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1.
This paper describes the development of a Livelihood Vulnerability Index (LVI) that estimates the relative ability of California commercial sea urchin fishermen to cope with the change associated with proposed marine protected areas. A key goal in establishing marine protected areas is to maximize conservation benefits while minimizing the potential negative impacts to local fishing communities. However, current impact analyses largely assume a linear relationship between percent of fishing area or revenue lost with the magnitude of impact to fishermen. The LVI described in this paper aims to provide an additional dimension to impact analyses in which the adaptive capacity of individual fishermen is examined to estimate the differential abilities of fishermen to cope with the loss of fishing areas or revenue. This paper advances vulnerability assessments as it develops a novel framework for identifying and measuring drivers of vulnerability for understudied fishing populations whose livelihoods depend upon marine resources. This vulnerability assessment is intended to inform the design of marine protected areas by enabling researchers to incorporate the adaptive capacity of fishermen into socioeconomic impact analyses. The LVI was developed for the California commercial sea urchin fishery in the context of proposed marine protected area networks develop through the California Marine Life Protected Act planning process. As climate change advances there is an increasing need to identify vulnerable and resilient populations and ways to bolster adaptive capacity given the environmental and economic changes ahead.  相似文献   

2.
James R. Coull 《GeoJournal》1996,39(2):185-194
Shetland, as an isolated group of islands on the north-west margin of Europe, has always depended in its economy on marine-based resources, and current trends suggest that this will continue for the future. Up to the oil era Shetland depended mainly on the fisheries around it, although for centuries externally-based fishermen have profited more from these fisheries than have the Shetland people. As well as the development of oil from the 1970s there has been the other major economic innovation of fish farming. The oil industry is on massive scale and has greatly changed the economy of the islands and brought notable social benefits; but the direct employment it provides is considerably exceeded by the fish-related industries, which include employment in fish processing and packing plants as well as in fish catching and fish farming. With the oil industry in Shetland now on a settled downward trajectory, the islands are inevitably now having to look more to fish-related employment for their future. In the internal structure of Shetland, fish farming has a notable effect in distributing employment throughout the islands. Activity in fishing and fish processing is more selectively located: fishing is mainly concentrated in certain islands in the archipelago, particularly Whalsay and Burra; and fish processing is mainly in central locations, especially Lerwick and Scalloway. A prominent problem for fish processors is getting reliable supplies in face of higher fish prices at markets on the Scottish mainland. The processors also now face the challenge of putting more value added on their products in an outlying location. For the future there is a major issue in getting more effective measures for conservation of fish stocks in the Shetland area; there is also the related issue of whether Shetland fishermen should get preference in the allocation of fish quotas in this area. For fish farming there is the basic issue of maintaining a pollution-free environment: this was emphasised by the oil spill from the Braer oil tanker, and there is also concern about potential polluution from the prospective development of oil fields in the more difficult deep-water environment to the west of the islands.  相似文献   

3.
This work addresses the mercury exposure scenarios through fish consumption in the urban area of Alta Floresta, by comparing the different patterns of mercury exposure from fish ingestion for different population groups. This study was based on field surveys that could provide background information, such as the characteristics of Hg sources, characteristics of local and regional environment, Hg concentrations in different media, and the characterization of the local urban population. The urban area of Alta Floresta is one of the most important gold-trading centers in Amazonia, where approximately 1 ton of gold has been commercialized monthly. The general adult urban population is exposed to low-level mercury concentration via fish consumption with an average daily intake of 0.2 μg/kg (b.w.) and an estimated hazard quotient of 0.7. However, the fishermen families present an average daily intake of 2.2 μg/kg (b.w.) and a hazard quotient of 8.6. The children of fishermen families between 5 and 14 years old are the main risk group for Hg exposure via fish ingestion. Based on the uncertainty analysis, the Hg fish concentrations and the fish ingestion rate were found to be the main parameters affecting the variability of the model outputs.  相似文献   

