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Nautical Miles (nautical + mile)

Distribution by Scientific Domains

Earth and Environmental Science	60%

Selected Abstracts

Inventory of shipping emissions in Izmit Gulf, Turkey

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2010
Alper Kiliç
Abstract Ships are significant emissions sources in transportation sector. The environmental effects of shipping emissions become more serious because of insufficient international rules and inspections. Especially in inland waters, canals, straits, gulfs, and port areas emissions effects on environment and health are more important. Izmit Gulf is the major industrial, transport, and inland water region which is affected from shipping emissions with 37 ports and industrial plants. In this study, NOx, SO2, CO2, HC, and PM emission amounts from 11,645 ships called to Izmit Gulf in 2005. These emissions are classified according to ships operation modes and ship types. Annual shipping emissions are estimated as 5,356 t yr,1 for NOx, 4,305 t yr,1 for SO2, 254,261 t yr,1 for CO2, 232 t yr,1 for HC and 487 t yr,1 for PM. To determine the most probably effected regions in the gulf, the spatial distribution of NOx emissions within the Gulf region has been prepared in 1 × 1 Nm2 (Nautical miles) grid cells based on ship movement data along the various routes. Ships in Izmit Gulf contribute to urban pollution with sulfur dioxide significantly. © 2009 American Institute of Chemical Engineers Environ Prog, 2010 [source]

Distribution of minke whales in the Bellingshausen and Amundsen Seas (60°W,120°W), with special reference to environmental/physiographic variables

FISHERIES OCEANOGRAPHY, Issue 3 2000
Fujio Kasamatsu
The relationship between the distribution of minke whales (Balaenoptera acutorostrata) in the Bellingshausen and Amundsen Seas (longitude between 60°W and 120°W), and environmental and physiographic variables (sea-surface temperature, sea-ice extension, and sea-floor-slope type), was studied to determine whether these environmental and physical factors affect the distribution and density of minke whales. The analysis was based on sightings data obtained from the 1989/90 and 1982/83 IWC/IDCR cruises. The mean sea-surface temperatures for comparable areas were significantly higher in 1989/90 (2.04°C) than in 1982/83 (1.12°C), and the area where the sea-surface temperature was greater than 1°C in the 1989/90 study was approximately twice that of the 1982/83 study. Additionally, during the surveys, the extent of the sea ice in 1989/90 was less than that in 1982/83, with the mean ice edge about 92.6 km (50 nautical miles; 1 nautical mile ,1.852 km) farther south in 1989/90 than in 1982/83. This is consistent with the sea ice extent observed in winter, when the sea ice extent was less in 1989 than in 1982. The distribution of minke whales was substantially different between the two surveys, with the density and abundance of minke whales being greater in 1982/83 than in 1989/90. The warmer sea-surface temperatures, fewer cold-water intrusions, and the smaller extent of sea ice in 1989/90 may be related to the difference in distribution of minke whales from 1982/83, possibly owing to the shift in availability of prey. [source]

Ichthyoplankton-based spawning dynamics of blue mackerel (Scomber australasicus) in south-eastern Australia: links to the East Australian Current

FISHERIES OCEANOGRAPHY, Issue 4 2008
FRANCISCO J. NEIRA
Abstract We describe findings of three ichthyoplankton surveys undertaken along south-eastern Australia during spring (October 2002, 2003) and winter (July 2004) to examine spawning habitat and dynamics of blue mackerel (Scomber australasicus). Surveys covered ,860 nautical miles between southern Queensland (Qld; 24.6°S) and southern New South Wales (NSW; 41.7°S), and were mainly centred on the outer shelf including the shelf break. Egg identifications were verified applying mtDNA barcoding techniques. Eggs (n = 2971) and larvae (n = 727; 94% preflexion) occurred both in spring and winter, and were confined to 25.0,34.6°S. Greatest abundances (numbers per 10 m2) of eggs (1214,7390) and larvae (437,1172) occurred within 10 nm shoreward from the break in northern NSW. Quotient analyses on egg abundances revealed that spawning is closely linked to a combination of bathymetric and hydrographic factors, with the outer shelf as preferred spawning area, in waters 100,125 m deep with mean temperatures of 19,20°C. Eggs and larvae in spring occurred in waters of the East Australian Current (EAC; 20.6,22.3°C) and mixed (MIX; 18.5,19.8°C) waters, with none occurring further south in the Tasman Sea (TAS; 16.0,17.0°C). Results indicate that at least some of the south-eastern Australian blue mackerel stock spawns during winter-spring between southern Qld and northern NSW, and that no spawning takes place south of 34.6°S due to low temperatures (<17°C). Spawning is linked to the EAC intrusion, which also facilitates the southward transport of eggs and larvae. Since spring peak egg abundances came from where the EAC deflects offshore, eggs and larvae are possibly being advected eastwards along this deflection front. This proposition is discussed based on recent data on blue mackerel larvae found apparently entrained along the Tasman Front. [source]

