The impact of mean sea level rise (SLR) on extreme water levels is investigated using a numerical model that covers the entire North Sea, but has its highest spatial resolution in the northern part of the German Bight. A 40-year hindcast covering the period 1970 to 2009 is conducted using observed mean sea level (MSL) changes, tides and atmospheric forcing as boundary conditions. The model reproduces the observed water levels well for this control period. A second 40-year run is then conducted considering the same atmospheric forcing but adding + 0.54 m to the MSL to explore the effects of sea level rise on storm surges in the investigation area. At most locations, the second model run leads to changes in the storm surge water levels that are significantly different from the changes in MSL alone. The largest increases of the order of 15 cm (in addition to the MSL changes) occur in the shallow water areas of the Wadden Sea. These increases in storm surge water levels are caused by nonlinear changes in the tidal constituents which are spatially not coherent. The response of the tidal propagation to SLR is investigated based on the results from a tidal analysis of each individual event. These analyses point to an increase in the M2 amplitude and decrease in the amplitudes of frictional and overtides accompanied by less tidal wave energy dissipation. Attributed effects are changes in phase lags of individual constituents leading to a different tidal modulation, thus additionally increasing tidal water levels. Finally, we estimate how SLR affects return water levels in the northern part of the German Bight, with the result that relevant design water levels increase due to the non-linear relationship between SLR and changes in extremes.
Sociospatial information is critical to marine and coastal ecosystem management. The Hawaii Coastal Uses Mapping Project used a participatory geographic information systems (PGIS) methodology to gather local knowledge regarding the location and intensity of coastal human activities in Hawaii's priority sites for coral reef management. PGIS provided an efficient and effective means of obtaining information in a data-poor context, particularly at a scale and location where considerable local knowledge is held by community members and resource users. We detail the PGIS methods developed to collect sociospatial data on human uses in the project regions and discuss important considerations regarding the practice of PGIS that emerged from the mapping process, as well as implications for the production and documentation of spatial knowledge. Key themes include: issues of scale and appropriateness in using PGIS as a method for mapping human coastal and marine activities; data validity, authority, and the nature of local knowledge; community trust, engagement, and collaboration; and utility for coral reef management. While several factors limit local agencies' ability to use this spatial information to date, natural resource managers found the participatory mapping process to be highly valuable for stakeholder identification and engagement, and the maps provide a resource to state and federal managers to better understand the human implications of future management scenarios.
Agencies in the US with oversight for marine renewable energy development idealistically have sought space where this new use might proceed unhindered by other uses. Despite experiential evidence of spatial overlap among existing ocean uses, a lack of documentation made the identification of potential space-use conflicts, communication between existing and potential ocean users, and the design of mitigation exceedingly challenging.
We conducted a study along the US Atlantic and Pacific coasts to gather and document available spatial information on existing use through a compilation and organization of geographic information system (GIS) data. Stakeholder group meetings were used to vet the collected spatial data, and ethnographic interviews were conducted to gather knowledge and cultural perspectives. Results show extensive coverage and overlap of existing ocean space uses and provide a visualization of the social and cultural landscape of the ocean that managers can use to determine which stakeholders to engage.
Marine resource managers are encouraged to recognize that marine space use is dynamic and multi-dimensional and as such research thereof requires a balance between the efficiency of GIS and the stories captured and told by ethnographic research. There are important linkages within and across fisheries and other uses, communities and interests, and across the land–sea interface. Therefore, it is important to use techniques demonstrated in this research that (1) integrate ethnographic and geospatial data collection and analysis; (2) engage stakeholders throughout the process; and (3) recognize the unique qualities of each geographic location and user group to support sound decision-making.
This paper integrates institutional theories of the commons with insights from geography and human behavioral ecology to explore the spatial and temporal dynamics of artisanal fishing in Ecuador's coastal mangrove swamps. The focus is on the cockle fishery commons characterized by a mixture of formal institutional arrangements and an informal division of fishing space that partially influences fisher decisions about where and when to fish. Individual decisions are further explained to a certain degree by the patch choice model since fishers often move on to new grounds when their catch rates fall below average. These optimizing strategies requiring rotation within a socially produced fishing space may contribute to resource renewal, perceived reliable returns for individuals, and a relative stability in fishing effort, potentially mitigating against resource depletion in open-access areas not managed as a common property regime. This study of the interaction between shellfish harvesters, cultural institutions, and the environment contributes to a spatially explicit theory of the commons and points to the crucial role of resource user mobility and dynamic cultural institutions for the ecological sustainability of shellfish fisheries. A better understanding of feedback between individual decision-making and the self-organization of a social-ecological system has critical implications for policy design and fisheries management at similar scales.
