Unintentional mortality of higher trophic-level species in commercial fisheries (bycatch) represents a major conservation concern as it may influence the long-term persistence of populations. An increasingly common strategy to mitigate bycatch of harbor porpoises (Phocoena phocoena), a small and protected marine top predator, involves the use of pingers (acoustic alarms that emit underwater noise) and time-area fishing closures. Although these mitigation measures can reduce harbor porpoise bycatch in gillnet fisheries considerably, inference about the long-term population-level consequences is currently lacking. We developed a spatially explicit individual-based simulation model (IBM) with the aim to evaluate the effectiveness of these two bycatch mitigation measures. We quantified both the direct positive effects (i.e., reduced bycatch) and any indirect negative effects (i.e., reduced foraging efficiency) on the population size using the inner Danish waters as a biological system. The model incorporated empirical data on gillnet fishing effort and noise avoidance behavior by free-ranging harbor porpoises exposed to randomized high-frequency (20- to 160-kHz) pinger signals. The IBM simulations revealed a synergistic relationship between the implementation of time-area fishing closures and pinger deployment. Time-area fishing closures reduced bycatch rates substantially but not completely. In contrast, widespread pinger deployment resulted in total mitigation of bycatch but frequent and recurrent noise avoidance behavior in high-quality foraging habitat negatively affected individual survival and the total population size. When both bycatch mitigation measures were implemented simultaneously, the negative impact of pinger noise-induced sub-lethal behavioral effects on the population was largely eliminated with a positive effect on the population size that was larger than when the mitigation measures were used independently. Our study highlights that conservationists and policy makers need to consider and balance both the direct and indirect effects of harbor porpoise bycatch mitigation measures before enforcing their widespread implementation. Individual-based simulation models, such as the one presented here, offer an efficient and dynamic framework to evaluate the impact of human activities on the long-term survival of marine populations and can serve as a basis to design adaptive management strategies that satisfy both ecological and socioeconomic demands on marine ecosystems.
The ecosystems of the Israeli Mediterranean coast have undergone significant changes in recent decades mainly due to species invasions and fishing. In order to characterize the structure and functioning of the marine continental shelf of the Israeli Mediterranean coast and assess temporal changes, we developed a food web model representing two time periods: 1990–1994 and 2008–2012.
The 1990–1994 and 2008–2012 food web models were composed of 39 and 41 functional groups, respectively. Functional groups ranged from primary producers to top predators, and included six and eight alien functional groups, respectively, encompassing several crustacean and fish species. Input data included local surveys and fishery statistics, published data on stomach content analyses, and the application of empirical equations to estimate consumption and production rates.
Results of the competitive interactions between alien and native species and changes in trophic flows between food web components highlight the increasing impact of alien species over time. Fishing had noticeable impacts in both time periods and played an important role in the ecosystem. Despite different productivity rates and other environmental differences, the Israeli marine ecosystem shared common structural and functional traits with other Mediterranean marine ecosystems. This is the first attempt to study the ecosystem of the Levant region using mass-balance models and to integrate such a large amount of alien species into food web analyses.
The growing literature on individual transferable quotas (ITQs) and on intensive salmon aquaculture and its negative impacts on the environment and other users of related marine space has been little connected to the developing literature on financialization and to the literature on ocean grabbing within fisheries. This paper seeks to address this gap through a case study of the recent history of herring fisheries and intensive aquaculture in New Brunswick, Canada, exploring how specific neoliberal processes – including privatization and marketization (in herring fleet ITQs and aquaculture lease systems), (re)regulation, financialization and globalization – have interacted to support the reshaping of regional fisheries from mixed small-scale, family-based, petty commodity fisheries towards vertically-integrated, corporate, financialized fisheries characterized by ocean grabbing.
