Marine fisheries plays an important role in ensuring food security and providing livelihoods in South Africa, as in many other developing coastal States. Transnational fisheries crime seriously undermines these goals. Drawing on empirical research this contribution highlights the complexity of law enforcement at the interface between low-level poaching and organised crime in the small-scale fisheries sector with reference to a South African case study. Specifically, this article examines the relationship between a fisheries-crime law enforcement approach and the envisaged management approach of the South African Small-Scale Fisheries Policy.
In this study, we estimate the shoreline retreat, the vulnerability and the erosion rates of an open beach-dune system under projected sea level rise (SLR) and the action of wind-waves (separately and in combination). The methodology is based on the combination of two state-of-the-art numerical models (XBeach and Q2D-morfo) applied in a probabilistic framework and it is implemented in an open sandy beach in Menorca Island (Western Mediterranean). We compute the shoreline response to SLR during the 21st century and we assess the changing impacts of storm waves on the aerial beach-dune system. Results demonstrate the relevant role that the beach backshore features, such as the berm, play as coastal defense, reducing the shoreline retreat and dune vulnerability rates in the near-term (a few decades ahead) and highlighting the importance of simulating the beach morphodynamic processes in coastal impacts assessments. Our findings point at SLR as the major driver of the projected impacts over the beach-dune system, leading to an increase of ∼25% of the volume eroded due to storm waves by the end of the century with respect to present-day conditions.
An efficient connectivity-based method for multi-objective optimization applicable to the design of marine protected area networks is described. Multi-objective network optimization highlighted previously unreported step changes in the structure of optimal subnetworks for protection associated with minimal changes in cost or benefit functions. This emphasizes the desirability of performing a full, unconstrained, multi-objective optimization for marine spatial planning. Brute force methods, examining all possible combinations of protected and unprotected sites for a network of sites, are impractical for all but the smallest networks as the number of possible networks grows as 2m, where mis the number of sites within the network. A metaheuristic method based around Markov Chain Monte Carlo methods is described which searches for the set of Pareto optimal networks (or a good approximation thereto) given two separate objective functions, for example for network quality or effectiveness, population persistence, or cost of protection. The optimization and search methods are independent of the choice of objective functions and can be easily extended to more than two functions. The speed, accuracy and convergence of the method under a range of network configurations are tested with model networks based on an extension of random geometric graphs. Examination of two real-world marine networks, one designated for the protection of the stony coral Lophelia pertusa, the other a hypothetical man-made network of oil and gas installations to protect hard substrate ecosystems, demonstrates the power of the method in finding multi-objective optimal solutions for networks of up to 100 sites. Results using network average shortest path as a proxy for population resilience and gene flow within the network supports the use of a conservation strategy based around highly connected clusters of sites.
The trade in coral reef fishes for aquariums encompasses over 1,800 species from over 40 exporting countries, yet the population status for most traded species is unknown and unevaluated. At the same time, these coral reef fishes face a growing number of threats and often occur in jurisdictions with limited management capacity and data. In response, we assess vulnerability to overfishing for 72 coral reef fishes popular in the aquarium trade for the United States – the top importer – from the top exporting countries (Indonesia and the Philippines). We use a data-limited assessment approach: productivity susceptibility analysis (PSA). PSA estimates relative vulnerability of species by assessing their biological productivity and susceptibility to overfishing. The most and least vulnerable stocks were differentiated by attributes related to the reproductive biology (e.g., breeding strategy, recruitment pattern, and fecundity), appropriateness, for an average home aquarium, ease of capture (e.g., schooling and aggregation), and rates of natural mortality. Our analysis identifies several of the most and least vulnerable species popular in the aquarium fish trade. The species that ranked as least vulnerable to overcollection were Gobiodon okinawae, Nemateleotris magnifica, Gobiodon acicularis, Salarias fasciatus, Ptereleotris zebra, Gobiodon citrinus, Pseudocheilinus hexataenia, Chaetodon lunula, Nemateleotris decora, and Halichoeres chrysus. In contrast, the ten most vulnerable species were Chromileptes altivelis, Plectorhinchus chaetodonoides, Pterapogon kauderni, Premnas biaculeatus, Echidna nebulosa, Centropyge bicolor, Zebrasoma veliferum, Pomacanthus semicirculatus, Zebrasoma scopas, and Thalassoma lunare. In a data-limited context, we suggest how these vulnerability rankings can help guide future efforts for reducing vulnerability risk. In particular, species that are relatively high-vulnerability are prime targets for research and aquaculture efforts, increased monitoring of collection and exports, species-specific stock assessments, and voluntary reductions by retailers and consumers to avoid overexploitation.
