Profiles of sex steroids, fecundity and spawning of a migratory characiform fish from the Paraguay–Paraná basin: a comparative study in a three-river system

This study investigated for the first time the reproductive biology of Prochilodus lineatus in a system of rivers in southeastern Brasil, relating it to the role of tributary rivers in the reproductive success of this important commercial fish in the Upper Paraná River basin, where a cascade of hydroelectric dams were deployed. Specimens were caught bimonthly in three river sites: (S1) Grande River, downstream from the Porto Colômbia dam; (S2) Pardo River; and (S3) Mogi Guaçu River. Sex steroid plasma levels, fecundity, follicular atresia, oocyte diameter and gonadosomatic index (GSI) were compared among sites. In S1, fish exhibited changes in the reproductive parameters: lower GSI, oocyte diameter and fecundity and higher follicular atresia index, when compared to S2 and S3. Frequency of maturing fish was higher in S3 and spawning was only registered in S3. In sites S2 and S3, plasma concentrations of testosterone and 17β-estradiol in females and testosterone in males showed wide variations following gonadal maturation. Fish from S1 showed few significant variations in sex steroid concentrations throughout the gonadal cycle. These results indicate that P. lineatus does not reproduce in Grande River (S1), but probably uses the Pardo River (S2) as a migratory route towards the Mogi Guaçu River (S3) where they complete gonadal maturation and spawning. Our findings contribute for understanding the reproductive biology of P. lineatus and to highlight the importance of tributaries in impounded rivers as a favourable environment for migration and spawning of fish.     

Sea cucumber fisheries: global analysis of stocks,management measures and drivers of overfishing

Worldwide, most sea cucumber fisheries are ineffectively managed, leading to declining stocks and potentially eroding the resilience of fisheries. We analyse trends in catches, fishery status, fishing participation and regulatory measures among 77 sea cucumber fisheries through data from recent fishery reports and fishery managers. Critical gaps in fisheries biology knowledge of even commonly targeted species undermine the expected success of management strategies. Most tropical fisheries are small‐scale, older and typified by numerous (>8) species, whereas temperate fisheries are often emerging, mono‐specific and industrialized. Fisher participation data indicated about 3 million sea cucumber fishers worldwide. Fisher participation rates were significantly related to the average annual yield. permanova analysis showed that over‐exploited and depleted fisheries employed different sets of measures than fisheries with healthier stocks, and a non‐metric multidimensional scaling ordination illustrated that a broad set of regulatory measures typified sustainable fisheries. SIMPER and regression tree analyses identified that the dissimilarity was most related to enforcement capacity, number of species harvested, fleet (vessel) controls, limited entry controls and rotational closures. The national Human Development Index was significantly lower in countries with over‐exploited and depleted fisheries. Where possible, managers should limit the number of fishers and vessel size and establish short lists of permissible commercial species in multispecies fisheries. Our findings emphasize an imperative to support the enforcement capacity in low‐income countries, in which risk of biodiversity loss is exceptionally high. Solutions for greater resilience of sea cucumber stocks must be embedded within those for poverty reduction and alternative livelihood options.     

A PCR-based assay for the detection and identification of <Emphasis Type="Italic">Pyrenochaeta lycopersici</Emphasis>

The isolation of Pyrenochaeta lycopersici, causal agent of corky root of tomato, is difficult because of its slow growth and poor sporulation. Identification is complicated due the existence of two morphologically similar forms, Types 1 and 2, that differ in several physiological and molecular features. For the rapid and unambiguous identification of isolates, two oligonucleotide primer pairs were designed using ITS region sequences. Specific PCR products of 147 and 209 bp were obtained for isolates of Type 1 and Type 2, respectively. Specificity of both primer pairs was verified using several fungal and bacterial species. As little as 0.7 pg of target DNA could be detected with the protocol. A nested PCR procedure was necessary for the detection of the fungus in plant tissue. This technique will be of use in epidemiological studies and in the implementation of control strategies.     

Asymptomatic double ureteral stricture in an 8-month-old Maine Coon cat: an imaging-based case report

Congenital ureteral strictures are rare both in human and veterinary medicine. While the diagnosis is generally made after a symptomatic or febrile urinary tract infection, we report here a case in which this condition represented an incidental finding during routine ultrasonography. To the best of the authors' knowledge imaging findings of a double monolateral ureteral stricture have not previously been reported.     