4.
This study assesses the condition of the fishing industry in Pakistan. It briefly reviews the ecological environment of Pakistan's fisheries and describes recent developments in technology and their impact on the catch. The factors contributing to growth include government efforts, fleet expansion and development of export markets. This study also points out the difficulties in arriving at a satisfactory management policy for the regulation of the industry. Development strategies seek rational, efficient exploitation of marine resources for the broad goals of national development. Consequently, policy makers' fisheries management concepts and techniques are generally less effective in addressing the need of the coastal communities. The conclusion is that fisheries development effort need balanced resource management, serving as an instrument for regional development while taking into account the traditional resource use rights of small-scale fishermen.  相似文献   

5.
Bruce Mitchell  Paul King 《Geoforum》1984,15(3):419-432
The Canadian marine fisheries are presently in the midst of a grave crisis. On both the Atlantic and Pacific coasts, fish stocks have been depleted through overfishing. Fish habitats are being damaged or permanently destroyed through industrial development. Gross overcapacity exists in both the primary and secondary sectors of the fishing industry, which is primarily attributable to the common property status of the resource. Many fishermen and processors have been or are in states of near bankruptcy as increasing energy costs, high product inventories and market weakness have crippled operations. A lack of alternative employment opportunities for many participants coupled with a high regional and community dependence on depressed resource-based industries has confounded attempts by government to introduce measures leading to more rational fisheries management. The outcome has been a strategy characterized as ‘incremental ad hocery’. Major inquiries were conducted into both the Atlantic and Pacific fisheries in the early 1980s. Conflict between and among the federal and provincial governments, various sectors of the commercial fishery, Indian and recreational usergroups, fishery interests and other industries, as well as Canada and other nations, has made it difficult to implement needed reforms. Stock and habitat maintainence and improvement; user regulations, coupled with tenure rights for fishermen; and marketing research and promotion are accepted as key components of any long-run fishery management strategy. In the short-run, the need is to develop approaches that are implementable in the context of diverse conflicting and vested interests.  相似文献   

6.
The demand for ecosystem services and the ability of natural ecosystems to provide those services evolve over time as population, land use, and management practices change. Regionalization of ecosystem service activity, or the expansion of the area providing ecosystem services to a population, is a common response in densely populated coastal regions, with important consequences for watershed water and nitrogen (N) fluxes to the coastal zone. We link biophysical and historical information to explore the causes and consequences of change in ecosystem service activity—focusing on water provisioning and N regulation—from 1850 to 2010 in a coastal suburban watershed, the Ipswich River watershed in northeastern Massachusetts, USA. Net interbasin water transfers started in the late 1800s due to regionalization of water supply for use by larger populations living outside the Ipswich watershed boundaries, reaching a peak in the mid-1980s. Over much of the twentieth century, about 20 % of river runoff was diverted from reaching the estuary, with greater proportions during drought years. Ongoing regionalization of water supply has contributed to recent declines in diversions, influenced by socioecological feedbacks resulting from the river drying and fish kills. Similarly, the N budget has been greatly perturbed since the suburban era began in the 1950s due to food and lawn fertilizer imports and human waste release. However, natural ecosystems are able to remove most of this anthropogenic N, mitigating impacts on the coastal zone. We propose a conceptual model whereby the amount and type of ecosystem services provided by coastal watersheds in urban regions expand and contract over time as regional population expands and ecosystem services are regionalized. We hypothesize that suburban watersheds can be hotspots of ecosystem service sources because they retain sufficient ecosystem function to still produce services that meet increasing demand from the local population and nearby urban centers. Historical reconstruction of ecosystem service activity provides a perspective that may help to better understand coupled human–natural system processes and lead to more sustainable management of coastal ecosystems.  相似文献   

