To examine down-estuary effects and how differences in food webs along a salinity gradient might influence mercury (Hg) biomagnification, we conducted a study from 2010 to 2015 in an estuary with a known biological hotspot at its headwaters. Over 907 samples of biota, representing 92 different taxa of fish and invertebrates, seston and sediments were collected from the upper, middle and lower reach for Hg determination and for stable nitrogen and carbon isotope analyses. Trophic magnification slopes (TMS; log Hg versus δ15N), as a measure of biomagnification efficiency, ranged from 0.23 to 0.241 but did not differ statistically among reaches. Hg concentrations were consistently highest, ranging as high as 4.9 mg/kg in top predatory fish, in the upper-reach of the estuary where basal Hg entering the food web was also highest, as evidenced by methylmercury concentrations in suspension feeders. Top predatory fish at the mouth of the estuary contained relatively low [THg], likely due to lower basal Hg. This was nonetheless surprising given the potential for down-estuary biotransport.
The science-policy nexus has long puzzled scholars and managers working across diverse public policy areas, including environment. The rise of science-based management, especially in an era of big data, assumes science can improve environmental policy. At the same time, increasing attention to stakeholder engagement provides avenues for non-scientists to participate in collaborative environmental management, which might displace science in decision-making processes. Prior research points to a variety of factors thought to affect the degree to which science is used in collaborative partnerships. Drawing on such research, we examine the use of science across 9 collaborative partnerships structured and resourced from the top-down by a state government agency. All of these partnerships are working in the U.S.’s second largest estuary, the Puget Sound in Washington State. Data from partnership meeting minutes indicates that science is scarcely discussed in executive committee meetings, but is more commonly discussed in technical committee meetings. We thus might expect that the ecosystem management plans produced by these technical committees would be closely informed by science. Results indicate these plans include few citations to peer-reviewed scientific studies, but they do draw consistently on scientific information from grey literature including scientific and technical reports from federal and state agencies. These results raise important questions about government efforts to foster the use of science in collaborative partnerships, including the benefits and drawbacks of using grey literature rather than scientific articles directly, the interaction of science with other forms of knowledge, and local actors’ capacity to understand and access science.
Aquaculture is supporting demand and surpassing wild-caught seafood. Yet, most fed aquaculture species (finfish and crustacea) rely on wild-captured forage fish for essential fatty acids and micronutrients, an important but limited resource. As the fastest growing food sector in the world, fed aquaculture demand will eventually surpass ecological supply of forage fish, but when and how best to avoid this ecological boundary is unclear. Using global production data, feed use trends, and human consumption patterns, we show how combined actions of fisheries reform, reduced feed use by non-carnivorous aquaculture and agricultural species, and greater consistent inclusion of fish by-products in China-based production can circumvent forage fish limits by mid-century. However, we also demonstrate that the efficacies of such actions are diminished if global diets shift to more seafood-heavy (that is, pescatarian) diets and are further constrained by possible ecosystem-based fisheries regulations in the future. Long-term, nutrient-equivalent alternative feed sources are essential for more rapid and certain aquaculture sustainability.
The aim of this research was to propose and evaluate a methodological approach to integration and spatial data analysis in order to generate information towards a participatory site selection for bivalve marine aquaculture in the Baía Sul, Florianópolis, Santa Catarina, Brazil. For this purpose, the Baía Sul was investigated considering an ecosystem approach for aquaculture leading to an assessment of its potential for marine aquaculture. The planning of the aquaculture parks was made through a participatory process to incorporate both environmental carrying capacity and social carrying capacity. Experts and modellers developed a GIS model to assess the potential for marine aquaculture in Baía Sul. Continuous (unclassified) maps were used to provide spatial information about the variation of the potential for marine aquaculture in the Baía Sul. The maps were used to plan 53 aquaculture parks over the Baía Sul. The site selection of the parks was made in six public hearings attended by 403 stakeholders from 38 institutions representing different sectors with diverse interests in coastal zone. The results showed that although the Baía Sul is suitable for the growth of bivalve molluscs, some hydrodynamic characteristics and the influence of urbanization constitute a sanitary risk for the activity. Experts, modellers and stakeholders had a different perception about the importance of criteria in the aquaculture parks site selection. While the experts and modellers considered the environmental criteria as the most important aspect to locate the aquaculture parks, the stakeholders took into account mainly the logistics. The final result of the aquaculture parks location, approved by the Brazilian Ministry of Fisheries and Aquaculture (MPA), adopted the site selection by the stakeholders, providing aquaculture parks in areas with sanitary risk for the bivalve cultivation. The main advantage of the adopted assessment strategy was to identify the divergence between experts, modellers and the stakeholders and the distance that still exist between scientist and decision makers in Brazil.