This study analyzes the “quantity” and “speed” decoupling relationship between marine pollution and economic growth in China from 2002 to 2013. The results show that, when the red-tide disaster areas by coastal region is used as marine pollution indicator, an inverted N-shaped relationship is observed between pollution and growth. However, this curve fluctuates slightly, and its shape is more similar to monotonic decreasing. There are three states of “speed” decoupling between each marine pollution and economic growth indicator. The decoupling state between pollution and the economy changes rapidly, the deterioration of marine pollution being rather frequent. In some years, the pressure on the marine environment aggravated dramatically. Having combined both analyses, the study determines that marine economic growth and pollution in China have not been entirely decoupled in recent years, and that environmental pressure on marine economic growth remains obvious.
Plastics, despite their great benefits, have become a ubiquitous environmental pollutant, with microplastic particles having come into focus most recently. Microplastic effects have been intensely studied in aquatic, especially marine systems; however, there is lack of studies focusing on effects on soil and its biota. A basic question is if and how surface-deposited microplastic particles are transported into the soil. We here wished to test if soil microarthropods, using Collembola, can transport these particles over distances of centimeters within days in a highly controlled experimental set-up. We conducted a fully factorial experiment with two collembolan species of differing body size, Folsomia candida and Proisotoma minuta, in combination with urea-formaldehyde particles of two different particle sizes. We observed significant differences between the species concerning the distance the particles were transported. F. candida was able to transport larger particles further and faster than P. minuta. Using video, we observed F. candida interacting with urea-formaldehyde particles and polyethylene terephthalate fibers, showing translocation of both material types. Our data clearly show that microplastic particles can be moved and distributed by soil microarthropods. Although we did not observe feeding, it is possible that microarthropods contribute to the accumulation of microplastics in the soil food web.
Livelihood diversification can increase the number of activities generating income and is often adopted as a means to reduce vulnerability to risk and provide a pathway out of poverty. Previous empirical studies, however, have found that this diversification carries no guarantee of success. This study examines the impacts of investments in conservation-based enterprises and micro-credit interventions implemented in coastal Tanzania. Project beneficiaries (n = 178) and non-beneficiaries (n = 117) from seventeen communities surrounding Saadani National Park and the Menai Bay Conservation area were surveyed in 2013, to gather quantitative and qualitative data on a suite of parameters including the number of livelihood activities, total annual income, and engagement in extractive activities. We found that the beneficiaries reported an average of 2.15 livelihoods, which was significantly higher than the 1.44 average reported by the non-beneficiaries. The beneficiaries also had significantly higher mean annual incomes than the non-beneficiaries as the former reported an annual mean income of US $2,076 while the latter reported US $646. The research found a complex relationship between occupational diversity and people's interactions with the environment and it is clear that livelihood diversification is not a blanket solution to reducing pressure on coastal resources. Another important finding from the research is that there are distinct differences between types of livelihood interventions and it is crucial to be clear about the goal of a livelihoods intervention. If the goal is diversifying livelihoods and strengthening resilience, then livelihoods that provide a small and steady income for many entrepreneurs may be enough. However, if the goal is to bring people out of a poverty trap, then it makes more sense to invest in livelihoods that bring in a higher income, even if that means reaching fewer beneficiaries.
At all levels of governance from international convention to local policy, the regulation of pollution from boats and ships has been steeped in conflict and subject to resistance. Recreational boaters, in particular, are often highly resistant to attempts to regulate their boating activity, particularly on environmental grounds. Such ongoing resistance poses a significant policy compliance challenge. This paper seeks to shed light on this complex, ongoing and broader field of opposition to environmental management by way of a case study analysis of resistance to on-board sewage regulations on the part of recreational boaters in Queensland, Australia. This resistance on the part of ‘everyday’ citizens is examined through the lens of heterotopia. In consequence, the paper can contribute to understandings more broadly of problems beleaguering environmental policy while also attending to the deeply implicated social roles of recreational boating spaces; namely as heterotopias of compensation and/or illusion. It also highlights how these heterotopic positionings are intensified by the scatological orientation of the policy under study.
