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1.
William SilvertAristides Moustakas 《Ocean & Coastal Management》2011,54(4):312-317
A dynamic one-dimensional model of Marine Protected Areas (MPAs) along a coastline has been developed to investigate their impact on fish stocks and landings over time. The model is basically a cellular automaton implemented with a spreadsheet and is used to trace stocks and landings from the initiation of the MPA for several years under a set of three different scenarios for the allocation of fishing effort. In all cases landings decline as soon as part of the coastline is protected, but in every case they recover to their original level and above. The time it takes for landings to recover ranges from four to nine years and with two small MPAs (several small) the recovery is faster than with one large one of the same spatial extent (single large). These results indicate that although fishery closures through an MPA will undoubtedly have an immediate adverse impact on the fishing industry, the chances of full recovery after several years are good, and both the fishery and the fish stocks will benefit in the long run. Further, our model provides a null model on the impacts over time of MPAs that may iteratively be compared with real cases that have biological and social variables. 相似文献
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Aristides Moustakas William Silvert 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(3):403-413
We have developed a spatially explicit model that simulates the interaction between fish and fishers based on past fish location,
abundance and fish dispersal. We have examined four scenarios for the design and management of Marine Protected Areas (MPA)
and for each we simulated fish biomass and fish catches: (1) No MPA. (2) A single MPA located at a feeding area. (3) A single
MPA designed to maximise its overlap with the predominant route of fish dispersal. (4) The use of two MPAs. Each scenario
was replicated with two scenarios regarding the time that fish remains within the MPA and two grid map scenarios to account
for time–space effects and map/coastline characteristics. Results showed that overall closing an area increased fish biomass.
However, an MPA located in the open sea for a limited time may have adverse effects on fish biomass. MPAs increased fish catches
when a single large MPA or two small MPAs were located in the open sea for a limited time. The effects of time that fish remains
protected in closed areas vary in combination with the spatial design: When examining time effects on the efficacy of MPAs
within each scenario with an MPA located in the open sea, fish biomass was always higher in the case where fish was protected
for more calendar days during each year. When comparing between different spatial designs, proximity to the coast was a more
predominant factor in the efficacy of MPAs rather than time that fish was protected. The scenario that gave the highest total
fish biomass was the one that covered the largest part of the migration route, despite increased edge effects. Our results
suggest that it is not per se the perimeter to surface ratio that matters, but the trade-off between edge effects and maximised
MPA surface in the predominant dispersal direction. Our results also have implications for the design of terrestrial reserves. 相似文献
3.
Takvor H. Soukissian Aristides M. Prospathopoulos Chrysoula Diamanti 《Journal of Atmospheric & Ocean Science》2002,8(2):163-189
In this paper, a statistical analysis on wind and wave buoy measurements and wind and wave model forecasts obtained during a two-year period (1999-2001) is presented with reference to four characteristic near-shore sites of the Aegean Sea. The measurements are a main product of the "POSEIDON" system aiming at the monitoring and forecasting of the state of the Greek seas, operated by the National Centre for Marine Research (NCMR). Although the two-year period is rather short for a thorough analysis of the local wind and wave climate, yet the obtained results, presented herein for the first time, reveal some interesting features of the corresponding wave and wind characteristics. Comparisons between the measurements and the forecast results are also performed at the locations under consideration. It is found that (i) wind speeds obtained from the POSEIDON weather forecasting system are, in general, in agreement with the measurements, except for high wind speeds which are systematically underestimated, (ii) the WAM model can successfully follow the monthly and over year trend of the evolution of wind and wave characteristics, but face significant problems for efficient sea-state forecasting. Finally, the overall pattern of the wind/wave climate for the entire Aegean Sea as obtained from the models is presented by means of the spatial distribution of the mean annual wind and sea-state intensity. 相似文献
4.
