With the increasing focus on marine plastic pollution, quantification of the environmental losses of plastics in the world, with differentiation into geographic regions, polymers and loss occurrences along the plastics value chains, is required. In this study, we make a global estimation of the losses of plastics to the environment across the entire plastic value chain, using existing literature and databases coupled with improved and additional methodological modelling of the losses. The resulting loss estimates are unprecedented in their detailed differentiations between polymers (23), plastic applications (13), geographical regions (11), and plastic value chain stages. Comprehensive sensitivity and uncertainty analyses were also conducted to identify key drivers in terms of plastic losses. We overall found that approximately 6.2 Mt (95% confidence interval, CI: 2.0–20.4 Mt) of macroplastics and 3.0 Mt (CI: 1.5–5.2 Mt) of microplastics were lost to the environment in 2015. The major macroplastic loss source was identified as the mismanaged municipal solid waste (MSW) management in low-income and lower-middle income countries (4.1 Mt). For microplastics, the major sources were abrasion of tyre rubbers, abrasion of road markings and plastics contributing to city dust generation. To curb marine plastic pollution, such quantified mapping as ours are needed to evaluate the magnitude of the plastics losses to environment from different sources and locations, and enable a further assessment of their environmental damage. Through our uncertainty and sensitivity analyses, we highlight plastics sources that should be prioritized in further research works to obtain a more comprehensive and accurate representation of global plastics losses.
Ingestion of microplastics (MPs) has been documented in several marine organisms, but their occurrence in deep-sea species remains almost unknown. In this study, MPs were investigated in two economically and ecologically key crustaceans of the Mediterranean Sea, the Norwegian lobster Nephrops norvegicus and the shrimp Aristeus antennatus. Both the species were collected from 14 sites around Sardinia Island, at depths comprised between 270 and 660 m. A total of 89 and 63 stomachs were analysed for N. norvegicus and A. antennatus respectively, and more than 2,000 MPs-like particles were extracted and sorted for identification and characterization by μFT-IR. In N. norvegicus, 83% of the specimens contained MPs, with an average abundance of 5.5 ± 0.8 MPs individual−1, while A. antennatus showed a lower frequency of ingestion (67%) and a lower mean number of MPs (1.66 ± 0.1 MPs individual−1). Composition and size of particles differed significantly between the two species. The non-selective feeding strategy of N. norvegicus could explain the 3–5 folds higher numbers of MPs in its stomach, which were mostly composed of films and fragments derived by polyethylene and polypropylene single-use plastic items. Contrarily, most MPs in the stomachs of A. antennatus were polyester filaments. The MPs abundance observed in N. norvegicus is among the highest detected in Mediterranean species considering both fish and invertebrates species, and provides novel insights on MPs bioavailability in deep-sea habitats. The overall results suggest that both N. norvegicus and A. antennatus, easily available in common fishery markets, could be valuable bioindicators and flagship species for plastic contamination in the deep-sea.
This paper estimates the price changes in global bluefin tuna (BFT) markets in response to shifts in regional and global landings to evaluate the conservation and economic incentives from changes in the Total Allowable Catch (TAC) managed by all three Regional Fisheries Management Organizations. A fisherman’s income, and thus the financial incentive to accept management measures controlling catch levels, depends in part on how responsive price is to overall catch. Individual fisherman, with their own best interest in mind, used to wish to increase their individual landings and create an incentive to ask to increase the TAC for the industry, without realizing the possible revenue loss due to the resulting falling prices. To protect the value of all stakeholders’ property rights, a consensus to avoid abruptly raising the TAC, without first considering the potential loss due to market response, is needed. Alternatively, if revenue increases with lower TAC, a positive economic incentive for conservation is created if price increasing proportionately more than the lower supply, with harvest profits boosted by lower costs of production. To capture the complexity of substituting across various sources of supply and product form, a general synthetic inverse demand system is estimated to identify the impact of overall landings on BFT prices. This system estimates price flexibilities of both fresh and frozen longline-caught sashimi-grade tunas (Pacific, Atlantic and southern bluefins, and bigeye) at the Tokyo Center Market in Japan, including the Tsukiji Market, the world’s largest fish auction market that served as the single global price leader for BFT. The resulting estimation shows that own-quantity price flexibilities of every type of fresh and frozen BFTs are less than unity and inflexible in their own consumption. This creates poor individual producer incentives for fishermen to reduce wild or farmed BFT supply, as there is a chance to increase their own revenue, under the unlikely condition that the total supply is fixed. However, by observing the rapid increases in the TAC of Eastern Atlantic bluefin tuna (EABFT) in the coming years, suppliers may not be better off as price will drop proportionally faster and total revenue if the estimated scale flexibility is greater than one. Based on the estimated scale flexibility of frozen BFT, which is slightly less than unity, the frozen subsector of EABFT suppliers is the only winner under the supply increases. Suppliers of frozen BFT in other regions, fresh BFT (in the Atlantic and elsewhere), and southern BFT and bigeye tuna will all be harmed through lower revenue by the supply increases. Additionally, while total revenue might stay the same for frozen BFT suppliers, fishermen will potentially receive lower profits due to higher operating costs associated with increased landings when the supply of EABFT increases. Given the number of sectors that ultimately lose financially in the short term and given the ecological (and production) risks accompanying an abrupt increase in fishing pressure in the long term, the global economic losses resulting from an increase in the allowable catch of Atlantic bluefin tuna will outweigh any potential increases to revenue.
