Microplastics (plastics <5 mm diameter) are at the forefront of current environmental pollution research, however, little is known about the degradation of microplastics through ingestion. Here, by exposing Antarctic krill (Euphausia superba) to microplastics under acute static renewal conditions, we present evidence of physical size alteration of microplastics ingested by a planktonic crustacean. Ingested microplastics (31.5 µm) are fragmented into pieces less than 1 µm in diameter. Previous feeding studies have shown spherical microplastics either; pass unaffected through an organism and are excreted, or are sufficiently small for translocation to occur. We identify a new pathway; microplastics are fragmented into sizes small enough to cross physical barriers, or are egested as a mixture of triturated particles. These findings suggest that current laboratory-based feeding studies may be oversimplifying interactions between zooplankton and microplastics but also introduces a new role of Antarctic krill, and potentially other species, in the biogeochemical cycling and fate of plastic.
Large pelagic fishes are assessed and managed by tuna Regional Fisheries Management Organizations (tRFMOs). These organizations have been criticized for not meeting conservation objectives, which may relate to aspects of governance and management. No previous studies have systematically evaluated why management performance differs among tRFMOs and among stocks within each tRFMO. In this study, we collected data on the nature of research, management, enforcement and socioeconomics of management systems in the five principal tRFMOs of the world's oceans. We quantified influences of economic and fishery‐related factors on these management characteristics and examined how these factors vary among tRFMOs. We found that tRFMOs with a greater number of member countries, a greater economic dependency on tuna resources, a lower mean per capita gross domestic product, a greater number of fishing vessels and smaller vessels were associated with less intensive research, management and enforcement in these tuna fisheries. We also quantified the influence of specific management attributes and of biological, economic and fishery‐related factors on the trends and current status of large pelagic fish stocks in these regions. The most important factors correlated with trends and current stock status were external to the management systems, and included stock size, age at maturity, ex‐vessel price and economic dependency of countries on tuna fisheries. To improve the overall status of large pelagic fish stocks in the global high seas, more intensive data collection, research and management are needed in certain areas, especially in the Indian Ocean, and for certain stocks, especially non‐target species.
This paper aims to highlight the risk of climate change on coupled marine human and natural systems and explore possible solutions to reduce such risk. Specifically, it explores some of the key responses of marine fish stocks and fisheries to climate change and their implications for human society. It highlights the importance of mitigating carbon emission and achieving the Paris Agreement in reducing climate risk on marine fish stocks and fisheries. Finally, it discusses potential opportunities for helping fisheries to reduce climate threats, through local adaptation. A research direction in fish biology and ecology is proposed that would help support the development of these potential solutions.
The Atlantic seabob (Xiphopenaeus kroyeri) trawl fishery is very important to Guyana, with 88 licensed industrial vessels harvesting about 15,000 mt annually, representing Guyana’s most valuable seafood export. All vessels are already using both teleost by—catch reduction devices (BRDs) and turtle excluder devices (TEDs) to satisfy international market standards. However, the key stakeholder, the Guyana Association of Private Trawler Owners and Seafood Processors, is now seeking to access sustainable seafood markets through pursuing Marine Stewardship Council (MSC) certification. To this end, this study documents elasmobranch by—catch in the current fishery and examines the effectiveness of a modified TED (with a reduced bar spacing and the addition of a brace bar) in reducing elasmobranch by—catch. From July—August 2014, 131 tows were made, 80 of which represented simultaneous hauls with control and modified TEDs. One shark and 8 ray species were recorded. A statistically significant 40% decline in the elasmobranch catch rate was observed when using modified TEDs compared with control TEDs (mean by—catch rate dropped from 2.3 to 1.4 individuals per twin—trawl/h). Furthermore, modified TEDs significantly reduced the mean size of rays caught by 6.3%. This also resulted in a virtual elimination of 3 IUCN—designated 'Near Threatened' ray species in the by—catch, although having little effect on the capture of small—sized elasmobranch species, including the 'Critically Endangered' Caribbean Electric Ray (Narcine bancroftii). We conclude that the modified TED was successful in reducing the by—catch of vulnerable elasmobranch species and should advance progress towards attaining by—catch standards required for MSC certification.
