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1.
E. Spanier    M. Tom    S. Pisanty  G. Almog-Shtayer   《Marine Ecology》1990,11(1):61-75
Abstract. Fishery yields in the oligotrophic waters of the Southeastern Mediterranean arc low due to habitat and food limitations. A four year study of a complex of artificial structures established in the coastal waters of Israel points to several possible solutions to these problems. One approach is the artificial enrichment of the man-made reef with trash fish. This, together with the configuration of the reef, caused a significant increase in the abundance of fish predators such as groupers of the genus Epinephclus. Omnivores and herbivores were attracted only by the presence of artificial structures. Some species, such as the slipper lobster Scyllurides lulus, only use the man-made reef for shelter during part of the day or season; they forage over a much larger area the rest of the time and are important "importers" of food to the artificial habitat. Artificial kelp were effective in recruiting juveniles and small fishes to the site.  相似文献   

2.
余辰星  杨岗  陆舟  李东  周放 《海洋与湖沼》2014,45(3):513-521
为了解迁徙季节水鸟在不同滨海湿地中的结构组成和行为特征,于2010年3月、4月、9月、11月和2011年3月,在山口自然保护区及其周边地区对不同滨海湿地类型的水鸟展开调查。结果显示:迁徙季节天然湿地共记录到水鸟6目8科39种,人工湿地有6目9科50种。天然湿地比人工湿地的物种数少,整体数量上,春季人工湿地大于天然湿地,秋季则为天然湿地水鸟数量更多。鹬鸻类在不同滨海湿地类型中觅食行为比例差异显著,在天然湿地中觅食比例达到76.67%,而在人工湿地中则以休息和睡眠等非觅食行为为主。天然湿地是鹬鸻类的重要觅食地,而人工湿地则是鹭类和鹬鸻类的主要休息地。鹭类在两种滨海湿地类型中觅食个体的数量不随潮汐的涨落而相应增减。鹬鸻类随潮汐高度上升,在两种滨海湿地类型中觅食的个体数量减少。山口地区的滨海人工湿地是水鸟在高潮期间天然湿地良好的替代栖息地。  相似文献   

3.
The elemental composition of otoliths from juvenile English sole Pleuronectes vetulus and speckled sanddab Citharichthys stigmaeus living in estuaries and sandy coastal habitats were compared to determine if a chemical habitat tag existed that could be used to differentiate fish living in the alternative juvenile habitats. Juveniles of both species were collected from seven estuaries and 11 coastal sites along 500 km of the central California coast. Collections occurred in three years: 1998, 1999 and 2000. The chemical composition of the otoliths was analyzed using solution-based inductively coupled plasma mass spectrometry. The multi-elemental composition (Sr, Li, Ba, Mn) of otoliths from estuarine and coastal fish differed significantly for all models (global, region and years models) examined in this study. For each species, discriminant function analysis (DFA) for the global model, which pooled juveniles collected from three regions over multiple years, classified fish into estuarine and coastal groups with close to 80% accuracy. The two main elements in the discriminant models, Sr and Li, differed consistently between habitats; Sr was higher and Li was lower in estuarine fish. Classification success was modestly improved by generating separate discriminant functions for each region (regions model) because of some regional differences in Sr and Li concentrations. Classification success also was improved in some cases by generating separate discriminant functions for each year (years model) because Ba and Mn differed between habitats in only some years. Despite this variability in the concentration of elements in some regions and years, a chemical habitat tag was present in each species that could be used to discriminate coastal and estuarine juveniles over a large geographic area and over three years with very different oceanographic conditions (e.g., El Niño, La Niña). In addition, I found that English sole and speckled sanddab had striking similarities in their chemical habitat tags and that, in some cases, one species could be used as a proxy to classify juveniles of the other species without compromising the accuracy of the habitat tag. The ability to use a proxy classification model would significantly reduce the number of juvenile fish that would need to be collected and analyzed in order to classify members of an ecologically similar species. The chemical habitat tags found in this study appears to be promising tools for identifying fish that have lived in alternative juvenile habitats and, ultimately, the proportional contribution of estuarine and coastal habitats to the central California populations of English sole and speckled sanddab.  相似文献   