Aristides?MoustakasEmail author Matthew?R.?Evans 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(2):315-328
Bovine tuberculosis (TB) poses a serious threat for agricultural industry in several countries, it involves potential interactions between wildlife and cattle and creates societal problems in terms of human-wildlife conflict. This study addresses connectedness network analysis, the spatial, and temporal dynamics of TB between cattle in farms and the European badger (Meles meles) using a large dataset generated by a calibrated agent based model. Results showed that infected network connectedness was lower in badgers than in cattle. The contribution of an infected individual to the mean distance of disease spread over time was considerably lower for badger than cattle; badgers mainly spread the disease locally while cattle infected both locally and across longer distances. The majority of badger-induced infections occurred when individual badgers leave their home sett, and this was positively correlated with badger population growth rates. Point pattern analysis indicated aggregation in the spatial pattern of TB prevalence in badger setts across all scales. The spatial distribution of farms that were not TB free was aggregated at different scales than the spatial distribution of infected badgers and became random at larger scales. The spatial cross correlation between infected badger setts and infected farms revealed that generally infected setts and farms do not coexist except at few scales. Temporal autocorrelation detected a two year infection cycle for badgers, while there was both within the year and longer cycles for infected cattle. Temporal cross correlation indicated that infection cycles in badgers and cattle are negatively correlated. The implications of these results for understanding the dynamics of the disease are discussed. 相似文献
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The inner bay of Lourenço Marques receives the untreated sewage of the city, the run-off from five rivers and metal and hydrocarbon pollution from the activities of the port. Iron ore handling results in an increase in iron and copper concentrations in the water, particularly since loading by slurry was introduced. Large quantities of metal pollutants are probably accumulating in muds and are likely to contaminate shellfish which are an important food source in the area. Untreated sewage discharges are at such a level that eutrophication of the bay is threatened, besides constituting a public health risk on bathing beaches. 相似文献
7.
Aristides Moustakas Matthew R. Evans 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(3):623-635
Bovine Tuberculosis (TB) is a major problem for the agricultural industry in several countries. TB can be contracted and spread by species other than cattle and this can cause a problem for disease control. In the UK and Ireland, badgers are a recognised reservoir of infection and there has been substantial discussion about potential control strategies. We present a coupling of individual based models of bovine TB in badgers and cattle, which aims to capture the key details of the natural history of the disease and of both species at approximately county scale. The model is spatially explicit it follows a very large number of cattle and badgers on a different grid size for each species and includes also winter housing. We show that the model can replicate the reported dynamics of both cattle and badger populations as well as the increasing prevalence of the disease in cattle. Parameter space used as input in simulations was swept out using Latin hypercube sampling and sensitivity analysis to model outputs was conducted using mixed effect models. By exploring a large and computationally intensive parameter space we show that of the available control strategies it is the frequency of TB testing and whether or not winter housing is practised that have the most significant effects on the number of infected cattle, with the effect of winter housing becoming stronger as farm size increases. Whether badgers were culled or not explained about 5 %, while the accuracy of the test employed to detect infected cattle explained less than 3 % of the variance in the number of infected cattle. 相似文献
8.
P. E. Tsakiridis P. Oustadakis K. Moustakas S. L. Agatzini 《International Journal of Environmental Science and Technology》2016,13(7):1793-1802
The present work aims at the characterization and leachability examination of aluminium dusts, generated during the secondary aluminium production from scrap. Two different types of dusts were examined: a cyclone aluminium dust and a fabric filter aluminium dust, derived from the waste gases de-dusting system, produced during the Al scrap meltdown. The characterization of both dusts was carried out using particle size distribution analysis, chemical analysis, X-ray diffraction and thermogravimetric/differential thermal analyses. Their microstructure and morphological characteristics were examined by scanning electron microscopy and transmission electron microscopy. The results showed that the basis of the examined dusts was different, as they consisted of different mixtures of metallic aluminium, salt flux constituents, aluminium oxide and aluminium nitrides. Their behaviour during leaching was determined by the toxicity characteristic leaching procedure test and the EN 12457-2 compliance leaching test. The results revealed that both dusts should be treated as hazardous wastes and in case of landfilling they should be disposed of at appropriate, regulation-prescribed waste dumps, after removing the water-soluble phases, such as chlorides or nitrides. 相似文献
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A numerical study of the Chicago lake breeze 总被引：3，自引：0，他引：3
A two-dimensional numerical model is presented for the study of the Chicago area lake breeze. The hydrostatic approximation used by previous workers in this field is not employed. Instead, the complete z-momentum equation is solved and the equation of continuity is retained in its original form. The numerical model employs a staggered mesh, and Alternating Direction Implicit methods are used for the integration of the equations. Computational stability is achieved without external filters, upstream space differencing, or artificial horizontal diffusion terms.The results obtained for realistic initial conditions but simplified boundary conditions compare reasonably well with observations obtained by Lyons in his 1967 observational study of the Chicago lake breeze. Limiting forms of the lower boundary condition bracket the observed wind speeds and other kinematic features of the breeze. Among the various eddy diffusivity models, that with constant eddy diffusivity with height produces the most realistic results. The models with a decrease of eddy diffusivity with height show unrealistic flow patterns in the upper layers. The stability of the atmosphere at the onset of the breeze is shown to have a pronounced effect on the intensity of the circulation, but not on the thickness of the inflow layer, which appears quite insensitive to large changes in the parameters involved. 相似文献