32 research outputs found
Recommended from our members
Ecopath-based simulation and optimization of management options for the Eastern Gulf of Mexico reef fish fishery
Ecological and economic tradeoffs of proposed management actions were assessed using the Ecopath with Ecosim (EwE) and Ecospace software. The model has 70 biomass pools (e.g., detritus, primary producers, invertebrates, fish, dolphins, sea birds), including multiple age-classes of key species. After mass-balancing, the model was driven using observed fishing mortality from 13 fleets (4 recreational, 9 commercial) and foraging behavior was adjusted to fit the model to historic abundance and catch trends. The mixed trophic impacts routine identified the most influential groups (i.e., recreational private boats, small mobile epifauna and sardines-herring). Simulations extended the status quo 20 years and examined the impact of: 1) rebuilding gag grouper, 2) reducing longline effort, 3) increasing baitfish harvests and 4) alternative closed areas. Results highlighted changes in biomass through both competition and predation within the food web. Next, fishing effort was optimized to maximize a weighted four-criterion objective function (profit, jobs, stock size, ecosystem structure). Tradeoff frontiers between profits and reef fish biomass arose. Results indicated the status quo of overfished gag grouper is sub-optimal but policies being considered should move the system closer to the frontier. Sensitivity analysis on the recreational and commercial prices revealed a stable frontier. Lastly, Ecospace predicted spillover effects from marine protected areas (MPAs) that benefit key species and fleets, however, negative effects of lost fishing grounds and subsequent concentration of effort occurred. Results indicated that MPAs would need to be relatively large in order to be effective at preventing overfishing.Keywords: Modeling & Economic Theory, Fisheries Economics, Coupled Econ.âEcol. Models for EBFM: Exploration of Tradeoffs Between Model Complexity and ManagementKeywords: Modeling & Economic Theory, Fisheries Economics, Coupled Econ.âEcol. Models for EBFM: Exploration of Tradeoffs Between Model Complexity and Managemen
Recommended from our members
Vertical Zoning in Marine Protected Areas: Ecological Considerations for Balancing Pelagic Fishing with Conservation of Benthic Communities
Marine protected areas (MPAs), ideally, manage human uses that threaten ecosystems, or components of ecosystems. During several recent MPA designation processes, concerns have arisen over the scientific justification for no-take MPAs, particularly those that restrict recreational fishing for pelagic species. An important question is: under what conditions might recreational pelagic fishing be compatible with the conservation goals of an MPA that is primarily focused on benthic Communities? In 2005, an expert workshop of fisheries biologists, marine ecologists, MPA managers, and recreational fishermen was convened by NOAAs National MPA Center to evaluate the limited empirical data on benthic-pelagic coupling and to help provide practical advice on this topic. The participants (i) proposed a preliminary conceptual framework for addressing vertical zoning, (ii) developed preliminary guidelines to consider when evaluating whether to allow or restrict pelagic fishing in an MPA, and (iii) identified future research priorities for understanding benthic-pelagic Coupling. A Suite of ecological conditions where recreational pelagic fishing may not be compatible with benthic conservation were identified: (1) high relief habitats, (2) depths shallower than 50-100 m (depending upon the specific location), (3) major topographic and oceanographic features, and (4) spawning areas. Similarly, pelagic fishing is not likely to affect benthic communities adversely in many circumstances. Until further scientific study can shed more light on the issue of how benthic-pelagic linkages affect specific conservation targets, the proposed framework in this manuscript provides practical, easily-applied guidance for using vertical zoning to manage fishing in multiple use MPAs that focus on benthic conservation.Areas Marinas Protegidas (AMP) idealmente, administran el uso humano que amenaza los ecosistemas o sus componentes. Durante el actual proceso de declaracion de AMP, han surgido algunas preocupaciones acerca de la justificacion cientifica para establecer areas de no pesca, particularmente aquellas que restringen la pesca recreativa de especies pelagicas. Una pregunta importante es QQQ ?bajo que condiciones la pesca pelagica recreativa es compatible con los objetivos de conservacion de un AMP que se enfoca principalmente en comunidades