The concept of place attachment has been studied extensively across multiple disciplines but only recently with empirical measurement using public participation GIS (PPGIS) and related crowd-sourcing mapping methods. This research trialed a spatially explicit method for identifying place attachment in a regional study in South Australia. Our research objectives were to (1) analyze and present the spatial results of the mapping method as a benchmark for future research, (2) compare mapped place attachment to the more common practice of mapping landscape values in PPGIS that comprise a values home range, (3) identify how participant socio-demographic and home location attributes influence place attachment, (4) provide some guidance for mapping place attachment in future research. We found large spatial variability in individual place attachment and mapped landscape values using both area and distance-based measures. The area of place attachment is influenced by occupational roles such as farming or conservation, as well as home location, especially in coastal versus non-coastal contexts. The spatial distribution of mapped landscape values or values home range is related to, but not identical to mapped place attachment with just over half of landscape values located outside the area of mapped place attachment. Economic livelihood values, as an indicator of place dependence, and social values, as an indicator of place identity, are more likely to be mapped within the place attachment area. Aggregated place attachment across participants in the region showed similar spatial intensity to aggregated values home range, but area-based assessment of place attachment and values home range are distorted by edge effects such as a coastline. To further develop the mapping of place attachment in PPGIS, we identify knowledge gaps from our study and offer suggestions for future research design.
At the world scale, many exploited species are currently threatened or undermined by human activities, particularly fishing. Given this situation, establishing artificial habitats (AHs) and marine protected areas (MPAs) is seen as a way of both conserving biodiversity and managing fishing activities. AHs have two main effects: (1) they attract fish from the surrounding areas and concentrate them in the AH, and (2) they increase the capacity of the environment, as a result of the installation of new individuals or, in some cases, of new species. MPAs decrease fish accessibility by constraining the spatial distribution of the fishing effort. We have developed a system of ordinary differential equations (ODEs) that can be used to describe the evolution of fish density, fishing effort, and landings depending on whether AHs are deployed in a MPA or in a fishing area. The analytical study of the ODE system is simplified by means of assuming that processes occur on different time scales. Fish reproduction and landings were assumed to occur at a “slow” time scale, whereas, fish displacement was assumed to occur at a “fast” time scale. For both scenarios of AHs implementation (in an MPA or in a fishing area), we show the existence of different equilibria according to hypotheses based on a purely attractive or purely productive effect of the AH. In all cases, the deployment of AHs in the fishing area leads to an equilibrium with lower fish biomass and lower fish landings than when AHs are deployed within the MPA. This suggests that AHs should not be fished in order to maximize long term fish productivity and fish landings in the surrounding areas. In addition, we attempt to establish a correspondence between our theoretical results and the management plan for artisanal fisheries on the Senegalese coast, which includes the implementation of both AHs and MPAs. This suggests that there is not enough coordination between the non-governmental organizations deploying the AHs and the institutions managing MPAs. Indeed, AHs are usually either immersed in an MPA or subject to local fishing ban, but in fact regulation is inadequate. In this context, the deployment of AHs as part of fisheries management would be premature and could have potentially adverse effects on the resource.