This study examines the use of water-use fees in California’s bidding-based power markets to balance freshwater conservation and reduction of the marine ecosystem impact of coastal once-through-cooled power plants. An hourly power dispatch is simulated using the state’s 2014 demand and generation capacity data. Fees on ocean water withdrawals of $5–120/acre-ft are simulated in three scenarios that test the grid’s ability to simultaneously mitigate its impact on marine ecosystems, conserve freshwater, and incentivize recycled water use. Although fees modeled represent a small share of generator fuel costs, results show that they trigger declines in ocean water withdrawals of up to 11% that are almost always cost-effective if accounting for effects on system-wide fuel costs and CO2 emissions. An appropriately designed fee-structure reduces ocean water withdrawals by 9% without increasing freshwater consumption elsewhere. Wholesale electricity price increases of 5–10% are concentrated in Northern California, and marine ecosystem benefits are partly offset by increases in NOx and SO2 emissions inland. Overall, this study finds that water-use fees could be an effective strategy for reducing the marine ecosystem impacts of California’s power sector, particularly because they can also address short term fluctuations in freshwater scarcity. Keywords: Energy-water nexus, once-through cooling, scarce water, environmental pricing, energy policy, electricity dispatch, power systems.
Sea-level rise (SLR) is predicted to elevate water depths above coral reefs and to increase coastal wave exposure as ecological degradation limits vertical reef growth, but projections lack data on interactions between local rates of reef growth and sea level rise. Here we calculate the vertical growth potential of more than 200 tropical western Atlantic and Indian Ocean reefs, and compare these against recent and projected rates of SLR under different Representative Concentration Pathway (RCP) scenarios. Although many reefs retain accretion rates close to recent SLR trends, few will have the capacity to track SLR projections under RCP4.5 scenarios without sustained ecological recovery, and under RCP8.5 scenarios most reefs are predicted to experience mean water depth increases of more than 0.5 m by 2100. Coral cover strongly predicts reef capacity to track SLR, but threshold cover levels that will be necessary to prevent submergence are well above those observed on most reefs. Urgent action is thus needed to mitigate climate, sea-level and future ecological changes in order to limit the magnitude of future reef submergence.
Coastal wetlands are some of the most valuable ecosystems on Earth because they provide many ecological services for coastal security. However, these wetlands are seriously threatened by accelerated climate change and intensive anthropogenic activities. To understand the impacts of land reclamation on landscape change of coastal wetlands and the long-term effects of disturbances of coastal wetlands on their sustainable management, we used time-series Landsat imagery with an object-oriented classification and Digital Shoreline Analysis System to map wetland changes within a reclaimed area in the Pudong District (PD), in Shanghai, China. Our analysis indicated that from 1989 to 2013, 19,793.4 ha of coastal wetlands have been changed to inland wetlands enclosed by a seawall and dike since 1989, thereby cutting off the exchange of sediment and water flux between the wetlands and the coastal ocean. Subsequently, under the increasing threats of anthropogenic activities, the wetland ecosystem collapsed sharply, in a transformation chain of inland wetland (fresh swamp), artificial wetland (agriculture and aquaculture wetland), and non-wetland (urban land). Under this explosive utilization following coastal reclamation, only 8.9% of natural wetlands remain in the reclaimed area, which has experienced an average annual wetland loss rate of 3.8% over the past 24 years. More than 80% of the wetlands have been developed for agricultural, industrial, and urban land uses, leading to an enormous loss of associated ecological services—benefits arising from the ecological functions provided by wetland ecosystems, thereby undermining the coastal protection these wetlands provided. Nevertheless, considerable regeneration of wetlands occurred because of their inherent resilience. This paper addresses the importance of maintaining a balance between economic growth and coastal ecological protection for sustainable management. It proposes a strategy for how ecosystem-based land planning and ecological engineering should be applied to ensure the effective and sustainable management of living shorelines so that the benefits of healthy ecological functions accrue to coastal ecosystems.