In this paper, we explore the Polish fishers' perception of marine spatial planning (MSP) processes off the Polish coast. Our research is guided by the radical approach to MSP which, at its centre, places the interplay between MSP actors and their stakes. Our approach certainly considers the relationship of MSP with politics and power, questioning the rational choice. Hence, we have selected fishers as a group which is often recognised as less privileged, with no or little influence on MSP. Firstly, using semi-structured interviews, we investigated the ways in which fishers identify the challenges inhibiting their meaningful participation in MSP. The fishers pointed out data and knowledge gaps as well as a perceived limited agency in decision-making. However, misconceptions about MSP, i.e., equating MSP to off-shore wind farms, appeared to be the most significant short-term challenge. Secondly, through a focus group with MSP planners, we explored what the planners recognised as barriers to the fishers' active participation, and gauged the planners' awareness regarding the problems identified by the fishers. Both groups, fishers and planners, identified similar challenges. The major difference between these two groups was the issue of who should be responsible for addressing the concerns they identified. We conclude that much of the fishers’ reluctance towards MSP stemmed from their negative experiences in previous marine management initiatives, leading to a general lack of trust among the members of this group. We speculate that this lack of trust could have been diminished through a properly implemented stakeholder mapping in the pre-planning phase. However, the schedule stipulated by the EU MSP Directive, i.e., to prepare the plans before early 2021, did not allow the necessary time for the accomplishment of this step. We, thus, postulate that the stakeholder consultation process should be decoupled from formal MSP, and it should be most active in the pre-planning phase.
Hurricanes Irma and Maria, two powerful storms that hit the U.S. Virgin Islands less than 2 weeks apart in September 2017, caused extensive damage to the natural resources on St. John. Damage was particularly severe in a unique mangrove/coral ecosystem in three bays within Virgin Islands Coral Reef National Monument, a National Park Service marine protected area. Many Red Mangrove (Rhizophora mangle) trees were uprooted and tossed into the sea, and the prop roots of others were stripped of corals, sponges and other marine life. No other mangrove area in the Caribbean is known to have so many scleractinian corals (about 30 species before the storms). Although many corals were overturned or buried in rubble, colonies of most of the species, including four that are listed as threatened under the U.S. Endangered Species Act, survived. Recovery of this ecosystem will depend on Red Mangrove propagules becoming established and producing prop roots to support rich marine life along with a canopy to provide the shade that was critical to the biodiversity that was present before the storms. Unlike in many situations where major disturbances reduce coral cover, the substrate that must be restored for full recovery to occur is a living substrate—the prop roots of the mangroves. Larvae of corals and sponges will need to recruit on to the roots. Future storms could hinder this process.