In just four decades, hundreds of hydrothermal vent fields have been discovered, widely distributed along tectonic plate boundaries on the ocean floor. Vent invertebrate biomass reaching up to tens of kilograms per square meter has attracted attention as a potential contributor to the organic carbon pool available in the resource-limited deep sea. But the rate of chemosynthetic production of organic carbon at deep-sea hydrothermal vents is highly variable and still poorly constrained. Despite the advent of molecular techniques and in situ sensing technologies, the factors that control the capacity of vent communities to exploit the available chemical energy resources remain largely unknown. Here, we review key drivers of hydrothermal ecosystem productivity, including (a) the diverse mechanisms governing energy transfer among biotic and abiotic processes; (b) the tight linkages among these processes; and (c) the nature and extent of spatial and temporal diversity within a variety of geological settings; and (d) the influence of these and other factors on the turnover of microbial primary producers, including those associated with megafauna. This review proposes a revised consideration of the pathways leading to the biological conversion of inorganic energy sources into biomass in different hydrothermal habitats on the seafloor. We propose a conceptual model that departs from the canonical conservative mixing-continuum paradigm by distinguishing low-temperature diffuse flows (LT-diffuse flows) derived from seawater and high-temperature fluids (HT-diffuse flow) derived from end-member fluids. We further discuss the potential for sustained organic matter production at vent-field scale, accounting for the natural instability of hydrothermal ecosystems, from the climax vent communities of exceptional productivity to the long-term lower-activity assemblages. The parameterization of such a model crucially needs assessment of in situ rates and of the largely unrecognized natural variability on relevant temporal scales. Beyond the diversity of hydrothermal settings, the depth range and water mass distribution over oceanic ridge crests, volcanic arcs and back-arc systems are expected to significantly influence biomass production rates. A particular challenge is to develop observing strategies that will account for the full range of environmental variables while attempting to derive global or regional estimates.
Climate change is outpacing existing rates of evolution and adaptation for many marine organisms. Human societies are pushing hard to find new solutions to save and protect marine ecosystems, generating research on manipulating genetics of wild organisms for the goal of conservation. This – “assisted evolution” – raises challenging ethical questions because the intention is not to revert to a previous status quo, but to modify a community so that it survives better in the conditions we have created. In so doing, our role changes toward “designers” of nature, which requires a rethinking of what is natural, and whether altering or influencing genetics of wild organisms changes the way we conceptualize nature. Assisted evolution could also perpetuate damaging habits and dispositions, such as commodification and technological intervention, which have caused the harm in the first place. Even if we feel morally obliged to repair ecosystems, we still risk further havoc if our attempts to fix our damage are affected by ignorance. Still, from an ethical point of view, we offer cautious support for research on assisted evolution tools. However, we must be clear that we are using these approaches for our own benefit, and should only proceed when they are adequately understood and other options are exhausted. In many cases, we should instead focus our efforts on protecting what we can, minimizing future damage, and understanding future changes. Either way, we need stronger ethical regulations on applying assisted evolution techniques in marine conservation so that there is sufficient deliberation before we use these tools.
Coastal communities, indigenous peoples, and small-scale fishers rely on the ocean for livelihoods, for subsistence, for wellbeing and for cultural continuity. Thus, understanding the human dimensions of the world’s peopled seas and coasts is fundamental to evidence-based decision-making across marine policy realms, including marine conservation, marine spatial planning, fisheries management, the blue economy and climate adaptation. This perspective article contends that the marine social sciences must inform the pursuit of sustainable oceans. To this end, the article introduces this burgeoning field and briefly reviews the insights that social science can offer to guide ocean and coastal policy and management. The upcoming United Nations Decade of Ocean Science for Sustainable Development (2021–2030) provides a tremendous opportunity to build on the current interest, need for and momentum in the marine social sciences. We will be missing the boat if the marine social sciences do not form an integral and substantial part of the mandate and investments of this global ocean science for sustainability initiative.
Forecasts of marine environmental and ecosystem conditions are now possible at a range of time scales, from nowcasts to forecasts over seasonal and longer time frames. Delivery of these products offers resource managers and users relevant insight into ecosystem patterns and future conditions to support decisions these stakeholders face associated with a range of objectives. The pace of progress in forecast development is so rapid that the scientific community may not be considering fully the impacts on stakeholders and their incentives. Delivery of information, particularly about future conditions and the uncertainties associated with it, involves a range of judgements, or “ethical” considerations, including treatment of forecast failure, inequity in stakeholder response options, and winners and losers in commercial markets. Here, we explore these often unanticipated considerations via a set of case studies spanning commercial fishing, recreational fishing, aquaculture, and conservation applications. We suggest that consideration of ethical issues by scientists and their research partners is needed to maintain scientific integrity and fairness to end users. Based on these case studies and our experience, we suggest a set of ten principles that might be considered by developers and users of ecological forecasts to avoid these ethical pitfalls. Overall, an interdisciplinary approach, and co-production with end users will provide insurance against many unanticipated consequences.
