Balancing sustainability and conservation concerns with the socioeconomic needs of small-scale fishers is a dilemma that is commonly faced by fisheries managers. In this paper, we present a case study on managing the developing small-scale purse seine (or ring net) fishery introduced to Kenya by migrant fishers. The fishery, which primarily targets coastal pelagics in offshore waters, was deduced to have the potential of reducing fishing effort on nearshore demersal reef fish stocks while enhancing fisheries production and fisher livelihoods. The expanding fishery elicited much controversy resulting in resource use conflicts related to gear competition and concerns about the environmental impacts of the gear. We detail the consultative planning process that was undertaken to develop a gear-based management plan spanning over 10 years from 2004 to 2016. We briefly document the catch dynamics and evolution of the fishery, and further detail the challenges and key outcomes of the decision-making process. Regulatory measures agreed by stakeholders include restrictions on gear dimensions as well as spatial restrictions defining the distance and depth of operation. Effective implementation and enforcement of the measures will require collective action from all stakeholders. Future considerations should focus on harmonization of proposed measures in transboundary areas.
Albacore tuna (Thunnus alalunga) is a highly commercial fish species harvested in the world's Oceans. Identifying the potential links between populations is one of the key tools that can improve the current management across fisheries areas. In addition to characterising populations' contamination state, chemical compounds can help refine foraging areas, individual flows and populations' structure, especially when combined with other intrinsic biogeochemical (trophic) markers such as carbon and nitrogen stable isotopes. This study investigated the bioaccumulation of seven selected trace metals - chromium, nickel, copper (Cu), zinc (Zn), cadmium (Cd), mercury (Hg) and lead - in the muscle of 443 albacore tunas, collected over two seasons and/or years in the western Indian Ocean (WIO: Reunion Island and Seychelles) and in the south-eastern Atlantic Ocean (SEAO: South Africa). The main factor that explained metal concentration variability was the geographic origin of fish, rather than the size and the sex of individuals, or the season/year of sampling. The elements Cu, Zn, Cd and Hg indicated a segregation of the geographic groups most clearly. For similar sized-individuals, tunas from SEAO had significantly higher concentrations in Cu, Zn and Cd, but lower Hg concentrations than those from WIO. Information inferred from the analysis of trophic markers (δ13C, δ15N) and selected persistent organic pollutants, as well as information on stomach contents, corroborated the geographical differences obtained by trace metals. It also highlighted the influence of trophic ecology on metal bioaccumulation. Finally, this study evidenced the potential of metals and chemical contaminants in general as tracers, by segregating groups of individuals using different food webs or habitats, to better understand spatial connectivity at the population scale. Limited flows of individuals between the SEAO and the WIO are suggested. Albacore as predatory fish also provided some information on environmental and food web chemical contamination in the different study areas.
Despite its recognised importance for species’ persistence, integrating genetics into conservation management has proved problematic, creating a “conservation genetics gap”, which could widen with the advent of advanced genomic techniques. Bridging this gap requires a clear understanding of the barriers to use of genetics by conservation practitioners, but few (if any) papers on this topic involve direct consultation with practitioners themselves. We surveyed 148 conservation practitioners in New Zealand’s Department of Conservation regarding their attitude to, knowledge of, and experiences with genetics for conservation. Although practitioners were largely receptive to using genetics for conservation management, access to expertise and funding remains a barrier to use. