALUE OF THE FISHERY No angling Static angling Endogenous angling Net Benefits of the Recreational fishery Discounted NPV of the commercial fishery Atso Romakkaniemi 20/07/

17 NUMBER OF SALMON SMOLTS 1.8 x 106 Number of salmon smolts No angling MSY Static angling Endogenous angling Period Atso Romakkaniemi 20/07/

18 SALMON SPAWNING STOCK SIZE 7 x 104 Spawning stock size Stock size in numbers Static angling No angling Endogenous angling Period Atso Romakkaniemi 20/07/

19 CONCLUSIONS Summed economic value is greatest under endogenous angling scenario Surprisingly, the highest commercial effort is realized in the Case 3 under complex angler behavior. This is a result of strong competition between the commercial and recreational fishery. When the utility of staying at home is low, it is possible that the fish stock crashes as the number of effort oriented anglers increase Atso Romakkaniemi 20/07/

20 REFERENCES Michielsens, C., McAllister, M., Kuikka, S., Pakarinen, T., Karlsson, L., Romakkaniemi, A., Perä, I., Mäntyniemi, S A Bayesian state space mark recapture model to estimate exploitation rates in mixed-stock fisheries. Canadian Journal of Fisheries and Aquatic Sciences 63, ICES Report of the Baltic Salmon and Trout Assessment Working Group (WGBAST), 30 March 6 April 2016, Klaipeda, Lithuania. ICES CM 2016/ACOM: pp. Johnston, F., Arlinghaus, R., and Dieckmann, U Diversity and complexity of angler behaviour drive socially optimal input and output regulations in a bioeconomic recreational-fisheries model. Can. J. Fish. Aquat. Sci. 67: Kulmala, S., Laukkanen, M., Michielsens, C., Reconciling economic and biological modeling of migratory fish stocks: Optimal management of the Atlantic salmon fishery in the Baltic Sea. Ecological Economics 64, Stoeven, M. T Enjoying catch and fishing effort: The effort effect in recreational fisheries. Environ. Resource Econ. 57: Atso Romakkaniemi 20/07/

21 THANK YOU Atso Romakkaniemi 20/07/

22 SALMON POPULATION MODEL Data provided by ICES Baltic Salmon and Trout Assessment Working Group (WGBAST 2016). ss ii,tt+1 = ss ii,tt AA tt ii 1,, 10 ss ii,tt+11 ss ii,tt AA tt ss 1,tt+1 ss 2,tt+1 ss ii 1,tt+1 ss ii,tt+1 = ss 1,tt ss 2,tt ss ii 1,tt ss ii,tt FFFFFF 1,tt FFFFFF 2,tt FFFFFF ii 1,tt FFFFFF ii,tt SSSSSS 1,tt SSSSSS 2,tt SSSSSS ii 1,tt 0 Atso Romakkaniemi 20/07/

23 Biomass in kg ENDOGENOUS ANGLING: RECREATIONAL HARVEST PER TRIP Catch oriented anglers Effort oriented anglers Time Atso Romakkaniemi 20/07/

24 COMMERCIAL COASTAL TRAP NET FISHING Dynamic optimization of the commercia fishing effort HH vv ii,tt = 1 ee qq iiee vv,tt hrr ii ss ii,tt 10 ππ vv,tt = ii=1 pp ii HH vv ii,tt gg ccee vv,tt HH vv ii,tt 0 ss ii,tt 0 NNNNNN vv = max EE vv,tt 50 ππ vv,tt / 1 + rr tt 1 tt=1 24 Atso Romakkaniemi 20/07/

25 ANGLER DECISION MAKING There are aa types of anglers: effort (denoted by f) and catch oriented (denoted by c). Effort per angler (ee aa,tt ) is the number of fishing days (nn aa,tt ) multiplied by fishing motivation (ε aa,tt ): Total type-specific effort depends on the number of anglers (NN aa,tt ) and the effort of single angler (ee aa,tt ): ee aa,tt = ε aa,tt nn aa,tt EE aa,tt = ee aa,tt NN aa,tt Atso Romakkaniemi 20/07/

26 ANGLER DECISION MAKING Total recreational effort: EE tttttt,tt = EE cc,tt +EE ff,tt Total recreational harvest in number of fish, summed over all salmon age-classes: HH RR,tttttt ii,tt = hrr ii ss ii,tt ee qq iiee vv,tt 1 ee qqrr iiee tttttt,tt Atso Romakkaniemi 20/07/

27 ANGLER DECISION MAKING Type-specific recreational harvest: HH ii,aa,tt = HH RR,tttttt ii,tt ( EE aa,tt ) EE tttttt,tt Atso Romakkaniemi 20/07/

28 ANGLER DECISION MAKING: Utilities Utility of catch oriented anglers depends on the number of fish caught per trip Utility of effort oriented anglers depends on the weight (W) UU tt cc = μμhh tt cc θθhh tt cc2 ee cc,tt UU ff tt = μμww ff ff ii,tt + θθww 2 ii,tt ee ff,tt Atso Romakkaniemi 20/07/

29 ANGLER DECISION MAKING Number of angling trips at t+1 (ee aa,tt+1 ) depends on last year s benefits from angling (UU aa,tt ) and the average utility obtained from leisure ( UU aa,tt ). Should I stay home or should I go fishing? ee aa,tt+1 = ee aa,tt UU aa,tt UU aa,tt Average utility obtained from leisure is the result of angling and the exogenous utility from staying home and doing an alternative activity UU. Free days per year is given by ee Discrete version of replicator equation (Sigmund 1986) UU aa,tt = ee aa,ttuu aa,tt + ee ee aa,tt ee UU Atso Romakkaniemi 20/07/

30 EVOLUTION OF ANGLER BEHAVIOR Total number of anglers is NN TT = NN ff,tt + NN cc,tt Adopting angling as a new hobby: ττnn tt stop and ττnn tt start angling Socialization determines the angler type according to the prevalence of each angler type ee ff,tt NN ff,tt ee cc,tt NN cc,tt + ee ff,tt NN ff,tt ee cc,tt NN cc,tt ee cc,tt NN cc,tt + ee cc,tt NN cc,tt Atso Romakkaniemi 20/07/

31 EVOLUTION OF ANGLER BEHAVIOR The difference equations of the angler types: ee ff,tt NN ff,tt NN ff,tt+1 = 1 θθ NN ff,tt + θθnn TT ee cc,tt NN cc,tt + ee ff,tt NN ff,tt NN cc,tt+1 = 1 θθ NN cc,tt + θθnn TT ee cc,tt NN cc,tt ee cc,tt NN cc,tt + ee cc,tt NN cc,tt Atso Romakkaniemi 20/07/

Samankaltaiset tiedostot

Socio-cultural valuation of ecosystem services provided by Baltic Salmon. Timo P. Karjalainen Thule Institute/University of Oulu Oulun yliopisto

Socio-cultural valuation of ecosystem services provided by Baltic Salmon Timo P. Karjalainen Thule Institute/University of Oulu Oulun yliopisto Sisällys/content The issue (kysymys): how to value and assess