bentonicas? En 2005, un taller de expertos en biologia pesquera, ecologfa marina, manejo de AMP y Pescadores recreativos fue convocado por el Centra Nacional de AMP de la NOAA para evaluar los pocos datos empiricos del acoplamiento entre los sistemas pelagico y bentonico, y ofrecer asesoria practica sobre el tema. Los participantes (i) propusieron un marco conceptual preliminar para abordar el tema de la zonacion vertical, (ii) desarrollar directrices preliminares para que cuando se haga una evaluation si se permite o restringe la pesca pelagica dentro de la AMP, y (iii) identificar futuras lineas de investigation para comprender mejor el acoplamiento entre el bentos y el sistema pelagico. Se identifico una serie de condiciones ecologicas en las que la pesca recreativa pelagica puede no ser compatible con la conservacion del bentos: (1) habitat de alto relieve, (2) profundidades menores a 50 m-100 m (dependiendo de la zona), (3) caracteristicas oceanograficas y topograficas sobresalientes, y (4) areas de desove. De igual forma, bajo varias circunstancias, la pesca pelagica puede no afectar las comunidades bentonicas. Hasta que los estudios cientificos brinden mas information acerca de como las relaciones entre el bentos y el ambiente pelagico afectan los objetivos especificos de la conservacion, el contexto propuesto en este trabajo provee una guia practica y de facil aplicacion para utilizar la zonacion vertical en el manejo pesquero en varios aspectos de las AMP que se enfocan en la conservacion del bentos.Keywords: Trophic level, Marine protected areas, Pelagic fisheries, Conservatio
International Society of Sports Nutrition Position Stand: Nutritional recommendations for single-stage ultra-marathon; training and racing
Background. In this Position Statement, the International Society of Sports Nutrition (ISSN) provides an objective and critical review of the literature pertinent to nutritional considerations for training and racing in single-stage ultra-marathon. Recommendations for Training. i) Ultra-marathon runners should aim to meet the caloric demands of training by following an individualized and periodized strategy, comprising a varied, food-first approach; ii) Athletes should plan and implement their nutrition strategy with sufficient time to permit adaptations that enhance fat oxidative capacity; iii) The evidence overwhelmingly supports the inclusion of a moderate-to-high carbohydrate diet (i.e., ~60% of energy intake, 5 â 8 gâž±kgâ1·dâ1) to mitigate the negative effects of chronic, training-induced glycogen depletion; iv) Limiting carbohydrate intake before selected low-intensity sessions, and/or moderating daily carbohydrate intake, may enhance mitochondrial function and fat oxidative capacity. Nevertheless, this approach may compromise performance during high-intensity efforts; v) Protein intakes of ~1.6 g·kgâ1·dâ1 are necessary to maintain lean mass and support recovery from training, but amounts up to 2.5 gâž±kgâ1·dâ1 may be warranted during demanding training when calorie requirements are greater; Recommendations for Racing. vi) To attenuate caloric deficits, runners should aim to consume 150 - 400 kcalâž±hâ1 (carbohydrate, 30 â 50 gâž±hâ1; protein, 5 â 10 gâž±hâ1) from a variety of calorie-dense foods. Consideration must be given to food palatability, individual tolerance, and the increased preference for savory foods in longer races; vii) Fluid volumes of 450 â 750 mLâž±hâ1 (~150 â 250 mL every 20 min) are recommended during racing. To minimize the likelihood of hyponatraemia, electrolytes (mainly sodium) may be needed in concentrations greater than that provided by most commercial products (i.e., >575 mg·Lâ1 sodium). Fluid and electrolyte requirements will be elevated when running in hot and/or humid conditions; viii) Evidence supports progressive gut-training and/or low-FODMAP diets (fermentable oligosaccharide, disaccharide, monosaccharide and polyol) to alleviate symptoms of gastrointestinal distress during racing; ix) The evidence in support of ketogenic diets and/or ketone esters to improve ultra-marathon performance is lacking, with further research warranted; x) Evidence supports the strategic use of caffeine to sustain performance in the latter stages of racing, particularly when sleep deprivation may compromise athlete safety
Potential for Hydrogen DDT with Ambient Vaporizers