The concept of spatial resilience has brought a new focus on the influence of multi-scale processes on the dynamics of ecosystems. Initial ideas about spatial resilience focused on coral reefs and emphasized escalating anthropogenic disturbances across the broader seascape. This perspective resonated with a new awareness of global drivers of change, such as growth in international trade and shifts in climate, and the need to respond by scaling up governance and management. We review recent trends and emerging ideas in spatial resilience, using coral reefs and dependent communities as exemplars of multi-scale social–ecological systems. Despite recent advances, management and governance of ecosystems remain spatially fragmented and constrained to small scales. Temporally, many interventions still miss or ignore warning signals and struggle to cope with history, politics, long-term cumulative pressures, feedbacks, and sudden surprises. Significant recent progress has been made in understanding the relevance of spatial and temporal scale, heterogeneity, networks, the importance of place, and multi-scale governance. Emerging themes include better integration of ecology and conservation with social and economic science, and incorporating temporal dynamics in spatial analyses. A better understanding of the multi-scale spatial and temporal processes that drive the resilience of linked social-ecosystems will help address the widespread mismatch between the scales of ongoing ecological change and effective long-term governance of land- and seascapes.
Multiple lines of observational evidence indicate that the global climate has been getting warmer since the early 20th century. This warmer climate has led to a global mean sea level rise of about 18 cm during the 20th century, and over 6 cm for the first 15 years of the 21st century. Regionally the sea level rise is not uniform due in large part to internal climate variability. To better serve the community, the uncertainties of predicting/projecting regional sea level changes associated with internal climate variability need to be quantified. Previous research on this topic has used single-model large ensembles with perturbed atmospheric initial conditions (ICs). Here we compare uncertainties associated with perturbing ICs in just the atmosphere and just the ocean using a state-of-the-art coupled climate model. We find that by perturbing the oceanic ICs, the uncertainties in regional sea level changes increase compared to those with perturbed atmospheric ICs. Thus, in order for us to better assess the full spectrum of the impacts of such internal climate variability on regional and global sea level rise, approaches that involve perturbing both atmospheric and oceanic initial conditions are necessary.
Phytoplankton form the basis of the marine food web and are responsible for approximately half of global carbon dioxide (CO2) fixation (∼ 50 Pg of carbon per year). Thus, these microscopic, photosynthetic organisms are vital in controlling the atmospheric CO2 concentration and Earth’s climate. Phytoplankton are dependent on sunlight and their CO2-fixation activity is therefore restricted to the upper, sunlit surface ocean (that is, the euphotic zone). CO2 usually does not limit phytoplankton growth due to its high concentration in seawater. However, the vast majority of oceanic surface waters are depleted in inorganic nitrogen, phosphorus, iron and/or silica; nutrients that limit primary production in the ocean (Figure 1). Phytoplankton growth is mainly supported by either the recycling of nutrients or by reintroduction of nutrients from deeper waters by mixing. A small percentage of primary production, though, is fueled by ‘external’ or ‘new’ nutrients and it is these nutrients that determine the amount of carbon that can be sequestered long term in the deep ocean. For most nutrients such as phosphorus, iron, and silica, the external supply is limited to atmospheric deposition and/or coastal and riverine inputs, whereas their main sink is the sedimentation of particulate matter. Nitrogen, however, has an additional, biological source, the fixation of N2 gas, as well as biological sinks via the processes of denitrification and anammox. Despite the comparatively small contributions to the overall turnover of nutrients in the ocean, it is these biological processes that determine the ocean’s capacity to sequester CO2 from the atmosphere on time scales of ocean circulation (∼ 1000 years). This primer will highlight shifts in the traditional paradigms of nutrient limitation in the ocean, with a focus on the uniqueness of the nitrogen cycling and its biological sources and sinks.
