scholarly journals Rational taxation in an open access fishery model

2017 ◽  
Vol 27 (1) ◽  
pp. 5-27
Author(s):  
Dmitry B. Rokhlin ◽  
Anatoly Usov
Keyword(s):  
Fishery Management ◽  
Value Function ◽  
Cooperative Behavior ◽  
Golden Rule ◽  
Growth Function ◽  
Single Population ◽  
Marginal Value ◽  
Resource Stock ◽  
Fishery Model ◽  
Taxation Scheme

Abstract We consider a model of fishery management, where n agents exploit a single population with strictly concave continuously differentiable growth function of Verhulst type. If the agent actions are coordinated and directed towards the maximization of the discounted cooperative revenue, then the biomass stabilizes at the level, defined by the well known “golden rule”. We show that for independent myopic harvesting agents such optimal (or ε-optimal) cooperative behavior can be stimulated by the proportional tax, depending on the resource stock, and equal to the marginal value function of the cooperative problem. To implement this taxation scheme we prove that the mentioned value function is strictly concave and continuously differentiable, although the instantaneous individual revenues may be neither concave nor differentiable.

From Catastrophe to Recovery: Stories of Fishery Management Success

2019 ◽  
Keyword(s):  
Endangered Species ◽  
Fishery Management ◽  
Drainage Area ◽  
Death Valley ◽  
Small Fish ◽  
Single Population ◽  
Complete Extinction ◽  
Species Preservation ◽  
The U.S ◽  
Reduced Flow

<i>Abstract</i>.—The Owens Pupfish <i>Cyprinodon radiosus</i> is a small fish (<6 cm [2.5 in]) in the killifish family once thought extinct but rediscovered in the early 1960s in Fish Slough in the Death Valley drainage area of eastern California, USA. At the time of discovery, the species was comprised of a single population of approximately 200 individuals. The species was listed as endangered on March 11, 1967 under the U.S. Endangered Species Preservation Act of 1966. During the summer of 1969, a spring that was feeding water to Fish Slough was discovered to have much reduced flow due to unusual precipitation patterns the previous 6 months and possibly water removals, and thus threatened complete extinction of the species. Quick actions by fish biologists prevented extinction by transporting the entire species in two buckets to nearby refuge waters similar to Fish Slough. The transplantation was successful, and six populations now exist 50 years later that each number from the hundreds to perhaps more than 10,000 fish. The species remains listed as endangered—but it did not go extinct!

scholarly journals Single population and common natal origin for Adriatic Scomber scombrus stocks: evidence from an integrated approach

2013 ◽  
Vol 70 (2) ◽  
pp. 387-398 ◽  
Author(s):  
Chiara Papetti ◽  
Antonio Di Franco ◽  
Lorenzo Zane ◽  
Paolo Guidetti ◽  
Valeria De Simone ◽  
...  
Keyword(s):  
Fishery Management ◽  
Adriatic Sea ◽  
Management Strategies ◽  
Integrated Approach ◽  
Geographic Area ◽  
Spawning Ground ◽  
Single Population ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
Natal Origin

Abstract Papetti, C., Di Franco, A., Zane, L., Guidetti, P., De Simone, V., Spizzotin, M., Zorica, B., Čikeš Keč, V. and Mazzoldi, C. 2013. Single population and common natal origin for Adriatic Scomber scombrus stocks: evidence from an integrated approach – ICES Journal of Marine Science, 70: 387–398. In order to implement proper fishery management strategies aimed at avoiding stock declines, information about connectivity among stocks and populations is critically required. In this perspective, the present study investigated population structure of the Atlantic mackerel Scomber scombrus in the northern–central Adriatic Sea by integrating multiple approaches (analysis of fisheries data, population genetics, and otolith chemistry). Monthly data of fishery landings indicate a latitudinal trend along the western Adriatic coast, with Atlantic mackerel disappearing from the northern waters in winter, corresponding to the reproductive season. Population genetic analyses by genotyping of eight microsatellites clearly point to the presence of a single panmictic population in the northern–central Adriatic Sea. Otolith cores of samples from the northern–central Adriatic were chemically homogeneous, suggesting a common spawning ground. These results strongly suggest that Atlantic mackerel perform an autumn–winter migration in the northern–central Adriatic Sea, from the northern to the central sector, to reach a single spawning ground, and that a single population is present in this area. Considering that S. scombrus has shown a marked decline in the last 40 years in the Adriatic, this study highlights a potential high vulnerability to collapse by overfishing for the Atlantic mackerel stocks in this geographic area.

scholarly journals Age and growth rate estimations of the commercially fished gastropod Buccinum undatum

2018 ◽  
Vol 75 (6) ◽  
pp. 2129-2144 ◽  
Author(s):  
Philip R Hollyman ◽  
Simon R N Chenery ◽  
Melanie J Leng ◽  
Vladimir V Laptikhovsky ◽  
Charlotte N Colvin ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fishery Management ◽  
Isotope Analysis ◽  
Age Determination ◽  
Growth Curves ◽  
Growth Function ◽  
Age And Growth ◽  
Growth Equation ◽  
Buccinum Undatum ◽  
The United Kingdom

Abstract Calculating age and growth rate for the commercially important whelk, Buccinum undatum in the aid of fishery management has historically been undertaken using growth rings on the organic operculum. This is difficult due to their poor readability and confusion between two different sets of growth lines present. Recent work presented the calcium carbonate statolith as an alternative for age determination of B. undatum. Here we compare the use of statoliths and opercula, comparing their readability and creating growth curves for three distinct populations across the United Kingdom. Using these data, we also test the most appropriate growth equation to model this species. Lastly, we use oxygen isotope analysis of the shells to assign accurate ages to several individuals from each site. These data were used to test the accuracy of statolith and operculum ages. Statoliths, whilst more time consuming to process have improved clarity and accuracy compared with the opercula. This improved readability has highlighted that a Gompertz growth function should be used for populations of this species, when in past studies, von Bertalanffy is often used. Statoliths are a viable improvement to opercula when assessing B. undatum in the context of fishery monitoring and management.

Search at the Margin

2017 ◽  
Vol 107 (10) ◽  
pp. 3146-3181
Author(s):  
José A. Carrasco ◽  
Lones Smith
Keyword(s):  
Opportunity Cost ◽  
Bargaining Power ◽  
Value Function ◽  
Search Theory ◽  
Reservation Price ◽  
Search Frictions ◽  
Marginal Value ◽  
Strictly Convex ◽  
Holding Costs

We extend search theory to multiple indivisible units and perfectly divisible assets, solving them respectively with induction and recursion. Buyer demands and prices are random, and the seller can partially exercise orders. With divisible assets, the Bellman value function is increasing and strictly concave, and the optimal reservation price falls in the position, reflecting increasing holding costs (opportunity cost of delaying optionality for inframarginal units). The marginal value exists, and is strictly convex with a falling purchase cap density. Our model is amenable to price-quantity bargaining; e.g., greater buyer bargaining power is tantamount to greater search frictions. (JEL C61, C78, D25, D83, G31)

scholarly journals A generic marginal value function for natural areas

2016 ◽  
Vol 58 (1) ◽  
pp. 159-179 ◽  
Author(s):  
Mark J. Koetse ◽  
Erik T. Verhoef ◽  
Luke M. Brander
Keyword(s):  
Value Function ◽  
Natural Areas ◽  
Marginal Value
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