Scientists have advocated for local interventions, such as creating marine protected areas and implementing fishery restrictions, as ways to mitigate local stressors to limit the effects of climate change on reef-building corals. However, in a literature review, we find little empirical support for the notion of managed resilience. We outline some reasons for why marine protected areas and the protection of herbivorous fish (especially parrotfish) have had little effect on coral resilience. One key explanation is that the impacts of local stressors (e.g., pollution and fishing) are often swamped by the much greater effect of ocean warming on corals. Another is the sheer complexity (including numerous context dependencies) of the five cascading links assumed by the managed-resilience hypothesis. If reefs cannot be saved by local actions alone, then it is time to face reef degradation head-on, by directly addressing anthropogenic climate change—the root cause of global coral decline.
The following titles are freely-available, or include a link to a preprint or postprint.
We present the design and preliminary results from ocean deployments of Zooglider, a new autonomous zooplankton‐sensing glider. Zooglider is a modified Spray glider that includes a low‐power camera (Zoocam) with telecentric lens and a custom dual frequency Zonar (200 and 1000 kHz). The Zoocam quantifies zooplankton and marine snow as they flow through a defined volume inside a sampling tunnel. Images are acquired on average every 5 cm from a maximum operating depth of ~ 400 m to the sea surface. Biofouling is mitigated using a dual approach: an ultraviolet light‐emitting diode and a mechanical wiper. The Zonar permits differentiation of large and small acoustic backscatterers in larger volumes than can be sampled optically. Other sensors include a pumped conductivity, temperature, and depth unit and chlorophyll a fluorometer. Zoogliderenables fully autonomous in situ measurements of mesozooplankton distributions, together with the three‐dimensional orientation of organisms and marine snow in relation to other biotic and physical properties of the ocean water column. It is well suited to resolve thin layers and microscale ocean patchiness. Battery capacity supports 50 d of operations. Zooglider includes two‐way communications via Iridium, permitting near‐real–time transmission of data from each dive profile, as well as interactive instrument control from remote locations for adaptive sampling.
Studying the feeding ecology of seabirds is important not only to understand basic aspects of their ecology and threats but also for the conservation of marine ecosystems. In this regard, tropical seabirds have been relatively neglected, and in particular the trophic ecology of tropicbirds is scarcely known. We combined GPS tracking, environmental variables and sampling of regurgitates during incubation and brooding to understand the feeding ecology of red-billed tropicbirds Phaethon aethereus as well as how foraging strategies may change between 2 contrasting marine environments: a coastal island in the Canary Current upwelling (Îles de la Madeleine) and an oceanic island in the middle of the south Atlantic (St Helena). Tropicbirds breeding on the Îles de la Madeleine headed west, foraging on and beyond the shelf slope, probably to associate with subsurface predators which bring pelagic fish close to the surface. Birds from St Helena showed a greater foraging effort and a strong attraction to areas with the greatest species richness of Scombridae, possibly due to a greater difficulty in finding prey in the oligotrophic oceanic waters. Tropicbirds ranged much beyond the extension of the protected areas around their colonies, indicating that current protected areas are insufficient for these populations. We found no evidence to suspect direct mortality of tropicbirds in regional fisheries, but overexploitation of small epipelagic fish and tuna may decrease feeding opportunities and lead to competition with fisheries. The substantial differences in foraging behaviour demonstrated by individuals from both colonies indicates that caution should be taken when extrapolating foraging patterns of tropical seabirds breeding in contrasting oceanographic environments.
The two stocks of Steller sea lions (Eumetopias jubatus) in Alaska include an endangered western stock, recently recovering in parts of its range following decades of decline, and an eastern stock which was removed from the U.S. Endangered Species List in 2013 following increasing numbers since the 1970s. Information on overlapping distributions of eastern and western sea lions is needed for management considerations. We analyzed >30,000 sightings collected from 2000–2014 of 2,385 sea lions that were branded as pups at 10 Alaskan rookeries to examine mesoscale (mostly <500km) spatial distribution, geographic range, and geographic population structure based on natal rookery, sex, and age during breeding and non-breeding seasons. Analyses of summary movement measures (e.g., natal rookery, sex, and age-class differences in spatial distribution and geographic range) indicate wide variation in rookery-specific movement patterns. Correlations between movement measures and population dynamics suggested movement patterns could be a function of density dependence. Animals from larger rookeries, and rookeries with slower population growth and lower survival, had wider dispersion than animals from smaller rookeries, or rookeries with high growth and survival. Sea lions from the largest rookery, Forrester Island, where survival and population trends are lowest, were the most widely distributed. Analysis of geographic population structure indicated that animals born in the eastern Aleutian Islands had the most distinct movements and had little overlap with other western sea lions. Northern Southeast Alaska, within the eastern stock, is the area of greatest overlap between stocks, and is important to western animals, especially those born in Prince William Sound. Detailed knowledge of distribution and movements of western sea lions is useful for defining recovery and population trend analysis regions that better reflect dispersion and population structure and provides valuable information to managers as critical habitat is re-evaluated and the location of the stock boundary reconsidered.