7.
Trotline blue crab (Callinectes sapidus) fishermen in the Patuxent, Chester, and Choptank tributaries of Chesapeake Bay set their gear in areas where the water quality, characterized by average mid-channel bottom dissolved oxygen, varies across the river systems and over the fishing season. Two harvest production models are developed to capture the potential effects of this source of environmental stress. One model treats the impact of water quality as influencing the availability of crabs to the gear, while the second treats the impact as another source of mortality. Both models are estimated assuming that dissolved oxygen has no effect on crab harvests above an upper threshold of 5 mg I−1. Contrary to the mortality model, the availability model produces estimates that are consistent with our prior beliefs that productivity will be negatively impacted by poor water quality. To determine the percentage of the available crab stock in an area that will be harvested by a given amount of gear under different water quality conditions a simulation of the availability model is developed. The simulations show that a decline in average mid-channel bottom dissolved oxygen in the Patuxent River to 4 mg I−1 may lead to a 48% decline in the percentage of the blue crab population in the area that will be harvested with the same amount of fishing effort.  相似文献   

8.
The coastal waters of the former GDR comprising more than 9000 sqkm with a maximum width of 12 n.m. from the baseline and the 1600 sqkm inner bodden waters with a volume of about 6 cu.km are of unique importance to trade by providing transport by sea including three ferry links, to fishing, recreaation and other uses. Based on the results of monitoring programmes carried out between 1973 and 1988 and reviewing existing literature, the state of these waters is discussed. The paper starts with a characterization of the environmental background conditions of the area including its catchment region. Data on population density, fishing, industry, agriculutre and other information is tabulated as deemed necessary to understand the sensitivity of the coastal water and potential impacts on their state.The contamination load released into bodden waters and further into the Baltic Sea by eight relatively small rivers is quantified. In relation to the concentrations of contaminants such as heavy metals, petroleum hydrocarbons and organochlorines, there are no severe environmental problems. However, nutrients and their cycling in the system cause eutrophication. This results (a) in reduced usefulness of the bodden waters for recreation and even fishing, (b) in anoxic sediments and (c) in declining benthos colonization. For some of the contaminants inter-annual and spatial trends were found to be of statistical significance. Summarizing the present knowledge on the state of the coastal waters and realising obvious gaps in the complex scientific understanding and forecasting, measures required to reduce the contaminant load are proposed.  相似文献   

9.
A study on the short term variability of the ocean and its effects on the distribution of fish shoals in the coastal area of NE Japan has been conducted. The efforts have been made to detect the temporal changes of the Tsugaru Warm Current in summer and autumn (i.e. fishing seasons) by using the satellite infrared images (NOAA7-9) and concurrent hydrographic observation data. Also fish shoal (mackerel and sardine) distribution was investigated by echo-sounder and fishing fleets' operation data. The satellite images revealed that the gyre of the Tsugaru Warm Current changed entirely in a short time, and sometimes the gyre was devided into two parts. The time scale of this process was estimated to be 1–2 weeks. Corresponding to this process, the fishing grounds changed rapidly. A part of the Tsugaru Warm Current flows from the gyre southward along the coast. The flow has a temperature front against the Oyasio water intrusion, showing a wave-like perturbation propagating to the S. At the perturbed frontal area, Mackerel fishing grounds formed frequently. The fish shoals distributed in the warmer side of this frontal zone. By revealing the mechanism of the characteristic variability, the movement of fishing rounds may be predicted.  相似文献   

10.
Climate changes affect marine ecosystems and the survival, growth, reproduction and distribution of species, including those targeted by commercial fisheries. The impact of climate change has been reported for many fish species, but studies focusing on the effects of climate on bivalve resources are lacking. In Portugal, the harvesting of bivalves is an old and artisanal activity, of special importance along the Algarve coast (South of Portugal). This study aims to evaluate the influence of climatic, environmental and fisheries factors on the landings of intertidal coastal lagoon and coastal bivalve species (subtidal nearshore species). The environmental and fisheries parameters considered to affect the landings of bivalves in the eastern Algarve were: fishing effort (number of fishing events), sea surface temperature, North Atlantic Oscillation (NAO) index, upwelling index, wind magnitude and direction and river discharges. Analysis of time series data using min/max autocorrelation factor analysis and dynamic factor analysis showed that, for most species, fishing effort was positively related with landings per unit effort trends in the following year. Lagoon bivalve species (Cerastoderma edule and Ruditapes decussatus) responded to different environmental variables than the coastal bivalve species (Chamelea gallina, Pharus legumen, Donax spp. and Spisula solida). Upwelling index had a significant effect on the lagoon bivalves while the NAO index, wind magnitude and direction, and river discharges only affected the coastal species. This study highlighted the need to adapt fishing effort regimes, while considering the background effects of environmental variability, in order to improve fisheries management.  相似文献   

