418 research outputs found
An Analysis of the Relationship between Fish Harvesting and Processing Sectors in New England
Using annual data from 1981 to 2002, the relationship between harvesting and processing of fish and the effects of imports on processing in New England were analyzed. Additionally, cause and effect relationships between harvesting and processing and between processing and imports were examined using Granger causality tests. Output from the fish processing sector is jointly driven by local fish landings and fish imports and unidirectional causalities exist from local landings to processing and from processing to imports. Generally, processors optimize business operations over multiple species and multiple supply sources. Rebuilding the groundfish stock would not lead to a dramatic and immediate increase in the processing industry. Instead, the actual growth in the processing sector would be relatively smaller than that in the harvesting sector.Fish processing, fish harvesting, fish imports, causality., Q2, Q22, L66, Resource /Energy Economics and Policy,
WILLINGNESS TO PARTICIPATE AND BIDS IN A FISHING VESSEL BUYOUT PROGRAM: A CASE STUDY OF NEW ENGLAND GROUNDFISH
An experimental fishing vessel buyout program was initiated in 1995 to remove vessels from the Northeast United States groundfish fishery. Information provided by the applicants to this program was used to evaluate the likely participation and potential cost of an expanded buyout initiative. This paper describes the pilot buyout program and the econometric procedures used to forecast participation and bids at various levels of program spending. Program participation and bid levels were modeled in two stages using participation and bid functions. The expanded buyout program, completed in April 1998, provided a unique opportunity to evaluate initial participation and cost forecasts. Methods used in this study are also applicable to modeling other fishery related economic decisions, such as the trading of individual transferable quota shares.Resource /Energy Economics and Policy,
BIOECONOMIC ANALYSIS OF ALTERNATIVE SELECTION PATTERNS IN THE UNITED STATES ATLANTIC SILVER HAKE FISHERY
In this paper a bioeconomic simulation of the U.S. fisheries for silver hake, Merluccius bilinearis, is presented. The model design combines elements of age-structured population and harvest yield models with economics of the silver hake fishery. The analysis evaluates both biological and economic effects of interest to mangers, such as future yields or rebuilding of parental stock, as well as future revenues and net returns to vessels. The bioeconomic model is used to evaluate the economic implications of tradeoffs between alternative selection patterns in the U.S. Atlantic silver hake fishery. Throughout the study, a selection pattern is defined as the suite of age-specific selection coefficients that are applied to a fish population over time. The results indicate that shifting fishing pressure to younger age classes could result in short-run gains in economic value that may not be sustainable due to longer run declines in biomass, hence lowered fishery yield and value. By contrast, strategies to delay age at first capture may improve economic value over current levels with only modest reductions in short-run fishery yield.Research Methods/ Statistical Methods, Resource /Energy Economics and Policy,
Economic impact of the 2005 red tide event on commercial shellfish fisheries in New England
Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Ocean & Coastal Management 51 (2008): 420-429, doi:10.1016/j.ocecoaman.2008.01.004.Over the last several decades, harmful algal bloom (HAB) events have been observed in more locations than ever before throughout the United States. The 2005 bloom of Alexandrium fundyense was the most widespread and intense in New England waters since a similar event more than three decades ago. In this study, using historical data from the National Marine Fisheries Service, the Massachusetts Division of Marine Fisheries, and other sources, we develop estimates of the direct economic impacts of the 2005 event on commercial shellfish fisheries in Maine and Massachusetts. Results of our regression analyses suggest that the 2005 event had broad spatial and temporal effects on the shellfish market. In response to a supply shortage resulting from local closures, there was an increase in shellfish imports to New England during the red tide. Further, shellfish closures in Maine were the most likely cause of observable price changes on the Fulton Fish Market in New York.This research was supported by the National Atmospheric and Oceanic Administration (NOAA) through the WHOI/NOAA Cooperative Institute on Climate and Ocean Research (CICOR) under award number NA17RJ1223
Cyber-Physical Systems: A Model-Based Approach
In this concise yet comprehensive Open Access textbook, future inventors are introduced to the key concepts of Cyber-Physical Systems (CPS). Using modeling as a way to develop deeper understanding of the computational and physical components of these systems, one can express new designs in a way that facilitates their simulation, visualization, and analysis. Concepts are introduced in a cross-disciplinary way. Leveraging hybrid (continuous/discrete) systems as a unifying framework and Acumen as a modeling environment, the book bridges the conceptual gap in modeling skills needed for physical systems on the one hand and computational systems on the other. In doing so, the book gives the reader the modeling and design skills they need to build smart, IT-enabled products. Starting with a look at various examples and characteristics of Cyber-Physical Systems, the book progresses to explain how the area brings together several previously distinct ones such as Embedded Systems, Control Theory, and Mechatronics. Featuring a simulation-based project that focuses on a robotics problem (how to design a robot that can play ping-pong) as a useful example of a CPS domain, Cyber-Physical Systems: A Model-Based Approach demonstrates the intimate coupling between cyber and physical components, and how designing robots reveals several non-trivial control problems, significant embedded and real-time computation requirements, and a need to consider issues of communication and preconceptions
A comparison of surface moisture budget and structural equation models in high latitudes: evapotranspiration and atmospheric drivers
