Estimating the value of in-season estimates of abundance of sockeye salmon (Oncorhynchus nerka)

1998 ◽  
Vol 55 (6) ◽  
pp. 1408-1418 ◽  
Author(s):  
Michael R Link ◽  
Randall M Peterman
Keyword(s):  
Monte Carlo Simulation ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Commercial Fishing ◽  
Variable Response ◽  
Net Benefit ◽  
Potential Benefits ◽  
Additional Costs ◽  
Perfect Monitoring ◽  
Monte Carlo Simulation Model

Fishwheels have recently replaced a gillnet test fishery for in-season estimation of escapement of sockeye salmon (Oncorhynchus nerka) to the Nass River, British Columbia. We used an empirically based Monte Carlo simulation model to estimate the potential benefits (in terms of future harvests) of using this new method. We found that using the information from the fishwheels in place of the gillnet test fishery may increase the average annual catch from current ocean fisheries by 2.7% ($229 000) due to the greater accuracy of in-season estimates. When the additional costs of operating the fishwheels instead of the gillnet test fishery were taken into account, the fishwheel program still resulted in an annual net benefit of about $180 000. Eliminating the deviations from the target escapement for Nass River sockeye salmon by having perfect monitoring of escapement and perfect control over harvesting has a potential annual value of more than $1 million (CAN). However, much greater benefits from fishwheels are unlikely to be realized because of the highly variable response of the commercial fishing fleet to additional fishing opportunities and the 5-day lag of the escapement estimates provided by fishwheels.

Cyclic Dominance and Optimal Escapement of Adams River Sockeye Salmon (Oncorhynchus nerka)

1990 ◽  
Vol 47 (4) ◽  
pp. 838-849 ◽  
Author(s):  
D. W. Welch ◽  
D. J. Noakes
Keyword(s):  
Sockeye Salmon ◽  
Net Present Value ◽  
Oncorhynchus Nerka ◽  
Total Yield ◽  
Confidence Regions ◽  
Parameter Estimates ◽  
Magnitude Comparison ◽  
Ricker Model ◽  
Stock Recruitment ◽  
Potential Benefits

We examined escapement policies for a stock-recruitment model with negative between-year interactions. Regardless of the degree of interaction present, the optimal policy is to always equalize escapement. Parameter estimates obtained for the Adams River sockeye salmon (Oncorhynchus nerka) indicate that between-year interactions may occur, but confidence regions include the null hypothesis of no interaction at all (the Ricker model). We conclude that the extreme amplitude of the current recruitment cycle in this stock frustrates statistical identification of interaction. It seems unlikely that between-year interactions will be measurable until the off year runs increase by at least two to three orders of magnitude. Comparison of total yields for the Adams River sockeye shows that an equal escapement policy could increase yields by at least 35% over that obtained by the current cyclic escapement pattern. This is equivalent to obtaining an additional $27 million in total yield per annum from the Adams River stock alone and, assuming a discount rate of 4%, translates into an increase in net present value of $675 million. If between-year interactions do not exist, the potential benefits of moving to an equal escapement policy are even larger, on the order of $3 to $4 billion.

Resumption of anadromy or straying? Origins of Sockeye Salmon Oncorhynchus nerka in the Elwha River

2021 ◽  
Author(s):  
Thomas P. Quinn ◽  
George R. Pess ◽  
Ben J.G. Sutherland ◽  
Samuel J. Brenkman ◽  
Ruth E. Withler ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Elwha River

Alternative Recruitment Models of Adams River Sockeye Salmon, Oncorhynchus nerka

1987 ◽  
Vol 44 (9) ◽  
pp. 1551-1561 ◽  
Author(s):  
Jeremy S. Collie ◽  
Carl J. Walters
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Status Quo ◽  
Management Policy ◽  
Best Management ◽  
Interaction Terms ◽  
Ricker Model ◽  
The Status ◽  
Stock Recruitment ◽  
High Yields

Despite evidence of depensatory interactions among year-classes of Adams River sockeye salmon (Oncorhynchus nerka), the best management policy is one of equal escapement for all year-classes. We fit alternative models (Ricker model and Larkin model) to 32 yr of stock–recruitment data and checked, using simulation tests, that the significant interaction terms in the Larkin model are not caused by biases in estimating the parameters. We identified a parameter set (Rationalizer model) for which the status quo cyclic escapement policy is optimal, but this set fits the observed data very poorly. Thus it is quite unlikely that the Rationalizer model is correct or that the status quo escapement policy is optimal. Using the fitted stock–recruitment parameters, we simulated the sockeye population under several management policies. The escapement policy optimal under the Ricker model is best overall because of the high yields if it should be correct. If the three stock–recruitment models are equally likely to be correct, the simulations predict that adopting a constant-escapement policy would increase long-term yield 30% over the current policy and that an additional 15% increase in yield could be obtained if the policy were actively adaptive.

Reduced growth in wild juvenile sockeye salmon Oncorhynchus nerka infected with sea lice

2017 ◽  
Vol 91 (1) ◽  
pp. 41-57 ◽  
Author(s):  
S. C. Godwin ◽  
L. M. Dill ◽  
M. Krkošek ◽  
M. H. H. Price ◽  
J. D. Reynolds
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Sea Lice

Validation of daily increments and a marine-entry check in the otoliths of sockeye salmon Oncorhynchus nerka post-smolts

2015 ◽  
Vol 87 (1) ◽  
pp. 169-178 ◽  
Author(s):  
C. Freshwater ◽  
M. Trudel ◽  
T. D. Beacham ◽  
C.-E. Neville ◽  
S. Tucker ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Daily Increments

نماذج المحاكاة- محاكاة مونتي كارلو- كأسلوب كمي من أساليب النمذجة واتخاذ القرارات - مقاربة نظرية وتطبيقية

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
محمد الأمين ◽  
بن حامد عبد الغني ◽  
مراس محمد
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Quantitative Methods ◽  
Practical Importance ◽  
Investment Project ◽  
Simulation Method ◽  
Period Analysis ◽  
Investment Projects ◽  
Monte Carlo Simulation Model

Our research aims to try to present the modeling mechanisms in the field of simulation and quantitative methods. The research is a presentation of the role of quantitative methods in making investment project evaluation decisions, more than that and is the use of the Monte Carlo simulation model in evaluation and multi-period analysis of investment projects under conditions Risk and uncertainty. And highlighting the theoretical, scientific and practical importance of the Monte Carlo simulation method in particular, and the importance of using quantitative methods in helping to make decisions in general

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