Habitat associations of Atlantic herring in the Shetland area: influence of spatial scale and geographic segmentation

FISHERIES OCEANOGRAPHY, Issue 3 2001
CHRISTOS D. Maravelias
This study considers the habitat associations of a pelagic species with a range of biotic and abiotic factors at three different spatial scales. Generalized additive models (GAM) are used to analyse trends in the distributional abundance of Atlantic herring (Clupea harengus) in relation to thermocline and water depth, seabed roughness and hardness, sea surface salinity and temperature, zooplankton abundance and spatial location. Two geographical segments of the population, those east and west of the Shetland Islands (northern North Sea, ICES Div IVa), are examined. The differences in the ecological preferences of the species in these two distinct geographical areas are elucidated and the degree that these environmental relationships might be modulated by the change of support of the data is also considered. Part of the observed variability of the pre-spawning distribution of herring was explained by different parameters in these two regions. Notwithstanding this, key determinants of the species' spatial aggregation in both areas were zooplankton abundance and the nature of the seabed substrate. The relative importance of the variables examined did not change significantly at different spatial scales of the observation window. The diverse significance of various environmental factors on herring distribution was attributed mainly to the interaction of species' dynamics with the different characteristics of the ecosystem, east and west of the Shetland Islands. Results suggest that the current 2.5 nautical miles as elementary sampling distance unit (ESDU) is a reasonable sampling scheme that combines the need to reduce the data volume while maintaining spatial resolution to distinguish the species/environment relationships. [source]

Distribution of minke whales in the Bellingshausen and Amundsen Seas (60°W,120°W), with special reference to environmental/physiographic variables

Patterns in marine hydrozoan richness and biogeography around southern Africa: implications of life cycle strategy

JOURNAL OF BIOGEOGRAPHY, Issue 4 2010
Mark J. Gibbons
Abstract Aim, To examine patterns of marine hydrozoan richness around southern Africa and to test the hypothesis that patterns of biogeography become weaker with increasing dispersal ability. Location, The coastline of southern Africa from 21° S, 14° E to 28° S, 33° E, extending from the intertidal zone seawards a distance of 200 nautical miles. Methods, Published and unpublished information on the distribution of marine Hydrozoa was entered as presence/absence data onto a gridded coastline of the region. A similarity matrix between the species composition of grid squares was constructed using the Bray,Curtis index and visualized using non-metric multidimensional scaling ordinations. Separate analyses were conducted, and compared, on the three major life cycle groupings: holoplanktic, meroplanktic and benthic. Results, Over 450 species of marine Hydrozoa have been reported from the region, and species richness increases eastwards, in a manner at odds with the distribution of sampling effort. There was a significant correlation between the geographic structures of the resemblance matrices generated for the three life cycle groupings. In other words, all three groups showed similar patterns of biogeography around the region, and these were broadly similar to those reported by others. However, there were differences between them that reflect the resolution at which the data were examined. At a level of 40% similarity, there was no biogeographic structure to the holoplanktic fauna, the meroplanktic taxa were simply sub-divided into cool- and warm-temperate/subtropical elements, and in the case of benthic taxa, the cool-water fauna was further split into a southern Namaqua and a depauperate northern Namib component. Even at a resolution of 70% similarity, the holopelagic taxa could be separated only into cool-temperate and warm-temperate/subtropical faunas. Main conclusions, Holoplanktic taxa show comparatively less biogeographic structure than meroplanktic taxa, which in turn show less clearly defined biogeographic structure than benthic taxa. It is suggested that this is related to the interaction between oceanography and dispersive-stage duration. The role that the Agulhas Current plays in influencing the Benguela Current fauna is highlighted. This study has implications for conservation planning exercises based on protecting representative biotopes in different biogeographic regions. [source]

Application of GIS for processing and establishing the correlation between weather radar reflectivity and precipitation data

METEOROLOGICAL APPLICATIONS, Issue 1 2005
Y. Gorokhovich
Correlation between weather radar reflectivity and precipitation data collected by rain gauges allows empirical formulae to be obtained that can be used to create continuous rainfall surfaces from discrete data. Such surfaces are useful in distributed hydrologic modelling and early warning systems in flood management. Because of the spatial relationship between rain gauge locations and radar coverage area, GIS provides the basis for data analysis and manipulation. A database of 82 radar stations and more than 1500 rain gauges in continental USA was compiled and used for the continuous downloading of radar images and rain data. Image sequences corresponding to rain events were extracted for two randomly selected radar stations in South and North Carolina. Rainfall data from multiple gauges within the radar zone of 124 nautical miles (nm) (,230 km) were extracted and combined with corresponding reflectivity values for each time interval of the selected rain event. Data were normalised to one-hour intervals and then statistical analysis was applied to study the potential correlation. Results of regression analysis showed a significant correlation between rain gauge data and radar reflectivity values and allowed derivation of empirical formulae. Copyright © 2005 Royal Meteorological Society. [source]

