bluuebunny/crossref_metadata_2025 huggingface dataset:
Female Labor Supply: Why Is the United States Falling Behind?
Authors: Blau Francine D , Kahn Lawrence M
Published: May 2013

In 1990, the US had the sixth highest female labor participation rate among 22 OECD countries. By 2010 its rank had fallen to seventeenth. We find that the expansion of “family-friendly” policies, including parental leave and part-time work entitlements in other OECD countries, explains 29 percent of the decrease in US women's labor force participation relative to these other countries. However, these policies also appear to encourage part-time work and employment in lower level positions: US women are more likely than women in other countries to have full time jobs and to work as managers or professionals.
Is Ignorance Bliss? The Effect of Asymmetric Information between Spouses on Intra-Household Allocations
Authors: Castilla Carolina , Walker Thomas
Published: May 2013

We conducted a field experiment in Southern Ghana to test the effect of asymmetric information on intrahousehold allocation. A lottery was conducted, where prizes were distributed in public and in private. The results indicate that asymmetric information over windfalls has a differential effect on observable and concealable expenses, consistent with hiding. Husbands' public windfalls increase investment in assets and social capital, while there is no such effect when wives win. Private windfalls of both spouses are committed to cash (wives) or in-kind gifts (husband) which are either difficult to monitor or to reverse if discovered by the other spouse.
Sexual Violence against Women and Labor Market Outcomes
Authors: Sabia Joseph J , Dills Angela K , DeSimone Jeffrey
Published: May 2013

This study is the first in the economics literature to explore the labor market consequences of sexual violence toward women. Using data from the Add Health, we find that sexual violence against women is associated with a 6.6 percent lower probability of labor force participation and 5.1 percent lower average wages. These estimates are robust to controls for unobserved heterogeneity at the school- and family-levels, as well as detailed controls for personality, personal discount rates, and risk preferences. We find that the adverse labor market effects of sexual violence are partially explained by its adverse psychological and physical consequences.
Fidelity Networks and Long-Run Trends in HIV/AIDS Gender Gaps
Authors: Pongou Roland , Serrano Roberto
Published: May 2013

More than half of the HIV/AIDS-infected population today are women. We study a dynamic model of (in)fidelity, which explains the HIV/AIDS gender gap by the configuration of sexual networks. Each individual desires sexual relationships with opposite sex individuals. Two Markov matching processes are defined, each corresponding to a different culture of gender relations. The first process leads to egalitarian pairwise stable networks in the long run, and HIV/AIDS is equally prevalent among men and women. The second process leads to anti-egalitarian pairwise stable networks reflecting male domination, and women bear a greater burden. The results are consistent with empirical observations.
Liquidity Constraints and Deforestation: The Limitations of Payments for Ecosystem Services
Authors: Jayachandran Seema
Published: May 2013

A popular environmental policy is to pay forest owners for avoiding deforestation on their land. This is an example of “payments for ecosystem services” (PES). This paper shows that liquidity constraints can limit the effectiveness of PES programs. If an individual would have cut down trees to sell them, his opportunity costs are more front-loaded than the stream of PES income. If credit constrained, he might decline the program even if the net present value (NPV) of the PES income exceeds the NPV of his opportunity costs. I present evidence consistent with this prediction using data on forest owners in Uganda.
Linking Numerical and Analytical Models of Carbon Leakage
Authors: Carbone Jared C
Published: May 2013

I use an applied general equilibrium model to quantify the influence of a new, theoretical channel for carbon leakage effects, as identified by Fullerton, Karney and Baylis (2012). I first produce parameterizations of the model that generate a close correspondence with the theory, isolating the quantitative effect of this channel. I then produce parameterizations that allow for an examination of net leakage rates in a model with a more comprehensive set of leakage channels. I find that the new channel exerts a negative influence on net leakage rates but that positive forces of leakage dominate in the comprehensive assessment.
Financial Innovation and Portfolio Risks
Authors: Simsek Alp
Published: May 2013

I illustrate the effect of financial innovation on portfolio risks by using an example with risk-sharing needs and belief disagreements. I consider two types of innovation: product innovation, formalized as an expansion of new financial assets; and process innovation, formalized as a reduction in transaction costs. When belief disagreements are large, both types of innovation increase portfolio risks. Moreover, endogenous financial innovation is directed towards speculative assets that increase portfolio risks.
Reflections on Finance and the Good Society
Authors: Shiller Robert J
Published: May 2013

The concept of the Good Society--grounded in principles of reciprocity and the Golden Rule--is as ancient as human civilization. To many the concept may appear in conflict with the goings-on of financial markets. This may be especially true after the financial crisis. Financial theory and financial legislation cannot ignore this apparent conflict, but must instead find ways to reduce it. When teaching economics it is important to convey how individuals and organizations impose rules and standards which help reconcile their deeply-held beliefs with their business practices.
Can Financial Engineering Cure Cancer?
Authors: Fagnan David E , Fernandez Jose Maria , Lo Andrew W , Stein Roger M
Published: May 2013