Regulating the global fisheries: The World Wildlife Fund, Unilever, and the Marine Stewardship Council

This analysis uses an analytical frameworkgrounded in political economy perspectives of theglobalization of the agro-food sector combined with acase study approach focusing on the Marine StewardshipCouncil (MSC) to inform discussions regarding thecharacteristics of societal regulation in thepost-Fordist era. More specifically, this analysisuses the case of the emergence of the MSC toinvestigate propositions regarding the existence of,and location of, nascent forms of a transnationalState. The MSC proposes to regulate the certificationof sustainable fisheries at the global level throughan eco-labeling program. The MSC was created in 1996by the transnational environmental organization theWorld Wildlife Fund and the transnational corporationUnilever. The emergence of the MSC has generatedheated discussion in fisheries management circles thatis in general divided along North/South lines. Thisanalysis indicates that the case of the MSC providesvaluable insights into the possible characteristics ofsupranational regulatory mechanisms that might emulatethe role of the nation-State in the post-Fordist era.     

Biochar impact on the estimation of the colorimetric‐based enzymatic assays of soil

This study was carried out in order to assess the influence of biochar applications on the estimation of colorimetric‐based enzymatic assays and to verify the effectiveness of the most common methods. Since most methods used to determine enzymatic activities in the soil are based on colorimetry, biochar may absorb substrates and/or coloured products thereby distorting the analytical result. Biochar was added to two soils, with different textures and cation exchangeable capacities, at a rate of 2% (w/w), and seven enzyme activities were determined following standard methods. The biochar amendment lowered the spectrophotometer reading of the activity of FDAase and dehydrogenase in the sandy soil. In the three enzymatic activities based on p‐nitrophenol production (β‐glucosidase, phosphatase and arylsulphatase), the addition of biochar did not change the enzyme assays. The biochar led to an overestimation in terms of the protease and urease activities in the sandy soil. In the clay loamy soil, biochar did not change the response of any of the enzyme activities tested. A biochar dose of up to 2% only guarantees the effectiveness of the most common spectrophotometric methods for not excessively sandy soils.     

Balancing wood market demand and common property rights: a case study of a community in the Italian Alps

Common property rights have a long tradition in the Italian Alps, dating back to the Middle Ages, when alpine village communities managed common forests. On these properties, in accordance with rules aimed at regulating the collective use of resources, shareholders have the right of common use of the land. As many mountainous areas still rely on firewood for the heating of homes, the right to gather firewood from common forests is the most important common property right. In the last few decades, renewable bio-energy production based on forest woody biomass has undergone significant development. In Italy, in communities where the right to gather wood still has economic, social, and cultural relevance, decision makers and community members have a different vision about the use of firewood. This paper focuses on this issue by presenting a case study located in the Italian Eastern Alps, characterised by a historical tradition of common property management. In order to define the optimal strategy to manage the common forests, taking into consideration the local community’s needs, a semi-structured questionnaire was submitted to the administrators of the common forests and to the shareholders. Different scenarios of wood use were developed to support managers and decision makers in identifying on-going trends in firewood demand. The results show that the economic scenario for the development of the bio-energy supply chain cannot be reconciled with the historical tradition and social needs.     

Natural selection favors a newly derived timeless allele in Drosophila melanogaster

Circadian and other natural clock-like endogenous rhythms may have evolved to anticipate regular temporal changes in the environment. We report that a mutation in the circadian clock gene timeless in Drosophila melanogaster has arisen and spread by natural selection relatively recently in Europe. We found that, when introduced into different genetic backgrounds, natural and artificial alleles of the timeless gene affect the incidence of diapause in response to changes in light and temperature. The natural mutant allele alters an important life history trait that may enhance the fly's adaptation to seasonal conditions.     

Some reflections on Eastern European agriculture an introductory essay to the special issue on “agriculture in Eastern Europe”

This article reviews three general themes pertaining to the transformation of Eastern European agriculture from a command system to a market oriented system. The first theme deals with the diverse character of Eastern European agriculture. In a context in which the agricultures of this region are often considered homogenous, acknowledgement of the varied dimension of this sector is a key element in both analytical and political terms. The second theme pertains to the market. The historical and theoretical dispute over the role of the market has not only been central in the socio-economic reorganization of Eastern European countries and agricultures but is also a common element shared with the West. The third and final theme refers to the changing social stratification of rural regions. The emergence of new and powerful social groups and the demise of others represent fundamental aspects in the understanding of possible trajectories for development. The article concludes with a review of the contributions contained in this special issue of Agriculture and Human Values.Alessandro Bonanno is Associate Professor of Rural Sociology at the University of Missouri-Columbia. He is the author of numerous journal articles and books, among themSmall Farms (1987),Sociology of Agriculture (1989),Agrarian Policies and Agricultural Systems (1990), andThe Agricultural and Food Sector in the New Global Era (1993). He is also co-editor of the forthcoming book From Columbus to ConAgra: The Globalization of Agriculture and Food. Since the late 1980s, he has been researching issues pertaining to the Agricultural and Food Sector in selected Eastern European Countries.