PresentationThe ignition of a hydrogen-air mixture that has engulfed a typical set of ambient vaporizers (i.e., an array of finned tubes) may result in a deflagration-to-detonation transition (DDT). Simplified curve-based vapor cloud explosion (VCE) blast load prediction methods, such as the Baker- Strehlow-Tang (BST) method, would predict a DDT given that typical ambient vaporizers would be rated as medium or high congestion and hydrogen is a high reactivity fuel (i.e., high laminar burning velocity). Computational fluid dynamic (CFD) analysis of a single vaporizer of typical construction was carried out using the FLACS code to evaluate the potential for a DDT with a vaporizer engulfed by a hydrogen-air mixture at the worst-case concentration. This analysis showed that while significant flame acceleration occurs within the vaporizer, as expected, a DDT is not predicted. However, the analysis did indicate that a DDT may occur for two or more closely spaced vaporizers. This is relevant since multiple vaporizers are frequently present at industrial installations and are typically placed closely together to limit the required area. Spacing adjacent vaporizers further apart could preclude a DDT. However, specification of the spacing to preclude a DDT would require refined CFD analysis and/or testing, neither of which has been performed at this time. This paper also discusses the application of simplified VCE blast load methods to ambient vaporizers engulfed in a flammable hydrogen-air cloud in order to illustrate the impact of a DDT
High Rate of Transfer of Staphylococcus aureus from Parental Skin to Infant Gut Flora
Many Swedish infants carry Staphylococcus aureus in their intestinal microflora. The source of this colonization was investigated in 50 families. Infantile S. aureus strains were isolated from rectal swabs and stool samples at 3 days and at 1, 2, 4, and 8 weeks of age. The strains were identified by using the random amplified polymorphic DNA method and compared to strains from swab cultures of the mothers' hands, nipples, and nares and from the fathers' hands and nares. Maternal stool samples were also obtained at a later stage to compare infant and adult intestinal S. aureus colonization. Although 60% of 1-month-old children had S. aureus in the stools, this was true of only 24% of the mothers. The median population numbers in colonized individuals also differed: 10(6.8) CFU/g of feces among infants at 2 weeks of age versus 10(3.2) CFU/g of feces in the mothers. Of S. aureus strains in the stools of 3-day-old infants, 90% were identical to a parental skin strain. A total of 96% of infants whose parents were S. aureus skin carriers had S. aureus in their feces and 91% had the same strain as at least one of the parents. In comparison, only 37% of infants to S. aureus-negative parents had S. aureus in the stool samples. Thus, infantile intestinal S. aureus colonization was strongly associated with parental skin S. aureus carriage (P = 0.0001). These results suggest that S. aureus on parental skin establish readily in the infantile gut, perhaps due to poor competition from other gut bacteria
Vertical Zoning in Marine Protected Areas: Ecological Considerations for Balancing Pelagic Fishing with Conservation of Benthic Communities
Marine protected areas (MPAs), ideally, manage human uses that threaten ecosystems, or components of ecosystems. During several recent MPA designation processes, concerns have arisen over the scientific justification for no-take MPAs, particularly those that restrict recreational fishing for pelagic species. An important question is: under what conditions might recreational pelagic fishing be compatible with the conservation goals of an MPA that is primarily focused on benthic communities? In 2005, an expert workshop of fisheries biologists, marine ecologists, MPA managers, and recreational fishermen was convened by NOAA\u27s National MPA Center to evaluate the limited empirical data on benthic-pelagic coupling and to help provide practical advice on this topic. The participants (i) proposed a preliminary conceptual framework for addressing vertical zoning, (ii) developed preliminary guidelines to consider when evaluating whether to allow or restrict pelagic fishing in an MPA, and (iii) identified future research priorities for understanding benthic-pelagic coupling. A suite of ecological conditions where recreational pelagic fishing may not be compatible with benthic conservation were identified: (1) high relief habitats, (2) depths shallower than 50â100 m (depending upon the specific location), (3) major topographic and oceanographic features, and (4) spawning areas. Similarly, pelagic fishing is not likely to affect benthic communities adversely in many circumstances. Until further scientific study can shed more light on the issue of how benthic-pelagic linkages affect specific conservation targets, the proposed framework in this manuscript provides practical, easily-applied guidance for using vertical zoning to manage fishing in multiple use MPAs that focus on benthic conservation