Harvesting wild seaweeds has a long history and is still relevant today, even though aquaculture now supplies >96% of global seaweed production. Current wild harvests mostly target canopy-forming kelp, rockweed and red macroalgae that provide important ecosystem roles, including primary production, carbon storage, nutrient cycling, habitat provision, biodiversity and fisheries support. Harvest methods range from selective hand-cutting to bottom trawling. Resulting ecosystem impacts depend on extraction method and scale, ranging from changes in primary production to habitat disruption, fragmentation, food-web alterations and bycatch of non-target species. Current management often aims for sustainable harvesting in a single-species context, although some agencies acknowledge the wider ecosystem structure, functions and services seaweeds provide. We outline potential ecosystem-based management approaches that would help sustain productive and diverse seaweed-based ecosystems. These include maintaining high canopy biomass, recovery potential, habitat structure and connectivity, limiting bycatch and discards, while incorporating seasonal closures and harvest-exclusion zones into spatial management plans. Other sustainability considerations concern monitoring, enforcement and certification standards, a shift to aquaculture, and addressing cumulative human impacts, invasive species and climate change. Our review provides a concise overview on how to define and operationalize ecosystem-based management of seaweed harvesting that can inform ongoing management and conservation efforts.
Biological fouling organisms on fish cages represent a major issue and costly factor in marine finfish aquaculture. Cnidarians have been identified as one of the most problematical groups, contributing significantly to the occlusion and structural stress of the cage nets, but also dramatically affecting farmed species health in aquaculture facilities worldwide. Recently, significant relationships were established in different Spanish aquaculture facilities between hydrozoans and juvenile fish affected by gill injuries and mortality episodes. Community composition, growth rate and reproductive potential of biofouling were monitored on fish cages over two seasonal periods of fry cages farming, located in southern Spain (SW Alboran Sea), with a special focus on cnidarians. Biomass and community composition of biofouling changed with time and between studied periods, with a marked seasonality in colonization periods and taxonomic composition, particularly for the colonial hydrozoans. The hydroids Ectopleura larynx and Pennaria disticha were found at the highest densities. P. disticha was responsible for major biomass contribution to total hydroid biomass with the fastest growth rates. In addition, actinulae larvae of E. larynx were identified in zooplankton samples at high densities especially during periods of fry introduction in sea cages (when fish are highly vulnerable). These results corroborate evidence of the detrimental influence of fouling cnidarians in Mediterranean finfish aquaculture due to a direct harmful impact on fish health. Investigations on population dynamics, reproductive biology and envenomation potential of fouling hydrozoans should be regarded as key component of best monitoring practices to ensure good farmed fish welfare, maximization of aquaculture production and overall marine spatial planning.
The Arctic is a complex geographical area to govern sustainably due to strong geopolitical and socio-economic interests, high ecological vulnerability and importance, and significant legal and institutional fragmentation. Intensifying human pressures in this area necessitate an ecosystem-based and adaptive governance approach, an approach that enables managing socio-ecological resilience in the Arctic. As the Arctic is a large geographic area crossing multiple national jurisdictions and maritime zones, including high seas areas, regionally coordinated and coherent governance approaches would be desirable. This paper assesses the status quo for ecosystem-based governance (EBG) in the Arctic, suggests a focus on three core components of EBG, and proposes three forms of legal coherence to foster these core components. The paper concludes with examining what role the Arctic Council plays and could play to strengthen EBG in the Arctic.
Effective marine spatial planning (MSP) requires evidence-based decision-making processes in order to achieve sustainable use of marine resources and ecosystem services. In accordance with this purpose, decision support tools (DSTs) were used as the primary assistant of planners and managers. As a further step of existing review efforts on DSTs, this research aimed to add value to current knowledge by capturing end user opinions on their applications in MSP processes. For this purpose, perceptions and experiences on tools were acquired using an inclusive questionnaire. In total, 92 MSP experts were reached from 28 countries to collect information on: (i) DST users’ profile; (ii) the contribution of tools in MSP implementation processes, (iii) user opinions and experiences; and (iv) their expectations to draw recommendations and to give insights for future developments. Results revealed that developers should keep tool-user interaction from development to application stage and focus on a publicly accepted MSP working flow. Besides, new efforts on environmental data collection are needed to enable ecosystem-based approach in MSP. Hereby, this research analysed end user perceptions and opinions on DSTs, and it concludes that users require tools providing multi-functionality, integrity and ease of use.
