Net economic impacts of achieving maximum economic yield in fisheries

Improving the economic performance of fisheries is becoming increasingly important in fisheries management, and in some cases, maximum economic yield (MEY) is set as a key management target. However, associated with MEY is a level of fishing activity that is lower than would otherwise occur, even in fisheries managed to achieve the maximum sustainable yield. This will result in losses in economic activity elsewhere in the economy, potentially resulting in a net loss to society in the short to medium term. In this paper, an input-output framework is used to estimate the net economic impact of achieving MEY in Australian fisheries. While incomes are reduced in other sectors of the economy, the net impact of achieving MEY in fisheries is dependent on how total catches are likely to change relative to their levels under current management. It is argued that, at least in most Australian fisheries, achieving MEY will result in a net economic benefit to society. Local communities are likely to be included among the set of main beneficiaries, with potential losses being incurred elsewhere in the economy. Sectors that potentially lose as a result of the transition to MEY previously benefited from overcapitalisation in fisheries, and hence higher incomes in these sectors were an artefact of the market failure in fisheries.maximum economic yield, fisheries management, net economic impact, input-output analysis, Resource /Energy Economics and Policy,

MAPS OF CONTINUOUS SPATIAL DEPENDENCE

Heterogeneity is one of the distinguishing features in spatial econometric models. It is a frequent problem in applied work and can be very damaging for statistical inference. In this paper, we focus on the problems implied by the existence of instabilities in the mechanism of spatial dependence in a spatial lag model, assuming that the other terms of the specification remain stable. We begin the discussion with the role played by the algorithms of local estimation in detecting the instabilities. Problems appear when one must decide what to do once the existence of heterogeneity has been confirmed. The logical reaction is trying to parameterize this lack of stability. However, the solution is not obvious. Assuming that a set of indicators related to the problem has been identified, we propose a simple technique to deal with the unknown functional form. In the final part of the paper, we present some Monte Carlo evidence and an application to evaluate the instability in the mechanisms of spatial dependence in the convergence process of the European Regions.DEPENDENCE, LOCAL ESTIMATION, MONTE-CARLO, SPATIAL INSTABILITY

Constraints to the magnetospheric properties of T Tauri stars - II. The Mg II ultraviolet feature

The atmospheric structure of T Tauri Stars (TTSs) and its connection with the large scale outflow is poorly known. Neither the effect of the magnetically mediated inter- action between the star and the disc in the stellar atmosphere is well understood. The Mg II multiplet is a fundamental tracer of TTSs atmospheres and outflows, and is the strongest feature in the near-ultraviolet spectrum of TTSs. The International Ultraviolet Explorer and Hubble Space Telescope data archives provide a unique set to study the main physical compounds contributing to the line profile and to derive the properties of the line formation region. The Mg II profiles of 44 TTSs with resolution 13,000 to 30,000 are available in these archives. In this work, we use this data set to measure the main observables: flux, broadening, asymmetry, terminal velocity of the outflow, and the velocity of the Discrete Absorption Components. For some few sources repeated observations are available and variability has been studied. There is a warm wind that at sub-AU scales absorbs the blue wing of the Mg II profiles. The main result found in this work is the correlation between the line broadening, Mg II flux, terminal velocity of the flow and accretion rate. Both outflow and magnetospheric plasma contribute to the Mg II flux. The flux-flux correlation between Mg II and C IV or He II is confirmed; however, no correlation is found between the Mg II flux and the ultraviolet continuum or the H2 emission.Comment: 21 pages, 20 figure