Plastic marine debris is increasingly recognised as one of the greatest threats to global oceans, and the humans who depend on them. This study documents plastic ingestion in 24 species caught or sold for human consumption in the South Pacific. Fish were collected from local fishermen and markets in remote locations, including French Polynesia, Lord Howe Island and Henderson Island (Pitcairn group). Gastrointestinal tracts of 126 fish were visually examined and plastic was found in 7.9% of individual fish and 25% of species. The plastics were mostly microplastics (fragments, nurdles and rope). There was no significant difference in plastic ingestion in relation to feeding style, length, region or species. This is concerning as plastic appears to be widespread across species, lifestyles and habitats. This is the first report of plastic in South Pacific fish, raising concerns about the transfer of pollutants in a region that is largely oceanic and heavily dependent on seafood. The remote locations of the study also provide evidence of the widespread nature of this issue.
With its never-ending blue color, the underwater environment often seems monotonic and featureless. However, to an animal with polarization-sensitive vision, it is anything but bland. The rich repertoire of underwater polarization patterns—a consequence of light’s air-to-water transmission and in-water scattering—can be exploited both as a compass and for geolocalization purposes. We demonstrate that, by using a bioinspired polarization-sensitive imager, we can determine the geolocation of an observer based on radial underwater polarization patterns. Our experimental data, recorded at various locations around the world, at different depths and times of day, indicate that the average accuracy of our geolocalization is 61 km, or 6 m of error for every 1 km traveled. This proof-of-concept study of our bioinspired technique opens new possibilities in long-distance underwater navigation and suggests additional mechanisms by which marine animals with polarization-sensitive vision might perform both local and long-distance navigation.
Fishermen seek to maximize profits so when choosing where to fish, they must consider interactions among the environment, costs, and fish prices. We examined catcher vessels in the U.S. Bering Sea fishery for walleye pollock (2003- 2015) to characterize fisher responses to environmental change (e.g., abundance and water temperature). When pollock were abundant and water warm, the fleet fished in similar locations. When temperatures were cooler or pollock abundance declined, two fishing strategies emerged, depending on the processor where a vessel delivered. One vessel group, whose catches were more likely to become fillets, often made shorter trips, requiring less fuel and time at-sea. A second vessel group, whose catches were more likely to become surimi, traveled farther from port, to regions with higher catch rates but generally smaller fish. By fishing in different locations to satisfy different markets, the fleet sustained revenues and buffered against environmental change. We identify a suite of socioeconomic indicators of the impacts of ecosystem change and illustrate that a one-vessel-fits-all approach may be insufficient for assessing the resilience of fleets.
Despite the devastating impact of the lionfish (Pterois volitans) invasion on NW Atlantic ecosystems, little genetic information about the invasion process is available. We applied Genotyping by Sequencing techniques to identify 1,220 single nucleotide polymorphic sites (SNPs) from 162 lionfish samples collected between 2013 and 2015 from two areas chronologically identified as the first and last invaded areas in US waters: the east coast of Florida and the Gulf of Mexico. We used population genomic analyses, including phylogenetic reconstruction, Bayesian clustering, genetic distances, Discriminant Analyses of Principal Components, and coalescence simulations for detection of outlier SNPs, to understand genetic trends relevant to the lionfish’s long-term persistence. We found no significant differences in genetic structure or diversity between the two areas (FSTp-values > 0.01, and t-test p-values > 0.05). In fact, our genomic analyses showed genetic homogeneity, with enough gene flow between the east coast of Florida and Gulf of Mexico to erase previous signals of genetic divergence detected between these areas, secondary spreading, and bottlenecks in the Gulf of Mexico. These findings suggest rapid genetic changes over space and time during the invasion, resulting in one panmictic population with no signs of divergence between areas due to local adaptation.
