An Optimal Harvest Policy for the Recently Renewed United States Pacific Sardine Fishery

2013 ◽  
Author(s):  
Samuel F. Herrick ◽  
Kevin Hill ◽  
Christian Reiss
Keyword(s):  
United States ◽  
Optimal Harvest ◽  
Pacific Sardine ◽  
Optimal Harvest Policy

Optimal harvesting of a prey–predator model with variable carrying capacity

2017 ◽  
Vol 10 (05) ◽  
pp. 1750069 ◽  
Author(s):  
Chaity Ganguli ◽  
T. K. Kar ◽  
P. K. Mondal
Keyword(s):  
Carrying Capacity ◽  
Intraspecific Competition ◽  
Dynamical Behavior ◽  
Optimal Harvesting ◽  
Main Concern ◽  
Interior Equilibrium ◽  
Optimal Harvest ◽  
Common Resource ◽  
Predator Model ◽  
Optimal Harvest Policy

This work deals with a prey–predator model in an environment where the carrying capacities are assumed to be variable with time and one species feeds upon the other. Independent harvesting efforts are applied in either species and asymmetrical intraguild predation occurs. A common resource is consumed by two competing species and at the same time predator also consumes the prey. At first we discuss the model under constant carrying capacity and make the conclusion that no limit cycle exists in this case. Then we discuss the model without intraspecific competition. Our main concern is to cover the above mentioned two cases together, i.e. the model with variable carrying capacity and intraspecific competition. We determine the steady states and examine the dynamical behavior. We also analyze the local and global stability of the interior equilibrium by Routh–Hurwitz criterion and a suitable Lyapunov function respectively. A Hopf bifurcation occurs with respect to a parameter which is the ratio of predator’s and prey’s intrinsic growth rate. The possibility of bionomic equilibrium has been considered. The optimal harvest policy is formulated and solved with Pontryagin’s maximum principle. Some numerical simulations are given to explain most of the analytical results.

Migration of Pacific Sardine (Sardinops Sagax) Off the West Coast of United States in 2003–2005

2011 ◽  
Vol 87 (3) ◽  
pp. 395-412 ◽  
Author(s):  
Nancy Ch Lo ◽  
Beverly J Macewicz ◽  
David A Griffith
Keyword(s):  
United States ◽  
West Coast ◽  
The West ◽  
Pacific Sardine ◽  
Sardinops Sagax

Bioeconomic Modelling of a Single Species Fishery with Gompertz Law of Growth

1998 ◽  
Vol 06 (04) ◽  
pp. 393-409 ◽  
Author(s):  
T. Pradhan ◽  
K. S. Chaudhuri
Keyword(s):  
Dynamic Control ◽  
Control Variable ◽  
Single Species ◽  
Fishing Effort ◽  
Catch Per Unit Effort ◽  
Bioeconomic Modelling ◽  
Optimal Harvest ◽  
Gompertz Law ◽  
Fishery Model ◽  
Optimal Harvest Policy

A single species fishery model has been developed using the Gompertz law of population growth and the CPUE (Catch-per-unit-effort) hypothesis. The dynamical and the bionomic steady states were determined and their natures were examined from the biological as well as economic view points. The optimal harvest policy is discussed by taking the fishing effort as a dynamic control variable. The results are compared with those of the Schaefer model [10].

scholarly journals A Dynamic Model for Fishery Resource with Reserve Area and Taxation

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Hai-Feng Huo ◽  
Hui-Min Jiang ◽  
Xin-You Meng
Keyword(s):  
Fish Population ◽  
Reaction Model ◽  
Dynamic Reaction ◽  
Fishery Resource ◽  
Control Instrument ◽  
Optimal Harvest ◽  
Over Exploitation ◽  
Theoretical Results ◽  
Resource System ◽  
Optimal Harvest Policy

The present paper deals with a dynamic reaction model of a fishery. The dynamics of a fishery resource system in an aquatic environment consists of two zones: a free fishing zone and a reserve zone. To protect fish population from over exploitation, a control instrument tax is imposed. The existence of its steady states and their stability are studied. The optimal harvest policy is discussed next with the help of Pontryagin's maximum principle. Our theoretical results are confirmed by numerical simulation.

scholarly journals A bioeconomic model of nonselective harvesting of two competing fish species

2004 ◽  
Vol 46 (2) ◽  
pp. 299-308 ◽  
Author(s):  
D. Purohit ◽  
K. S. Chaudhuri
Keyword(s):  
Fish Species ◽  
Bioeconomic Model ◽  
Optimal Harvest ◽  
Gompertz Law ◽  
Rate Functions ◽  
Saturation Effects ◽  
The Stability ◽  
Optimal Harvest Policy ◽  
Nonselective Harvesting ◽  
Stock Abundance