The Ecosystem Approach in Ocean Planning and Governance takes stock of the challenges associated with implementing an ecosystem approach in ocean governance. In addition to theorizing the notion of Ecosystem Approach and its multifaceted implications, the book provides in depth analyses of lessons learned and remaining challenges associated with making the Ecosystem Approach fully relevant and operational in different marine policy fields, including marine spatial planning, fisheries, and biodiversity protection. In doing so, it adds much needed legal and social science perspectives to the existing literature on the Ecosystem Approach in relation to the marine environment. While focusing predominantly on the European context, the perspective is enriched by analyses from other jurisdictions, including the USA.
Principal approaches to ecosystem-based ocean management in the United States include five major strands: Legislation for EBM, Ecosystem-Based Fisheries Management, Integrated Ecosystem Assessment, Coastal and Marine Spatial Planning and Marine Protected Areas. The presence of multiple strands of action is indicative of a lack of an agreed goal for what ecosystem-based management of the ocean is expected to achieve. It also leads to uncoordinated and sometimes competitive processes that are confusing to ocean users and observers. This paper identifies the principal evolving trends in ecosystem-based approaches in the federal arena in the United States in both sectoral and integrated regional approaches. How these emerging national policies work illustrates how such approaches are generally inadequate to implement EBM.
Due to its dependence on fossil fuel combustion, emissions from the marine transport sector can significantly contribute to air pollution. This work aims to evaluate the impact of maritime transport emissions on air quality in Portugal using a numerical air quality modelling approach, with high-resolution emission data. Emissions from the European TNO inventory were compiled and pre-processed at hourly and high spatial (∼3 × 3 km2) resolutions. Scenarios with and without these maritime emissions were then simulated with the WRF-CHIMERE modelling system, extensively tested and validated for Portugal domain, in order to evaluate their impact on air quality. A simulation was performed for one year (2016) and the resulting differences were analysed in terms of spatial distribution, time series and deltas. The main deltas for NO2 and PM10 are located over international shipping routes and major ports, while O3 concentrations are impacted in a larger area. The modelling results also indicate that shipping emissions are responsible for deltas in the concentration of NO2higher than 20% over specific urban areas located in the west coast of Portugal, and less than 5% for PM10. For O3 the relative contribution is low (around 2%) but this contribution is also observed at locations more than 50 km from the coast.
Resilience underpins the sustainability of both ecological and social systems. Extensive loss of reef corals following recent mass bleaching events have challenged the notion that support of system resilience is a viable reef management strategy. While resilience-based management (RBM) cannot prevent the damaging effects of major disturbances, such as mass bleaching events, it can support natural processes that promote resistance and recovery. Here, we review the potential of RBM to help sustain coral reefs in the 21st century. We explore the scope for supporting resilience through existing management approaches and emerging technologies and discuss their opportunities and limitations in a changing climate. We argue that for RBM to be effective in a changing world, reef management strategies need to involve both existing and new interventions that together reduce stress, support the fitness of populations and species, and help people and economies to adapt to a highly altered ecosystem.
Analysis that link hydrological processes with oceanographic dispersion offer a promising approach for assessing impacts of land-based activities on marine ecosystems. However, such an analysis has not yet been customised to quantify specific pressures from mining activities on marine biodiversity including those from spillages resulting from tailing dam failure. Here, using a Brazilian catchment in which a tailing dam collapsed (Doce river) as a case study, we provide a modelling approach to assess the impacts on key ecosystems and marine protected areas subjected to two exposure regimes: (i) a pulse disturbance event for the period 2015–2016, following the immediate release of sediments after dam burst, which witnessed an average increase of 88% in sediment exports; and (ii) a press disturbance phase for the period 2017–2029, when impacts are sustained over time by sediments along the river's course. We integrated four components into impact assessments: hydrological modelling, coastal-circulation modelling, ecosystem mapping, and biological sensitivities. The results showed that pulse disturbance causes sharp increases in the amount of sediments entering the coastal area, exposing key sensitive ecosystems to pollution (e.g. rhodolith beds), highlighting an urgent need for developing restoration strategies for these areas. The intensity of impacts will diminish over time but the total area of sensitive ecosystems at risk are predicted to be enlarged. We determined monitoring and restoration priorities by evaluating and comparing the extent to which sensitive ecosystems within marine protected areas were exposed to disturbances. The information obtained in this study will allow the optimization of recovery efforts in the marine area affected, and valuation of ecosystem services lost.