The ocean is the next frontier for many conservation and development activities. Growth in marine protected areas, fisheries management, the blue economy, and marine spatial planning initiatives are occurring both within and beyond national jurisdictions. This mounting activity has coincided with increasing concerns about sustainability and international attention to ocean governance. Yet, despite growing concerns about exclusionary decision-making processes and social injustices, there remains inadequate attention to issues of social justice and inclusion in ocean science, management, governance and funding. In a rapidly changing and progressively busier ocean, we need to learn from past mistakes and identify ways to navigate a just and inclusive path towards sustainability. Proactive attention to inclusive decision-making and social justice is needed across key ocean policy realms including marine conservation, fisheries management, marine spatial planning, the blue economy, climate adaptation and global ocean governance for both ethical and instrumental reasons. This discussion paper aims to stimulate greater engagement with these critical topics. It is a call to action for ocean-focused researchers, policy-makers, managers, practitioners, and funders.
This study aimed to determine the main anthropogenic pressures and the effectiveness of management practices in marine protected areas (MPAs) (Rocas Atoll and Fernando de Noronha Archipelago, South Atlantic). The MPAs exhibited high management effectiveness over the last 25 years due to the control of local pressures (i.e., fishing and tourism). However, the increase in regional and global pressures, such as invasive species, marine debris, and climate change stressors (sea-level rise, extreme events, range shifts of species, warming, and ocean acidification), are environmental risks that need to be considered during conservation. Strategies for large scale marine spatial planning, as well as proposals for an integrated management of MPAs (including coral reef islands and seamounts) by the articulation of a network, which reduces regional human pressures and improves ocean governance were discussed. This study provided insights into the challenges faced in the management of MPAs in a rapidly changing ocean.
Increased loads of land-based pollutants are a major threat to coastal-marine ecosystems. Identifying the affected marine areas and the scale of influence on ecosystems is critical to assess the impacts of degraded water quality and to inform planning for catchment management and marine conservation. Studies using remotely-sensed data have contributed to our understanding of the occurrence and influence of river plumes, and to our ability to assess exposure of marine ecosystems to land-based pollutants. However, refinement of plume modeling techniques is required to improve risk assessments. We developed a novel, complementary, approach to model exposure of coastal-marine ecosystems to land-based pollutants. We used supervised classification of MODIS-Aqua true-color satellite imagery to map the extent of plumes and to qualitatively assess the dispersal of pollutants in plumes. We used the Great Barrier Reef (GBR), the world's largest coral reef system, to test our approach. We combined frequency of plume occurrence with spatially distributed loads (based on a cost-distance function) to create maps of exposure to suspended sediment and dissolved inorganic nitrogen. We then compared annual exposure maps (2007–2011) to assess inter-annual variability in the exposure of coral reefs and seagrass beds to these pollutants. We found this method useful to map plumes and qualitatively assess exposure to land-based pollutants. We observed inter-annual variation in exposure of ecosystems to pollutants in the GBR, stressing the need to incorporate a temporal component into plume exposure/risk models. Our study contributes to our understanding of plume spatial–temporal dynamics of the GBR and offers a method that can also be applied to monitor exposure of coastal-marine ecosystems to plumes and explore their ecological influences.
Although the importance of Maritime Spatial Planning (MSP) as a concept is know acknowledged and the legal framework is in place, the task of applying it remains a delicate one. One of the keys to success is having pertinent data. Knowing how maritime uses unfold in a spatio-temporal context, and what conflicting or synergistic interactions exist between activities, is crucial. However, this information is especially hard to obtain in a marine environment. As a result this information has often been identified as the missing layer in information systems developed by maritime stakeholders. Since 2002, the Automatic Identification System (AIS) has been undergoing a major development. Allowing for real time geo-tracking and identification for equipped vessels, the data that issues from AIS data promises to map and describe certain marine human activities.