11.
The scarcity of animal products negatively influences nutrition in tropical inland areas, which lack large rivers. Consuming cured marine fish mitigates this deficiency. In Panama, trading cured fish from coastal to inland sites is documented ethnohistorically and can be inferred from the current archaeozoological record. Very large numbers of marine fish remains have been recovered at pre-Columbian sites located on and around Parita Bay, a mangrove-fringed estuary on the central Pacific coast. At Sitio Sierra, a farming village 12 km inland from the active marine shore, more than 70% of fish remains deposited between ca. 1800 and 1500 uncalibrated radiocarbon years BP proved to be of marine origin. Two small rock-shelters located downriver from Sitio Sierra and now 2.6 km from the marine shore (Vampiros-1 and Vampiros-2) show evidence for having been used intensively for fishing and preparing fish between ca. 2200 and 1900 BP. A prior model based on air photograph interpretation and sedimentological analyses of marine and terrigenous sediments suggest that these shelters would have been on or very near the active marine shore at this time. A much earlier occupation at Vampiros-1 dating to ca. 11,500–7700 BP corresponds to pre-agricultural (Paleoindian) and early agricultural (Early Preceramic) people who camped occasionally in this shelter when the transgressing ocean was in the process of flooding Parita Bay. No shell or bone was recovered in this earlier cultural component. In the more recent (2200–1900 BP), component abundant remains of marine mollusks and crustaceans and vertebrate bones (mostly fish) are in excellent condition. A synopsis of the geological and cultural history of the Vampiros shelters is followed by preliminary observations on the relationship between pre-Columbian human activities and these sites’ formation processes, soil chemistry, bone integrity and animal species. Evidence is accruing for human impacts on fish skeletons resulting from the in situ preparation of fish (i.e., gutting, cutting and smoking) providing the opportunity to compare our archaeofaunal data with the results of Irit Zohar's ethno-archeological research, which identified how preparing fish for salting and sun-drying at present-day Panamanian fishing villages around Parita Bay affects the fish skeleton physically and proportionally. There is a strong possibility that the Vampiros shelters were used to provision inland sites like Sitio Sierra with inshore marine fish although we cannot yet ascertain the means by which coastal foodstuffs may have arrived at the latter site.  相似文献   

12.
涪陵页岩气二期开发过程中,为了能够及时发现地层变化,钻井平台部署的第一口井在三开井段一般使用近钻头仪器,以便及时调整井眼轨迹,提高优质页岩的钻遇率。动力钻具前面安装近钻头仪器和钻头,导致动力钻具传动轴负载增加,传动轴易发生疲劳破坏。焦页XX-HF井钻进至3971.42 m处,近钻头仪器无信号,起钻后发现动力钻具传动轴断裂,近钻头仪器和钻头落井。本井“落鱼”较短且处于水平段,“鱼头”难找,起下钻摩阻大,不易通过遇阻判断打捞工具是否接触“鱼顶”。通过对孔内情况仔细分析,制定可行的打捞方案,现场加工母锥打捞工具,最终成功将井下“落鱼”安全捞出。本井所采取的处理思路和技术措施对今后同类事故的处理具有一定的借鉴意义。  相似文献   