Thesis (M.S.) University of Alaska Fairbanks, 2021Arctic soil moisture is one of the most impactful and unknown aspects of the Arctic climate system. As the climate changes, surface soil moisture can impact water supplies, wildfire risk, and vegetation stress, all of which have consequences for terrestrial ecosystems and human activities. The present analysis is intended to (1) document seasonal and interannual variations of surface moisture fluxes in the Arctic region and (2) clarify the drivers of variations of net Precipitation minus Evapotranspiration (P-ET) across Arctic tundra and boreal vegetation and permafrost status. Forty-five flux tower sites were examined across boreal and tundra ecosystems across the Arctic and sub-arctic. The surface moisture budget at boreal forest sites in permafrost areas generally shows a moisture deficit in late spring and early summer, followed by a moisture surplus from late summer into autumn. The annual net P-ET is generally positive but can vary interannually by more than an order of magnitude. A factor analysis found the primary drivers of variations in evapotranspiration to be radiative fluxes, air temperature, and relative humidity, while a path analysis found windspeed to have the largest independent influence on evapotranspiration. Overall, the ET at boreal forest sites shows a stronger dependence on relative humidity, and ET at tundra sites shows the stronger dependence on air temperature. These differences imply that tundra sites are more temperature-limited and boreal sites are more humidity-dependent. Relative to nearby unburned sites, the recovery time of ET after disturbance by wildfire was found to vary from several years on the Alaska tundra to nearly a decade in the Alaska boreal forest.National Science Foundation, Office of Polar Programs Grant ARC-183013
Statistical stability and limit laws for Rovella maps
We consider the family of one-dimensional maps arising from the contracting
Lorenz attractors studied by Rovella. Benedicks-Carleson techniques were used
by Rovella to prove that there is a one-parameter family of maps whose
derivatives along their critical orbits increase exponentially fast and the
critical orbits have slow recurrent to the critical point. Metzger proved that
these maps have a unique absolutely continuous ergodic invariant probability
measure (SRB measure).
Here we use the technique developed by Freitas and show that the tail set
(the set of points which at a given time have not achieved either the
exponential growth of derivative or the slow recurrence) decays exponentially
fast as time passes. As a consequence, we obtain the continuous variation of
the densities of the SRB measures and associated metric entropies with the
parameter. Our main result also implies some statistical properties for these
maps.Comment: 1 figur
Cyber-Physical Systems: A Model-Based Approach
In this concise yet comprehensive Open Access textbook, future inventors are introduced to the key concepts of Cyber-Physical Systems (CPS). Using modeling as a way to develop deeper understanding of the computational and physical components of these systems, one can express new designs in a way that facilitates their simulation, visualization, and analysis. Concepts are introduced in a cross-disciplinary way. Leveraging hybrid (continuous/discrete) systems as a unifying framework and Acumen as a modeling environment, the book bridges the conceptual gap in modeling skills needed for physical systems on the one hand and computational systems on the other. In doing so, the book gives the reader the modeling and design skills they need to build smart, IT-enabled products. Starting with a look at various examples and characteristics of Cyber-Physical Systems, the book progresses to explain how the area brings together several previously distinct ones such as Embedded Systems, Control Theory, and Mechatronics. Featuring a simulation-based project that focuses on a robotics problem (how to design a robot that can play ping-pong) as a useful example of a CPS domain, Cyber-Physical Systems: A Model-Based Approach demonstrates the intimate coupling between cyber and physical components, and how designing robots reveals several non-trivial control problems, significant embedded and real-time computation requirements, and a need to consider issues of communication and preconceptions
Recreational anglers' valuation of near-shore marine fisheries in Florida
This report describes and summarizes the results from a state-wide survey of Florida
resident saltwater anglers. The survey was designed to provide estimates of the economic value
anglers place on marginal changes in management of selected near-shore marine species.
The Contingent valuation method was used to elicit angler willingness to pay for changes
in management for redfish, seatrout , mullet, sheepshead, pompano. and king mackerel.
Contingent valuation is a process in which respondents are presented with a detailed scenario that
describes an opportunity to express their willingness to pay for a proposed change in current
conditions. The process consists of three parts. First. the change in current conditions, or the
"good" to be valued is described. Second, the payment method is described. The payment
method is usually closely related to typical methods of buying goods similar to the one to be
valued. Finally. the respondent is asked how much they would pay for the good described in
the scenario. A special saltwater fishing license stamp that would allow the holder to take
advantage of the described management change was used as a payment mechanism. (PDF contains 147 pages.
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Latent Fishing Effort and Vessel Ownership Transfer in the Northeast U.S. Groundfish Fishery
Management of fishing effort and fishing capacity is receiving increased attention world-wide. In the Northeast region of the U. S., the principal focus has been on managing “active” fishing vessels, although concerns have increased over the magnitude of “latent” effort and its implications for resource recovery and sustainability. This paper reviews current and historic levels of latent fishing effort in the Northeast U.S. groundfish fishery and examines patterns of latent to and active effort, particularly as they may be affected by vessel ownership transfer.Keywords: latent effort, ownership transfer, multispecies fisher
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