Traditional financing sources such as private and public equity may not be ideal for investment projects with low probabilities of success, long time horizons, and large capital requirements. Nevertheless, such projects, if not too highly correlated, may yield attractive risk-adjusted returns when combined into a single portfolio. Such “megafund” portfolios may be too large to finance through private or public equity alone. But with sufficient diversification and risk analytics, debt financing via securitization may be feasible. Credit enhancements (i.e., derivatives and government guarantees) can also improve megafund economics. We present an analytical framework and illustrative empirical examples involving cancer research.
HIV Risk and Adolescent Behaviors in Africa
Authors: Case Anne , Paxson Christina
Published: May 2013

We investigate the relationship between HIV, marriage and nonmarital sexual activity, with a focus on adolescent behaviors. We use data from 45 Demographic and Health Surveys to examine how adolescent behavior among women born from 1958 to 1965 are related to the subsequent spread of HIV over time. These women were adolescents during the early 1980s, a time when HIV had started to spread but the cause was still unknown. We find that areas with currently high HIV rates had greater female education and more premarital sexual activity in the cohorts that came of age before HIV was understood.
Do Sex Workers Respond to Disease? Evidence from the Male Market for Sex
Authors: Shah Manisha
Published: May 2013

Sex markets play a key role in the transmission of sexually transmitted infections (STI) and HIV/AIDS in developing countries. While individuals should substitute away from risky sex as STI prevalence rises, female sex workers draw a premium for engaging in unprotected sex, mitigating their propensity to use condoms. We provide the first evidence of a positive premium for non-condom sex in developing country male sex markets. Testing whether this is a compensating differential for disease risk, we find that a one percentage point increase in the STI rate increases the premium 28 percent. Market forces may curb the self-limiting effect of STI epidemics.
Inheritances, Intergenerational Transfers, and the Accumulation of Health
Authors: Carman Katherine Grace
Published: May 2013

This paper considers the mechanisms behind a positive correlation between inheritances and health. First, there may merely be a correlation: those from families with enough wealth to provide an inheritance tend to have better health. Second, financial resources could be used to purchase inputs to health. Third, bequests may signal a stronger interest in one's child. This reminder to the child could improve their emotional well-being. On average, the positive correlation suggests merely correlation. However, among subsets of the population, particularly men and those expecting to receive an inheritance, there is a causal relationship likely driven by the third mechanism.
Adult Antiretroviral Therapy and Child Health: Evidence from Scale-up in Zambia
Authors: Lucas Adrienne M , Wilson Nicholas L
Published: May 2013

One in five Zambian children lives with an HIV/AIDS-infected adult. We estimate the effect that the availability of adult antiretroviral therapy (ART) has on the health of such children. Using a triple difference specification, we find that adult access to ART resulted in increased weight-for-age and decreased incidence of stunting among children younger than 60 months who resided with an infected father or other infected adult in an intact household. Because the increased availability of adult ART in sub-Saharan Africa has multigenerational effects, cost-effectiveness estimates restricted to direct recipients understate the economic benefit of the treatment.
Incentive Effects of Inheritances and Optimal Estate Taxation
Authors: Kopczuk Wojciech
Published: May 2013

I consider optimal nonlinear taxation of income and bequests with a joy-of-giving bequest motive and explicitly characterize the optimal estate tax rate. The optimal formula trades off correction of externality from giving and discouraging effort of children due to income effect generated by bequests. The analysis shows that optimality of a positive tax on bequests rests on the strength of the effect of bequests on behavior of future generations. The analysis also suggests that inheritance, rather than estate tax, is better suited to implement the optimal policy.
Shifting Mandates: The Federal Reserve's First Centennial
Authors: Reinhart Carmen M , Rogoff Kenneth S
Published: May 2013

The Federal Reserve's mandate has evolved considerably over the organization's hundred-year history. It was changed from an initial focus in 1913 on financial stability, to fiscal financing in World War II and its aftermath, to a strong anti-inflation focus from the late 1970s, and then back to greater emphasis on financial stability since the Great Contraction. Yet, as the Fed's mandate has expanded in recent years, its range of instruments has narrowed, partly based on a misguided belief in the inherent stability of financial markets. We argue for a return to multiple instruments, including a more active role for reserve requirements.
Optimal Pension Systems with Simple Instruments
Authors: Golosov Mikhail , Shourideh Ali , Troshkin Maxim , Tsyvinski Aleh
Published: May 2013

We analyze optimal pension systems relying on simple policy instruments in a lifecycle environment which admits endogenous decisions of how much to work as well as when to retire. The optimality in this context means the highest welfare that can be achieved within a restricted set of instruments, while keeping the total cost of the pension system unchanged. The policy instruments we consider are the optimized retirement benefit functions modeled after a stylized version of the current US Social Security.
Some Basic Economics of National Security
Authors: Murphy Kevin M , Topel Robert H
Published: May 2013

We define national security (NS) as public policies that protect the safety or welfare of a nation's citizens from substantial threats. NS capital provides societal insurance against widespread harm or catastrophe, so optimal NS investments may have very low expected rates of return. Investment targeted at extreme events (war) has spillovers, reducing potential harm in less threatening situations as well. Potential threats are highly uncertain, which raises the value of ex-post scalability of NS technologies. Higher probabilities of extreme events raise the demand for flexibility, so ex-post responses to threats are more elastic, but may reduce current precaution.
Modest, Secure, and Informed: Successful Development in Conflict Zones
Authors: Berman Eli , Felter Joseph H , Shapiro Jacob N , Troland Erin
Published: May 2013

