Substituting model based indicators in Harvest Control Rules by observations using fuzzy logic methodology

The accepted manuscript (AM) is the final draft author manuscript, as accepted for publication by a journal, including modifications based on referees’ suggestions, before it has undergone copyediting, typesetting and proof correction. This is sometimes referred to as the post-print version. Source at: http://doi.org/10.1093/icesjms/fsx227Harvest Control Rules are predefined heuristic decision rules to provide quota advices for managed fisheries. Frequently statistical methods and biological assumptions expressed in mathematical models, are used to provide the Harvest Control Rules with initial information (indicators values). The aim of this article is to investigate a possible way forward of replacing these inputs by quantities of measurable observations, e.g. catch-at-age statistics. The article presents a method by which recruitment indexes and stock biomass indicators are obtained by non-parametric use of annual catch-at-age records, without filtering the raw data (observations) through mathematical models. Two related methods, applied on three empirical cases, are provided: First, showing that recruitment strengths of the Northeast Arctic cod, haddock, and saithe stocks, obtained by fuzzy logic methodology, are satisfactory captures by the use of catch-at-age data. Second, stock size indicators are estimated for the three species by the same catch-at-age data. The second task turns out to be more challenging than the first, but also in the case of stock size evaluation, the suggested procedure provides reasonable results when compared to standard stock assessment method

HARVEST FUNCTIONS: THE NORWEGIAN BOTTOM TRAWL COD FISHERIES

A detailed and comprehensive set of catch and effort data for the cod fisheries of 18 Norwegian bottom trawlers have been obtained for the period 1971–85, a period with few binding quota restrictions on vessel operations. Harvest functions have been designed and estimated. The independent variables are hours of trawling per vessel day and biomass of the cod stock (3+). Daily biomass estimates have been calculated by polynomial interpolation of the annual estimates of the International Council for the Exploration of the Sea (ICES). By maximizing the log-likelihood function using numerical methods, parameter estimates and performance indicators of the different models were obtained. The best result was obtained for a harvest model allowing for seasonal changes and with an autocorrelated error term. For this model, the stock-output elasticity is estimated at 0.424, the effort-output elasticity at 1.232, and the technological change at about a 2% annual increase in productivity. The seasonal changes in catchability are significant, with the lowest intra-annual catchability being less than 30% of the annual maximum.Resource /Energy Economics and Policy,

Disability and Poverty

This book is about being disabled and being poor and the social, cultural and political processes that link these two aspects of living in what has been characterised as a “vicious circle” (Yeo & Moore 2003). It is also about the strengths that people show when living with disability and being poor. How they try to overcome their problems and making the best out of what little they have. This book will appeal to academics, postgraduates and policymakers in disability studies, development studies, poverty and social exclusion

On Cost Efficiency in the Barents Sea Cod Fisheries

The theoretical economic performance of the year 2000 Norwegian fishing fleet in the Barents Sea cod fisheries are studied under different stock biomass levels and age compositions by applying the EconMult fleet model. Quarterly stock conditions during the period 1946-2004 have been investigated as this represent stock conditions which may naturally occur. Cost profiles and prices are from Norwegian official statistics of year 2000, while the harvest production equations are from the EconSimp2000 model. The study confirms a close relationship between relative economic performance between fleet segments and the stock properties. No dominant factor is found, as both stock properties, stock-output elasticities and fleet cost compositions are all important factors influencing the final result. Stock size and age composition in stock are however important factors, particularly the latter. The study indicates that bottom trawl may be relatively more efficient the second half of each year when the cod availability is reduced, while gill netters and long liners dominate the first half; except in years of extreme biomasses, as these often are characterised by large biomasses of young cod which suits the trawler fleet better than the conventional fleet

An Integrated Study of Possible Economic Effects of Global Warming on the Barents Sea Cod Fisheries