Social perception is key to the success of biodiversity conservation policies. A range of socioeconomic guilds can be affected by marine conservation. Among them, fishers are the ones most likely affected and affecting marine protected areas (MPAs). Here, we assessed the perceptions on the sustainability of a type of multiple-use MPA, Fishing Reserves (FRs), by a broad spectrum of national (n = 16) and local (n = 14) stakeholder organisations pertaining to six socioeconomic sectors via two online surveys in Spain. We compared organisational perception by stakeholder organisations, and specifically by the fishing guild, with official fishing statistics for six FRs between 1998 and 2016 using a Before-After-Impact (BAI) research design. Spanish FRs were regarded as sustainable marine management tools by most marine and coastal stakeholders, with environmental effects perceived to be more positive than social and economic ones, respectively. However, primary sector organisations stated null or negative effect of FR designation on their activities, although official statistics showed a moderate to large increase in a number of professional fishing-related variables, including number of boats and crews, after designation of most FRs. Spatial scale did not affect stakeholder perception of local socioeconomic effects of FRs, although some relevant local socioeconomic variables that were thought to vary most after FR designation differed across scales. Some suggested managerial improvements for increased socioeconomic sustainability of Spanish FRs by the professional fishing guild included: greater stakeholder engagement in FR designation and operation, more flexible fishing regulations and stricter control of recreational fishing.
The dramatic decline of European eel (Anguilla anguilla) populations over recent decades has attracted considerable attention and concern. Furthermore, little is known about the sensitivity of the early stages of eels to projected future environmental change. Here, we investigated, for the first time, the potential combined effects of ocean warming (OW; Δ + 4°C; 18°C) and acidification (OA; Δ − 0.4 pH units) on the survival and migratory behaviour of A. anguilla glass eels, namely their preference towards riverine cues (freshwater and geosmin). Recently arrived individuals were exposed to isolated and combined OW and OA conditions for 100 days, adjusting for the salinity gradients associated with upstream migration. A two-choice test was used to investigate migratory activity and shifts in preference towards freshwater environments. While OW decreased survival and increased migratory activity, OA appears to hinder migratory response, reducing the preference for riverine cues. Our results suggest that future conditions could potentially favour an early settlement of glass eels, reducing the proportion of fully migratory individuals. Further research into the effects of climate change on eel migration and habitat selection is needed to implement efficient conservation plans for this critically endangered species.
Understanding the social dimensions of marine and coastal conservation is considered integral to better inform governance and management actions. Perceptions are recognized as a way to understand these dimensions, which can evidence limitations of current efforts, while facilitating more informed policy-making and provide a basis for more robust management actions. Following a qualitative and case study approach, this paper utilizes stakeholder interviews to explore the perceptions on marine ecosystems and current management actions that include marine protected areas (MPAs) in the Central American country of Guatemala. Results identify similarities and contrasts in the perception of marine conservation and MPAs, where weak local governments and limited community participation in the decision-making process can be considered the underlying problems. Recommendations are made which can capitalize upon multi-level improvements that need to integrate all stakeholder groups. Improvements should also consider the regional setting and must reflect Guatemala’s historical and social context. This paper highlights that stakeholder perceptions need a central role to further improve the quality of governance in coastal Guatemala. Recommendations can further assist other developing countries facing similar challenges.
Central to appropriate wildlife management is an effective monitoring program. Monitoring wildlife in urban environments offers unique challenges in the form of barriers, prohibited access and crime. It also, however, provides a unique opportunity to enlist residential communities in collecting data on distribution of a number of species. Opportunistic sightings data has its flaws, including the lack of data on species absences, and unequal sampling effort. Yet these data may still provide reliable information on the distribution of species and complement localized, hypothesis driven research. Where possible opportunistic sightings data should be validated against traditional methods to determine their value for long term monitoring programmes. We use Maxent to model citizen-reported sightings to determine whether sightings of Cape clawless otters (Aonyx capensis) can complement standardized river occupancy surveys to monitor an elusive, widely distributed species living within a fragmented urban/natural matrix. The drivers of otter presence and the predicted distribution of otters modelled from citizen sightings mirrored that provided by previously published results based on occupancy models in the same system, and highlighted further areas of suitable otter habitat and routes for dispersal. Involving citizens in the monitoring of the urban otter population complemented standardized occupancy surveys and provided additional benefits. In addition to alleviating the pressure on local authorities to allocate resources to routine monitoring, citizen involvement provides an opportunity to gather supplementary data on behaviour and/or threats to the species; shed light on the potential dispersal routes, and promote awareness and encourage coexistence with urban adapted wildlife.
