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Multispecies perspectives on the Bering Sea Ground Fishery Management
Multispecies perspectives on the Bering Sea Ground Fishery Management
Changes in the Bering Sea
Changes in the Bering Sea
Levels of fishing mortality used in MSFOR AND SSFOR
Levels of fishing mortality used in MSFOR AND SSFOR
Objective
Objective
Biomass flow in the system defined for the eastern Bering Sea
Biomass flow in the system defined for the eastern Bering Sea
MSVPA and MSFOR equations
MSVPA and MSFOR equations
Multispecies forecasting assumptions
Multispecies forecasting assumptions
Input and output data for the MSFOR model
Input and output data for the MSFOR model
Methods
Methods
Results: total population
Results: total population
Results: yield
Results: yield
Long-term percentage changes of yield
Long-term percentage changes of yield
Long-term percentage changes of total and spawning biomass (Fref vs
Long-term percentage changes of total and spawning biomass (Fref vs
Long-term percentage changes of total and spawning biomass (Fref vs F
Long-term percentage changes of total and spawning biomass (Fref vs F
Conclusions
Conclusions
Future tasks
Future tasks

Презентация на тему: «Multispecies perspectives on the Bering Sea Ground Fishery Management Regime». Автор: Jesus Jurado-Molina; Patricia Livingston. Файл: «Multispecies perspectives on the Bering Sea Ground Fishery Management Regime.ppt». Размер zip-архива: 491 КБ.

Multispecies perspectives on the Bering Sea Ground Fishery Management Regime

содержание презентации «Multispecies perspectives on the Bering Sea Ground Fishery Management Regime.ppt»
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1 Multispecies perspectives on the Bering Sea Ground Fishery Management

Multispecies perspectives on the Bering Sea Ground Fishery Management

Regime

Jes?s Jurado-Molina School of Fisheries, University of Washington Patricia Livingston Alaska Fisheries Science Center-NMFS

2 Changes in the Bering Sea

Changes in the Bering Sea

3 Levels of fishing mortality used in MSFOR AND SSFOR

Levels of fishing mortality used in MSFOR AND SSFOR

PLK - walleye pollock, COD - Pacific cod, GTB - Greenland turbot, YFS - yellowfin sole, SOL - rock sole, HER - Pacific herring

4 Objective

Objective

To apply the single and multispecies forecasting models to assess the long-term effects produced by three harvesting regimes (Fref, FABC and F = 0) on yield, total and spawning biomass of some species from the Bering Sea.

5 Biomass flow in the system defined for the eastern Bering Sea

Biomass flow in the system defined for the eastern Bering Sea

6 MSVPA and MSFOR equations

MSVPA and MSFOR equations

BS - suitable prey biomass S - suitability coefficient of predator i and prey p R - annual consumption of the predator i W - weight at age of prey p M1- residual mortality M2 - predation mortality

7 Multispecies forecasting assumptions

Multispecies forecasting assumptions

M = M1 + M2 Constant annual consumption of predators. Other food = constant Constant suitability coefficients (from MSVPA) Constant recruitment Recruitment of age-0 individuals takes place in the third quarter

8 Input and output data for the MSFOR model

Input and output data for the MSFOR model

9 Methods

Methods

MSVPA run updated to 1998 data to obtain average suitabilities, average recruitment values and population initial values (1998) for all species. Three MSFOR runs (Fref, FABC and F = 0) to obtain three equilibrium indicators: yield, total and spawning biomass Three Single species runs using the same fishing mortalities and obtaining the same indicators Comparison of the relative change of the indicators using:

10 Results: total population

Results: total population

11 Results: yield

Results: yield

12 Long-term percentage changes of yield

Long-term percentage changes of yield

MSP- Multispecies forecast, SSP - single species forecast

13 Long-term percentage changes of total and spawning biomass (Fref vs

Long-term percentage changes of total and spawning biomass (Fref vs

FABC)

Biomass - total biomass SSB - spawning biomass

Proportion of Pacific herring population consumed by predators

Proportion of pollock total population consumed by predators

14 Long-term percentage changes of total and spawning biomass (Fref vs F

Long-term percentage changes of total and spawning biomass (Fref vs F

= 0)

Biomass - total biomass SSB - spawning biomass

Proportion of rock sole population consumed by predators

Proportion of pollock population consumed by predators

15 Conclusions

Conclusions

SSFOR and MSFOR suggest that the implementation of FABC would produce small long-term changes in the structure of the eastern Bering Sea groundfish populations compared to Fref. Changes in the F regime can indirectly affect the predation mortality of prey due to decreases in predator population and consumption of prey. The implementation of the FABC regime resulted in no significant change in pollock predation mortality due to canceling effects of pollock consumption by arrowtooth flounder and adult pollock (cannibalism) When FABC was implemented, SSFOR and MSFOR predicted almost the same trends for the indicators analyzed. However, some differences in magnitude and direction due to predation interactions were observed for rock sole and Pacific herring. Multispecies simulations of no fishing scenarios change our perspective on recovery times for depleted populations.

16 Future tasks

Future tasks

To simulate the system with different levels of recruitment associated to climate shifts To carry out Monte Carlo simulations for MSFOR and SSFOR incorporating different assumptions on recruitment (Ricker/B&H and stochastic components) To include the predation equations in a system of linked catch at age models (Multispecies CAGEAN?)

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