A large percentage of the world’s population is concentrated along the coastal zones. These environmentally sensitive areas are under intense pressure from natural processes such as erosion, accretion and natural disasters as well as anthropogenic processes such as urban growth, resource development and pollution. These threats have made the coastal zone a priority for coastline monitoring programs and sustainable coastal management. This research utilizes integrated techniques of remote sensing and geographic information system (GIS) to monitor coastline changes from 1989 to 2010 at Hatiya Island, Bangladesh. In this study, satellite images from Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) were used to quantify the spatio-temporal changes that took place in the coastal zone of Hatiya Island during the specified period. The modified normalized difference water index (MNDWI) algorithm was applied to TM (1989 and 2010) and ETM (2000) images to discriminate the land–water interface and the on-screen digitizing approach was used over the MNDWI images of 1989, 2000 and 2010 for coastline extraction. Afterwards, the extent of changes in the coastline was estimated through overlaying the digitized maps of Hatiya Island of all three years. Coastline positions were highlighted to infer the erosion/accretion sectors along the coast, and the coastline changes were calculated. The results showed that erosion was severe in the northern and western parts of the island, whereas the southern and eastern parts of the island gained land through sedimentation. Over the study period (1989–2010), this offshore island witnessed the erosion of 6476 hectares. In contrast it experienced an accretion of 9916 hectares. These erosion and accretion processes played an active role in the changes of coastline during the study period.
No-take marine reserves (NTMRs) are increasingly being established to conserve or restore biodiversity and to enhance the sustainability of fisheries. Although effectively designed and protected NTMR networks can yield conservation and fishery benefits, reserve effects often fail to manifest in systems where there are high levels of non-compliance by fishers (poaching). Obtaining reliable estimates of NTMR non-compliance can be expensive and logistically challenging, particularly in areas with limited or non-existent resources for conducting surveillance and enforcement. Here we assess the utility of density estimates and re-accumulation rates of derelict (lost and abandoned) fishing line as a proxy for fishing effort and NTMR non-compliance on fringing coral reefs in three island groups of the Great Barrier Reef Marine Park (GBRMP), Australia. Densities of derelict fishing line were consistently lower on reefs within old (>20 year) NTMRs than on non-NTMR reefs (significantly in the Palm and Whitsunday Islands), whereas line densities did not differ significantly between reefs in new NTMRs (5 years of protection) and non-NTMR reefs. A manipulative experiment in which derelict fishing lines were removed from a subset of the monitoring sites demonstrated that lines re-accumulated on NTMR reefs at approximately one third (32.4%) of the rate observed on non-NTMR reefs over a thirty-two month period. Although these inshore NTMRs have long been considered some of the best protected within the GBRMP, evidence presented here suggests that the level of non-compliance with NTMR regulations is higher than previously assumed.
Coastal resources are coming under increasing pressure from competition between recreational, commercial and conservation uses. This is particularly so in coastal areas adjacent to major population centres. Given high recreational and conservation values in such areas, economic activities need to be highly efficient in order to persist. Management of these industries must therefore also encourage efficient production and full utilisation of the areas available. In order to achieve this, managers must first understand the level and drivers of productivity, and how these can be influenced. In this study, by way of illustration, the focus was on the Sydney rock oyster industry within Queensland's Moreton Bay, a multiple use marine park with high recreational and conservation value adjacent to Australia’s third largest city. Productivity of the oyster industry in Moreton Bay is currently low compared to historic levels, and management has an objective of reversing this trend. It is unclear whether this difference is due to oyster farmers’ business choices and personal characteristics or whether varying environmental conditions in the Moreton Bay limit the capacity of the oyster industry. These require different management responses in order to enhance productivity. The study examined different productivity measures of the oyster industry using data envelopment analysis (DEA) to determine where productivity gains can be made and by how much. The findings suggest that the industry is operating at a high level of capacity utilisation, but a low level of efficiency. The results also suggest that both demographic and environmental conditions affect technical efficiency in the Bay, with water characteristics improvements and appropriate training potentially providing the greatest benefits to the industry. Methods used in this study are transferable to other industries and provide a means by which coastal aquaculture may be managed to ensure it remains competitive with other uses of coastal resources.