Small Island Developing States (SIDS) are often burdened with high electricity prices whilst being bestowed with excellent wind resources. Wind energy is the most proven of the modern renewable energy technologies and, in areas with a good resource, is often the cheapest form of electricity generation. Many small island states have yet to tap into their wind energy potential. Using the Caribbean island of Barbados as a case study, this paper applies basic engineering processes and a spatial planning methodology to determine an island's maximum potential installed wind capacity. In order to encourage repeated studies for other islands, publicly available global historical hourly weather data is identified and forms part of a technical assessment to estimate the expected annual energy yield. The paper highlights the complexities of wind energy development on small islands when compared with mainland countries and explores the key factors that are to be addressed if SIDS are to make use of their wind resource. Economic analysis of the expected annual energy yield for Barbados predicts a levelized cost of energy (LCOE) for wind of 0.13 US$/kWh (±0.01 US$/kWh), which compares favourably with other forms of generation that are an option for the island.
The southern California rock crab fishery targets stocks comprised of three species: red (Cancer productus), yellow (Metacarcinus anthonyi), and brown rock crab (Romaleon antennarium). Fishers have expressed concern about the sustainability of the fishery due to increased fishing effort over the past decade, and because it is managed as one assemblage despite distinct life history differences among the species. We collaborated with fishers to test for stock-specific declines in key fishery-dependent indicators by replicating a 2008 study in 2016–2017 and comparing indicator values between years using multiple regression techniques. Indicators included spatially explicit species-level data for size, catch-per-unit-effort (CPUE), discard rate, sex composition, and trap location and depth across the heavily fished Santa Barbara Channel and Northern Channel Islands. Results showed significant declines in male size, overall CPUE, and proportion of crab landed versus discarded for heavily targeted stocks, translating to fewer pounds per trap and potential financial losses for fishers. Fishing and environmental conditions may have both contributed to stock declines. Evidence of decline differed substantially across space, species, and sex. We suggest that a spatially explicit and adaptive approach to empirically managing southern California rock crab may help to protect fishers from financial loss and avoid continued depletion of certain stocks, and we show that relatively simple collaborative approaches can provide defensible insight into complex systems.
Mangroves, one of the major coastal ecosystems of tropical and subtropical regions, are critical habitats for fish and crustaceans, and provide a number of ecosystem services to people. While mangrove uses have been widely documented based on local ecological knowledge, seldom has this approach been used to analyse the mangrove-fishery relationship. By conducting semi-structured interviews (n = 82) with fishers in three different villages surrounding the Ciénaga Grande de Santa Marta, the most important lagoon system in the Colombian Caribbean because of its size and productivity, we evaluated fishing activity over time, mangrove use and mangrove-fishery linkage, and fishing and gear spatial distribution. Respondents believed that mangroves are critical habitats for fishery resources because they function as nurseries, food source and reproduction areas, and considered that the resource would be in jeopardy in the absence of mangroves. While fishing is the main activity in mangroves, they are also used for firewood, construction and to make fishing gear, but how fishers use mangroves varies across villages. Fishing is concentrated close to mangroves (<20 m) and fishers' villages though there was some gear and species-dependent spatial variation across villages. Given that the system is highly degraded and conservation and fishery management plans are urgently required, we suggest combining scientific with local ecological knowledge in the planning and implementation of restoration and conservation plans to increase the chances of such programs being successful.
Discard has long been recognized a serious problem in the world’s oceans affecting not only the non-target species but also entire trophic food chain and habitats thus disrupting marine ecosystem functioning. Due to global declines, species of conservation interest (e.g. sharks, rays, turtles, dolphins) which are crucial for maintaining a healthy ecosystem have become a focus of marine conservation in recent years. Although effort has been made to elucidate the historical trends of discards and, its effects on the marine fisheries worldwide, most of these are based on the data-rich developed countries. This has been largely unexplored in many of the developing countries such as Bangladesh, especially for industrial marine fisheries. Here in this study, we tried to fill this knowledge gap using discard data collected from the bottom and mid-water freezer trawler from the marine water of Bangladesh in the Bay of Bengal. It was revealed that both the bottom and mid-water trawling has the similar level of effect on the number of total discarded species of conservation interest (SOCI) although the number of shark discard was significantly higher in bottom trawling. The historical reconstruction of total discards of SOCI from freezer trawler suggests an increase of over six times between 1990 and 2014. The increasing number of trawls (both in the bottom and mid-water trawl) and the increase in the speed at bottom trawling both have a significant negative effect on SOCI especially shark. We suggest a strong implementation of existing laws, increasing the capacity of surveillance and the monitoring systems as well as improved technological fix such as gear modification can substantially lower the discarded bycatch from Bangladesh marine water.