Marine and coastal tourism as one of the largest segments of the maritime economy sector, as well as the largest component of the tourism industry, often leads to controversy over environmental impact and compatibility with other human activities. The application of economic and tourism concepts that are oriented towards environmental conservation and natural resources is one option to overcome the problem. The Blue Economy concept offers an economic concept based on ecosystem principles, where the development will not only generate economic growth but also ensure ecological and social sustainability. In addition, the concept of ecotourism also offers a tourism activity that prioritizes aspects of nature conservation and improving the welfare of the community
Ecosystems services (ES) provide food and recreation to humans, but are fast being degraded. Marine Protected Areas (MPAs) have been proposed as a way to protect some of these ES, but decisions regarding what gets protection and what gets consumed can be a source of conflicts. One such example is the Fernando de Noronha MPA (Brazil), where there is a conflict between shark-directed tourism and fishers who would like to access the no-take part of the MPA during part of the year. A contingent valuation method (Willingness to Pay) was used to ascertain if tourists would accept compensating fishers for not disturbing the sharks during a specific period of the year, by adding a symbolic increase in the taxes they already pay to either visit the island or to visit the no-take part of the MPA. Tourists were open to this alternative (67–71%), regardless of the fee being paid. However, there was a slight tendency to reject the fee when the tourists saw sharks during their stay, suggesting that a closer contact with these animals triggered a less sympathetic attitude towards fishers, probably because they start seeing fishers as wrongdoers, even if this is the worst choice for conservation. Although such a hypothetical payment was easily accepted by the majority of the tourists and could represent an affordable solution to conflicts, convincing those who reject such social compensation, especially if based on an irrational choice, would be an important step for sharks and for the MPA as a whole.
Coverage of issues by news media is known to impact on both public perceptions and policy development aimed at addressing the featured issues. We examine the potential impact of news media coverage regarding the health and potential future of the World heritage-listed Great Barrier Reef, which is under multiple pressures, both natural and anthropogenic. We draw on the extant literature regarding the impact of news media coverage of other complex issues, linking to relevant, albeit limited theoretical concepts that have been applied to previous media studies. We find that media coverage is predominately sensationalized and negative, with the potential to reinforce perceptions that mitigation attempts will be ineffective and thus likely to inhibit future policy development. We discuss the need for a review of existing science communication models and strategies to reduce the knowledge-practice gap between scientists and policy makers, together with proactive strategies to counter negative news coverage.
The California's Marine Life Protection Act (MLPA) is a recent high-profile initiative that led to the implementation of a network of 124 marine protected areas (MPAs) encompassing 16% of state waters. The effort was conducted through six different regional processes that incorporated stakeholder and scientific involvement, ending with the North Coast region. While the initiative has been described as a success in terms of implementation, there has been relatively little empirical research about social perceptions of the MPA network in order to examine whether stakeholders view the effort as successful. Our research team conducted surveys with 178 commercial and charter fishermen and held five focus groups in each of the major ports of the region in order to assess fishermen's perceptions of the California North Coast MPA network – including perceptions of both the process of implementation and potential outcomes from the network. Among fishermen, satisfaction with the overall process was low; however, the level of satisfaction with the inclusion of local input and the final location of the MPAs was more evenly divided. Levels of trust in management entities, including those who implemented the MPA network, were low. Additionally, in focus group discussions, fishermen described several perceived shortcomings of the process, including an overall “top-down” approach, a failure to consider the local context, and the appearance of being dismissive of fishermen's perspectives. In terms of outcomes, fishermen overwhelmingly did not believe that the MPA network would improve ocean health or their income from fishing. Qualitatively, fishermen reported that while they were experiencing some minor adverse effects from the MPA network, overall they did not believe that socioeconomic impacts on the fishing industry from the MPA network would be substantial. Many expressed relief that the location of MPAs avoided many important fishing grounds. Trust emerged as an important variable. For example, the reported level of trust by fishermen in the entity that implemented the MPA network had a statistically significant correlation with their level of satisfaction with the overall process, including the final location of the MPA network. Findings complicate initial assessments of the MLPA implementation process as an overall success, and highlight the importance of trust to building successful and lasting marine conservation initiatives.
