Download presentation

Presentation is loading. Please wait.

Published byKamron Maddern Modified over 3 years ago

1
Approaches to estimate proxy BRP values Estimate equilibrium yield by a deterministic method, identify F and related BRPs, perform sensitivity analysis of various input parameter values Estimate equilibrium yield by a deterministic method, identify F x% and related BRPs, perform sensitivity analysis of various input parameter values Estimate average yields from 100-year fishery by projection modeling with stochastic S-R, identify F and related BRPs Estimate average yields from 100-year fishery by projection modeling with stochastic S-R, identify F x% and related BRPs Perform various diagnostic tests on selected F by projection modeling with stochastic S-R: (a) rebuilding possibility of a severely depleted stock under the chosen F with a less productive S-R curve (B-H with Tau=0.3), (b) distribution of relative mean ESB for a range of F ( c) CV of yield for a range of F values, and (d) extinction probability of the stock for a range of F values Perform various diagnostic tests on selected F x% by projection modeling with stochastic S-R: (a) rebuilding possibility of a severely depleted stock under the chosen F x% with a less productive S-R curve (B-H with Tau=0.3), (b) distribution of relative mean ESB for a range of F x% values, ( c) CV of yield for a range of F x% values, and (d) extinction probability of the stock for a range of F x% values

2
Equilibrium Approach – Deterministic Simulation

3
Stochastic Approach – Projection Modeling

4
What is F%? SSB/R 0 SSB/R F e.g. F 20% is an F which produces a SSB/R F equivalent to 20% SSB/R 0

5
Identification of F Identification of F X% Red king crab example - EXCEL

6
Year123456789101112 Age 1R1,1R2,1R3,1R4,1R5,1R6,1R7,1R8,1R9,1 2R1,2R2,2R3,2R4,2R5,2R6,2R7,2R8,2 3R1,3R2,3R3,3R4,3R5,3R6,3R7,3 4R1,4R2,4R3,4R4,4R5,4R6,4 5R1,5R2,5R3,5R4,5R5,5 6R1,6R2,6R3,6R4,6 Year class development for stochastic simulation – stock projection modeling

7
Testing the Stochastic Program Stochastic program produced results coinciding with the deterministic estimates. e.g., R and Y predictions

8
Rebuilding red king crab stock from a 20%ESB MSY to MSY level under proposed harvest control rule with F 50. The data points correspond to 100-year fishery simulation under stochastic Beverton-Holt S-R model with female ESB, overall recruitment variability, =0.7, serial correlation, =.5, M = 0.18, h = 0.2, mating ratio=1:3, and =0.3

9
Proportion of years ESB has depleted to < 25%ESB vs. relative ESB/R from 100-year fishery for the red king crab stock. The estimates are made under stochastic Beverton and Holt and Ricker stock-recruitment models with female ESB, M = 0.18, h = 0.2, mating ratio = 1:3, overall recruitment variability, = 0.7, serial correlation, = 0.5, and τ = 0.1-0.3. The proportion of years ESB has depleted below 25%ESB is < 0.02 at F for all τ values up to 0.3. Proportion of years ESB has depleted to < 25%ESB MSY vs. relative ESB/R from 100-year fishery for the red king crab stock. The estimates are made under stochastic Beverton and Holt and Ricker stock-recruitment models with female ESB, M = 0.18, h = 0.2, mating ratio = 1:3, overall recruitment variability, = 0.7, serial correlation, = 0.5, and τ = 0.1-0.3. The proportion of years ESB has depleted below 25%ESB MSY is < 0.02 at F 50 for all τ values up to 0.3.

Similar presentations

OK

Descriptor 3 for determining Good Environmental Status (GES) under the MSFD was defined as “Populations of all commercially exploited fish and shellfish.

Descriptor 3 for determining Good Environmental Status (GES) under the MSFD was defined as “Populations of all commercially exploited fish and shellfish.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google