Ecosystems store vast quantities of wealth, but difficulties measuring wealth held in ecosystems prevent its inclusion in accounting systems. Ecosystem-based management endeavors to manage ecosystems holistically. However, ecosystem-based management lacks headline indicators to evaluate performance. We unify the inclusive wealth and ecosystem-based management paradigms, allowing apples-to-apples comparisons between the wealth of the ecosystem and other forms of wealth, while providing a headline performance index for evaluating the performance of ecosystem-based management. We project that the Baltic Sea fishery ecosystem yields increasing stores of wealth over the next 50 y under the ecosystem-based management-inspired multispecies maximum sustainable yield management beginning in 2017, whereas the previous single-species management generally results in declining wealth.
Shark-diving is part of a rapidly growing industry focused on marine wildlife tourism. Our study aimed to provide an estimate of the economic value of shark-diving tourism across Australia by comprehensively surveying the whale shark (Rhincodon typus), white shark (Carcharodon carcharias), grey nurse shark (Carcharias taurus), and reef shark (mostly Carcharhinus amblyrhynchos and Triaenodon obesus) diving industries using a standardised approach. A socio-economic survey targeted tourist divers between March 2013 and June 2014 and collected information on expenditures related to diving, accommodation, transport, living costs, and other related activities during divers’ trips. A total of 711 tourist surveys were completed across the four industries, with the total annual direct expenditure by shark divers in Australia estimated conservatively at $25.5 M. Additional expenditure provided by the white-shark and whale-shark-diving industries totalled $8.1 and $12.5 M for the Port Lincoln and Ningaloo Reef regions respectively. International tourists diving with white sharks also expended another $0.9 M in airfares and other activities while in Australia. These additional revenues show that the economic value of this type of tourism do not flow solely to the industry, but are also spread across the region where it is hosted. This highlights the need to ensure a sustainable dive-tourism industry through adequate management of both shark-diver interactions and biological management of the species on which it is based. Our study also provides standardised estimates which allow for future comparison of the scale of other wildlife tourism industries (not limited to sharks) within or among countries.
The surface oil burns conducted by the U.S. Coast Guard from April to July 2010 during the Deepwater Horizon disaster in the Gulf of Mexico were simulated by small scale burns to characterize the pollutants, determine emission factors, and gather particulate matter for subsequent toxicity testing. A representative crude oil was burned in ocean-salinity seawater, and emissions were collected from the plume by means of a crane-suspended sampling platform. Emissions included particulate matter, aromatic hydrocarbons, polychlorinated dibenzodioxins/dibenzofurans, elements, and others, the sum of which accounted for over 92% by mass of the combustion products. The unburned oil mass was 29% of the original crude oil mass, significantly higher than typically reported. Analysis of alkanes, elements, and PAHs in the floating residual oil and water accounted for over 51% of the gathered mass. These emission factors, along with toxicity data, will be important toward examining impacts of future spill burning operations.
Millions of marine ornamental fishes are traded every year. Today, over half of the known nearly 4000 coral reef fish species are in trade with poor or no monitoring and demand is increasing. This study investigates their trade into and through Switzerland by analyzing import documents for live animals. In 2009, 151 import declarations with attached species lists for marine ornamental fishes from non-EU countries totaled 28 356 specimens. The 62% of the fishes remaining in Switzerland, comprised 440 marine species from 45 families, the rest transited to EU and non-EU countries. Despite the recognized large trade volume for the European region, due to bilateral agreements, no data is collected for imports from the EU. However, inferred data shows that more than 200 000 marine ornamental fishes could be imported into Switzerland every year and an unknown quantity re-exported. As biggest import region, it is therefore safe to assume, that the European region is importing at least as many marine ornamental fishes as the US. There is no adequate data-collecting system known to be in place in any country for monitoring this trade. The EU Trade Control and Expert System (TRACES) to monitor animal diseases could be adjusted to gather compulsory information for the EU and Switzerland. More than half of the species imported into Switzerland are not assessed by the IUCN and therefore marked as ‘not evaluated’ on the Red List. Overall, 70% of all known coral reef fish species have not been evaluated. If coral reef fishes are threatened or endangered due to large, possibly unsustainable numbers traded, it may be rational to monitor the trade in these species through the Convention on International Trade of Endangered Species (CITES).
