Ecosystem-based Management of Fisheries Resources in Marine Ranching Areas Chang Ik Zhang, Sung Il Lee, and Jong-Man Kim * Pukyong National University * Korea Ocean Research and Development Institute
Introduction Contents - Introducing an ecosystem-based approaches in fisheries management for marine ranching area - Analysis of ecosystem changes before and after marine ranching activities - Comparison of the results from the ecosystem model and the population model In marine ranching project - for providing a stable habitat -> construction of seaweed bed and artificial reefs - for stock enhancement -> artificial releasing activity
A map showing the marine ranching area of Tongyeong, Korea Area -Total -Main : 9000 ha : 2000 ha - Protection waters : 540 ha
Bird-eye view of the marine ranching area Marine ranching area projects - 1998 year Tongyeong (1998-2004 : 9 yrs) - 2001 year Yeosu (2001-2008 : 8 yrs) - 2003 year Jeju (2003-2010 : 8 yrs)
The status of Tongyeong marine ranching Construction of seaweed 6 months after construction - Species : two brown algae Ecklonia stolonifera, Ecklonia cava -Below 6 m - Area : 1,117,118 m 2 2 years after construction
The status of the Tongyeong marine ranching Construction of artificial reefs - Area : 752 ha - Numbers of artificial : 7,852 Ship reef
Rocky bottom and location of artificial reefs in marine ranching area
Location of releasing and released target species in the Tongyeong marine ranching area Jacopever rockfish Black rockfish Abalone Black seabream Red seabream
Data and Methods Ecosystem model - Ecosystem structure model : Ecopath model -> Analyzing the ecosystem structure (Christensen and Pauly, 1992) - Ecosystem dynamic model : Ecosim model (Walters et al., 1997) -> Estimating changes in quality of organisms and carrying capacity of ecosystem Population model - Stock enhancement model -> Estimating a carrying capacity, potential production, and the optimum number for the stock enhancement - Stock management model -> Estimation a acceptable biological catch (ABC)
Schematic diagram of ecosystem models
Methods of input parameter estimation Biomass (B) - Being obtained from oceanographic and fisheries resources surveys, or estimated from cohort analysis Production/Biomass (P/B) ratio - Being estimated by three methods 1) the instantaneous coefficient of total mortality (Z) : 2) growth rate (G) : 3) von Bertalanffy growth equation : Z B P = / G B P = / ] 3 1 2 3 3 1 [ ] 3 1 2 2 1 [ 3 K Z K Z K Z Z K Z K Z K Z K B P + + + + + + + + =
Methods of input parameter estimation Consumption/Biomass (Q/B) ratio - Being calculated from survey data and references - For a group which consisted of multi-species is estimated to be the weighted mean by the biomasss of the associated species Diet composition (DC) Q k ij - DC ij = = 1 Q DC ij i j= 1 Catch (C) - Catch per unit area by species and by gear, obtained from a field survey
