Oceanographic features, such as eddies and fronts, enhance and concentrate productivity, generating high-quality patches that dispersive marine larvae may encounter in the plankton. Although broad-scale movement of larvae associated with these features can be captured in biophysical models, direct evidence of processes influencing survival within them, and subsequent effects on population replenishment, are unknown. We sequentially sampled cohorts of coral reef fishes in the plankton and nearshore juvenile habitats in the Straits of Florida and used otolith microstructure analysis to compare growth and size-at-age of larvae collected inside and outside of mesoscale eddies to those that survived to settlement. Larval habitat altered patterns of growth and selective mortality: Thalassoma bifasciatum and Cryptotomus roseus that encountered eddies in the plankton grew faster than larvae outside of eddies and likely experienced higher survival to settlement. During warm periods, T. bifasciatum residing outside of eddies in the oligotrophic Florida Current experienced high mortality and only the slowest growers survived early larval life. Such slow growth is advantageous in nutrient poor habitats when warm temperatures increase metabolic demands but is insufficient for survival beyond the larval stage because only fast-growing larvae successfully settled to reefs. Because larvae arriving to the Straits of Florida from distant sources must spend long periods of time outside of eddies, our results indicate that they have a survival disadvantage. High productivity features such as eddies not only enhance the survival of pelagic larvae, but also potentially increase the contribution of locally spawned larvae to reef populations.
We review the state of knowledge of the individual and community responses of euthecosome (shelled) pteropods in the context of global environmental change. In particular, we focus on their responses to ocean acidification, in combination with ocean warming and ocean deoxygenation, as inferred from a growing body of empirical literature, and their relatively nascent place in ecosystem-scale models. Our objectives are: (1) to summarize the threats that these stressors pose to pteropod populations; (2) to demonstrate that pteropods are strong candidate indicators for cumulative effects of OA, warming, and deoxygenation in marine ecosystems; and (3) to provide insight on incorporating pteropods into population and ecosystem models, which will help inform ecosystem-based management of marine resources under future environmental regimes.
Information on the movements and population connectivity of the oceanic manta ray (Manta birostris) is scarce. The species has been anecdotally classified as a highly migratory species based on the pelagic habitats it often occupies, and migratory behavior exhibited by similar species. As a result, in the absence of ecological data, population declines in oceanic manta have been addressed primarily with international-scale management and conservation efforts. Using a combination of satellite telemetry, stable isotope and genetic analyses we demonstrate that, contrary to previous assumptions, the species appears to exhibit restricted movements and fine-scale population structure. M. birostris tagged at four sites in the Indo-Pacific exhibited no long-range migratory movements and had non-overlapping geographic ranges. Using genetic and isotopic analysis, we demonstrate that the observed movements and population structure persist on multi-year and generational time scales. These data provide the first insights into the long-term movements and population structure of oceanic manta rays, and suggest that bottom-up, local or regional approaches to managing oceanic mantas could prove more effective than existing, international-scale management strategies. This case study highlights the importance of matching the scales at which management and relevant ecological processes occur to facilitate the effective conservation of threatened species.
Coral reefs are highly productive shallow marine habitats at risk of degradation due to CO2-mediated global ocean changes, including ocean acidification and rising sea temperature. Consequences of coral reef habitat loss are expected to include reduced reef fisheries production. To our knowledge, the welfare impact of reduced reef fish supply in commercial markets has not yet been studied. We develop a global model of annual demand for reef fish in regions with substantial coral reef area and use it to project potential consumer surplus losses given coral cover projections from a coupled climate, ocean, and coral biology simulation (CO2-COST). Under an illustrative high emission scenario (IPCC RCP 8.5), 92% of coral cover is lost by 2100. Policies reaching lower radiative forcing targets (e.g., IPCC RCP 6.0) may partially avoid habitat loss, thereby preserving an estimated $14 to $20 billion in consumer surplus through 2100 (2014$ USD, 3% discount). Avoided damages vary annually, are sensitive to biological assumptions, and appear highest when coral ecosystems have moderate adaptive capacity. These welfare loss estimates are the first to monetize ocean acidification impacts to commercial finfisheries and complement the existing estimates of economic impacts to shellfish and to coral reefs generally.