Most interpretations of prevalent counterinsurgency theory imply that increasing government services reduces rebel violence. Empirically, however, development programs and economic activity sometimes increase violence. Using new panel data on development spending in Iraq, we show that violence-reducing effects of development assistance are greater when: (i) projects are small; (ii) troop strength is high; and (iii) professional development expertise is available. These findings are consistent with an information-centric (“hearts and minds”) model, which implies that violence-reduction is greatest when projects are secure, valued by community members, and services derived are conditional on government control of the territory.
Insurgent Compensation: Evidence from Iraq
Authors: Bahney Benjamin W , Iyengar Radha K , Johnston Patrick B , Jung Danielle F , Shapiro Jacob N , Shatz Howard J
Published: May 2013

Participating in insurgency is physically risky. Why do people do so? Using new data on 3,799 payments to insurgent fighters by Al Qa'ida Iraq, we find that: (i) wages were extremely low relative to outside options, even compared to unskilled labor; (ii) the estimated risk premium is negative; and (iii) the wage schedule favors equalization and provides additional compensation for larger families. These results challenge the notion that fighters are paid their marginal product, or the opportunity cost of their time. They may be consistent with a “lemons” model in which fighters signal commitment by accepting low wages.
Not the Opium of the People: Income and Secularization in a Panel of Prussian Counties
Authors: Becker Sascha O , Woessmann Ludger
Published: May 2013

The interplay between religion and the economy has long occupied social scientists. We construct a unique panel of income and Protestant church attendance using 175 Prussian counties, presented in six waves from 1886 to 1911. The data reveal a marked decline in church attendance coinciding with increasing income. The cross-section also shows a negative association between income and church attendance. The associations disappear in panel analyses, including first-differenced models of the 1886 to 1911 change, panel models with county and time fixed effects, and panel Granger-causality tests. The results cast doubt on causal interpretations of the religion-economy nexus in Prussian secularization.
From Stagnation to Sustained Growth: The Role of Female Empowerment
Authors: Diebolt Claude , Perrin Faustine
Published: May 2013

This paper explores the role of gender equality over a long-run economic and demographic development path of industrialized countries. Our unified cliometric growth model of female empowerment suggests that changes in gender relations are a key ingredient of economic development. The economy evolves from a Malthusian regime--with slow technological progress, low income and low fertility--to a Modern Growth regime, with high living standards and low fertility. The rise in technological progress, together with improvements in gender equality, generates a positive feedback loop that engages the process of human capital accumulation (economic transition) and triggers the demographic transition.
Nonparametric Instrumental Variables Estimation
Authors: Newey Whitney K
Published: May 2013

In many economic models, objects of interest are functions which satisfy conditional moment restrictions. Economics does not restrict the functional form of these models, motivating nonparametric methods. In this paper we review identification results and describe a simple nonparametric instrumental variables (NPIV) estimator. We also consider a simple method of inference. In addition we show how the ability to uncover nonlinearities with conditional moment restrictions is related to the strength of the instruments. We point to applications where important nonlinearities can be found with NPIV and applications where they cannot.
What Do Instrumental Variable Models Deliver with Discrete Dependent Variables?
Authors: Chesher Andrew , Rosen Adam M
Published: May 2013

We compare nonparametric instrumental variables (IV) models with linear models and 2SLS methods when dependent variables are discrete. A 2SLS method can deliver a consistent estimator of a Local Average Treatment Effect but is not informative about other treatment effect parameters. The IV models set identify a range of interesting structural and treatment effect parameters. We give set identification results for a counterfactual probability and an Average Treatment Effect in a IV binary threshold crossing model. We illustrate using data on female employment and family size (employed by Joshua Angrist and William Evans (1998)) and compare with their LATE estimates.
What Goes Up Must Come Down? Experimental Evidence on Intuitive Forecasting
Authors: Beshears John , Choi James J , Fuster Andreas , Laibson David , Madrian Brigitte C
Published: May 2013

Do laboratory subjects correctly perceive the dynamics of a mean-reverting time series? In our experiment, subjects receive historical data and make forecasts at different horizons. The time series process that we use features short-run momentum and long-run partial mean reversion. Half of the subjects see a version of this process in which the momentum and partial mean reversion unfold over ten periods (“fast”), while the other subjects see a version with dynamics that unfold over 50 periods (“slow”). Typical subjects recognize most of the mean reversion of the fast process and none of the mean reversion of the slow process.
The Importance of Being Marginal: Gender Differences in Generosity
Authors: DellaVigna Stefano , List John A , Malmendier Ulrike , Rao Gautam
Published: May 2013

Do men and women have different social preferences? Previous findings are contradictory. We provide a potential explanation using evidence from a field experiment. In a door-to-door solicitation, men and women are equally generous, but women become less generous when it becomes easy to avoid the solicitor. Our structural estimates of the social preference parameters suggest an explanation: women are more likely to be on the margin of giving, partly because of a less dispersed distribution of altruism. We find similar results for the willingness to complete an unpaid survey; women are more likely to be on the margin of participation.
Two Happiness Puzzles
Authors: Deaton Angus , Stone Arthur A
Published: May 2013