Alternative livelihood projects are criticised as having minimal effect on biodiversity conservation. Studies are rare and where success is claimed, outcomes and reasons why projects work, have not been documented. Livelihoods are an essential element of sustainable integrated coastal management, an accepted framework for conserving coral reefs and marine resources in the tropics. It is not known whether alternative livelihood projects contribute to the goal of improving biodiversity conservation through sustainable integrated coastal management. Here, we examine Oslob Whale Sharks, an alternate livelihoods project in the Philippines built on provisioning whale sharks for community based dive tourism. We investigate how Oslob Whale Sharks contributes to sustainable integrated coastal management and whether it has any effect on biodiversity conservation. Using key stakeholder interviews with artisanal fishers, their community, local politicians and government, we found that Oslob Whale Sharks contributes to all nine factors required for sustainable integrated coastal management. Fishers and local authorities report their perception that whale sharks are protected from poaching and finning and destructive fishing has decreased, while fish abundance, pelagic fish species and catch have increased. Our findings further suggest that as there is little evidence that this type of tourism has any negative impacts on the biology or behaviour of whale sharks, Oslob Whale Sharks provides sustainable livelihoods and a delivery mechanism for sustainable integrated coastal management.
The objective of this study is to investigate the impact of the projected sea-level rise to the coastal land use/land cover (LULC) at a disaster-prone coastal area, encompassing an engineering time-scale, based on a couple of sea-level rise scenarios. We investigate the Banda Aceh coast, a low-lying coastal area vulnerable to multiple hazards such as tsunamis and co-seismic land subsidence, which is typical along the Indonesian coastlines. Three sets of multi-temporal Google Earth Engine images acquired in 2004 (pre-tsunami December 2004), 2011 and 2017 were utilized to obtain the areal coverage of various types of LULC. The scenarios of coastal inundation were pre-determined at elevation +1.0 m and +1.5 m projecting the sea-level rise in the next couple centuries. Aquaculture ponds, buildings and bare land are the top three most pre-dominant land covers in Banda Aceh coast. The finding of this study reveals that the aquaculture ponds are at the highest risk to the future sea-level rise, and potentially contribute to the unproductive seawater inundated area. The bare land which has a huge potential to be converted into settlement area (buildings, housing, etc.), experienced remarkable loss due to both future inundation scenarios. The coastal area of Banda Aceh in the next couple of centuries, thus, will be highly vulnerable to the projected sea-level rise, providing the fast-growing and ever-expanding built environment very close to the coastline. A sustainable coastal management taking into account the disaster risk should, therefore, be incorporated within the decision making for the protection of the coastal area.
Sea-level rise is a highly publicized issue in the Hawaiian Islands because it is one of the main drivers for coastal hazards. In our study, multiple geodetic and in situ datasets are integrated to investigate the sea-level rise and vertical land motion on the islands of Oahu and Hawaii, Hawaii. The rates of relative sea-level changes are derived from the tide-gauge stations in the Hawaiian Islands, however the station located at Kawaihae, Hawaii presents a much higher trend than other stations. Our analysis shows that the questionable trend results from the sudden movement of the equipment on land, which is caused by a pair of earthquakes. After adjustment, we arrive at a revised and more consistent relative sea-level trend at this station. Our study shows that Oahu is vertically ‘stable’ (i.e., near-zero vertical land movement within uncertainties), and the relative sea-level change is dominated by the absolute sea-level change. However, the island of Hawaii was subsiding at -3.3±0.9 mm/year before 1973 and changed to -1.2±0.2 mm/year after 1975, which may relate to seismic activities and where relative sea-level change is attributed to both absolute sea-level change and vertical land motion. The difference in relative sea-level change between the islands of Oahu and Hawaii is due to the difference in vertical land motion rather than steric sea-level change. In addition, the ocean-mass components are the predominant factors that influence the long-term trends of absolute sea level on the islands of Oahu and Hawaii.