4.
Although the use of coastal defence structures is expected to increase, little is known about the ecological impact of such structures on the natural environment. In particular, the temporal and spatial patterns of communities in association with artificial substrate are still poorly understood. This study examined possible effects of experimental tetrapod fields on the decapod crustacean community in a subtidal hard-bottom area in the southern North Sea. We performed in situ studies in the fields and along transects oriented away from the tetrapod fields. Species composition and abundances were assessed before and after the introduction of the artificial material. The study revealed a significant decrease of smaller, less vagile species (Pisidia longicornis, Pilumnus hirtellus, Galathea squamifera) over the entire study area in the years following the tetrapod introduction. For 2 species, Hyas araneus and Homarus gammarus, the tetrapods appeared to be highly attractive as habitat and shelter because their abundance increased over time. No distinct spatial or temporal effects were observed for mobile predatory crabs, such as Cancer pagurus and Liocarcinus spp. The results of the study demonstrate that possible effects of artificial structures on macro-invertebrates in temperate hard-bottom areas are highly species-specific and depend on the size, lifestyle and ecological requirements of the species. This work highlights the importance of long-term studies. Our findings clearly indicate that more time is needed to distinguish between natural and anthropogenic influences on species distributions.  相似文献   

5.
《Coastal Engineering》2005,52(10-11):1073-1087
Coastal areas play a crucial role in the economical, social and political development of most countries; they support diverse and productive coastal ecosystems that provide valuable goods and services. Globally flooding and coastal erosion represent serious threats along many coastlines, and will become more serious as a consequence of human-induced changes and accelerated sea-level rise. Over the past century, hard coastal defence structures have become ubiquitous features of coastal landscapes as a response to these threats. The proliferation of defence works can affect over half of the shoreline in some regions and results in dramatic changes to the coastal environment. Surprisingly little attention has been paid to the ecological consequences of coastal defence. Results from the DELOS (Environmental Design of Low Crested Coastal Defence Structures, EVK3-CT-2000-00041) project indicate that the construction of coastal defence structures will affect coastal ecosystems. The consequences can be seen on a local scale, as disruption of surrounding soft-bottom environments and introduction of new artificial hard-bottom habitats, with consequent changes to the native assemblages of the areas. Proliferation of coastal defence structures can also have critical impacts on regional species diversity, removing isolating barriers, favouring the spread of non-native species and increasing habitat heterogeneity. Knowledge of the environmental context in which coastal defence structures are placed is fundamental to an effective management of these structures as, while there are some general consequences of such construction, many effects are site specific. Advice is provided to meet specific management goals, which include mitigating specific impacts on the environment, such as minimising changes to surrounding sediments, spread of exotic species or growth of nuisance species, and/or enhancing specific natural resources, for example enhancing fish recruitment or promoting diverse assemblages for eco-tourism. The DELOS project points out that the downstream effects of defence structures on coastal processes and regional-scale impacts on biodiversity necessitate planning and management at a regional (large coastline) scale. To effectively understand and manage coastal defences, environmental management goals must be clearly stated and incorporated into the planning, construction, and monitoring stages.  相似文献   

6.
Benthic communities colonizing two different typologies of artificial structures, Tecnoreef® pyramids (PY), and plinth modules (PL), differing for material and shape, were investigated for three years after their deployment on a soft bottom offshore Pedaso (Western Adriatic Sea). The aims were to describe the colonization patterns of benthic assemblages on the two artificial modules, to highlight possible differences between them and to detect the effectiveness of the artificial reef on the ecosystem functioning.The composition of the benthic communities settled on the two types of artificial substrates was different especially just after the reef deployment. Abundance and species richness were higher on PL in the first two years, while an explosion of individuals characterized PY in the third year. This suggested a delay of about one year in the colonization processes on PY likely due to the material and shape. The community settled of the artificial structures was dominated by hard-substrate species which are commonly absent in the natural environment. The occurrence of these organisms enriched the local soft-bottom communities and contributed to habitat diversification. This, together with the importance of these species in the diet of a few reef-dwelling fish, confirms the trophic role and the ecological importance of artificial reefs in areas characterized by soft seabed.  相似文献   