We consider two happiness puzzles. First, many studies show that only relative income matters for well-being. Yet the Gallup data for the United States and from the rest of the world show no such result, at least for life evaluation. There may be relative income effects in hedonic well-being though other interpretations are available. Second, more religious people typically report higher experiential well-being but more religious places have worse well-being on average, both across US states and across countries. More religious states and counties in the US also have worse murder rates, deaths from cardiovascular disease and from cancer.
Subjective Well-Being and Income: Is There Any Evidence of Satiation?
Authors: Stevenson Betsey , Wolfers Justin
Published: May 2013

Many scholars have argued that once “basic needs” have been met, further rises in income are not associated with further increases in subjective well-being. We assess the validity of this claim in comparisons of both rich and poor countries, and also of rich and poor people within a country. Analyzing multiple datasets, multiple definitions of “basic needs” and multiple questions about well-being, we find no support for this claim. The relationship between well-being and income is roughly log-linear and does not diminish as incomes rise. If there is a satiation point, we are yet to reach it.
Aggregating Local Preferences to Guide Marginal Policy Adjustments
Authors: Benjamin Daniel J , Heffetz Ori , Kimball Miles S , Szembrot Nichole
Published: May 2013

We propose a social choice rule for aggregating preferences elicited from surveys into a marginal adjustment of policy from the status quo. The mechanism is: (i) symmetric in its treatment of survey respondents; (ii) ordinal, using only the orientation of respondents' indifference surfaces; (iii) local, using only preferences in the neighborhood of current policy; and (iv) what we call “first-order strategy-proof,” making the gains from misreporting preferences second order. The mechanism could be applied to guide policy based on how policy affects responses to subjective well-being surveys.
Not Just the Great Contraction: Friedman and Schwartz's A Monetary History of the United States 1867 to 1960
Authors: Bordo Michael D , Rockoff Hugh
Published: May 2013

Milton Friedman and Anna J. Schwartz published A Monetary History of the United States: 1867 to 1960 with Princeton University Press in 1963, to critical acclaim. Since then the book's reputation has grown and it clearly has become one of the most influential volumes in economics in the twentieth century. In this paper we document the extraordinary impact of A Monetary History and argue that the key to this success was the use of the "narrative approach" to the problem of identifying the effects of monetary policy on economic activity.
The Psychology of Tail Events: Progress and Challenges
Authors: Barberis Nicholas
Published: May 2013

Over the past decade there has been a surge of interest in “tail events,” or rare, high-impact events. In this article, I start by summarizing some recent progress in our understanding of the psychology of tail events. I suggest that much of this progress has centered on the concept of “probability weighting” and, in particular, on applications of this concept in various fields of economics. I then describe some major open questions in this area.
Salience and Asset Prices
Authors: Bordalo Pedro , Gennaioli Nicola , Shleifer Andrei
Published: May 2013

We present a simple model of asset pricing in which payoff salience drives investors' demand for risky assets. The key implication is that extreme payoffs receive disproportionate weight in the market valuation of assets. The model accounts for several puzzles in finance in an intuitive way, including preference for assets with a chance of very high payoffs, an aggregate equity premium, and countercyclical variation in stock market returns.
Views among Economists: Professional Consensus or Point-Counterpoint?
Authors: Gordon Roger , Dahl Gordon B
Published: May 2013

To what degree do economists disagree about key economic questions? We provide evidence by using the responses to a series of questions posed to a distinguished panel of economists put together by the Chicago School of Business. Based on our analysis, we find a broad consensus on these many different economic issues, particularly when the past economic literature on the question is large. Any differences are unrelated to observable characteristics of the Panel members, other than men being slightly more likely to express an opinion. These differences are idiosyncratic, with no support for liberal versus conservative camps.
Economic Experts versus Average Americans
Authors: Sapienza Paola , Zingales Luigi
Published: May 2013

We compare answers to policy questions by economic experts and a representative sample of the US population. We find a 35 percentage point difference between the two groups. This gap is only partially explained by differences in ideological or personal characteristics of the two samples. Interestingly, the difference is the largest on the questions where economists agree the most and where there is the largest amount of literature. Informing people of the expert opinions does not seem to have much of an impact. Ordinary people seem to be skeptical of the implicit assumptions embedded into the economists' answers.
The Missing Transmission Mechanism in the Monetary Explanation of the Great Depression
Authors: Romer Christina D , Romer David H
Published: May 2013

This paper examines the missing transmission mechanism in Friedman's and Schwartz's monetary explanation of the Great Depression. We review the challenge provided by the decline in nominal interest rates in the early 1930s, and show that the monetary explanation requires not just that there were expectations of deflation, but that they were caused by monetary contraction. Using a detailed analysis of Business Week magazine, we find evidence that monetary contraction and Federal Reserve policy contributed to expectations of deflation during the downturn. This suggests that monetary shocks may have depressed spending and output in part by raising real interest rates.
Shadowy Banks and Financial Contagion during the Great Depression: A Retrospective on Friedman and Schwartz
Authors: Mitchener Kris James , Richardson Gary
Published: May 2013