After recapitulating the main characteristics of AIS and the data it provides, this article proposes to evaluate how AIS is currently used in MSP at a European level, and to concisely present a series of methods and results obtained within the framework of several operational research projects. The objective is to illustrate how the AIS data processing and analysis can produce adequate information for MSP: maritime traffic density, shipping lanes and navigation flows, hierarchical network of maritime routes, alleged fishing zones, spatio-temporal interactions between activities (potential conflicting uses or synergies). The conclusion looks in particular at the legal questions concerning the use of AIS.
The status of fisheries requires establishing and evaluating benchmarks derived from unfished ecosystems. Habitats, environmental conditions, properties of the fish communities and management systems could potentially influence the variability surrounding benchmarks. Consequently, eighteen variables including habitat, number of species, life histories, thermal and productivity environments were tested for influences on reef fish biomass in 62 reefs within old high compliance closures along the east African coastline. Biomass and weighted life history characteristics were classified and described for total, fishable, target and non‐target groups. Benchmark biomass fell within a 95% confidence interval of ~1,030–1,250 kg/ha and equally distributed among target and non‐target groups. While some relationships were statistically significant, most were weak, poorly sampled (ocean exposed reefs), had uncertain relationships with biomass (number of species), or the explained variation was bounded within the above confidence intervals (habitat and environment). Therefore, a regional unfished biomass benchmark (B0) of 1,150 and 560 kg/ha is recommended for total and target biomasses, respectively. Weighted life history metrics indicate that the target had slower life histories than the non‐target fish communities. Consequently, they will be fished unsustainably if yield recommendations are derived from the total, resilient or non‐target fish life history metrics. The intrinsic rates of increase (r) and target categorization of biomass were the most influential metrics in estimating yields.
Human and natural systems have adapted to and evolved within historical climatic conditions. Anthropogenic climate change has the potential to alter these conditions such that onset of unprecedented climatic extremes will outpace evolutionary and adaptive capabilities. To assess whether and when future climate extremes exceed their historical windows of variability within impact‐relevant socioeconomic, geopolitical, and ecological domains, we investigate the timing of perceivable changes (time of emergence; TOE) for 18 magnitude‐, frequency‐, and severity‐based extreme temperature (10) and precipitation (8) indices using both multimodel and single‐model multirealization ensembles. Under a high‐emission scenario, we find that the signal of frequency‐ and severity‐based temperature extremes is projected to rise above historical noise earliest in midlatitudes, whereas magnitude‐based temperature extremes emerge first in low and high latitudes. Precipitation extremes demonstrate different emergence patterns, with severity‐based indices first emerging over midlatitudes, and magnitude‐ and frequency‐based indices emerging earliest in low and high latitudes. Applied to impact‐relevant domains, simulated TOE patterns suggest (a) unprecedented consecutive dry day occurrence in >50% of 14 terrestrial biomes and 12 marine realms prior to 2100, (b) earlier perceivable changes in climate extremes in countries with lower per capita GDP, and (c) emergence of severe and frequent heat extremes well‐before 2030 for the 590 most populous urban centers. Elucidating extreme‐metric and domain‐type TOE heterogeneities highlights the challenges adaptation planners face in confronting the consequences of elevated twenty‐first century radiative forcing.
Socio-economic development of small-island fishing communities is greatly dependent on local coastal and marine resources. However, illegal fishing and aggressive practices in insular ecosystems lead to over-exploitation and environmental deterioration. Moreover, a lack of scientific data increases uncertainty and prevents the adequate monitoring of marine resources. This paper focuses on the integration of local fishing communities into decision-making processes with the aim of promoting artisanal fishing on the Island of Tenerife (the Canary Islands), as a way to preserve the marine ecosystem and socio-economic development of traditional cofradias (fishers' organisations). A qualitative methodological framework, based on participatory problem-solution trees and focus groups, was used to identify the main factors impeding the sustainable development of the artisanal fishing sector on the island and to elaborate collective proposals with policy implications. The fishing community involved identified four main issues that are maintaining an unsustainable island fishery: 1) Over-exploitation; 2) Poor self-management of cofradias and commercialisation problems; 3) Fisher individualism and low co-management strategies, and 4) Illegal fishing increase vs. artisanal fishing decline. Results show the required policy enhancements to tackle them and the need to adapt regulations to the local situation.