Even in the presence of environmental safeguards, catastrophic accidents related to anthropogenic activities occur that can result in both immediate and chronic impacts on local biota. However, due to the unplanned nature of catastrophes, studies aimed to identify the effects of these accidents on an ecosystem and its inhabitants often have imperfect study designs that are reactive rather than proactive, resulting in methodological and analytical challenges. On 20 April 2010, following an explosion on the Deepwater Horizon oil rig, a well blowout occurred on the seafloor approximately 80 km off the Louisiana coast in the Gulf of Mexico. This blowout resulted in the largest marine oil spill in United States history, which impacted critical migratory stopover and overwintering habitat for many seabird and shorebird species, including species of high conservation concern such as the piping plover (Charadrius melodus). Here, we assessed the potential longer-term demographic impacts of the Deepwater Horizon oil spill on piping plovers in a capture-mark-recapture framework. We examined whether a series of demographic processes, including probabilities of remaining at a specific wintering site, over-winter and annual apparent survival, winter stopover duration, and abundance varied among oiled and unoiled habitats. We found that the perceived amount of oiling on land, in water, and on individual birds, as well as numerous demographic processes, were spatially or temporally variable. However, we found little support that piping plover demography was negatively influenced by the magnitude of oil observed at an impacted area, or that demographic rates substantially varied between reference and oil impacted areas. Nor did we find that piping plovers that were observed to be oiled had lower survival probabilities following the DWH oil spill relative to non-oiled individuals from the same winter population. Although we did not find that the Deepwater Horizon oil spill substantially influenced piping plovers, our methods provide an analytical framework to more appropriately address both the near or long-term impacts of an anthropogenic disturbance on a species.
During the last decade a number of Large Marine Protected Areas (LMPAs) – marine protected areas that exceed a minimum size threshold and are often in offshore or open ocean waters – have been designated in an effort to meet marine conservation objectives. Research on the human dimensions of LMPAs is limited, though comprehensive policy analysis requires an understanding of the full range of social, cultural and economic benefits associated with LMPA designation. This paper addresses this need by employing a stated preference choice experiment survey of U.S. west coast households to examine public preferences for different protected area designs sited off the U.S. west coast. Using data from over 3000 randomly selected households in California, Oregon, and Washington we estimate choice models and calculate economic values for a suite of LMPAs that vary in size and in the types of restrictions within area boundaries. Results show that the LMPA size yielding the highest value is ~15.6% of the west coast Federal waters. Results also underscore the importance of restriction type, as there are considerably different threshold sizes above which diminishing returns and negative economic values are derived from no-access reserves, no-take, and multiple-use designations. While the value of any specific configuration can be estimated using the model, results offer insight on optimal use designations from a public perspective for small (< 2.5% of west coast Federal waters), medium (2.5%–~10%) and large (> 10%) LMPAs sited off the U.S. west coast.
Increasing numbers of people are living in and using coastal areas. Combined with the presence of pervasive coastal threats, such as flooding and erosion, this is having widespread impacts on coastal populations, infrastructure and ecosystems. For the right adaptive strategies to be adopted, and planning decisions to be made, rigorous evaluation of the available options is required. This evaluation hinges on the availability and use of suitable datasets. For knowledge to be derived from coastal datasets, such data needs to be combined and analysed in an effective manner. This paper reviews a wide range of literature relating to data-driven approaches to coastal risk evaluation, revealing how limitations have been imposed on many of these methods, due to restrictions in computing power and access to data. The rapidly emerging field of ‘Big Data’ can help overcome many of these hurdles. ‘Big Data’ involves powerful computer infrastructures, enabling storage, processing and real-time analysis of large volumes and varieties of data, in a fast and reliable manner. Through consideration of examples of how ‘Big Data’ technologies are being applied to fields related to coastal risk, it becomes apparent that geospatial Big Data solutions hold clear potential to improve the process of risk based decision making on the coast. ‘Big Data’ does not provide a stand-alone solution to the issues and gaps outlined in this paper, yet these technological methods hold the potential to optimise data-driven approaches, enabling robust risk profiles to be generated for coastal regions.
