Thirty years of change and the future of Alaskan fisheries: Shifts in fishing participation and diversification in response to environmental,regulatory and economic pressures

Heterogeneity in human responses and decision‐making can contribute to the resilience of social–ecological systems in the face of environmental, political and economic pressures. In fishery systems worldwide, the ability of harvesters to maintain a diverse portfolio of fishing strategies is important for building adaptive capacity. We used a case‐study approach to examine the complexity of factors that inhibit or promote diversification in fisheries of Alaska, one of the major fishing regions of the world. Through a combination of harvest records and literature review, we explored shifts in participation and portfolio diversity in Alaskan fisheries over three decades. The four case‐studies examined the responses of fishers, fleets and communities to multiple, intersecting pressures, including biological declines, market and price dynamics, fishery privatization and the 1989 Exxon Valdez oil spill. These cases illustrate how stressors acting at multiple scales can encourage or constrain opportunities for diversification, and that these opportunities may be spread inequitably across participants. Overall, we found evidence for reduced participation and increasing specialization in Alaskan commercial fisheries. While numerous factors explain these trends, policies like individual quota systems and the increasing cost of entry into fisheries are forcing consolidation at local to regional scales. A portfolio approach to managing fisheries that reduces barriers to diversification and includes broad representation of resource users and communities in management may help to maintain opportunity and choice for fishers.     

Effects of mountaintop mining on fish distributions in central Appalachia

Mountaintop mining with valley fills (MTM/VF) is the main source of landscape change in central Appalachia. While our knowledge of the local‐scale effects of MTM/VF on stream chemistry and biotic assemblages has recently improved, the effects at the landscape scale are less well known. In this study, we explore the effects of MTM/VF on the distributions of six fish species with contrasting ecologies in the upper Kentucky River basin, an area heavily affected by MTM/VF. Using a museum‐based data set of 239 occurrence records, land use/land cover data and boosted regression tree modelling, we were able to create robust predictive models for the focal species (AUCs = 0.82–0.93). Models explained from 41.2 to 71.9% of the variation in species distributions. We detected a marked negative influence of MTM/VF in four of the six species distribution models – with relative influences ranging from 5.9–12.7%. Species typically inhabiting faster‐flowing riffle and run mesohabitats appeared to respond more strongly to MTM/VF. Interestingly, the mean patch size of MTM/VF was more influential than the overall proportion of the watershed affected by MTM/VF in our models. Thus, our data suggest the spatial pattern of mining disturbance is very important in determining the cumulative impact of MTM/VF. Considering the central Appalachian region is a continental hot spot for freshwater biodiversity, establishing a firm understanding of the effects of MTM/VF at the landscape scale is essential if we wish to protect these natural resources.     

An Improved Synthesis of 7, 8-Epoxy-1,3,11-cembratriene- 15R(α), 16-diol,a Cembranoid of Marine Origin with a Potent Cancer Chemopreventive Activity

An effective method for the synthesis of 7,8-epoxy-1,3,11-cembratriene- 15R(α),16-diol and its in vitro Epstein-Barr Virus Early Antigen (EBV-EA) Activation Chemopreventive Assay are reported. This semisynthetic product is a new cembranoid with a potent tumor inhibitory activity that is expected to be a lead compound for a new class of chemopreventive agents of marine origin.     

An economic feasibility assessment of autonomous field machinery in grain crop production

Precision Agriculture - A multi-faceted whole farm planning model is developed to compare conventional and autonomous machinery for grain crop production under various benefit, farm size, suitable...     

Sampling Strategies for Mapping Soil Phosphorus and Soil Potassium Distributions in Cool Temperate Grassland

Unlike the situation for arable soils, virtually nothing is known about the spatial dependencies of soil properties in cool temperate grassland or about what the optimal sampling strategies ought to be for mapping soil nutrient distributions in such situations. The aim of this study was to investigate the spatial variability in plant-available (soil) phosphorus and potassium in a grass silage field in Northern Ireland and devise optimal sampling strategies for mapping their distributions. Soil samples were collected from the field at 25 m intervals in a regular rectangular grid to provide a database of soil properties. Different data combinations were subsequently abstracted from this database for comparison purposes, and ordinary kriging used to produce interpolated soil maps. Soil potassium displayed greater spatial variability than soil phosphorus. In keeping with this observation, the results of three separate statistical procedures demonstrated that the optimal sample size for estimating the true population means was about twice as large for soil potassium as for soil phosphorus. Optimal sampling strategies, however, related not just to sample size but to sample combination and field shape as well.     

A simulation model for studying the role of pre-slaughter factors on the exposure of beef carcasses to human microbial hazards.

A Monte Carlo simulation model was constructed for assessing the quantity of microbial hazards deposited on cattle carcasses under different pre-slaughter management regimens. The model permits comparison of industry-wide and abattoir-based mitigation strategies and is suitable for studying pathogens such as Escherichia coli O157:H7 and Salmonella spp. Simulations are based on a hierarchical model structure that mimics important aspects of the cattle population prior to slaughter. Stochastic inputs were included so that uncertainty about important input assumptions (such as prevalence of a human pathogen in the live cattle-population) would be reflected in model output. Control options were built into the model to assess the benefit of having prior knowledge of animal or herd-of-origin pathogen status (obtained from the use of a diagnostic test). Similarly, a facility was included for assessing the benefit of re-ordering the slaughter sequence based on the extent of external faecal contamination. Model outputs were designed to evaluate the performance of an abattoir in a 1-day period and included outcomes such as the proportion of carcasses contaminated with a pathogen, the daily mean and selected percentiles of pathogen counts per carcass, and the position of the first infected animal in the slaughter run. A measure of the time rate of introduction of pathogen into the abattoir was provided by assessing the median, 5th percentile, and 95th percentile cumulative pathogen counts at 10 equidistant points within the slaughter run. Outputs can be graphically displayed as frequency distributions, probability densities, cumulative distributions or x-y plots. The model shows promise as an inexpensive method for evaluating pathogen control strategies such as those forming part of a Hazard Analysis and Critical Control Point (HACCP) system.