This essay assesses whether network linkages within the banking system amplified the real effects of bank failures during the Great Contraction. In 1929, nearly all interbank deposits held by Federal Reserve member banks belonged to “shadowy” nonmember banks which were outside the regulatory reach of federal regulators. Regional banking panics in the early 1930s drained these interbank deposits from central reserve city banks. Money-center banks in Chicago and New York responded to volatile and declining interbank deposits by changing their asset composition. They reduced their lending to businesses and individuals, and increased their holdings of cash and government bonds.
Married to Intolerance: Attitudes toward Intermarriage in Germany, 1900–2006
Authors: Voigtländer Nico , Voth Hans-Joachim
Published: May 2013

We analyze under what conditions intermarriage can be used as an indicator of tolerance, and whether such tolerant attitudes persisted in Germany during the twentieth century. We find strong evidence for the persistence of tolerant attitudes towards intermarriage with Jews. At the same time, our empirical analysis also cautions against using intermarriage as a simple proxy for tolerance: The size of Jewish communities in the early twentieth century is an important confounding factor.
On the occurrence of the Bull Ray Pteromylaeus bovinus (Chondrichthyes: Myliobatidae) in the Amvrakikos Gulf, Greece
Authors: ZOGARIS S. , DUSSLING U.
Published: May 2013

We document in this note the occurrence of the Bull Ray Pteromylaeus bovinus (Geoffroy St-Hilaire, 1817) (Chondrichthyes: Myliobatidae) in the Amvrakikos Gulf (eastern Ionian Sea), within a recently designated Wetlands National Park. Although distributional data for this species are scant, there is circumstantial evidence depicting the species as rare in Greece and the Mediterranean.
Polychaetes of commercial interest from the Mediterranean East Coast of Algeria
Authors: YOUNSI M. , DAAS T. , DAAS O. , SCAPS P.
Published: May 2013

Three species of polychaetous annelids are commercially collected, as baits, from natural populations along the coast of Algeria. They are collected by semi-professional bait harvesters supplying a variety of local outlets and are used as bait by local fishermen. Bait harvesters commonly use bleaching liquid (10% in sea water) or a KMnO4 (0.5 to 1% in sea water) solution to force Perinereis cultrifera (Nereididae) individuals out of their algal mat. Hediste diversicolor (Nereididae) and Scolelepis squamata(Spionidae) are dug from intertidal mudflats and sandy beaches. Commercial prices and ways of utilization are given for each species. The necessity for the legislative establishment of a regulatory management plan for worm angling is demonstrated.
Growth, mortality and spawning stock biomass of the striped red mullet Mullus surmuletus, in the Egyptian Mediterranean waters
Authors: MEHANNA S.F.
Published: May 2013

Population parameters such as age, growth, mortality and maturity-at-age are crucial parameters for accurate stock assessment and management plans to ensure the sustainable development of fisheries. Also, they are essential for the calculation of spawning stock biomass (SSB) and equilibrium yield as well as biological reference points including Fmax, F0.1 and F30%SSB. Age and growth parameters were estimated for the striped red mullet, Mullus surmuletus, sampled from commercial landings of the trawl fishery in the Egyptian Mediterranean waters, using the otolith reading technique. M. surmuletus has a longevity of 5 years, but over 70% of fish were less than 2 years old. The growth parameter estimates were K= 0.47 yrs-1, L∞= 31.74 cm, and to= -0.3 yrs. Natural mortality (M) was 0.43 yrs-1, fishing mortality (F) was 0.73 yrs-1, survival rate (S) was 0.31 and exploitation ratio was 0.63 yr-1. Length-at-50% maturity was estimated at 15.1 cm TL, while the length at first capture was estimated at 11.6 cm TL. SSB analysis showed that effort reduction is strongly recommended such that F be reduced by 40% to rebuild spawner biomass to acceptable levels. Per-recruit analysis revealed that F should be reduced by about 27% to achieve the maximum Y/R. All approaches point to the need for drastic reduction in fishing pressure by about 30-40% in the Egyptian Mediterranean fisheries.
Occurrence and distribution of different bed types of seagrass Posidonia oceanica around the Maltese Islands
Authors: BORG J.A. , ROWDEN A.A. , ATTRILL M.J. , SCHEMBRI P.J. , JONES M.B.
Published: May 2013