Conflicts among and between local, national, regional and international stakeholders involved in marine turtle conservation are increasing. Often, they arise because of different socio-economic backgrounds of the people or groups involved. Here, we identified and assessed the conservation-based conflicts occurring in 24 of the 39 Caribbean countries, including their frequency, level of severity, number of stakeholders' groups involved, the degree to which they hinder conservation goals, and potential solutions. Using a cross-sectional social survey, we evaluated the presence and details of conservation conflicts provided by 72 respondents. The respondents included conservation-based project leaders, researchers, people involved in policy-based decision-making, conservation volunteers (community-based conservation groups), and species experts with experience working on marine turtle conservation programs in the Caribbean. The respondents identified 136 conflicts, and we grouped them into 16 different categories. The most commonly mentioned causes of conflicts were: 1) the ‘lack of enforcement by local authorities to support conservation-based legislation or programs’ (18%); 2) ‘legal consumption of turtles by one sector of community clashing the conservation aspirations of other sectors of community (14%); and 3) ’variable enforcement of legislation to limit/prohibit use across range states of the species (10%). From our data it is also apparent that illicit activities in the region are also likely to impact the future success of conservation or monitoring based projects and programs. Overall, an exhaustive review was carried out, and the potential solutions were gathered. Due to the level of severity (physical violence) that some conflicts have reached, achieving solutions will be challenging without mediation, mutual cooperation around shared values, and adaptive management arrangements. Achieving this will require combinations of bottom up and top down collaborative governance approaches.
Procellariiform seabirds are both the most threatened bird group globally, and the group with the highest incidence of marine debris ingestion. We examined the incidence and ecological factors associated with marine debris ingestion in Procellariiformes by examining seabirds collected at a global seabird hotspot, the Australasian - Southern Ocean boundary. We examined marine debris ingestion trends in 1734 individuals of 51 Procellariform species, finding significant variation in the incidence of marine debris abundance among species. Variation in the incidence of marine debris ingestion between species was influenced by the taxonomy, foraging ecology, diet, and foraging range overlaps with oceanic regions polluted with marine debris. Among the ecological drivers of marine debris ingestion variability in Procellariiformes, we demonstrate that the combination of taxonomy, foraging method, diet, and exposure to marine debris are the most important determinants of incidence of ingestion. We use these results to develop a global forecast for Procellariiform taxa at the risk of highest incidence of marine debris ingestion. We find seabirds that forage at the surface; especially by surface seizing, diving and filtering, those with a crustacean dominant diet, and those that forage in or near marine debris hotspots are at highest risk of debris ingestion. We predict that family with the highest risk are the storm petrels (Hydrobatidae and Oceanitidae). We demonstrate that the greater the exposure of high-risk groups to marine debris while foraging, the greater the incidence and number of marine debris items will be ingested.
The conceptual framework of evolutionary governance theory (EGT) is deployed and extended to rethink the idea of coastal governance and the possibilities of a coastal governance better adapted to challenges of climate change and intensified use of both land and sea. ‘The coastal condition’ is analyzed as a situation where particular modes of observation and coordination were possible and necessary, and those observations (and derived calculations of risk and opportunity) are valuable for the governance of both land and an argument is constructed for a separate arena for coastal governance, without erasing the internal logic of pre-existing governance for land and sea. This entails that coastal governance is destined to be a place of (productive) conflict, as much as of policy integration. Policy integration will be more difficult and more important in coastal governance, as this is an arena where the effects of many land based activities and activities at sea become visible and entangled. Policy integration in coastal governance does however require deep knowledge of the governance path and existing forms of integration there (e.g. in planning), and it exists in an uneasy tension with the requirements of adaptive governance. This tension further contributes to the complexity and complex-prone character of coastal governance. Neither complexity nor conflict can be avoided, and coastal governance as an image of balanced decision-making is (positively) presented as a productive fiction.