Flow chart for stock enhancement system Age-specific length (weight) Catch by ages Age composition longevity von Bertalanffy growth parameters Survival rate Age at recruitment Instantaneous coefficient of natural mortality Instantaneous coefficient of fishing mortality Recruitment Carrying capacity by species from ecosystem model Yield per recruit per unit area Beverton and Holt model Virgin biomass per recruit per unit area (F=0) Current bimass " (F=Fc) The number of current recruitment The number of recruitment, when F=0 Optimum number of recruitment for stock enhancement Area Age at being juvenile Optimum individual number for stock enhancement Age-specific maturity ratio Spawning biomass per recruit per unit area Expected yield increasing Expected biomass increasing Expected spawning biomass
Flow chart for the TAC estimation Longevity Age-specific length (weight) von Bertalanffy growth parameters Catch by ages Length composition Catch and fishing effort Survival rate Age at recruitment Instantaneous coefficient of natural mortality Instantaneous coefficient of fishing mortality Biomass(individual) and fishing mortality by ages Pelagic stocks Environmental factors (temperature, plankton, etc.) MSY and F MSY : Zhang model MSY and f MSY : G-S, Fox, P-T, Schnute, and Deriso models Age-specific maturity ratio F max, F 0.1 and Opt t c : B-H model F 40%, F 35% : B-H model Future biomass Simulation : Zhang, and Deriso models Considering the structure and function of ecosystem A B C Social and economical factors T A C
ABC estimation model ABC estimation for a single species ABC = F 0.1 M B + F 0.1 (1 e ( M + F 0.1 ) ) ABC estimation for multi-species by a single gear ABC j = ABC B i i B j ABC i and B i : the acceptable biological catch and biomass of target species (i) by single gear, respectively ABC j and B j : the acceptable biological catch and biomass of stock (j), although they are included in same group, the are target of other fishing gear and the population parameters are unknown, respectively
Input parameters in the Tongyeong ecosystem before marine ranching activities Group name Habitat area (fraction) Biomass in hab. Area (t/km 2 ) Production /Biomass (/year) Consumption /Biomass (t/km 2 ) Catch (t/km 2 ) Finless porpoise 0.003 0.020 13.108 0.000 Otter Pisc. Birds Skates Flatfishes Adult jacopever rockfish Juv. Jacopever rockfish Other rockfishes Sparidae Anguilliformes Moronidae Grey mullet Hairtail Other demersal fish 0.400 0.400 0.001 0.001 0.258 0.396 0.032 0.972 0.108 0.230 2.514 0.164 0.184 0.457 0.239 0.060 0.800 1.565 1.365 1.368 2.772 1.368 1.409 1.368 1.455 1.300 1.460 1.155 91.250 60.000 2.560 2.490 10.790 37.176 12.061 2.500 2.600 26.160 2.500 2.600 18.293 0.000 0.000 0.387 0.414 0.011 0.034 0.078 0.149 3.301 0.019 0.001 0.545 0.018
Input Parameters in the Tongyeong Ecosystem before Marine Ranching Activities Group name Habitat area (fraction) Biomass in hab. Area (t/km 2 ) Production /Biomass (/year) Consumption /Biomass (t/km 2 ) Catch (t/km 2 ) Large pelagics 0.480 2.214 3.000 0.311 Small pelagics 12.380 2.800 3.500 31.579 Cephalopoda 1.640 3.300 0.278 Benthic feeders 3.850 2.534 7.100 0.293 Infauna 25.585 1.722 11.226 0.017 Epifauna 11.464 1.217 5.777 10.314 Gastropoda 1.786 2.303 5.777 0.147 Zooplankton 12.796 9.000 22.000 - Benthc algae 9.200 534.068-2.760 Phytoplankton 0.400 91.276 170.000 - - Detritus - - - -