Most larger water bodies worldwide are used for navigation, and the intensity of commercial and recreational navigation is expected to further increase. Navigation profoundly affects aquatic ecosystems. To facilitate navigation, rivers are trained and developed, and the direct effects of navigation include chemical and biological impacts (e.g., inputs of toxic substances and dispersal of non-native species, respectively). Furthermore, propagating ships create hydrodynamic alterations, often simply summarized as waves. Although ship-induced waves are recognized as influential stressors, knowledge on their effects is poorly synthesized. We present here a review on the effects of ship-induced waves on the structure, function and services of aquatic ecosystems based on more than 200 peer reviewed publications and technical reports. Ship-induced waves act at multiple organizational levels and different spatial and temporal scales. All the abiotic and biotic components of aquatic ecosystems are affected, from the sediment and nutrient budget to the planktonic, benthic and fish communities. We highlight how the effects of ship-induced waves cascade through ecosystems and how different effects interact and feed back into the ecosystem finally leading to altered ecosystem services and human health effects. Based on this synthesis of wave effects, we discuss strategies for mitigation. This may help to develop scientifically based and target-oriented management plans for navigational waters that optimize abiotic and biotic integrity and their ecosystem services and uses.
The excessive combustion of fossil fuels for energy provision have altered natural planetary functions, resulting in adverse biophysical and societal implications. Such implications have prompted many governments globally to advocate for the adoption of renewable energy systems in order to reduce GHG emissions. While renewable energy technologies such as solar and biogases have been thoroughly researched and deployed, tidal current turbines (TCTs) that harness kinetic energy from the lateral movement of the tides are a comparatively emerging renewable energy technology, and thus has received relatively less attention with respect to their potential to supplement the renewable energy transition. This paper examines the physics behind tidal movements and cycles, and the technological operation of TCTs. Environmental impacts and economic barriers are analyzed. Best practices of MSP from world leading nations are examined, along with current deploy-andmonitor-consenting regimes of TCT test facilities. An optimal TCT design is suggested based on a synthesis of information from proceeding sections. Finally, an analysis of the implementation of TCTs in Canada, China, and Norway is presented, the results of which demonstrate that harnessing the accessible and sustainably extractable resource of each nation can result in an aggregate installed capacity of 9076 MW through the deployment of 7564 TCTs at a cost of $5,740,964,430, thereby creating 14,467 jobs. This would produce 29,829,711 MW h/yr of electricity sold at approximately 22 cents/kWh, eliminating a total of 14,914,855,258 kg of CO2e, approximately 0.1%. of the projected global electricity demand for 2016.
Plastics in the marine environment have become a major concern because of their persistence at sea, and adverse consequences to marine life and potentially human health. Implementing mitigation strategies requires an understanding and quantification of marine plastic sources, taking spatial and temporal variability into account. Here we present a global model of plastic inputs from rivers into oceans based on waste management, population density and hydrological information. Our model is calibrated against measurements available in the literature. We estimate that between 1.15 and 2.41 million tonnes of plastic waste currently enters the ocean every year from rivers, with over 74% of emissions occurring between May and October. The top 20 polluting rivers, mostly located in Asia, account for 67% of the global total. The findings of this study provide baseline data for ocean plastic mass balance exercises, and assist in prioritizing future plastic debris monitoring and mitigation strategies.