Identification of critical life-stage habitats is key to successful conservation efforts. Juveniles of some species show great flexibility in habitat use while other species rely heavily on a restricted number of juvenile habitats for protection and food. Considering the rapid degradation of coastal marine habitats worldwide, it is important to evaluate which species are more susceptible to loss of juvenile nursery habitats and how this differs across large biogeographic regions. Here we used a meta-analysis approach to investigate habitat use by juvenile reef fish species in tropical coastal ecosystems across the globe. Densities of juvenile fish species were compared among mangrove, seagrass and coral reef habitats. In the Caribbean, the majority of species showed significantly higher juvenile densities in mangroves as compared to seagrass beds and coral reefs, while for the Indo-Pacific region seagrass beds harbored the highest overall densities. Further analysis indicated that differences in tidal amplitude, irrespective of biogeographic region, appeared to be the major driver for this phenomenon. In addition, juvenile reef fish use of mangroves increased with increasing water salinity. In the Caribbean, species of specific families (e.g. Lutjanidae, Haemulidae) showed a higher reliance on mangroves or seagrass beds as juvenile habitats than other species, whereas in the Indo-Pacific family-specific trends of juvenile habitat utilization were less apparent. The findings of this study highlight the importance of incorporating region-specific tidal inundation regimes into marine spatial conservation planning and ecosystem based management. Furthermore, the significant role of water salinity and tidal access as drivers of mangrove fish habitat use implies that changes in seawater level and rainfall due to climate change may have important effects on how juvenile reef fish use nearshore seascapes in the future.
The life history of the whale shark (Rhincodon typus), including its reproductive ecology, still remains largely unknown. Here, we present results from the first whale shark population study around Darwin Island, Galapagos Marine Reserve. Following a diversified approach we characterized seasonal occurrence, population structure and size, and described habitat use of whale sharks based on fine scale movements around the island. Whale shark presence at Darwin Island was negatively correlated with Sea Surface Temperature (SST), with highest abundance corresponding to a cool season between July and December over six years of monitoring. From 2011 to 2013 we photo-identified 82 whale sharks ranging from 4 to 13.1 m Total Length (TL). Size distribution was bimodal, with a great majority (91.5%) of adult female individuals averaging 11.35 m±0.12 m (TL±SE), all but one showing signs of a potential pregnancy. Population dynamics models for apparently pregnant sharks estimated the presence of 3.76±0.90 (mean ± SE) sharks in the study area per day with an individual residence time of 2.09±0.51 (mean ± SE) days. Movement patterns analysis of four apparently pregnant individuals tracked with acoustic tags at Darwin Island revealed an intense use of Darwin's Arch, where no feeding or specific behavior has been recorded, together with periodic excursions around the island's vicinity. Sharks showed a preference for intermediate depths (20–30 m) with occasional dives mostly to mid-water, remaining the majority of their time at water temperatures between 24–25°C. All of our results point to Darwin Island as an important stopover in a migration, possibly with reproductive purposes, rather than an aggregation site. Current studies carried out in this area to investigate regional scale movement patterns may provide essential information about possible pupping grounds for this enigmatic species.
Claisse et al. (1) show that not only do oil platforms produce fish, but they do so at a rate far greater than our most productive marine habitats, such as coral reefs and mangroves. Because this information may be used to justify increased “reefing” of obsolete oil infrastructure worldwide, we offer some caveats.
Although Claisse et al.’s (1) production estimates further our understanding of the habitat value of oil platforms, they bring us little closer to deciding the fate of these structures worldwide. It has been known for more than a decade that platforms are capable of providing valuable habitat for fish, yet habitat value appears to vary greatly among platforms, even among those located in similar ecological settings (2). This conclusion is supported by the total production values in figure 3 of Claisse et al. (1), with some platforms off California producing nearly nine times more fish biomass than others. Productivity data for one platform therefore cannot be used to infer the productivity of other platforms. Crucially, this means that the productivity values obtained by Claisse et al. (1) should not be used to inform “rigs-to-reefs” decisions for the remaining 11 platforms off California, nor should they be used to inform rigs-to-reefs policies in other regions of the world.