The small-scale distribution of Posidonia oceanica bed types were mapped at four locations off the northern coast of the Maltese Islands, using aerial photography supplemented by surveys using SCUBA diving. Results showed a similar pattern of occurrence of the seagrass at all locations surveyed. In shallow waters (2 m – 4 m), P. oceanicaoccurred as patches of variable size on a rocky and/or sandy substratum. In deeper waters (5 m – 10 m), the patches of seagrass were often replaced by reticulate beds consisting of P. oceanicainterspersed with areas of bare sand. Deeper still (11 m – 13 m), a transition from reticulate to continuous beds occurred. Continuous beds extended to depths of around 25 - 30 m and eventually became reticulate or patchy in deeper waters (>25 m). Values of total seagrass percentage cover increased, while the ratio of fragmented:continuous bed cover decreased for the four study locations on moving southwards (Ramla Bay to St Thomas Bay), indicating that P. oceanica habitat was more abundant and less fragmented in the south-eastern parts of the Maltese Islands. However, values calculated using an exposure index did not did indicate a relationship between exposure and the observed decease in fragmentation of seagrass beds on moving northwest to southwest along the north-eastern coast. Data from the four sites surveyed, together with data from other surveys, were used to show the large-scale distribution of P. oceanica beds around the Maltese Islands. The implications of the study findings for the conservation and management of P. oceanica habitat around the Maltese Islands are discussed.
The presence of the Indo-Pacific symbiont-bearing foraminifer Amphistegina lobifera in Greek coastal ecosystems (Aegean Sea, Eastern Mediterranean)
Authors: TRIANTAPHYLLOU M.V. , KOUKOUSIOURA O. , DIMIZA M.D.
Published: May 2013

During the last decades, hundreds of species of Indo-Pacific origin from the Red Sea have traversed the Suez Canal and settled in the Eastern Mediterranean. Nowadays, Amphistegina lobifera Larsen, is known to be a successful immigrant that is widely distributed in the coastal ecosystems of the Eastern Mediterranean Sea. Amphistegina is the most common epiphytic, symbiont- bearing large foraminifer. In this study we provide additional data on the presence of this species in the coastal ecosystems of Aegean Sea, Greece. The high relative abundance of A. lobifera is the result of very successful adaptation of this species to local conditions and suggests that it has become a significant part of the epiphytic foraminiferal fauna.
Records of alien marine species in the shallow coastal waters of Chios Island (2009)
Authors: KATSANEVAKIS S. , TSIAMIS K.
Published: May 2013

The shallow coastline of Chios Island was surveyed for the presence of any alien marine benthic species, during August 2009. Fourteen randomly selected sites were surveyed by snorkeling during standardized one-hour transects at depths between 0 and 10 m, and the presence of all identified alien benthic species was recorded. Six alien species were identified: Asparagopsis taxiformis, Caulerpa racemosa var. cylindracea, Stypopodium schimperi, Halophila stipulacea, Percnon gibbesi, and Siganus luridus. The green alga C. racemosa var. cylindracea was found in high densities in all the surveyed sites and was characterized as invasive in the island. The brown alga S. schimperi, the crab P. gibbesi, and the fish S. luridussustain established populations in the area. For three of the recorded marine alien species (S. schimperi, P. gibbesi, and S. luridus),Chios Island seems to be the northernmost margin of their geographical range in the Aegean Sea.
Inventory of alien marine species of Cyprus (2009)
Authors: KATSANEVAKIS S. , TSIAMIS K. , IOANNOU G. , MICHAILIDIS N. , ZENETOS A.
Published: May 2013

An updated inventory of alien marine species from coastal and offshore waters of Cyprus is presented. Records were compiled based on the existing scientific and grey literature, including HCMR database of Mediterranean alien species, technical reports, scientific congresses, academic dissertations, and websites, as well as on unpublished/personal observations. The listed species were classified in one of five categories: established, invasive, casual, cryptogenic, and questionable. The mode of introduction and the year of first sighting were also reported for each species. Eight new records based on personal observations of the authors were reported (Chondria coerulescens, Neosiphonia sphaerocarpa, Enchelycore anatina, Lagocephalus spadiceus, Lagocephalus suezensis, Scomberomorus commerson, Sillago sihama, and Sphoeroides pachygaster). Nine species, previously reported as aliens in Cypriot waters, were excluded from the inventory for various reasons. Ten established species were characterized as invasive (Caulerpa racemosa var. cylindracea, Cerithium scabridum, Strombus persicus, Trochus erythraeus, Brachidontes pharaonis, Pinctada radiata, Fistularia commersonii, Lagocephalus sceleratus, Siganus luridus, and Siganus rivulatus) as they have a substantial impact on biodiversity and/or local economy. The impact of alien marine species in Cyprus is expected to grow in the close future, and further effort directed towards recording alien invasions and their impact will be needed.
Occurrence of Paraleucilla magna Klautau et al., 2004 (Porifera: Calcarea) in Malta
Authors: ZAMMIT P.P. , LONGO C. , SCHEMBRI P.J.
Published: May 2013

The calcareous sponge Paraleucilla magna, first recorded from the Mediterranean in 2001 (southern Tyrrhenian, southern Adriatic and northwest Ionian coasts of Italy), is recorded from Malta (Central Mediterranean) where it was found forming part of the fouling community on small, surface marker-buoys around a fish-farm in Marsaxlokk Bay.
Presence of Marphysa disjuncta (Polychaeta: Eunicidae) in the Mediterranean Sea
Authors: KURT SAHIN G. , CINAR M.E.
Published: May 2013