7.
The consistency of habitat-related differences in coastal lagoon fish assemblages was assessed across different spatial and temporal scales. Multimesh gillnets were used to sample assemblages of fish on a monthly basis for 1-year in three habitats (shallow seagrass, shallow bare and deep substrata) at two locations (>1 km apart), in each of two coastal lagoons (approximately 500 km apart), in southeastern Australia. A total of 48 species was sampled with 34 species occurring in both lagoons and in all three habitats; species caught in only one lagoon or habitat occurred in low numbers. Ten species dominated assemblages and accounted for more than 83% of all individuals sampled. In both lagoons, assemblages in the deep habitat consistently differed to those in the shallow strata (regardless of habitat). Several species were caught more frequently or in larger numbers in the deep habitat. Assemblages in the two shallow habitats did not differ consistently and were dominated by the same species and sizes of fish, possibly due to habitat heterogeneity and the scale and method of sampling. Within each lagoon, very few between location differences in assemblages within each habitat were observed. Consistent differences in assemblages were detected between lagoons for the shallow bare and deep habitats, indicating there were some intrinsic differences in ichthyofauna between lagoons. Assemblages in spring differed to those in summer, which differed to those in winter for the shallow bare habitat in both lagoons, and the deep habitat in only one lagoon. Fish-habitat relationships are complex and differences in the fish fauna between habitats were often temporally inconsistent. This study highlights the need for greater testing of habitat relationships in space and time to assess the generality of observations and to identify the processes responsible for structuring assemblages.  相似文献   

8.
Macrofauna composition and diversity in soft sediments are commonly used as “health indicators” in various pollution monitoring programmes worldwide. Hence, finding a modelling method for predicting the presence of soft sediments and enable production of digital maps of where soft sediments are likely to be found would be valuable for developing a cost-effective sampling design. This study presents a first-generation model that can predict where to find soft sediments in coastal areas with a complex topography and a mosaic of seabed habitat types. We used geophysical data that were quantitative, objectively defined (through GIS modelling) and integrated over time. We analysed, using a Generalised Additive Model (GAM) and the model-selection approach Akaike Information Criterion (AIC), the influence of in-situ measured depth and GIS-modelled terrain structures, wave exposure and current speed on the distribution of soft sediment measured using a Sediment Profile Image (SPI) camera. Our analyses showed that the probability of finding soft sediment was best determined by depth, terrain curvature and median current speed at the seafloor. These predictors were used to develop a spatial predictive GIS-model/-map (for parts of Skagerrak, Norway, with a spatial resolution of 25 m × 25 m) of the probability of soft seabed occurrence.  相似文献   

9.
In the marine environment, artificial structures are not, in general, managed for their value as habitat and are often built with no a priori expectation as to the assemblages which may colonise them. It may, however, become increasingly important to consider the value of such structures as habitat when decisions are made with respect to the management of artificial structures. This study investigates the role marinas play as habitat for fish by examining the distribution of fish associated with these urban developments and how this distribution relates to the physical characteristics of marinas. Assemblages of fish associated with marinas in waterways around Sydney were sampled in August and December 2002 and May 2003. Counts were done around structures present at marinas, i.e. pontoons and pilings and in the open water immediately adjacent to these structures. Within marinas, spatial patterns were particular to the types of fish examined. Large mobile species, such as Acanthopagrus australis and Girella tricuspidata, moved between structures and the open water between them. Smaller species, such as Trachinops taeniatus and Microcanthus strigatus, were found only in the immediate vicinity of these structures. At a larger spatial scale, assemblages of fish varied markedly between different marinas. This variability could not, however, be attributed to the depth of water, the age or size of marinas, nor the type of material with which marinas were constructed (i.e. pontoons or jetties).  相似文献   

10.
This study was carried out to learn about differences in the sessile macrobenthic fauna communities between the artificial and natural habitats. There were some differences in terms of species composition and dominant species and community structure between two habitat types. The dominant species include Pollicipes mitella and Granuilittorina exigua in natural rocky intertidal zones; Monodonta labio confusa, Ligia exotica, Tetraclita japonica in the artificial rocky intertidal zones. Among all the species, L. exotica and T. japonica occurred only in the artificial rocky intertidal zone. The results of cluster analysis and nMDS analysis showed a distinct difference in community structure between artificial and natural rocky intertidal zones. The fauna in the natural rocky intertidal zones were similar to each other and the fauna in the artificial rocky intertidal zones were divided depending on the slope of the substratum. In the case of a sloping tetrapod, M. labio confusa and P. mitella were dominant, but at the vertical artificial seawall, Cellana nigrolineata, L. exotica T. japonica were dominant. The analysis of the species presented in natural and artificial rocky intertidal areas showed the exclusive presence of 10 species on natural rocks and 12 species on artificial rocks. The species in the natural rocky intertidal area included mobile gastropods and cnidarians (i.e. rock anemones), and the species in the artificial rocky intertidal area mostly included non-mobile attached animals. The artificial novel structure seems to contribute to increasing the heterogeneity of habitats for marine invertebrate species and an increase the species diversity in rocky coastal areas.  相似文献   