Diet composition by group in the Tongyeoung ecosystem before marine ranching activities Prey \ Predator 1 2 3 4 5 6 7 8 9 10 11 1 Finless porpoise 2 Otter 3 Pisc. Birds 0.070 4 Skates 0.023 5 Flatfishes 0.023 0.050 0.176 6 Adult Jacopever rockfish 0.035 0.050 0.029 0.004 7 Juv. Jacopever rockfish 0.035 0.050 0.457 0.054 0.115 0.194 8 Other rockfishes 0.035 0.050 0.023 0.004 9 Sparidae 0.035 0.050 0.023 0.029 0.037 10 Anguilliformes 0.035 0.050 0.023 0.029 0.037 0.004 11 Moronidae 0.035 0.050 0.176 0.023 0.024 0.037 0.004 12 Grey mullet 0.035 0.050 0.176 0.023 0.029 0.037 0.004 13 Hairtail 0.039 0.050 0.023 0.029 0.037 0.004 14 Other demersal fishes 0.035 0.050 0.176 0.023 0.044 0.062 0.004 15 Large pelagics 0.006 0.050 0.029 0.029 0.159 0.020 0.011 16 Small pelagics 0.018 0.026 0.057 0.031 0.044 0.054 0.027 0.056 0.033 0.080 17 Cephalopoda 0.045 0.229 0.088 0.009 0.019 0.059 0.194 18 Benthic feeders 0.433 0.217 0.088 0.266 0.120 0.067 0.244 0.059 0.194 0.307 19 Infauna 0.384 0.264 20 Epifauna 0.121 0.102 0.197 21 Gastropoda 0.013 22 Zooplankton 0.003 0.229 0.088 0.020 0.363 0.933 0.196 0.474 0.386 0.613 23 Benthic algae 0.102 24 Phytoplankton 0.025 25 Detritus SUM
Diet composition by group in the Tongyeoung ecosystem before marine ranching activities Prey \ Predator 12 13 14 15 16 17 18 19 20 21 22 1 Finless porpoise 2 Otter 3 Pisc. Birds 4 Skates 5 Flatfishes 6 Adult Jacopever rockfish 7 Juv. Jacopever rockfish 0.214 0.029 0.129 8 Other rockfishes 0.011 9 Sparidae 0.011 10 Anguilliformes 0.011 11 Moronidae 0.011 12 Grey mullet 0.011 0.014 13 Hairtail 0.005 14 Other demersal fishes 0.011 15 Large pelagics 0.003 0.012 16 Small pelagics 0.036 0.010 0.052 0.390 0.030 17 Cephalopoda 0.179 0.014 0.184 18 Benthic feeders 0.355 0.107 0.026 0.020 19 Infauna 0.107 0.147 0.141 0.429 0.327 20 Epifauna 0.107 0.300 0.053 0.009 21 Gastropoda 0.107 0.065 0.019 0.046 22 Zooplankton 0.214 0.355 0.200 0.581 0.678 0.774 0.070 0.054 23 Benthic algae 0.107 0.134 24 Phytoplankton 0.020 0.800 25 Detritus 0.107 0.429 0.544 0.200 SUM
Input parameters in the Tongyeong ecosystem after marine ranching activities Group name Habitat area Biomass in hab. Area Production /Biomass Consumption /Biomass (fraction) (t/km 2 ) (/year) (t/km 2 ) Finless porpoise 0.004 0.020 13.108 Otter Pisc. Birds Skates Flatfishes Adult jacopever rockfish Juv. Jacopever rockfish Other rockfishes Sparidae Anguilliformes Moronidae Grey mullet Hairtail Other demersal fish 0.400 0.400 0.001 0.010 0.101 0.479 1.779 2.279 0.136 0.549 0.522 0.596 1.922 0.528 1.850 0.060 0.800 1.365 1.365 1.386 2.772 1.368 1.309 1.386 1.055 1.200 1.360 1.055 91.250 60.000 2.560 2.490 10.790 37.176 12.061 2.500 2.600 26.160 2.500 2.600 18.293
Input Parameters in the Tongyeong Ecosystem after Marine Ranching Activities Group name Habitat area Biomass in hab. Area Production /Biomass Consumption /Biomass (fraction) (t/km 2 ) (/year) (t/km 2 ) Large pelagics 1.606 2.214 3.000 Small pelagics 2.536 2.700 3.500 Cephalopoda 0.953 3.300 Benthic feeders 8.740 2.534 7.100 Infauna 30.695 1.722 11.226 Epifauna 26.421 0.717 5.777 Gastropoda 7.930 1.703 5.777 Zooplankton 15.955 9.000 22.000 Benthc algae 27.000 534.068 - Phytoplankton 0.400 71.001 170.000 - Detritus - - -