A number of simulations have been carried out to study different management scenarios in the Barents Sea cod fisheries when implementing physical and biological effects of global warming. A regional representation of the IPCC SPRES B2 scenario (world region OECD90) has been obtained through the REMO5.1 model. Water temperatures and plankton biomasses are calculated by the SinMod model, employing the REMO5.1 results. This study therefore represents a fully integrated model project, linking the global circulation model to the Barents Sea fisheries through regional downscaling for the investigated area. The presence of significant dynamic systems represents a major difficulty in isolating the global warming effects from the natural variations on all levels. One natural fluctuating factor, namely the occasional inflow of herring into the Barents Sea, is represented stochastically, while the effects of choice of management regimes are studied by selecting six possible management scenarios. The study seems however to support earlier study, claiming that the choice of management regimes potentially will have a greater impact on the biological and economic performance of the Barents Sea system when assuming the system to preserve its basic composition. Significant shifts in ecosystem structure as in the case of a high degree of alien species are not considered

Measuring Disability and Inclusion in relation to the 2030 Agenda on Sustainable Development

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When, Where and What to Fish? Fishermen's Behaviour When Choosing Optional Seasonal Profiles

Most fishermen are faced with several options in both long and short term planning of their activity. In this paper we study fishers short term decisions when different seasonal fishery options are available. This involves choices of spatial and temporal allocation of effort as well as use of varying fishing gears in order to obtain the planned target specie mix. In a heterogeneous fishing fleet the seasonal options may differ considerably from vessel to vessel, also depending on its home port. The paper presents a framework wherein the seasonal choices are understood on the basis of economically rational behaviour where expected marginal benefit of the different options are evaluated and the most profitable season chosen. A monthly model is developed to describe the marginal profitability of the various fishing opportunities based on Norwegian data. The impact management decisions may have on the chosen seasonal profile and the vessel profitability is then discussed on the basis of the presented seasonal model. In particular we study the impacts of different quota allocation regimes. A diverse fleet structure may be an efficient response on highly fluctuating and unpredictable fish resources, while fisheries regulations may have the effect of reducing the flexibility by which the fleet can respond to such changes

Using prospective methods to identify fieldwork locations favourable to understand divergences in health care accessibility

Central to this article is the issue of choosing sites for where a fieldwork could provide a better understanding of divergences in health care accessibility. Access to health care is critical to good health, but inhabitants may experience barriers to health care limiting their ability to obtain the care they need. Most inhabitants of low-income countries need to walk long distances along meandering paths to get to health care services. Individuals in Malawi responded to a survey with a battery of questions on perceived difficulties in accessing health care services. Using both vertical and horizontal impedance, we modelled walking time between household locations for the individuals in our sample and the health care centres they were using. The digital elevation model and Tobler’s hiking function were used to represent vertical impedance, while OpenStreetMap integrated with land cover map were used to represent horizontal impedance. Combining measures of walking time and perceived accessibility in Malawi, we used spatial statistics and found spatial clusters with substantial discrepancies in health care accessibility, which represented fieldwork locations favourable for providing a better understanding of barriers to health access.publishedVersio

Access to assistive technology in two Southern African countries

Background Millions of people in Southern Africa are deprived of basic human rights such as the right to education and work because of the large and growing unmet demand for assistive technologies (AT). Evidence is needed to better characterize the lack of AT access. Methods This study serves to identify the sociodemographic factors that are associated with access to AT in two countries in Southern Africa, Botswana and Swaziland. To achieve this aim, logistics regression was applied to a subset of variables from two Living Conditions Studies, nationally representative surveys that were conducted in Southern Africa (2014 and 2010). Results In Botswana, 44% of people who needed AT did not receive it, while in Swaziland the unmet need was 67%. Among the sociodemographic variables tested, the type of disability was the most important factor in determining AT access in both countries. The likelihood of AT access was highest in both countries for those who had mobility limitations (i.e., difficulty walking/climbing stairs) [Botswana: 6.4 odds ratio (OR) = 6.4., 95% confidence internal (CI) (3.6–11.3); Swaziland: OR = 3.2, CI (1.4–7.3)], in comparison to those with non-mobility types of disabilities. Conclusions These findings provide support for governments and other stakeholders in the AT sector to prioritize AT to address the large unmet demand, and expand the range of AT products provided so that people with hearing, seeing, self-care, communication and cognition difficulties have equal access to AT as those with mobility impairments. A step toward achieving these aims is to inventory AT product types that are commonly covered through the public sector in each country, and identify common gaps (e.g., daily living aids). Advancing the AT sector as a whole within Southern Africa will require large scale qualitative studies that achieve a comprehensive understanding of the bottlenecks in regional AT supply, procurement, and delivery systems