Marine conservation zones (MCZs) are a form of spatial marine management, increasingly popular since the move towards ecosystem-based fisheries management. Implementation, however, is somewhat contentious and as a result of their short history, their effects are still widely unknown and understudied. Here, we investigate the population and health of the European lobster (Homarus gammarus) in the Lundy Island Marine Conservation Zone, Bristol Channel, UK. Using the fished refuge zone (RZ) as a control area, catch per unit effort was calculated for both the no-take zone (NTZ) and RZ and binomial logistic regression models were used to examine the effects of site, sex, landing size, and loss of chelae on the probability of shell disease and injury presence in individuals. Lobsters were also tested for the causative agent of gaffkaemia, Aerococcus viridans var. homari, and white spot syndrome virus (WSSV). The analysis revealed a higher lobster density and larger lobsters in the NTZ compared with the RZ. Shell disease was present in 24% of lobsters and the probability of shell disease occurrence increased notably for individuals over the minimum landing size (MLS) of 90 mm carapace length. Shell disease was also more prevalent in lobsters displaying injury, and in males. Injury was present in 33% of lobsters sampled and prevalence was higher in lobsters in the NTZ compared with the RZ, and in lobsters >MLS. Aerococcus viridans var. homari was detected in <1% of individuals, but WSSV was absent from all sampled lobsters. Overall, the study demonstrates both positive and potentially negative effects of NTZs, methods for effective non-lethal sampling of disease agents, and highlights the need for more comprehensive, long-term monitoring within highly protected MCZs, both before and after implementation.
Nearshore bathymetry is likely to be the coastal variable that most limits the investigation of coastal processes and the accuracy of numerical models in coastal areas, as acquiring medium spatial resolution data in the nearshore is highly demanding and costly. As such, the ability to derive bathymetry using remote sensing techniques is a topic of increasing interest in coastal monitoring and research. This contribution focuses on the application of the linear transform algorithm to obtain satellite-derived bathymetry (SDB) maps of the nearshore, at medium resolution (30 m), from freely available and easily accessible Landsat 8 imagery. The algorithm was tuned with available bathymetric Light Detection and Ranging (LiDAR) data for a 60-km-long nearshore stretch of a highly complex coastal system that includes barrier islands, exposed sandy beaches, and tidal inlets (Ria Formosa, Portugal). A comparison of the retrieved depths is presented, enabling the configuration of nearshore profiles and extracted isobaths to be explored and compared with traditional topographic/bathymetric techniques (e.g., high- and medium-resolution LiDAR data and survey-grade echo-sounding combined with high-precision positioning systems). The results demonstrate that the linear algorithm is efficient for retrieving bathymetry from multi-spectral satellite data for shallow water depths (0 to 12 m), showing a mean bias of − 0.2 m, a median difference of − 0.1 m, and a root mean square error of 0.89 m. Accuracy is shown to be depth dependent, an inherent limitation of passive optical detection systems. Accuracy further decreases in areas where turbidity is likely to be higher, such as locations adjacent to tidal inlets. The SDB maps provide reliable estimations of the shoreline position and of nearshore isobaths for different cases along the complex coastline analysed. The use of freely available satellite imagery proved to be a quick and reliable method for acquiring updated medium-resolution, high-frequency (days and weeks), low-cost bathymetric information for large areas and depths of up to 12 m in clear waters without wave breaking, allowing almost constant monitoring of the submerged beach and the shoreface.
Wave power devices offer great prospects for the marine renewable energy sector. But in comparison to wind energy, wave power is still in its infancy, mainly prototype-based, with technological gaps akin to those experienced in the wind sector some 15 years ago. Several aspects that did not seem significant at a first glance in the design phase, such as the interaction with the marine environment, turned out to be important when the first prototypes were put in the water. In fact, these devices have to face great challenges once at sea and several prototypes have not survived. Firstly, ocean waves are not such an innocuous, predictable flow of water and secondly, life thrives in the ocean. Wave power devices are perfect artificial reefs suitable for algal growth and colonization by many species. And they will have to sustain harsh conditions for over two decades while producing energy. For obvious reasons, there is a lack of existing literature on the subject. In this short review we address a simple question: how tough will the life of wave power devices at sea be? The answer is based on available evidence. We provide as well some ideas to take up the challenge.
In Norwegian fisheries policy, strict gear regulation is a central instrument actively used to achieve fisheries political objectives. Gear regulations are locked in rigid regulative structures that limit the actors׳ ability to adapt practices to changing conditions. This article shows that gear liberalization could take place within the framework of sustainable resource harvest, while also contributing to improved economic efficiency and reduced greenhouse gas emissions. Institutions, such as gear regulations, do not exist in a vacuum, but are linked to other institutional structures. Hence, within a framework of sustainability, the relaxation of one regulation may induce new regulations and institutions.
