Stock (geology)

About: Stock (geology) is a research topic. Over the lifetime, 31009 publications have been published within this topic receiving 783542 citations.

Population dynamics and potential of fisheries stock enhancement: practical theory for assessment and policy analysis

Abstract: The population dynamics of fisheries stock enhancement, and its potential for generating benefits over and above those obtainable from optimal exploitation of wild stocks alone are poorly understood and highly controversial. I review pertinent knowledge of fish population biology, and extend the dynamic pool theory of fishing to stock enhancement by unpacking recruitment, incorporating regulation in the recruited stock, and accounting for biological differences between wild and hatchery fish. I then analyse the dynamics of stock enhancement and its potential role in fisheries management, using the candidate stock of North Sea sole as an example and considering economic as well as biological criteria. Enhancement through release of recruits or advanced juveniles is predicted to increase total yield and stock abundance, but reduce abundance of the naturally recruited stock component through compensatory responses or overfishing. Economic feasibility of enhancement is subject to strong constraints, including trade-offs between the costs of fishing and hatchery releases. Costs of hatchery fish strongly influence optimal policy, which may range from no enhancement at high cost to high levels of stocking and fishing effort at low cost. Release of genetically maladapted fish reduces the effectiveness of enhancement, and is most detrimental overall if fitness of hatchery fish is only moderately compromised. As a temporary measure for the rebuilding of depleted stocks, enhancement cannot substitute for effort limitation, and is advantageous as an auxiliary measure only if the population has been reduced to a very low proportion of its unexploited biomass. Quantitative analysis of population dynamics is central to the responsible use of stock enhancement in fisheries management, and the necessary tools are available.

Industry Returns and the Fisher Effect

Abstract: We investigate the cross-sectional relation between industry-sorted stock returns and expected inflation, and we find that this relation is linked to cyclical movements in industry output. Stock returns of noncyclical industries tend to covary positively with expected inflation, while the reverse holds for cyclical industries. From a theoretical perspective, we describe a model that captures both (i) the cross-sectional variation in these relations across industries, and (ii) the negative and positive relation between stock returns and inflation at short and long horizons, respectively. The model is developed in an economic environment in which the spirit of the Fisher model is preserved. THE FISHER MODEL STATES that expected nominal rates of return on assets should move one-for-one with expected inflation. This belief is generally attributed to Irving Fisher's (1930) work on interest rates, in particular, to his view that the real and monetary sectors are causally independent. In an apparent contradiction to the Fisher hypothesis, however, it is a common empirical finding that stock returns are negatively related to both expected and realized inflation.1 This negative correlation is especially surprising for stocks, which, as claims against real assets, should compensate for movements in inflation. We provide two main contributions to the existing literature on the relation between stock returns and inflation. The first contribution of the article is to provide a theoretical description of the cross-sectional relation between stock returns and expected inflation. We describe an asset pricing model that predicts cross-sectional variation in the coefficients of expected inflation across various industry portfolios. An interesting feature of the model is that it synthesizes some of the more palatable features of existing explanations of the negative relation between inflation and returns. Of special interest is the development of the model in a money-neutral world, so that the basic premise underlying Fisher's work is maintained. Since most theoretical models of the

Which Firms Follow the Market? An Analysis of Corporate Investment Decisions

Abstract: We test whether stock market mispricing or private investor information in stock prices affects corporate investment. We develop an econometric methodology that disentangles stock-price movements that are relevant for investment from those that are not. We combine this decomposition with proxies for private information and mispricing to devise unbiased tests for the effects of mispricing and information on investment. We depart from much of the literature by finding that stock market mispricing does not affect investment, especially that of large firms and firms subject to mispricing. In contrast, we confirm previous evidence that managers incorporate private investor information when making investment decisions. The Author 2010. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org., Oxford University Press.