11.
This study examined seasonal and annual occurrences of warm oceanic tintinnid species in southern Korea coastal waters. The indicative species of tintinnids was monitored using three approaches: monitoring from cruises traveling from the warm pool in the western North Pacific to the Korea Strait; biweekly or monthly monitoring in the Korea Strait; and daily monitoring in the nearshore water. Annual pulses of warm oceanic indicator species were regularly observed in the Korea Strait. In September 2008 recorded a maximum species number of warm water indicators, a representative species for warm oceanic waters, Climacocylis scalaroides was simultaneously detected in the nearshore water as well as the Korea Strait. The result indicates that the greater warm water extension into Korean coastal areas was in September 2008. Sharp declines in species diversity were observed in the transitional area between neritic and Kuroshio zone in East China Sea (ECS). Epiplocyloides reticulata, reported previously as a Kuroshio indicator, was considered an ECS indicator species, as it was undetected in the western North Pacific central zone but was found abundantly in the ECS. Tintinnid species can be used as biological indicators to detect the inflow of warm oceanic waters into Korean coastal waters.  相似文献   

12.
Survival and growth of early fish stages are maximal in coastal and estuarine habitats where natural shallow areas serve as nurseries for a variety of widely distributed species on the continental shelf. Processes occurring in these nursery grounds during the juvenile stage affect growth and may be important in regulating the year-class strength of fishes and population size. The need, therefore, exists to protect these essential fish habitats hence to develop indicators to estimate their quality.The purpose of the present study was to use the growth of juvenile sole as a means of comparing the quality of coastal and estuarine nursery habitats in the Bay of Biscay (France). These sole nurseries were clearly identified from studies based on trawl surveys carried out during the last two decades. The size of 1-group juveniles at the end of their second summer, as estimated from these surveys, is an indicator of growth in these habitats during the juvenile phase and can be used to compare habitat quality. A model taking into account the role of seawater temperature in spatial and interannual variations of juvenile size was developed to compare growth performance in the different nursery sectors.This study shows that the size of juvenile sole after two summers of life is not density-dependent, probably because the size of the population adapts to habitat capacity after high mortality during early-juvenile stages. Size is on one hand positively related to temperature and on the other hand higher in estuarine than in non-estuarine habitats. This high growth potential of juvenile fish in estuarine areas confirms the very important role played by estuaries as nursery grounds and the essential ecological interest of these limited areas in spite of their low water quality. If a general conclusion on habitat quality is to be reached about studies based on the growth of juvenile fish, it is necessary to use not only an integrative indicator of growth, like size, representative of the intrinsic habitat quality, but also more sensitive and less integrative means, such as otolith increments or caging experiments, which better respond to anthropogenic disturbance. Moreover, it is necessary to take juvenile densities into account.  相似文献   

13.
基于波浪数据的完备性对于海岸海洋工程设计而言非常关键,详细阐述了风浪观测数据补足神经网络模型的建立方法,构建了两个网络模型,以已有观测资料为样本进行了验证.结果表明,两个网络的训练效果均很好,且单输出目标的分层模拟要优于多输出目标的单层模拟.表明了利用人工神经网络推导缺失波浪条件的可行性.  相似文献   

14.
《Journal of Sea Research》2007,57(2-3):126-136
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15.
The use of artificial reefs in the Arabian Gulf have a history extending back over a century, when date palm trunks, stones, pottery and other materials were sunk in coastal areas to enhance fish catch. Historically, such artificial reefs formed an important component of the socio-economic development of coastal fisheries. In comparison, modern artificial reefs have taken on a variety of forms. The most widely recognized are purpose-build modular artificial reefs designed for the enhancement of fisheries yield, diving, and various other benefits. However, far more common within the Gulf are the large-scale unplanned artificial reefs that have been formed as a result of human activities in the marine system, such as large-scale coastal breakwaters, seawalls, jetties, pipelines, and oil and gas infrastructure. Although there is limited information on the role of these constructions in structuring Gulf marine communities, increasing evidence suggests that abundant and diverse communities of reef fish, coral and other benthos can develop on these structures, with important ecological implications in urbanized coastal areas in the Gulf. However, due to a variety of unintended consequences of artificial reef development such structures may also pose challenges to coastal marine management. We review the current published literature on artificial reefs in the Gulf in order to improve our understanding of the role that these structures play in Gulf coastal ecosystems, and to further develop regional management of artificial reefs. We explore the various types of artificial reef that exist in the Gulf and examine the benefits and challenges that these structures represent for coastal ecology and economics. Such information is essential for our improved understanding and management of these increasingly important ecosystems in the Gulf.  相似文献   