The sustainable use of global marine resources depends upon science-based decision processes and systems. Informing decisions with science is challenging for many reasons, including the nature of science and science-based institutions. The complexity of ecosystem-based management often requires the use of models, and model-based advice can be especially difficult to convert into policies or decisions. Here, we suggest five characteristics of model-based information and advice for successfully informing ocean management decision-making, based on the Ocean Modeling Forum framework. Illustrated by examples from two fisheries case studies, Pacific sardines Sardinops sagaxand Pacific herring Clupea pallasii, we argue that actionable model-based output should be aspirational, applicable, parsimonious, co-produced, and amplifying.
Mining impacts will affect local populations to different degrees. Impacts range from removal of habitats and possible energy sources to pollution and smaller-scale alterations in local habitats that, depending on the degree of disturbance, can lead to extinction of local communities. While there is a shortage or even lack of studies investigating impacts that resemble those caused by actual mining activity, the information available on the potential long-lasting impacts of seabed mining emphasise the need for effective environmental management plans. These plans should include efforts to mitigate deep-sea mining impact such as avoidance, minimisation and potentially restoration actions, to maintain or encourage reinstatement of a resilient ecosystem. A wide range of mitigation and restoration actions for deep-sea ecosystems at risk were addressed. From an ecological point of view, the designation of set-aside areas (refuges) is of utmost importance as it appears to be the most comprehensive and precautionary approach, both for well-known and lesser studied areas. Other actions range from the deployment of artificial substrates to enhance faunal colonisation and survival to habitat recreation, artificial eutrophication, but also spatial and temporal management of mining operations, as well as optimising mining machine construction to minimise plume size on the sea floor, toxicity of the return plume and sediment compression. No single action will suffice to allow an ecosystem to recover, instead combined mitigation/restoration actions need to be considered, which will depend on the specific characteristics of the different mining habitats and the resources hosted (polymetallic sulphides, polymetallic nodules and cobalt-rich ferromanganese crusts). However, there is a lack of practical experience regarding mitigation and restoration actions following mining impacts, which severely hamper their predictability and estimation of their possible effect and success. We propose an extensive list of actions that could be considered as recommendations for best environmental practice. The list is not restricted and, depending on the characteristics of the site, additional actions can be considered. For all actions presented here, further research is necessary to fully encompass their potential and contribution to possible mitigation or restoration of the ecosystem.
The offshore and deep-sea marine environment provides many ecosystem services (i.e., benefits to humans), for example: climate regulation, exploitable resources, processes that enable life on Earth, and waste removal. Unfortunately, the remote nature of this environment makes it difficult to estimate the values of these services. One service in particular, waste removal, was examined in the context of the Deepwater Horizon oil spill. Nearly 5 million barrels of oil were released into the offshore Gulf of Mexico, and 14 billion dollars were spent removing about 25% of the oil spilled. Using values for oil spill cleanup efforts, which included capping the wellhead and collecting oil, surface combustion, and surface skimming, it was calculated that waste removal, i.e., natural removal of spilled oil, saved BP over $35 billion. This large amount demonstrates the costs of offshore disasters, the importance of the offshore environment to humans, as well as the large monetary values associated with ecosystem services provided.