AbstractThis paper deals with the combined bioeconomic harvesting of two competing fish species, each of which obeys the Gompertz law of growth. The catch-rate functions are chosen so as to reflect saturation effects with respect to stock abundance as well as harvesting effort. The stability of the dynamical system is discussed and the existence of a bionomic equilibrium is examined. The optimal harvest policy is studied with the help of Pontryagin's maimum principle. The results are illustrated with the help of a numerical example.

scholarly journals Influence of Harvest Date and 2C Storage on Floral Development of Dutch-grown Astilbe

1994 ◽  
Vol 119 (2) ◽  
pp. 144-149
Author(s):  
Gwendolyn H. Pemberton ◽  
A.A. De Hertogh
Keyword(s):  
United States ◽  
The Netherlands ◽  
Floral Development ◽  
Physiological State ◽  
Floral Organ ◽  
The United States ◽  
Harvest Date ◽  
Observational Period ◽  
Physiological Maturity ◽  
Optimal Harvest

Dutch-grown `Deutschland', `Fanal', and `Rheinland' Astilbe, harvested 1 Nov. 1992 and shipped to the United States, were dissected to determine the stage of floral development after 0, 2, 4, 6, 8, 10, 12, or 15 weeks of 2C storage. Astilbe crowns were also planted after 15 weeks of 2C storage and floral development was determined after 1, 2, or 3 weeks of greenhouse forcing. On arrival, multiflower inflorescences were clearly visible. A pattern of abortion and reinitiation occurred during 2C storage. Floral development was markedly repressed when ecodormancy was imposed, but development resumed during greenhouse forcing. During the observational period, floral organ numbers were variable, and morphological abnormalities were observed. In a second experiment, physiological maturity of the crowns was evaluated by harvesting crowns of `Bumalda', `Europa', `Federsee', and `Rheinland' on 15 Sept., 1 Oct., 15 Oct., 1 Nov., and 15 Nov. in The Netherlands. Optimal harvest period was from 1 Oct. to 1 Nov., depending on the cultivar. Crowns harvested before this period were physiologically immature. Crowns harvested during the 4-week window produced the highest overall plant quality and performed as physiologically mature crowns. Astilbe crowns harvested after the 4-week window produced plants with lower forcing qualities and were determined to be beyond the optimal physiological state for forcing.

Optimal Harvest Rate Policies for Rebuilding the Adams River Sockeye Salmon (Oncorhynchus nerka)

1991 ◽  
Vol 48 (4) ◽  
pp. 526-535 ◽  
Author(s):  
David W. Welch ◽  
Donald J. Noakes
Keyword(s):  
Economic Benefit ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Optimization Techniques ◽  
Current Management ◽  
Sources Of Uncertainty ◽  
Optimal Harvest ◽  
Management Policies ◽  
Over Time ◽  
Optimal Harvest Policy

This paper examines how a currently depressed population, the Adams River sockeye salmon (Oncorhynchus nerka), should be rebuilt over time in order to maximize the economic benefit. We use dynamic optimization techniques to answer two questions which previous static optimization work on the Adams River sockeye controversy did not address: (1) what changes from current management policies are required over time to maximize the net economic yield from the population and (2) just how much economic benefit can accrue from following such a policy? We find that following the optimal policy identified by this methodology could contribute more than $600 million to the net value of the Adams River stock. Examination of various confounding factors (co-migrating stocks, parameter uncertainty, and the discount rate applied) indicates that the optimal harvest policy is remarkably robust to these sources of uncertainty. The study also lays the basis for repeating such numerical analysis on other populations of interest.

scholarly journals Harvesting in a two-prey one-predator fishery: a bioeconomic model

2004 ◽  
Vol 45 (3) ◽  
pp. 443-456 ◽  
Author(s):  
T. K. Kar ◽  
K. S. Chaudhuri
Keyword(s):  
Lyapunov Function ◽  
Prey Density ◽  
Feeding Rate ◽  
Bioeconomic Model ◽  
Numerical Examples ◽  
The Third ◽  
Optimal Harvest ◽  
Predator Response ◽  
Maximal Principle ◽  
Optimal Harvest Policy

AbstractA multispecies harvesting model with interference is proposed. The model is based on Lotka-Volterra dynamics with two competing species which are affected not only by harvesting but also by the presence of a predator, the third species. In order to understand the dynamics of this complicated system, we choose to model the simplest possible predator response function in which the feeding rate of the predator increases linearly with prey density. We derive the conditions for global stability of the system using a Lyapunov function. The possibility of existence of a bioeconomic equilibrium is discussed. The optimal harvest policy is studied and the solution is derived in the equilibrium case using Pontryagin's maximal principle. Finally, some numerical examples are discussed.

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