An individual belonging to the eunicid polychaete species Marphysa disjuncta Hartman, 1961 was collected on muddy substratum at 100 m deep in Fethiye Bay (Levantine Sea, eastern Mediterranean). This species is new to the Mediterranean fauna. It closely resembles to Marphysa bellii, a native species, but it lacks compound falcigers and has unidentate subacicular hooks. This species was only reported from the eastern and western Pacific Ocean and could have been introduced to the Mediterranean Sea via ballast waters of vessels.
Studies on the allometric growth of the caramote prawn Melicertus kerathurus (Decapoda, Penaeidae) in Western Greece (E. Mediterranean)
Authors: KAPIRIS K. , KALLIAS E. , CONIDES A.
Published: May 2013

The relative growth of eleven body parts (carapace length, height, width, abdominal length, height and width, rostral length and telson length) of males and females of the caramote prawn Melicertus kerathurus was studied in samples from the Amvrakikos Gulf (Western Greece, E. Mediterranean). In addition to this, the relative growth of the length and the maximum width – and consequently the surface - of the appendix masculina of males was also studied. In general, both sexes showed similar patterns of relative growth. However, the females’ body appendages were significantly greater than those of the males. A negative allometry of escaping appendages (telson), abdomen (related to the metabolic processes, rapid locomotion and reproduction), rostrum, appendix masculina (related to mating and sperm transfer) and carapace height and width was found in both sexes. The biometric studies in this species in the central and western Mediterranean are in agreement with those from the eastern part of the basin, suggesting that all the populations throughout the Mediterranean could be considered as uniform.
Influence of Levantine Artificial Reefs on the fish assemblage of the surrounding seabed
Authors: EDELIST D. , SPANIER E.
Published: May 2013

Four Artificial Reef (AR) units were deployed at a 20m depth on a flat hard substrate 3 km west of Haifa, Israel and then surveyed for fish for 12 months. AR units supported 20 times the biomass of control quadrates and their enrichment impact was still significant at a radius of 13m away from units. The 13m values were also significantly higher than those of quadrates adjacent to units, suggesting the existence of a halo of relative depletion within the outer enrichment halo. The main species contributing to this pattern was the migrant herbivore Siganus rivulatus. A decrease in grazing resources is thus suggested as an explanation for creation of this halo. The most consistent AR residents were also Lessepsian migrants - Sargocentron rubrum, nocturnal predators which displayed high microhabitat fidelity and a steady increase in density. The 6 species of migrants recorded accounted for 65.3% of the commercially exploitable biomass and 25.2% of the specimens in the AR site. Other constant AR residents were the groupers Epinephelus costae and Epinephelus marginatus, which are rare and commercially important species. Site protection from fishing and storms were found to be of utmost importance, and design and deployment considerations are discussed.
Distribution and biology of the Blackmouth catshark Galeus melastomus in the Strait of Sicily (Central Mediterranean Sea)
Authors: RAGONESE S. , NARDONE G. , OTTONELLO D. , GANCITANO S. , GIUSTO G.B. , SINACORI G.
Published: May 2013

The Blackmouth catshark, Galeus melastomus, Rafinesque, 1810 (Carcharhiniformes; Scyliorhinidae), is a common, although at present discarded, by- catch of the bottom trawl fisheries in the Strait of Sicily. Given its ecological interest, data gathered in experimental bottom trawl surveys were analysed in order to describe its distribution and main biological traits. The Blackmouth catshark was sampled almost exclusively on the upper slope (200-800), showing the highest frequency of occurrence (69-100%), biomass (BI; 10-85 kg*km-2) and density (DI; 54-506 N*km-2) indexes in the deeper (501-800m) grounds. Individual size (total length, TL, mm) were between 70-590 and 90-510 in females and males, respectively. The sex ratio (SR) was around 0.5. The SR by size showed a gradual decrease till 450 mm class size, followed by an increase up 1 after 500 mm. Virginal/immature specimens represented the bulk of the samples in both females (77%) and males (65%); the length at 50% of sexual maturity (Lm50%) and corresponding maturity range (Lm25% - Lm75% ) was 433 (423-443) and 380 (366-394) mm, respectively.
Avoidance within a changing assessment paradigm for Mediterranean Hake stocks
Authors: RAGONESE S.
Published: May 2013

The Mediterranean hake Merluccius merluccius L., 1758, is the emblem of the so-called Mediterranean demersal fisheries paradox, showing a persistent, although stable, status of growth overexploitation and an impressive gap between current and any biological reference point. Almost full avoidance capability of large size females to bottom trawls, higher overall growth rates than previously believed and higher natural mortality in juveniles than adult, were considered among the most plausible explanation factors of such persistence. In the present note, arguments are illustrated to raise some concern about avoidance and highlight the important role of the other factors in improving assessments and launching a short term recovery plan for Mediterranean Hake stocks which is more acceptable to fishermen.
Occurrence of the alien nudibranch Melibe viridis (Kelaart, 1858) (Opisthobranchia, Tethydidae), in the Maltese Islands
Authors: BORG J.A. , EVANS J. , SCHEMBRI P.J.
Published: May 2013