Disturbances such as disease can reshape communities through interruption of ecological interactions. Changes to population demographics alter how effectively a species performs its ecological role. While a population may recover in density, this may not translate to recovery of ecological function. In 2013, a sea star wasting syndrome outbreak caused mass mortality of the keystone predator Pisaster ochraceus on the North American Pacific coast. We analyzed sea star counts, biomass, size distributions, and recruitment from long‐term intertidal monitoring sites from San Diego to Alaska to assess regional trends in sea star recovery following the outbreak. Recruitment, an indicator of population recovery, has been spatially patchy and varied within and among regions of the coast. Despite sea star counts approaching predisease numbers, sea star biomass, a measure of predation potential on the mussel Mytilus californianus, has remained low. This indicates that post‐outbreak populations have not regained their full predation pressure. The regional variability in percent of recovering sites suggested differences in factors promoting sea star recovery between regions but did not show consistent patterns in postoutbreak recruitment on a coast‐wide scale. These results shape predictions of where changes in community composition are likely to occur in years following the disease outbreak and provide insight into how populations of keystone species resume their ecological roles following mortality‐inducing disturbances.
Spatial closure regimes such as marine protected areas (MPAs) have emerged as a prominent tool in the effort to balance ecosystem health and fishery productivity. As MPAs have proliferated, the conservation community has begun to supplement traditional biological metrics with social and community considerations in the way it seeks to manage and evaluate such tools. To assess management outcomes and opportunities for a network of community-based, marine no-take zones (NTZs) in the Mexican Caribbean, semi-structured interviews were carried out with fishers and key management stakeholders. Findings indicate that the community-based management strategy has inherent tradeoffs between community engagement and conservation potential. Managers have succeeded in fostering high levels of community support for the initiative, but significant challenges remain, most notably the high presence of illegal fishing within NTZs. Successes and challenges of the community-based management strategy are documented and evaluated within a fisheries resource management framework. As the NTZ network undergoes legal renovation following the completion of its initial five-year term, this work serves as an important resource for both reflection on, and adaptation of, the community-based NTZ management regime.
Many coastlines throughout the world are retreating, as a result of erosion and sea level rise. The damage incurred to property, infrastructure, coastal flood defence, and the loss of ecosystem services and agricultural land have substantial economic repercussions. For many coastal regions located in developing countries, the assessment of the spatial extent of coastal erosion is very time-consuming and is often hampered by lack of data. To investigate the suitability of global open access data for coastal erosion assessments at regional scale six biogeophysical variables (geological layout, waves, sediment balance, tides, storms, and vegetation) were integrated using the Coastal Hazard Wheel approach (CHW). Original datasets with global coverage were retrieved from the internet and from various research institutes. The data were processed and assigned to the CHW classes, so that the CHW method could be applied to assess coastal erosion hazard levels. The data can be viewed in the Coastal Hazard Wheel App (www.coastalhazardwheel.org) that also allows the coastal erosion hazard levels to be determined for each point at coastlines around the world. The application of the CHW with global open access data was tested for the Caribbean and Pacific coasts of Colombia and revealed a high to very high erosion hazard along 47% of the Caribbean coast and along 23% of the Pacific coast. The application provides additional information on capital stock near the coast, as a tentative indication of assets at risk. This approach provides a straightforward and uniform erosion hazard identification method that can be used for spatial planning on coastal developments at a regional scale.
Fisheries depredation by marine mammals is an economic concern worldwide. We combined questionnaires, acoustic monitoring, and participatory experiments to investigate the occurrence of bottlenose dolphins in the fisheries of Northern Cyprus, and the extent of their conflict with set-nets, an economically important metier of Mediterranean fisheries. Dolphins were present in fishing grounds throughout the year and were detected at 28% of sets. Net damage was on average six times greater where dolphins were present, was correlated with dolphin presence, and the associated costs were considerable. An acoustic deterrent pinger was tested, but had no significant effect although more powerful pingers could have greater impact. However, our findings indicate that effective management of fish stocks is urgently required to address the overexploitation that is likely driving depredation behaviour in dolphins, that in turn leads to net damage and the associated costs to the fisheries.
