Stock assessment of the gulf menhaden, Brevoortia patronus, fishery

A stock assessment of the gulf menhaden. Brevoortia patronus, fishery was conducted with data on purse-seine landings from 1946 to 1985 and port sampling data from 1964 to 1985. These data were analyzed to determine growth rates, yield-per-recruit, spawner-recruit relationships, and maximum sustainable yield (MSY). Virtual population analysis was used to estimate stock size, year-class size, and fishing mortality rates. During the period studied, an average of 27% of age-l fish and 55% of age-2 and age-3 fish were taken by the fishery, and 54% for age-I and 38% for age-2 and -3 fish were lost annually to natural causes. Annual yield-per-recruit estimates ranged from 6.9 to 19.3 g, with recent mean conditions averaging 12.2 g since 1978. Surplus production models produced estimates of MSY from 620 to 700 kilometric tons. Recruits to age-I ranged from 8.3 to 41.8 billion fish for 1964-82. Although there was substantial scatter about the fitted curves, Ricker·type spawner-recruit relationships were found suitable for use in a population simulation model. Estimates of MSY from population simulation model runs ranged from 705 to 825 kilometric tons with F -multiples of the mean rate of fishing ranging from 1.0 to 1.5. Recent harvests in excess of the historical MSY may not be detrimental to the gulf menhaden stock. However, one should not expect long-term harvesting above the historical MSY because of the short life span of gulf menhaden and possible changes from currently favorable environmental conditions supporting high recruitment.(PDF file contains 24 pages.

Odysseus' "Winnowing-Shovel" (Horn. Od. 11. 119-37) and the Island of the Cattle of the Sun

published or submitted for publicatio

Beyond the Border Buildup: Towards a New Approach to Mexico-U.S. Migration

A proper understanding of the causes of international migration suggests that punitive immigration and border policies tend to backfire, and this is precisely what has happened in the case of the United States and Mexico. Rather than raising the odds that undocumented immigrants will be apprehended, U.S. border-enforcement policies have reduced the apprehension rate to historical lows and in the process helped transform Mexican immigration from a regional to a national phenomenon. The solution to the problems associated with undocumented migration is not open borders, but frontiers that are reasonably regulated on a binational basis

Abandonment and Reconciliation: Addressing Political and Common Law Objections to Fetal Homicide Laws

Fetal homicide laws criminalize killing a fetus largely to the same extent as killing any other human being. Historically, the common law did not generally recognize feticide as a crime, but this was because of the evidentiary born-alive rule, not because of the substantive understanding of the term human being. As medicine and science have advanced, states have become increasingly willing to abandon this evidentiary rule and to criminalize feticide as homicide. Although most states have recognized the crime of fetal homicide, fourteen have not. This is largely the result of two independent obstacles: (judicial) adherence to the born-alive rule and (legislative) concern that fetal homicide laws could erode constitutionally protected reproductive rights. This Note explores a variety of fetal homicide laws that states have adopted, demonstrating that popular opinion has shifted toward recognizing this crime. It then directly confronts the objections that have prevented other states from adopting such laws: it first reviews the literature suggesting that the born-alive rule should be abandoned, as it is an obsolete evidentiary standard; it then argues that constitutionally protected reproductive liberties can be reconciled with, and in fact augmented by, punishing the killing of a fetus as a homicide

Determinants of Historic and Cultural Landmark Designation: Why We Preserve What We Preserve

There is much interest among cultural economists in assessing the effects of heritage preservation policies. There has been less interest in modeling the policy choices made in historic and cultural landmark preservation. This paper builds an economic model of a landmark designation that highlights the tensions between the interests of owners of cultural amenities and the interests of the neighboring community. We perform empirical tests by estimating a discrete choice model for landmark preservation using data from Chicago, combining the Chicago Historical Resources Survey of over 17,000 historic structures with property sales, Census, and other geographic data. The data allow us to explain why some properties were designated landmarks (or landmark districts) and others were not. The results identify the influence of property characteristics, local socio-economic factors, and measures of historic and cultural quality. The results emphasize the political economy of implementing preservation policies.heritage preservation policy, landmark designation

Empowerment Zones, Neighborhood Change and Owner Occupied Housing

This paper examines the effects of a generous, spatially-targeted economic development policy (the federal Empowerment Zone program) on local neighborhood characteristics and on the neighborhood quality of life, taking into account the interactions amongst the policy, changes in neighborhood demographics and neighborhood housing stock. Urban economic theory posits that housing prices in a small area should increase as quality of life increases, because people will be more willing to pay to live in the area, but these changes in prices and quality of life will also affect the demographics of the population through sorting and the housing stock through reinvestment. Using census block-group-level data, we examine how housing prices respond to the Empowerment Zone policy intervention. Changes in the other dimensions of neighborhood quality (demographics and housing stock characteristics) will also help determine the total, or full effect on housing values of the policy intervention. This paper estimates these direct and indirect effects in a simultaneous equations setting, compares indirect and full effects, and examines the robustness of the effects to alternate estimation strategies. We find strong evidence for substantively large and highly significant direct price effects, while results suggest that the indirect effects are substantively small or even negative.economic development, empowerment zones, porperty values, household mobility, sorting

Making – or Picking – Winners: Evidence of Internal and External Price Effects in Historic Preservation Policies

Much has been written identifying property price effects of historic preservation policies. Little attention has been paid to the possible policy endogeneity in hedonic price models. This paper outlines a general case of land use regulation in the presence of externalities and then demonstrates the usefulness of the model in an instrumental-variables estimation of a hedonic price analysis – with an application to historic preservation in Chicago. The theoretical model casts doubt on previous results concerning price effects of preservation policies. The comparative statics identify some determinants of regulation that seem, on the face of it, most unlikely to also belong in a hedonic price equation. The analysis employs these determinants as instruments for endogenous regulatory treatment in a hedonic price analysis. OLS estimation of the hedonic offers results consistent with much of previous literature, namely that property values are higher for historic landmarks. In the 2SLS hedonic, robust estimates of the "own" price effect of historic designation are shown to be large and negative (approx. -27%) for homes in landmark districts. Further, significant and substantively important (positive) external price effects of landmark designations are found. The paper concludes with a discussion of the policy implications of these findings for historic preservation.hedonics, built heritage, heritage valuation, real estate economics

Neighborhood Dynamics and the Housing Price Effects of Spatially Targeted Economic Development Policy

Neighborhoods are the result of a complicated interplay between residential choice, housing supply and the influences of the larger metropolitan system on its constituent parts. We model this interplay as a system of reduced-form equations in order to examine the effects of a generous spatially targeted economic development program (the federal Empowerment Zone program) on neighborhood characteristics, especially housing values. This system of equations approach allows us to compute direct effects of the policy intervention as well as the effects mediated through non-price channels such as changes in the housing stock or neighborhood demographics. In the process, we are able to shed light on the rich simultaneity among neighborhood characteristics, including housing prices.economic development, simultaneity

Commentary on "Trajectories for the immigrant second generation in New York City"

This article is commentary on a paper presented at a conference organized by the Federal Reserve Bank of New York in April 2005, "Urban Dynamics in New York City." The goal of the conference was threefold: to examine the historical transformations of the engine-of-growth industries in New York and distill the main determinants of the city's historical dominance as well as the challenges to its continued success; to study the nature and evolution of immigration flows into New York; and to analyze recent trends in a range of socioeconomic outcomes, both for the general population and recent immigrants more specifically.Immigrants - New York (N.Y.) ; Economic conditions - New York (N.Y.) ; Federal Reserve District, 2nd ; Urban economics