Closing the open sea: Development of fishery management in four Icelandic fisheries

NATURAL RESOURCES FORUM, Issue 1 2003
Thórólfur Matthíasson
The article outlines the development of Iceland's fishery rights and the extension of its territorial waters between the 1950s and the mid-1970s, whereby Iceland gained exclusive control and use of the marine resources of the waters within 12, later 50, and ultimately 200 nautical miles around the island. The article concentrates on four of Iceland's main fisheries: shrimp, herring, capelin and cod. These four fisheries are discussed separately and in depth, presenting the beginnings and growth of the industry and detailing the development of management practices and the corresponding legislation and regulatory measures. Iceland's initial concern was to gain control over the marine resources surrounding the island, but once this was achieved, the focus of attention shifted to managing first the economic and soon also the ecological aspects of its tremendous resource. Informed mainly by indigenous expertise, Iceland's concern was to limit overfishing, manage its fisheries sustainably both from the economic and ecological points of view, and find the best ways to distribute the revenues from the marine harvest. The article looks at each of the four fisheries to clarify how the individual transferable quota (ITQ) system came into being, how initial quota holdings were allotted, and analyses the circumstances under which the ITQ system became the management tool of choice. For each fishery, the process of regulatory evolution was quite unique. At the same time, there is a common pattern to all the fisheries, which may be summarized as follows. Firstly, serious attempts to reform management practices only got underway when the fishery had collapsed or was close to collapse. Secondly, stakeholders invariably started the process of regulation by limiting access to the fishery. Thirdly, a variety of rules were implemented to allocate rights to participate in the fishery to additional entrants once membership had been closed. Finally, prior to the invention of the ITQ system, prices were used to manage fisheries in Iceland. It may be concluded that the management of fisheries by ITQs may be a historical accident, rather than the end point of a logical evolution. [source]

The Riskiest Job in Medicine: Transplant Surgeons and Organ Procurement Travel

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 10 2009
M. J. Englesbe
Transplant surgeons are exposed to workplace risk due to the urgent nature of travel related to organ procurement. A retrospective cohort study was completed using data from the Scientific Registry of Transplant Recipients and the National Transportation Safety Board. A web-based survey was administered to members of the American Society of Transplant Surgeons. The survey response rate was 38% (281/747). Involvement in ,1 procurement-related travel accident was reported by 15% of respondents; surgeons reported 61 accidents and 11 fatalities. Air travel was used in 26% of procurements and was involved in 56% of accidents. The risk of fatality while traveling on an organ procurement flight was estimated to be 1000 times higher than scheduled commercial flight. Involvement in a ,near miss accident' was reported by 80.8%. Only 16% of respondents reported feeling ,very safe' while traveling. Procurement of organs by the geographically closest transplant center would have reduced the need for air travel (>100 nautical miles) for lung, heart, liver and pancreas procurement by 35%, 43%, 31% and 49%, respectively (p < 0.0001). These reductions were observed in each Organ Procurement and Transplantation Network region. Though these data have important limitations, they suggest that organ procurement travel is associated with significant risk. Improvements in organ procurement travel are needed. [source]

Seasonal changes in distribution of Hector's dolphin at Banks Peninsula, New Zealand: implications for protected area design

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 1 2010
William Rayment
Abstract 1.The efficacy of protected areas for wildlife management is largely dependent on appropriate design. It is therefore crucial that the distribution of target species is well understood. 2.The Banks Peninsula Marine Mammal Sanctuary (BPMMS) was designed to protect Hector's dolphins from bycatch in gillnets. However, the Banks Peninsula dolphin population is likely to be still declining, partly due to continued bycatch outside the boundaries of the BPMMS. 3.A three year series of aerial line-transect surveys around Banks Peninsula was carried out to investigate seasonal changes in distribution of Hector's dolphins out to 20 nautical miles (37,km) from the coast. 4.Dolphin sightings were concentrated close to shore in shallow water in summer, but were more evenly distributed throughout the study area in winter. A greater proportion of dolphins were sighted outside the 4 nautical miles (7.4,km) offshore boundary of the BPMMS in winter (mean=56%) than in summer (mean=19%) (G=88.25, df=1, P<0.001). 5.Partial Mantel tests revealed the effects of distance offshore and depth on dolphin occurrence while controlling for spatial autocorrelation and multicollinearity within the data. Distance offshore had the strongest and most consistent effect on dolphin presence, while depth had a strong effect in summer only. 6.It is proposed that restrictions on gillnetting around Banks Peninsula must be extended in order to reduce bycatch of Hector's dolphins to a sustainable level, and that a new offshore boundary of the BPMMS would be best defined by distance from the coast. Copyright © 2009 John Wiley & Sons, Ltd. [source]