Marine animals face increased pressure through expanded shipping and recreational activities. Effective conservation and management of large species like marine mammals or sea turtles depend on knowledge of movement and habitat use. Previous studies have used data collected from either satellite or acoustic telemetry but rarely both. In this study, data from satellite and acoustic technologies were used to: determine the efficacy of satellite and acoustic telemetry to define dugong movement patterns; compare the benefits and limitations of each approach; examine the costs of each approach in relation to the amount and type of data provided; and relate telemetry data to the boundaries of a Go Slow area designed to protect dugongs and turtles from vessel strike within an urbanised coastal embayment (Moreton Bay, Queensland, Australia). Twenty-one dugongs were captured in seagrass habitats on the Eastern Banks of Moreton Bay in July–September 2012 and July 2013 and fitted with GPS and acoustic transmitters. Both satellite and acoustic telemetry produced reliable presence and movement data for individual dugongs. When the dugongs were within the range of the acoustic array, there was relatively good correspondence between the overall space use measures derived from GPS and acoustic transmitters, demonstrating that acoustic tracking is a potentially valuable and cost-effective tool for monitoring local dugong habitat use in environments equipped with acoustic receiver arrays. Acoustic technology may be particularly useful for species that establish home ranges with stable residency especially near large urban or port environs. However, the relative merits of the two technologies depend on the research question in the context of the species of interest, the location of the study and whether the study site has an established acoustic array.
A fully four-dimensional (3D × time) object-oriented biophysical dispersal model was developed to simulate the movement of marine larvae over semi-continuous surfaces. The model is capable of handling massive numbers of simulated larvae, can accommodate diverse life history patterns and distributions of characteristics, and saves point-level information to a relational database management system. The model was used to study Australia's northwest marine region, with attention given to connectivity patterns among Australia's north-western Commonwealth Marine Reserves (CMRs). Animations of larval movement near the Gascoyne canyon CMR, dispersal surfaces over depth and time for CMRs and Key Ecological Features in the northwest, as well as matrices of connectivity values among CMRs are shown. The matrices are further analysed to identify the sensitivity and elasticity of their values. The results generated by this model can aid in designing and managing marine protected area networks that incorporate extensive and complex benthic terrain (including the identification of marine ‘corridors’), and for developing targeted field sampling strategies.
This article aims to identify conditions of success for European fisheries co-management and its integration in broader strategies for sustainable resource management. Co-management of fisheries, broadly defined as the involvement of users in management, developed in Europe in various experimental forms of participation of fishermen in the management process, in advisory roles or through delegation and sharing of power. During its history, fisheries co-management has been revealed as multi-functional, addressing different knowledge and resource management problems, with varying success. This analysis focuses on knowledge-related issues that are important for the functioning of co-management, especially the combination of scientific and local knowledge. First we review European literature on co-management and secondly we analyse two exemplary case studies (EU Regional Advisory Councils and Fisheries Local Action Groups). Thereupon the possibilities for future development of co-management in Europe are discussed with regard to knowledge integration and environmental governance. Under the influence of the ideas of adaptive governance and sustainable resource management, modifications of forms and functions of co-management systems are described.
Bahrain, a group of islands, is facing several environmental challenges, including degradation of coastal and marine environments due to intensive dredging and reclamation activities. Presently, reclamation activities have resulted in adding around 110 km2 representing an increase of 14% of the total land area of Bahrain. Recognizing the role of Environmental Impact Assessment (EIA) in protecting environment from degradation and pollution associated with coastal developments, Bahrain formally adopted EIA in its environmental system in 1998. The present study investigated the practice and effectiveness of EIA in protecting coastal and marine environments in Bahrain by reviewing selected EIA reports and soliciting views of EIA experts, consultants, academics and other relevant bodies. Shortcomings in environmental and ecological assessment practices related to coastal and marine developments were recognized and constrains that restrict the effectiveness of EIA in protecting coastal and marine environments in Bahrain were identified. Maintaining a sustainable use of coastal and marine natural resources in Bahrain requires measures to holistically address the interactions among the several dredging and reclamation projects and their additive and cumulative impacts. This could be achieved through enhancing the current practice of EIA process and adopting Strategic Environmental Assessment (SEA) for dredging and reclamation activities.