Small-scale fisheries (SSFs) constitute a critical socioeconomic sector by providing a source of income and animal protein for fishing communities worldwide. In Uruguay this sector has traditionally been neglected. More recently, the Uruguayan government has shown an increasing interest in readdressing this situation by setting a high-level policy for SSFs. This paper addresses the long-term process from conceptualization to operationalization of the Ecosystem Approach to Fisheries (EAF) in Uruguayan SSFs. An overview of the social-ecological enabling conditions that facilitated EAF operationalization across four pilot sites is also provided. Long-term results showed that the intrinsic characteristics of each fishery conditioned the goals achieved. Fishery systems with more favorable enabling conditions served as starting points for operationalizing an EAF strategy. By contrast, SSFs with historical conflicts of use and a complex relationship between the fisheries management agency and fishing communities are still challenging. These results were used as learning platforms to strength and enhance the normative framework regarding management of SSFs. Progresses in EAF implementation at pilot sites have provided initial building blocks for scaling practices to other Uruguayan SSFs. The translation of processes and results into the long-term fishery policy allowed establishing an appropriate legal basis for further EAF development at a national level. Despite the above, long-term political will is critical for sustaining responsible fishing practices and the involvement of fishers as stewardships of their own activity.
Research has suggested there is a need for an increased attention to the socio-cultural lifeworlds of fishers and fisheries and its importance for fisheries management. An emerging response to this call has been to examine the social and cultural contexts of ‘good fishing’ – an idea which, drawing on the work of Pierre Bourdieu, has sought to move the discussion beyond simply the economic aspects of fishing to also understand the importance of other forms of capital. Utilising these concepts together with the conceptual idea of ‘knowledge cultures’, the following paper examines the ‘cultural sustainability’ of different ways of governing fishing practices – in particular Marine Conservation Zones and voluntary lobster v-notching using a case study approach to the small-scale fishery of Llŷn peninsula, North Wales (UK). The paper observes that those approaches that allow fishers to demonstrate skills and recognises the temporal contingency of fishing lives can be considered more culturally sustainable than others. This paper also notes that culturally acceptable changes to fishing practices can be supported by fishing regulations and, the paper suggests, such innovations are more likely to be taken up by fishers in their everyday fishing practices. The paper recommends that policies seeking to alter fishing practices consider: i) the importance fishers’ hold in demonstrating their skills; ii) how social relations are as important as economic aspects to fishers’ long-term uptake of new practices; and iii) how the past and the future (such as if a successor is present) holds significance for fishers’ actions in the present.
Recreational fishing is an important activity that delivers substantial social and economic values. Proper management of recreational fisheries relies on information about resource use and associated values by different fishers, but such information is rare, particularly for open access fisheries. In this study a survey of 471 fishers on the Swedish island of Gotland in the Baltic Sea, assessed catches, proportion of catch-and-release (C&R), and economic value (expenditures and willingness to pay, WTP) of sea trout fishing in 2015–2016. Data was analysed in relation to gear used (fly and spin angling, nets and mixed fishery) and fisher connection to fishing site (permanent and temporary residents, Swedish and international tourists). There were marginal differences in daily catch rates, but significant differences in effort and annual catches between different fishers, with resident fishers having the highest catches. Anglers had 86% C&R rates, and fly fishers (>95%) differed significantly from other anglers. Anglers, particularly fly fishers and fishing tourists, had much higher expenditures per year, fish caught and fish kept compared to net fishers. WTP before refraining from fishing, for doubling of fish supply and for potential fishing license was also highest among anglers. Our findings are discussed in terms of distinguishing characteristics for different types of recreational fishers. Fishing efforts, economic values and the need for further studies are also outlined in the context of fisheries and tourism management.
Due to the socioeconomic importance of sardines in the South Atlantic, the aim of this study was to evaluate the fishers’ LEK and the attitudes towards conservation of S. brasiliensis in the fishing village of the Arraial do Cabo, Rio de Janeiro, Brazil. A total of 134 semi-structured interviews were conducted from April to July 2016. The LEK was classified as moderate (0.56) as well as the conservation attitudes (0.60). It was shown that there was a correlation between LEK and income of fishers. There were differences in LEK and attitudes regarding conservation of sardines in all educational groups analyzed in the sampling population. The LEK and the attitudes also show significant association with boat ownership, occupation and if the fisherman belonged to the local fishing association. As a way to improve fishers’ attitudes in practice, we also encouraged the promotion of education among youth and adults is recommended so that the behavior of fishers becomes more favorable to the conservation of sardines in this fishing community. We also emphasize that local management must take into account the sociodemographic variables of fishers since these can influence LEK and their predisposition to conserve sardines. This approach would increase the likelihood of ensuring the efficient support of the local community in the conservation of this small pelagic fish.