Coastal “blue carbon,” (carbon sequestered in salt marsh, mangroves, and seagrasses) is a newly recognized benefit. The National Oceanic and Atmospheric Administration (NOAA), with partners, has been exploring and developing new policy opportunities for coastal conservation using the climate benefits of these ecosystems. We detail NOAA's efforts (federal and international, market and non-market) to leverage blue carbon for coastal conservation including: (1) how blue carbon is or could be incorporated into U.S. federal policies (both existing and new policy activities); (2) market-based policy solutions including the development of a Verified Carbon Standard methodology for carbon credits for wetland restoration and two landscape assessments of the climate mitigation benefits of watershed-scale restoration; and (3) international efforts to build a North American community of practice for blue carbon science and policy with the Commission for Environmental Cooperation, Canada, and Mexico, and an assessment of where blue carbon can be incorporated into international policy frameworks (including the Intergovernmental Panel on Climate Change (IPCC) Wetlands Supplement and the United Nations Framework Convention on Climate Change (UNFCCC)). Protecting coastal carbon leads to co-benefits including resilience to storms and erosion, and fishery benefits, thus blue carbon is a “triple win” for climate mitigation, adaptation, and conservation.
The knowledge of fisheries features in emerging markets is an essential step to identify gaps in the management and opportunities for socio-economic development. Mediterranean coastal area of Egypt is subjected to a high level of anthropogenic pressure due to fishing activities and bottom trawling is considered as the most important as well as troubling fisheries, for the impact exerted on the bottom communities. In this context, the knowledge of fleet composition, technical properties of fishing gears and vessels, catch composition and distribution of vessels along the coast are considered as key factors for fisheries management and for the introduction-development of new technology and market opportunities. In this study, an overview of the fishing activities in Egypt, with a focus on the bottom trawling was carried out to provide fisheries managers with information suitable for the development of reliable technical measures. A SWOT analysis based on technical information gathered with direct measurement, interviews with net makers-fishermen and official data collected from the Egyptian General Authority for Fish Resources Development, enabled to explore current constraints and future possibilities for the fishing sector in Egypt. Technical information also allowed to develop a model which enabled to estimate the area swept by bottom trawling. The results obtained from the model show that potentially an area of more than 40 km2/h can be impacted by the Egyptian fleet in the Mediterranean. This model can be considered as a cheap tool to be used by fisheries managers for a rough estimation of bottom trawl impact and for a reasonable marine spatial planning.
Governance across the land-sea interface is an emerging challenge. The propensity for, and intensity of social-ecological interactions across this interface (e.g., eutrophication, sedimentation) are being exacerbated by cross-system threats (e.g., climate change). We draw on a systematic review of 151 peer-reviewed papers on governance and land-sea connections to (1) outline the current state of the literature, (2) examine the predominance of different approaches to address land-sea interactions, (3) characterize how governance is conceptualized within these approaches, (4) investigate governance challenges, and (5) provide insights into effective governance. The review finds that the number of relevant papers published per year has generally been increasing, and most of these papers are found in interdisciplinary journals. Ecosystem-based management is the most predominant approach found in the literature as a means to address land-sea interactions. Papers referring to ecosystem-based management are more likely than those referring to alternative management approaches (e.g., integrated management) to highlight science-policy integration and the need to account for interactions between ecosystem components as elements of effective governance. The main governance challenges include determining boundaries, addressing cross-scale effects, and accessing knowledge. However, few empirical studies of governance across the land-sea interface have been completed. A richer conceptual framework of governance is required to improve our ability to navigate the rapid social and environmental change occurring across the land-sea interface.
Optimization of the layouts of arrays of wave energy converters (WECs) is a challenging problem. The hydrodynamic analysis and performance estimation of such systems are performed using semi-analytical and numerical models such as the boundary element method. However, the analysis of an array of such converters becomes computationally expensive, and the computational time increases rapidly with the number of devices in the system. As such determination of optimal layouts of WECs in arrays becomes extremely difficult. In this paper, a methodology involving multiple optimization strategies is presented to arrive at the solution to the complex problem. The approach includes a statistical emulator to predict the performance of the WECs in arrays, followed by an innovative active learning strategy to simultaneously explore and focus in regions of interest of the problem, and finally a genetic algorithm to obtain the optimal layouts of WECs. The method is extremely fast and easily scalable to arrays of any size. Case studies are performed on a wavefarm comprising of 40 WECs subject to arbitrary bathymetry and space constraints.
This report explains the information sources and analysis underlying Eunomia’s marine plastics infographic, Where do they come from? Where do they go?
A multi-site, multi-device and multi-criteria decision support tool designed to support the development of tidal current energy in the Philippines was developed. Its platform is based on Geographic Information Systems (GIS) which allows for the collection, storage, processing, analyses and display of geospatial data. Combining GIS tools with open source web development applications, it becomes a webGIS-based marine spatial planning tool. To date, the webGIS-based tool displays output maps and graphs of power and energy density, site suitability and site-device analysis. It enables stakeholders and the public easy access to the results of tidal current energy resource assessments and site suitability analyses. Results of the initial development showed that it is a promising decision support tool for ocean renewable energy project developments.