16.
On a global scale, urbanization has resulted in substantial proportions of coasts being replaced by artificial structures such as marinas, breakwaters and seawalls. There is broad consensus that coastal defense structures are poor surrogates of the natural habitats that they replace. Here we investigated the effects of the type and roughness of materials used for the construction of artificial structures on the surrounding biota by comparing abundances and distribution of key inter‐tidal taxa between natural shores and coastal defenses. Lower abundances of gastropods and barnacles were found on artificial coastal defense structures (regardless of the material type). At small spatial scales, abundances of key taxa increased with increasing roughness. Our results suggest that the choice of materials used for the construction of coastal defense structures has little effect on community structure per se, but that enhanced roughness could make coastal defenses better surrogates of natural habitats by supporting assemblages that are more similar to those found on natural shores.  相似文献   

17.
Multivariate principal components analysis and cluster analysis were performed on data representing presence or absence of 498 species of juvenile and adult fish species in twenty-four coastal marine systems (bays, coastal lagoons, estuaries and coastal zones) distributed from southeast to southern Brazil. Five groups of coastal systems were identified based on fish assemblage similarity: estuaries and bays of the southeast area; an estuary of the southern area; coastal lagoons; rocky coastal zones; and the continental platform. Species assemblages for each zone were identified and used as surrogate habitat indicators to compare and contrast the groups. Stepwise multiple regression of environmental and physical variables as predictors of the number of species indicated that only ‘ area ’ was included in the model as the most important variable explaining the variation of the number of species in these data sets. The total number of fish species increased as surface area increased.  相似文献   

18.
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19.
The installation of urban and commercial infrastructures on the coast has a severe impact on the marine environment. This impact is mostly negative but, simultaneously, some of the species that colonize artificial substrata (sometimes rare or threatened) find refuge in man‐made structures. The protection of endangered species is usually provided by marine protected areas or by laws that punish their damage or collection, but effective enclosure and custody must be achieved in the case of easily accessible intertidal species. We used the ferruginous limpet, Patella ferruginea, as a case study because it is the most endangered invertebrate in the Mediterranean. This species, which lives in the intertidal zone and is very accessible to people, is a free‐spawning, protandric hermaphrodite, highly dependent on population density and individual size for its reproductive success. Previous work by the authors found the species is especially abundant on artificial substrates on both shores of the Strait of Gibraltar, where people collect fewer of them. Spanish laws of coastal management do not allow the enclosure of the natural coastline, but artificial installations like harbour breakwaters may be closed or guarded, and visits for educational purposes may be carried out under control. The possibility of declaring some kind of environmental protection for these artificial areas would be a very helpful tool for conservation and management purposes. Protected individuals would grow larger and eventually produce exponentially more offspring, which could be transported by currents to adjacent habitats. Here we propose a protection concept for artificial sites termed Artificial Marine Micro‐Reserve (AMMR), where some endangered species experience a refuge from human disturbance. This concept is a modification of the land micro‐reserves that have been recently declared in small natural sites that keep rare plant species. A network of AMMRs would be the final objective, allowing the creation of a great metapopulation of P. ferruginea and also giving refuge to other endangered species that have been found to grow in this type of substratum. Critically, the declaration of a micro‐reserve cannot be used as a reason in favour of new construction because of the negative influence of such structures on the marine environment, together with the fact that there is no certainty that valuable species will settle on them.  相似文献   

20.
Uncertainty in the behaviour of future storm events and extreme water levels means that the introduction of Early Warning Systems for coastal inundation risk at vulnerable local sites becomes increasing paramount. In this study the coupled hydro-morphodynamic model XBeach is used at two sites along the Emilia-Romagna coastline in northern Italy to predict coastal inundation risk in the presence of coastal structures and temporary artificial dunes. These dunes are typically formed by beach scraping and are used on this coastline to protect beach-front infrastructure during the winter period. Coastal inundation risk is defined by the cross-shore distance between the seaward edge of the building and the time-varying waterline predicted by XBeach. A series of synthetic storm events as well as a real-world scenario that caused dune failure at one of the sites are tested. Comparisons between XBeach results and the Van Der Meer empirical formula for wave transmission behind offshore structures show a very strong agreement, while the real-world scenario indicates promising model prediction performance of dune failure at least one day in advance. A new model tool known as DuneMaker is developed that modifies XBeach model grids to simulate the impacts of scraped/placed artificial dunes of varying size, shape and configuration. The use of this tool is demonstrated on the same model test runs, where it is shown that improved dune design can reduce the predicted coastal inundation risk at critical points of vulnerability identified by the model.  相似文献   

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