Diet composition by group in the Tongyeoung ecosystem after marine ranching activities Prey \ Predator 1 2 3 4 5 6 7 8 9 10 11 1 True porpoise 2 Otter 3 Pisc. Birds 0.070 4 Skates 0.023 5 Flatfishes 0.023 0.050 0.176 6 Adult Jacopever rockfish 0.035 0.050 0.029 0.004 7 Juv. Jacopever rockfish 0.035 0.050 0.457 0.054 0.115 0.194 8 Other rockfishes 0.035 0.050 0.023 0.004 9 Sparidae 0.035 0.050 0.023 0.029 0.037 10 Anguilliformes 0.035 0.050 0.023 0.029 0.037 0.004 11 Moronidae 0.035 0.050 0.176 0.023 0.024 0.037 0.004 12 Grey mullet 0.035 0.050 0.176 0.023 0.029 0.037 0.004 13 Hairtail 0.039 0.050 0.023 0.029 0.037 0.004 14 Other demersal fishes 0.035 0.050 0.176 0.023 0.044 0.062 0.004 15 Large pelagics 0.006 0.050 0.029 0.029 0.159 0.020 0.011 16 Small pelagics 0.018 0.026 0.057 0.031 0.044 0.054 0.027 0.056 0.033 0.080 17 Cephalopoda 0.045 0.229 0.088 0.009 0.019 0.059 0.194 18 Benthic feeders 0.433 0.217 0.088 0.266 0.120 0.067 0.244 0.059 0.194 0.307 19 Infauna 0.384 0.264 20 Epifauna 0.121 0.102 0.197 21 Gastropoda 0.013 22 Zooplankton 0.003 0.229 0.088 0.020 0.363 0.933 0.196 0.474 0.386 0.613 23 Benthic algae 0.102 24 Phytoplankton 0.025 25 Detritus SUM
Diet composition by group in the Tongyeoung ecosystem after marine ranching activities Prey \ Predator 12 13 14 15 16 17 18 19 20 21 22 1 Finless porpoise 2 Otter 3 Pisc. Birds 4 Skates 5 Flatfishes 6 Adult Jacopever rockfish 7 Juv. Jacopever rockfish 0.214 0.029 0.129 8 Other rockfishes 0.011 9 Sparidae 0.011 10 Anguilliformes 0.011 11 Moronidae 0.011 12 Grey mullet 0.011 0.014 13 Hairtail 0.005 14 Other demersal fishes 0.011 15 Large pelagics 0.003 0.012 16 Small pelagics 0.036 0.010 0.052 0.390 0.030 17 Cephalopoda 0.179 0.014 0.184 18 Benthic feeders 0.355 0.107 0.026 0.020 19 Infauna 0.107 0.147 0.141 0.429 0.327 20 Epifauna 0.107 0.300 0.053 0.009 21 Gastropoda 0.107 0.065 0.019 0.046 22 Zooplankton 0.214 0.355 0.200 0.581 0.678 0.774 0.070 0.054 23 Benthic algae 0.107 0.134 24 Phytoplankton 0.020 0.800 25 Detritus 0.107 0.429 0.544 0.200 SUM
A flow chart showing the structure and trophic interactions in the Tongyeong ecosystem Before marine ranching ecosystem After marine ranching ecosystem
A dynamic simulation showing the effect on the Tongyeong ecosystem by the annual increase in the benthic algae and recruitment of jacopever rockfish 200 Change in biomass (%) 150 100 50 0 1999 2001 2003 2005 2007 2009 2011 2013-50 Year Adult Jacopever rockfish2+ Juv. Jacopever rockfish0-1 Sparidae Moronidae Large pelagics Small pelagics Cephalopoda Epifauna Gastropoda Benthic algae
The carrying capacity estimates for major fisheries resources in the Tongyeong ecosystem Carrying capacity (mt/year) Group name Ecosystem modeling Population modeling Skates 34.43825 Flatfishes 2.63 Adult Jacopever rockfish 2.12 Juv. Jacopever rockfish 3.05 7.12 Other rockfishes 1.53 Sparidae 0.89 Anguilliformes 15.17 Moronidae 1.62 Grey mullet 5.30 Hairtail 3.93 Other demersal fishes 5.99 Large pelagics 3.97 Small pelagics 5.68 Cephalopoda 2.72 Benthic feeders 32.05 Infauna 976.32 Epifauna 133.48 Gastropoda 20.30 Benthic algae 20.25 Total
Comparison of the results from ecosystem model and population model Carrying capacity estimates of rockfish - Population modeling : 4.5 mt - Ecosystem modeling : 3.5 mt ABC estimates - Rockfish : 2.076 mt (before marine ranching : 0.056 mt)