13.
Three quarters of the global human population will live in coastal areas in the coming decades and will continue to develop these areas as population density increases. Anthropogenic stressors from this coastal development may lead to fragmented habitats, altered food webs, changes in sediment characteristics, and loss of near-shore vegetated habitats. Seagrass systems are important vegetated estuarine habitats that are vulnerable to anthropogenic stressors, but provide valuable ecosystem functions. Key to maintaining these habitats that filter water, stabilize sediments, and provide refuge to juvenile animals is an understanding of the impacts of local coastal development. To assess development impacts in seagrass communities, we surveyed 20 seagrass beds in lower Chesapeake Bay, VA. We sampled primary producers, consumers, water quality, and sediment characteristics in seagrass beds, and characterized development along the adjacent shoreline using land cover data. Overall, we could not detect effects of local coastal development on these seagrass communities. Seagrass biomass varied only between sites, and was positively correlated with sediment organic matter. Epiphytic algal biomass and epibiont (epifauna and epiphyte) community composition varied between western and eastern regions of the bay. But, neither eelgrass (Zostera marina) leaf nitrogen (a proxy for integrated nitrogen loading), crustacean grazer biomass, epifaunal predator abundance, nor fish and crab abundance differed significantly among sites or regions. Overall, factors operating on different scales appear to drive primary producers, seagrass-associated faunal communities, and sediment properties in these important submerged vegetated habitats in lower Chesapeake Bay.  相似文献   

14.
The designation of Texas as a “hotspot” for fish mortalities relative to the other 22 coastal US states is of serious concern for scientists, resource managers, and the public alike. We investigated the major sources and causes of fish kills in coastal Texas from 1951 to 2006. During this 55-year period, more than 383 million fish were killed, 72% of which were Gulf menhaden (Brevoortia spp.). We examined the relationships between climate and the physical features of Texas bays and estuaries as well as the consequences of high-density industrialization and urbanization along several coastal centers on fish kills, including the impact of eutrophication, algal blooms (toxic and nontoxic), and hypoxia. Galveston and Matagorda Bays had the highest number of fish kill events and total number of fish killed. The largest number of fish kill events and the highest number of fish killed occurred during the warmest months, particularly in August. The leading cause of fish kills was found to be low dissolved oxygen concentrations caused by both physical and biological factors. From 1958 to 1997, about two thirds of the mortalities from low oxygen concentrations were caused by human activities. With the population predicted to double in Texas by 2050, mostly along the coastal areas, natural resources will require additional protection. Further increases in nutrient loading are expected in areas unable to keep up with construction of sewage treatment facilities. Defining the sources and causes of fish kill events in Texas will allow better management and conservation efforts.  相似文献   

15.
This paper explores social, and economic aspects of coastal communities crucial to the management of estuaries in the Pacific Northwest. These aspects include the changing demographics and economies of coastal communities, and the public perceptions, attitudes, and values pertaining to estuarine ecosystems. Information from Willapa Bay and Grays Harbor in Washington and Tillamook, Yaquina, and Coos Bays in Oregon shows that the coastal communities are growing more slowly than the states overall., that the populations are relatively old, and that, although the local economies continue to rely on them, the extractive natural resource industries (fishing, aquaculture, agriculture, forest products) are declining in importance relative to tourism, recreation, and retirement industries. These trends suggest that human uses of the estuaries are changing in character, and altering the management problems. Coastal residents choose to live in these communities to enjoy the views and scenery, to experience rural living, to be near the ocean, and to recreate outdoors. People express coherent perceptions of risks to the estuaries, especially the threats of declining fish habitats, oil spills, shoreline development, invasive species, and logging in upland areas> Residential land values are enhanced by the presence of wetlands and forests and are diminished by the presence of hazardous waste sites. We conclude that, if recent trends in population age structure, income sources, and employment status continue, public attitudes and values will move towards stronger environmental protection. Because ecosystem management involves local public participation and collaboration, estuarine managers will be faced with both increased demands and opportunities.  相似文献   