Multihost infectious disease outbreaks have endangered wildlife, causing extinction of frogs and endemic birds, and widespread declines of bats, corals, and abalone. Since 2013, a sea star wasting disease has affected >20 sea star species from Mexico to Alaska. The common, predatory sunflower star (Pycnopodia helianthoides), shown to be highly susceptible to sea star wasting disease, has been extirpated across most of its range. Diver surveys conducted in shallow nearshore waters (n = 10,956; 2006–2017) from California to Alaska and deep offshore (55 to 1280 m) trawl surveys from California to Washington (n = 8968; 2004–2016) reveal 80 to 100% declines across a ~3000-km range. Furthermore, timing of peak declines in nearshore waters coincided with anomalously warm sea surface temperatures. The rapid, widespread decline of this pivotal subtidal predator threatens its persistence and may have large ecosystem-level consequences.
Plastics in the ocean are of great concern nowadays, and are often referred to as the apocalyptic twin of climate change in terms of public fear and the problems they pose to the aquatic and terrestrial environment. The number of studies focusing on the ecological effects and toxicity of plastics has substantially increased in the last few years. Considering the current trends in the anthropogenic activities, the amount of plastics entering the world oceans is increasing exponentially, but the oceans have a low assimilative capacity for plastics and the near-surface layer of it is a finite space. If loading of the oceans with plastics continues at the current rate, the thin sea surface microlayer can have a substantial amount of plastics comparable to the distribution of phytoplankton, at least in the major oceanic gyres and coastal waters in the future. Also, processes like biofouling can cluster microplastics in dense fields in the near-surface layer. Plastics can contribute to the warming or cooling of the water column by scattering and attenuating incoming solar radiation, leading to a potential change in the optical and other physico-chemical properties of the water column. We propose a new notion that changes in solar radiation in the water column due to the plastics have the potential to affect the physical processes in the ocean surface and near-surface layers, and can induce climate feedback cycles. The future can be very different, if plastics evolve as one of the key players affecting the ocean physical processes and hence this is the time to tackle this puzzle with appropriate strategies or let the genie out of the bottle.
Dams are known to trap pollutants such as metals and PCBs in the sediment that accumulates within their reservoirs. As more attention is paid to microplastics, an emerging contaminant in waterways worldwide, and how they move along rivers, whether microplastic particles also accumulate behind dams is an important question for informing estimates of global river inputs to oceans. In this study, we measured microplastic concentrations above, below, and within the reservoirs of six dams near Ithaca, NY USA. Samples were processed following the wet peroxide oxidation method and visual counting, followed by Raman Spectroscopy validation. We found that microplastic concentrations in sediment within reservoirs was significantly higher than in sediment above the dams (p = 0.005), and in water samples, concentrations within reservoirs was significantly lower (p = 0.02). Plastic fibers were the dominant plastic type, but in within-reservoir sediment samples, less abundant plastic types such as plastic fragments were found in higher proportions. These results show that the sediment collecting behind dams is one sink for microplastics in river systems at long timescales, indicating that accounting for dams may be important when modeling global riverine microplastic transport.
Plastic pollution is a pervasive problem to marine life. This study aimed (1) to investigate levels of microplastic in wild and farmed mussels (Perna perna), and (2) to assess the effectiveness of depuration in reducing microplastics. Wild and farmed mussels were sampled from Guanabara Bay (Southwestern Atlantic). Four treatments were compared (N = 10 mussels/treatment): wild non-depurated mussels, wild depurated mussels, farmed non-depurated mussels, and farmed depurated mussels. Up to 31.2 ± 17.8 microplastics/mussel (≥0.45 μm) were detected (means ± SD), and microplastics were present in all 40 individuals analyzed. Nylon fibers were more abundant than polymethyl methacrylate (PMMA) fragments. Blue, transparent, and red nylon fibers were more abundant in both wild and farmed mussels. Although 93 h-depuration significantly reduced microplastics (ANOVA, p = 0.02) in both wild (46.79%) and farmed mussels (28.95%), differences between farmed and wild mussels were not significant (p > 0.05). Depuration was more effective in removing blue fibers. Our results highlight the importance of depuration in reducing microplastic pollution in seafood.
This paper provides a quantitative assessment of students' attitude and behaviors towards marine litter before and after their participation to SEACleaner, an educational and citizen science project devoted to monitor macro- and micro-litter in an Area belonging to “Pelagos Sanctuary” (Mediterranean Sea). This approach produced interesting outcomes both for the research sector of marine pollution and environmental monitoring, as well for the scientific and environmental education. Here we focus on citizen science as an effective vector for raising young people awareness of marine litter and fostering sound behaviors. A specially designed questionnaire was administered to 87 High School students, to test the validity of such approach. The results state that the students change quantitatively their perception of beach-litter causes and derived problems, and they improved their knowledge about the main marine litter sources and the role of the sea in the waste transport and deposition along the coast.