Floating litter in the estuarine system of Santos-São Vicente is common and is part of day-to-day activities of various users of the area. The objective of the present study was to carry out a quali-quantitative evaluation of the occurrence of floating litter, to infer their sources, and to identify environmental factors that are likely to control occurrence and distribution, with particular emphasis on the effects of tidal regimes. Six sampling stations were selected along the aforementioned estuary and visited monthly between July 2010 and January 2012. Floating litter was counted from a fixed sampling station. Plastics prevailed (89.64%) and their main source was domestic activities (55.41%). More litter was found during ebb spring tides, with higher concentrations obeying confluence patterns of the estuary's channels. Results indicated that occurrence can be attributed to the deficiency in basic sewage system in the area and the deliberate disposal into the estuary by the local population.
This manuscript examines marine resource users' perceptions of, experiences with, and responses to federal and territorial fisheries management processes in St. Croix, United States Virgin Islands. Drawing on anthropological critiques of common pool resources (CPR) institutions and political ecology, I describe the historical, social, and political factors that influence how fisheries management occurs at multiple scales and how it is experienced by fishers, managers, and other stakeholders. This multi-scale approach is both timely and important, as resources and communities throughout the world are increasingly globalized and inter-connected; it is virtually impossible to find an example of a CPR being managed at the local scale, devoid of the influence of external factors. As a result, it is becoming more common for resources and resource users to be subject to regulations and management regimes at multiple levels and scales (such as federal and territorial). For this reason, it is critical to examine how management institutions across scales impact one another and influence key elements of management, such as stakeholder participation. Fisheries management in St. Croix provides an opportunity to explore how the complexities of multi-scale resource management occur at the local level and how resource users and other stakeholders experience and perceive those processes. Specifically, this manuscript describes whether and how fishers and other marine resource stakeholders participate in management processes and how factors such as demographic heterogeneity, historical patterns of social group interactions, and the complexity of management processes influence participation.
There is a growing recognition for the need to understand how seawater carbonate chemistry over coral reef environments will change in a high-CO2 world to better assess the impacts of ocean acidification on these valuable ecosystems. Coral reefs modify overlying water column chemistry through biogeochemical processes such as net community organic carbon production (NCP) and calcification (NCC). However, the relative importance and influence of these processes on seawater carbonate chemistry vary across multiple functional scales (defined here as space, time, and benthic community composition), and have not been fully constrained. Here, we use Bermuda as a case study to assess (1) spatiotemporal variability in physical and chemical parameters along a depth gradient at a rim reef location, (2) the spatial variability of total alkalinity (TA) and dissolved inorganic carbon (DIC) over distinct benthic habitats to infer NCC:NCP ratios [< several km2; rim reef vs. seagrass and calcium carbonate (CaCO3) sediments] on diel timescales, and (3) compare how TA-DIC relationships and NCC:NCP vary as we expand functional scales from local habitats to the entire reef platform (10's of km2) on seasonal to interannual timescales. Our results demonstrate that TA-DIC relationships were strongly driven by local benthic metabolism and community composition over diel cycles. However, as the spatial scale expanded to the reef platform, the TA-DIC relationship reflected processes that were integrated over larger spatiotemporal scales, with effects of NCC becoming increasingly more important over NCP. This study demonstrates the importance of considering drivers across multiple functional scales to constrain carbonate chemistry variability over coral reefs.