16.
There is growing interest in applying ??15N in biota as an indicator of anthropogenic nutrient inputs to coastal environments because changes in ??15N correlate to inputs of land-based nutrients. In complex coastal receiving waters, however, land-use effects on biota ??15N may be masked by local hydrologic processes, especially exchange with coastal waters of different geochemical character. We examined ??15N differences among larval fish, a novel biotic indicator, in coastal receiving waters at both among and within watershed scales. Our goal was to characterize how hydrologic processes within coastal river mouths and embayments mediate the effect of land-based N sources on larval fish ??15N. We sampled three Lake Superior river-embayment systems from watersheds that span a large population density gradient. Over all stations, mean fish ??15N ranged from 2.7??? to 10.8???. Within each system, we found a different pattern in ??15N across the river?Clake transition zone. Correlations between fish ??15N and water quality, particularly NH 4 + and total nitrogen, were highly significant and corresponded to known differences in sewage waste water inputs. A multivariate model that included both watershed-based population density and NH 4 + was found to provide the best fit to the ??15N data among a series of multi- and univariate candidate models. These results demonstrate that: (1) fish larvae ??15N responded at within watershed scales, and (2) within coastal receiving waters, fish larvae ??15N was related to waste water inputs at the watershed scale; however, expression at specific locations within a coastal system was strongly influenced by local hydrologic processes.  相似文献   

17.
海岸带是位于海陆结合部的复杂环境系统,是人类活动最集中的地区。中国大陆海岸线约18000km,涉及沿海11个省,由于经济社会高速发展,海岸带地区的人口、资源、环境矛盾日益突出,面临海岸带资源无序开发、水土污染、滨海湿地退化、海岸侵蚀、地面沉降等一系列生态环境与灾害地质问题,已成为影响生态文明建设的主要问题之一。因此中国持续加大海岸带生态环境保护力度,并提出实施重要生态系统保护和修复重大工程、强化湿地保护和修复等政策措施。美国国家海洋和大气管理局主导的海岸带损害评估及修复计划已实施了近30年,并取得了显著效果,其完善的法律制度体系、规范的损害评估和修复程序、数据集成管理和共享应用等成功经验值得学习借鉴。建议加快完善中国海岸带生态环境损害评估与修复的技术方法体系和制度体系、有序开展海岸带自然资源和生态环境调查、加强海岸带及滨海湿地等重要生态系统的演化和修复技术研究与示范,并构建统一的海岸带基础调查数据库、建立海岸带监测预警体系。  相似文献   

18.
Metrics of fish production are often used to guide habitat restoration in coastal ecosystems. In this study, we present a general model framework to estimate the absolute production potential of fish (i.e., fish and large decapods) derived from coastal habitats. Production potential represents lifetime production, whether or not the fish uses the habitat of interest for their entire lifespan. The framework uses an age-structured Leslie population matrix with length-dependent survival and fecundity, coupled with growth and length-weight functions. Uncertainty quantification was also included and accounted for parameter dependencies using copulas. Given the limited abundance data available, we made the simplifying assumptions of steady-state populations and a direct scaling of the resultant proportional stable age distribution with observed fish density (in at least one age class). Literature values for regional estimates of mortality and growth were used. We applied our model using data of fish density from seagrass (Zostera marina, eelgrass) beds and bare soft-sediment bottom on the Atlantic coast of Nova Scotia, Canada. A total of 22 species of fish was collected. Species-specific estimates of fish production potential from seagrass ranged from 8.6 × 10?3 to 50.0 g WW m?2 year?1, with uncertainty estimates being within the same order of magnitude as the median. Production potential of most fishes was enhanced by seagrass relative to adjacent bare sediment. The model framework can be adapted and extended to include increasing complexity (e.g., time dependencies) as more extensive data are acquired, and thus has application beyond that presented here.  相似文献   