The alien dendronotacean nudibranch Melibe viridis (Kelaart, 1858), a tropical Indo-Pacific species that seems to have been introduced by shipping into the Mediterranean via the Suez Canal, and which has established populations in Greece, Turkey, Cyprus, Montenegro, Croatia, NW Sicily, southern peninsular Italy and Djerba Island in the Gulf of Gabes, is recorded for the first time from Malta. A thriving population was observed on a soft sediment bottom at a depth of 18-20 m off the western coast of the island of Comino (Maltese Islands). It is suggested that this species was introduced into Malta due to a natural range expansion of surrounding populations.
Additional records of the alien gastropod, Ergalatax junionae Houart, 2008 (Gastropoda: Muricidae), from the eastern Mediterranean
Authors: KARHAN S.U. , YOKES M.B.
Published: May 2013

The alien muricid gastropod Ergalatax junionae Houart, 2008 has been known to inhabit the shallow waters of the eastern Mediterranean. The chronology of its recorded observations, beginning in eastern Turkey and proceeding to the south and west, suggests that it was first introduced to eastern Turkey via shipping, and was then spread in the Levantine Sea. The recent record from Greece indicates that its range of distribution is still expanding. Here we report local population densities and additional records of E. junionae from the eastern Mediterranean basin, including its first occurrence from the Turkish coastof the Aegean Sea.
Evidence of lipofuscin accumulation in the deep-water red shrimp Aristaeomorpha foliacea (Risso, 1827)
Authors: MEZZASALMA V. , ZAGRA M. , DI STEFANO L. , RAGONESE S. , BIANCHINI M.L.
Published: May 2013

Lipofuscin, a non-degradable, degenerative fluorescent pigment which accumulates in post-mitotic cells, represents a promising method for ageing marine crustaceans. The presence and accumulation of lipofuscin has been studied in the deep-water red shrimp Aristaeomorpha foliacea (Risso, 1827) to assess its use as a tool for ageing larger (i.e., older) specimens and thus improve knowledge of the growth and longevity of this species. Specimens, gathered during experimental trawl surveys carried out in the Strait of Sicily (Mediterranean Sea), were stored directly on-board in 10% buffered formaldehyde solution; their brain was thereafter removed, prepared with various current histological techniques and examined with a binocular microscope. Thin sections of the olfactory lobe cell mass were also analyzed using fluorescence microscopy, and the lipofuscin concentration was measured through image analysis. Various indices were computed for each individual by pooling data from many images: number and coverage of the lipofuscin granules per unit area, and mean individual area of the granules. Lipofuscin was detected in all specimens investigated with characteristics (grain typology and dimension) strictly resembling those already described in other crustacean species. The present preliminary results encourage further studies to develop and validate a methodology based on the use of lipofuscin for improving the relative ageing of large A. foliacea shrimps.
Some observations on the morphology of Sclerasterias richardi a rarely encountered Mediterranean Sea star (Echinodermata: Asteriidae)
Authors: MASTROTOTARO F. , MIFSUD C.
Published: May 2013

The presence of specimens of the asteroid Sclerasterias richardi(Perrier, 1882) in Maltese waters,with some new details of its morphology (observed by SEM) and with special reference to its madreporites,is reported.
Expanding distribution and occurence of the Indo-Pacific Stomatopod, Erugosquilla massavensis (Kossmann, 1880) on the Aegean coast of Turkey
Authors: OZCAN T. , ATES A.S. , KATAGAN T.
Published: May 2013

The indo-Pacific mantis shrimp, Erugosquilla massavensis was recently collected from Sigacik Bay,located on the Aegean coast of Turkey. It is the first record of the species along the Aegean coast of Turkey
The northernmost record of the blue-spotted cornetfish from the Mediterranean Sea
Authors: OCCHIPINTI-AMBROGI A. , GALIL B.S.
Published: May 2013

A school of Fistularia commersonii was sighted off Laigueglia (Italy), Northwestern Ligurian Sea, inAugust 2008. This fast spreading invasive Indo-Pacific fish was first recorded in the Mediterranean fromIsrael, and it has since spread clear across the sea. This is the northernmost record from the Mediterranean.
Trends in trawl and purse seine catch rates in the north-eastern Mediterranean
Authors: MACHIAS A. , STERGIOU K.I. , SOMARAKIS S. , KARPOUZI V.S. , KAPANTAGAKIS A.
Published: May 2013

Data on fishing effort expressed in vessel days at sea and corresponding landing/day for a large number of species have been collected by the Institute of Marine Biological Resources (IMBR) since the second half of 1995. Data were collected over a grid of 21 stations throughout the Greek seas. In the present study we analyzed the monthly days at sea as well as catch per day for trawlers and purse seiners from 1996 to 2000, by general linear models and trend analysis. The following vessel size groups per gear were considered: (a) trawlers smaller and larger than 20m; (b) purse-seiners smaller and larger than 15m. Collected data were also aggregated for five fishing sub-areas: the North Aegean, the Central Aegean, the South Aegean, Cretan waters and the Ionian Sea. Trend analysis of landing/day time series indicated that demersal and pelagic resources are declining in the main fishing grounds. Declining landing/day trends are regarded as indicators of overfishing, especially in the light of the fact that high catch rates are maintained by fishing in ‘hot spots’. The results of the present analysis provide, for the first time, important information on the sustainability of the fisheries in the north-eastern Mediterranean, an area characterized by a complete lack of accurate long-term data on effort and catch per effort