The use of aquatic mammals as bait to enhance the harvest of fisheries species has garnered little attention by the scientific and conservation communities, often receiving only brief mention in reports focused on the human consumption or bycatch of aquatic mammals. A number of studies, however, highlight the negative impact of this practice on affected mammal populations. A systematic review of relevant literature published since 1970 yields new insight into the scope of the issue. Findings indicate that the practice of using aquatic mammals for bait has been and continues to be geographically widespread, has affected at least 42 species, and often involves deliberate killing for the express purpose of securing bait. The nature of the fisheries involved is diverse, encompassing a wide range of target species and gear types; however, shark fisheries that employ longlines appear to be the most widely engaged in using aquatic mammals as bait. This practice appears to be most common in Latin America and Asia. It is evident, based on our review, that there is little information on the impact of the direct take on most targeted mammal populations, commonly small cetaceans, and increased monitoring efforts are needed in many locales. In most instances, the ecology and population dynamics of the targeted fishery species is poorly understood and in some cases the species is classified as threatened, suggesting a fishery sustainability issue that cannot be fully addressed with a substitute for the aquatic mammal bait. It is essential that natural resource managers implement mitigation approaches that consider the socio-economic, cultural, political, and ecological circumstances leading to the use of aquatic mammal bait in each fishery.
Globally, tropical coral reefs are being degraded by human activities, and as a result, reef-building corals have declined while macroalgae have increased. Recent work has focused on measuring macroalgal abundance in response to anthropogenic stressors. To accurately evaluate the effects of human impacts, however, it is necessary to understand the effects of natural processes on reef condition. To better understand how coral reef communities are influenced by natural processes, we investigated how spatial and seasonal changes in environmental conditions (temperature and PAR) influence benthic community structure, and the composition and frequency of coral-algal interactions across eight distinct zones and over a 23-month period at Heron reef on the southern Great Barrier Reef. Hard coral cover and macroalgal density showed distinct spatio-temporal variations, both within and between zones. Broad hard coral cover was significantly higher at the reef slope sites compared to the lagoon and was not significantly influenced by season. The composition and biomass of macroalgae increased in spring and declined in summer, with maximum macroalgal abundance corresponding with average temperatures of between 22 and 24°C and average 24 h PAR of 300–500 μmol qanta m−2 s−1. Changes in macroalgal biomass further influenced the composition and frequency of coral-algal interactions, however the incidence of coral-algal contact was best explained by coral cover. The results presented here emphasize that natural levels of macroalgae and coral-algal interactions are context-specific, and vary not only with-in zones, but in somewhat predictable seasonal cycles. Further, these results emphasize that the frequency of coral-algal interactions is dependent on hard coral, not just macroalgal cover, and an increase in coral-algal interactions does not necessarily translate to degradation of coral reefs.
Biological invasions threaten biodiversity in terrestrial, freshwater and marine ecosystems, requiring substantial conservation and management efforts. To examine how the conservation planning literature addresses biological invasions and if planning in the marine environment could benefit from experiences in the freshwater and terrestrial systems, we conducted a global systematic review. Out of 1,149 scientific articles mentioning both “conservation planning” and “alien” or any of its alternative terms, 70 articles met our selection criteria. Most of the studies were related to the terrestrial environment, while only 10% focused on the marine environment. The main conservation targets were species (mostly vertebrates) rather than habitats or ecosystems. Apart from being mentioned, alien species were considered of concern for conservation in only 46% of the cases, while mitigation measures were proposed in only 13% of the cases. The vast majority of the studies (73%) ignored alien species in conservation planning even if their negative impacts were recognized. In 20% of the studies, highly invaded areas were avoided in the planning, while in 6% of the cases such areas were prioritized for conservation. In the latter case, two opposing approaches led to the selection of invaded areas: either alien and native biodiversity were treated equally in setting conservation targets, i.e., alien species were also considered as ecological features requiring protection, or more commonly invaded sites were prioritized for the implementation of management actions to control or eradicate invasive alien species. When the “avoid” approach was followed, in most of the cases highly impacted areas were either excluded or invasive alien species were included in the estimation of a cost function to be minimized. Most of the studies that followed a “protect” or “avoid” approach dealt with terrestrial or freshwater features but in most cases the followed approach could be transferred to the marine environment. Gaps and needs for further research are discussed and we propose an 11-step framework to account for biological invasions into the systematic conservation planning design.