19.
 An integrated geochemical and toxicological assessment of environmental mercury contamination and attendant human exposure in Honda Bay, Palawan was undertaken in 1995 following a nationally reported pollution scare centered on a coastal jetty, Sitio Honda Bay, constructed using approximately 1 million tons of tailings and beneficiation waste from a cinnabar mine. Mercury (Hg) data for marine and fluvial sediments, fish tissues and human hair indicate that the toxicological hazard is considerably lower than initially reported by state environment and health officials. Typical Hg concentrations in surficial Honda Bay sediments were found to lie within the global background range (<60 μg/kg). Downcore profiles provide no evidence of enhanced Hg fluxes coincident with the onset of mining and/or coastal tailings disposal. The mean and median Hg concentrations recorded in tissues of six species of Honda Bay fish are compliant with thresholds established by the US Environmental Protection Agency (US-EPA) for marketable stocks. Earlier reports of 'Minamata range' Hg concentrations in fish and shellfish from Honda Bay remain unsubstantiated. Geochemical analyses of samples of the Sitio Honda Bay substrate have confirmed the prevalence of solid-phase Hg concentrations to ca. 340 mg/kg. The speciation of Hg is, however, dominated by secondary oxides of low bioavailability. The mean Hg concentration in hair from Sitio Honda Bay residents (4.41 mg/kg) was found to be statistically analogous to that for a neighbouring coastal community unimpacted by the coastal disposal of mine waste. A negligible residential exposure factor is thus inferred for the former. Relatively high hair Hg burdens prevail throughout the coastal Honda Bay population, consistent with significant methyl Hg ingestion through daily fish consumption. The data presented provide no environmental or toxicological justification for immediate remedial action. Received: 14 May 1998/Accepted: 1 September 1998  相似文献   

20.
In Mabahiss Bay, north Hurghada City, Red Sea, Egypt, the bathymetric measurements show the irregular topography of the bottom. The bottom sediments are mainly composed of sand fractions (average 73.5%). Gravel and sand contents decrease with depth. On the other hand, silt and clay percents show indirect relation with depth. Abnormally, there are some spots found near the coast where the percent of both silt and clay increases. They also show carbonate sediments (average 90.15%) increasing toward the bay center. The narrow belt adjacent to the shore area has lower carbonate content reflecting the effect of clastic sediments input into the area. The sediments in the study area have more than one source as indicated from the results of the mechanical analysis. Wide range of grain size distributions, clay spots and low carbonate content near the shore indicate change in the nature of sedimentary environment (i.e., pollution) which may be caused by land filling accompanied with urbanization and building of touristic resorts and centers. The organic matter content in the sediments is much higher than that of the other areas in the Red sea (average 4.8%) with considerable accumulation in the inner most parts of the bay. This may be due to relative abundance of organic productivity, direct discharge of domestic waste in some spots along the coast of the study area, and/or local contamination of hydrocarbons (i.e., tar balls thrown out on shore by weak waves through the few inlets of the study area). The average concentrations of lead, nickel, copper, and cadmium are 44, 34, 51, and 3.1?ppm, respectively. The suggested origin of these metals is either organic (localized oil pollution), or using of antifouling and anticorrosive paints from fishing and tourist boats. Other metals, particularly manganese (average 77?ppm), cobalt (average 51?ppm), and zinc (average 16?ppm) as well as sodium (average 0.32%) and potassium (av. 0.10%) show a common trend of increasing concentration toward the outermost parts of the bay. Some parts along shoreline have increasing concentrations, even if these parameters having a common trend of increase towards the center of the bay. This may be either due to sewage and wastewaters discharges from many outlets of tourist centers and fishermen and cargo boats, and/or terrestrial sediments input. Direct comparison of the present levels of heavy metals in Mabahiss Bay with other published data along the Red Sea and Gulf of Suez shows that the study area has higher concentrations. Dredging, land filling, localized oil pollution, using of antifouling and anticorrosive paints from fishing and tourist boats (where the bay is used as harbor for many of fishermen and cargo boats), sewage, variable amounts of municipal wastewater from many outlets of tourist centers considered to be the sources of pollution within Mabahiss bay. There are many effects of pollution on Mabahiss Bay environment among which: (1) death of fishes, seaweeds, birds, marine mammals, etc., (2) damage of beaches and other recreational areas, (3) damage of marine ecosystem by eliminating or decreasing population of certain species, (4) hazard to human from ingesting contaminated food, and more.  相似文献   

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