The global oil and gas industry holds a vast archive of Remotely Operated Vehicle (ROV) inspection footage potentially containing useful long-term data on marine biological communities. With the upcoming era of decommissioning of oil and gas structures, it is timely to assess the usefulness of this footage for researching these communities. We used ROV inspection footage to characterize the sessile invertebrates and fishes associated with the Goodwyn Alpha Production Platform (GWA) on the North West Shelf of Australia between depths of 10 and 125 m during 2006 and 2008. Depth was a major driver of invertebrate assemblages, most likely due to specific requirements such as light, and differences between years were most likely from the physical detachment of species by cyclones and internal waves. Phototrophic species were mostly limited to the upper 50 m of the platform, including the hard coral Pocillopora sp. and the soft corals Nephthea sp. and Scleronephthya sp. In contrast, heterotrophic species including sponges, anemones, bryozoans, hydroids, bivalves such as Lopha folium and the hard coral Tubastrea spp., were distributed across all depths. We observed 1791 fish from at least 10 families and 19 species, including commercial species such as crimson seaperch (Lutjanus erythropterus), red emperor (L. sebae), saddle-tailed seaperch (L. malabaricus), mangrove jack (L. argentimaculatus) and trevally (Caranx spp.). Fish density increased significantly with depth during 2008, from a mean of 23 fish/50 m2 between 10 and 25 m to 3373 fish/50 m2 at 125 m, where small unidentified baitfish were abundant. The highest densities of commercial species occurred between 25 and 75 m depth, suggesting that mid-depth platform sections had high habitat value, a consideration when selecting decommissioning options. The greatest difficulties using the video were the poor lighting and resolution that inhibited our ability to identify sessile species with high taxonomic precision. However, the footage was useful for evaluating high-level biodiversity of the platform, understanding how fish and invertebrate communities changed with depth and comprehending the dynamic nature of the invertebrate community over time. Understanding the habitat value of structures will be necessary for making environmentally sound decommissioning decisions in the future.
Commercial seabed mining seems imminent, highlighting the urgent need for coherent, effective policy to safeguard the marine environment. Reconciling seabed mining with the United Nations Sustainable Development Goals will be difficult because minerals extraction will have irreversible consequences that could lead to the loss of habitats, species and ecosystems services. A dialog needs to take place around social, cultural, environmental and economic costs and benefits. Governance of human interactions with the seabed is fragmented and lacks transparency, with a heavy focus on facilitating exploitation rather than ensuring protection. In the light of high uncertainties and high stakes, we present a critical review of proposed policy options for the regulation of seabed mining activities, recommend actions to improve seabed governance and outline the alternatives to mining fragile deep-sea ecosystems.
Air-breathing marine animals, such as seals and seabirds, undertake a special form of central-place foraging as they must obtain their food at depth yet return to the surface to breathe. While telemetry technologies have advanced our understanding of the foraging behavior and physiology of these marine predators, the proximate and ultimate influences controlling the diving behavior of individuals are still poorly understood. Over time, a wide variety of analytical approaches have been developed for dive data obtained via telemetry, making comparative studies and syntheses difficult even amongst closely-related species. Here we review publications using dive telemetry for 24 species (marine mammals and seabirds) in the Southern Ocean in the last decade (2006–2016). We determine the key questions asked, and examine how through the deployment of data loggers these questions are able to be answered. As part of this process we describe the measured and derived dive variables that have been used to make inferences about diving behavior, foraging, and physiology. Adopting a question-driven orientation highlights the benefits of a standardized approach for comparative analyses and the development of models. Ultimately, this should promote robust treatment of increasingly complex data streams, improved alignment across diverse research groups, and also pave the way for more integrative multi-species meta-analyses. Finally, we discuss key emergent areas in which dive telemetry data are being upscaled and more quantitatively integrated with movement and demographic information to link to population level consequences.
Three decades following the onset of efforts to revert widespread eutrophication of coastal ecosystems, evidence of improvement of ecosystem status is growing. However, cumulative pressures have developed in parallel to eutrophication, including those associated with climate change, such as warming, deoxygenation, ocean acidification and increased runoff. These additional pressures risk countering efforts to mitigate eutrophication and arrest coastal ecosystems in a state of eutrophication despite the efforts and significant resources already invested to revert coastal eutrophication. Here we argue that the time has arrived for a broader, more comprehensive approach to intervening to control eutrophication. Options for interventions include multiple levers controlling major pathways of nutrient budgets of coastal ecosystems, i.e., nutrient inputs, which is the intervention most commonly deployed, nutrient export, sequestration in sediments, and emissions of nitrogen to the atmosphere as N2 gas (denitrification). The levers involve local-scale hydrological engineering to increase flushing and nutrient export from (semi)enclosed coastal systems, ecological engineering such as sustainable aquaculture of seaweeds and mussels to enhance nutrient export and restoration of benthic habitats to increase sequestration in sediments as well as denitrification, and geo-engineering approaches including, with much precaution, aluminum injections in sediments. These proposed supplementary management levers to reduce eutrophication involve ecosystem-scale intervention and should be complemented with policy actions to protect benthic ecosystem components.