Shellfish aquaculture in the United States contributes to the global seafood supply, provides habitat and restoration opportunities, and enhances the economic sustainability of coastal communities. Most marine aquaculture production (two-thirds by value) in the United States comprises bivalve shellfish (oysters, clams, and mussels). As the marine aquaculture footprint grows, so too does the potential for negative environmental and space–use interactions. To streamline shellfish aquaculture permitting, many states have developed web-based aquaculture map viewers to communicate critical regulatory, space–use, and natural resource information. In this study, 18 state-level shellfish aquaculture map viewers were reviewed for common design approaches, important data considerations, and useful tools and functions. Key characteristics of a successful shellfish aquaculture map viewer include a user-friendly interface, instructional guidance, the ability to assess both opportunity and risk, inclusion of authoritative data, and a long-term maintenance plan for the viewer and data. The most common design approaches reviewed were Esri Web AppBuilder and Google. Viewers ranged from having 3–27 layers, with “view orthoimagery” (94%) as the most commonly occurring function. This review provides valuable information on using map viewers and technological innovation to communicate shellfish aquaculture planning and permitting information to a variety of stakeholders.
The framework proposed by Ostrom (2009) has become one of the most utilized tools to address the complexity of social-ecological systems. Most cases use this framework to analyze the systems from the perspective of a single resource unit. However, the livelihoods in several coastal communities are diverse, so that the users interact with multiple common-pool resources, which makes their analysis difficult. In this sense, it is important to identify the key elements of management to achieve the sustainable use of the resources. In this study, we were able to do this in a coastal community where commercial fishing, ecotourism, and recreational fishing coexist. The system of interest, located in the state of Quintana Roo, Mexico, was subdivided by resource type using a multi-method approach to data collection including surveys, interviews, and records review. A conceptual map was developed that shows how the second-tier variables are integrated through the governance and actors with the biophysical system. The actors involved in lobster fishing achieved a more complex governance system, followed by the ecotourism and recreational fishing; the complexity of the governance was related with the equity level of the actors. The analysis revealed the research gaps to develop management strategies and improve the sustainability of the system.
Microplastic fibers represent a significant share of the global marine micrcroplastic pollution, particularly in coastal areas. In controlled laboratory experiments, we offered fluorescent microplastic fibers (40–4400 μm lengths, median 150 μm) and spherical microplastic beads (9.9 μm Ø) together with commercial fish food to the Atlantic ditch shrimp Palaemonetes varians. The shrimps ingested fibers and beads along with the food. Upon ingestion, the beads and the shortest fibers (up to 100 μm) passed from the stomach into the gut and were egested within the fecal strings. The longer fibers first remained in the stomach but were regurgitated, i.e. extruded through the esophagus, within 12–14 h. Regurgitation is an evolutionary adaptation of particular crustacean species and other invertebrates to remove large and indigestible food particles from the stomach. Accordingly, the process of regurgitation attained a new task nowadays, i.e. the elimination of anthropogenic filamentous microplastic debris from the stomach to avoid harm. This behavioral feature may represent a selective advantage in view of the continuously increasing environmental plastic pollution.
Marine spatial planning (MSP) has been put forward as a way to more comprehensively manage marine environments by balancing human demands and protecting areas that support ecosystem function. Given the recent motivations for countries to adopt large-scale marine spatial planning approaches, ensuring these plans are grounded in social-ecological resilience theories is essential for long-term success. Drawing upon recent academic attention from a range of disciplinary areas, this review explores current practices and applied examples of published case studies from around the world that have integrated social and ecological spatial information using GIS techniques. This review intended to use these case studies to guide directions of future MSP research that considers social-ecological resilience theories. Five overall themes were uncovered. First, extractive uses, such as fisheries, were often given priority in MSP processes, which even though important, may undermine the social resilience of coastal communities by not supporting the diversity of non-extractive economies. Second, the quality of ecological spatial data used in the studies varied greatly, often with little consideration of how ongoing human demands may influence long-term ecological resilience. Thrid, many GIS techniques were used to integrate social and ecological data including: descriptive maps, site prioritisation techniques, and predictive modelling. Lastly, only a small number of studies considered cross-ecosystem influences and only two incorporated potential climate change impacts on social institutions and marine ecosystems. Overall, there is a need for progressing GIS predictive modelling techniques to assess and link the responses of social and ecological systems to MSP solutions in order to support long-term social-ecological resilience.