Matrix approaches are useful for linking ecosystem services to habitats that underpin their delivery. Matrix applications in marine ecosystem services research have been primarily qualitative, focusing on 'habitat presence' without including other attributes that effect service potential. We developed an evidence-based matrix approach of Ecosystem Service Potential (ESP) for New Zealand benthic marine habitats, and used two marine reserves to demonstrate that integrating information on the spatial extent and quality of habitats improved ESP evaluation. The two case studies identified substantial spatio-temporal variability in ESP: within one reserve, specific ESP showed an approximately 1.5-fold increase in the 29 years following protection. A comparison of two reserves found that the spatial extent of habitats contributing to the medicinal resources and waste-water treatment were 5 and 53 times greater respectively in one relative to the other. Integrating habitat area and quality with the ESP matrix improves on previous marine matrix-based approaches, providing a better indication of service potential. The matrix approach helps to communicate the non-market value of supporting and regulating services and can be used by resource managers to identify and track the potential for benefits derived from benthic marine habitats within existing, or new, marine protected areas.
Global environmental change has the potential to disrupt well established species interactions, with impacts on nutrient cycling and ecosystem function. On coral reefs, fish living within the branches of coral colonies can promote coral performance, and it has been hypothesized that the enhanced water flow and nutrients provided by fish to corals could ameliorate coral bleaching. The aim of this study was to evaluate the influence of small, aggregating damselfish on the health of their host corals (physiology, recovery, and survival) before, during, and after a thermal-bleaching event. When comparing coral colonies with and without fish, those with resident fish exhibited higher Symbiodinium densities and chlorophyll in both field and experimentally-induced bleaching conditions, and higher protein concentrations in field colonies. Additionally, colonies with damselfish in aquaria exhibited both higher photosynthetic efficiency (FV/FM) during bleaching stress and post-bleaching recovery, compared to uninhabited colonies. These results demonstrate that symbiotic damselfishes, and the services they provide, translate into measureable impacts on coral tissue, and can influence coral bleaching susceptibility/resilience and recovery. By mediating how external abiotic stressors influence coral colony health, damselfish can affect the functional responses of these interspecific interactions in a warming ocean.
Nesting sea turtles appear to avoid brightly lit beaches and often turn back to sea prematurely when exposed to artificial light. Observations and experiments have noted that nesting turtles prefer darker areas where buildings and high dunes act as light barriers. As a result, sea turtles often nest on darker beaches, creating spatial concentrations of nests. Artificial nighttime light, or light pollution, has been quantified using a variety of methods. However, it has proven challenging to make accurate measurements of ambient light at fine scales and on smaller nesting beaches. Additionally, light has traditionally been measured from stationary tripods perpendicular to beach vegetation, disregarding the point of view of a nesting sea turtle. In the present study, nighttime ambient light conditions were assessed on three beaches in central North Carolina: a developed coastline of a barrier island, a nearby State Park on the same barrier island comprised of protected and undeveloped land, and a completely uninhabited wilderness on an adjacent barrier island in the Cape Lookout National Seashore. Using an autonomous terrestrial rover, high resolution light measurements (mag/arcsec2) were collected every minute with two ambient light sensors along transects on each beach. Spatial comparisons between ambient light and nesting density at and between these locations reveal that highest densities of nests occur in regions with lowest light levels, supporting the hypothesis that light pollution from coastal development may influence turtle nesting distribution. These results can be used to support ongoing management strategies to mitigate this pressing conservation issue.
Killer whales have a cosmopolitan distribution and as a species are generalists, feeding on a variety of prey. However, local populations tend to specialise on specific prey types. In Icelandic waters, killer whales are generally associated with herring and, thus, have been presumed to be herring specialists. However, recent studies suggest a more complex foraging ecology, possibly including a mosaic of strategies. With increased observational effort in recent years due to research and whale-watching activities, there have been several reports of interactions with different prey, including confirmed predation events. In this study we aimed to summarise the range of potential prey of killer whales observed in Icelandic waters. We report on 12 previously unpublished accounts and review 15 accounts published in the scientific literature or local newspapers, making a total of 27 events where killer whales were observed interacting with actual or potential prey. Thirteen different species, including birds (n = 1), cephalopods (n = 1), fish (n = 5) and marine mammals (n = 6), are reported, although herring is by far the species that killer whales are most often observed interacting with. This study provides the first summary of actual and suspected killer whale prey in Icelandic waters, and contributes towards our understanding of this population’s prey preferences. However, describing the diet of individuals/groups was not possible and this study points to a need for continued monitoring to understand the intricacies of killer whale foraging behaviour in this area.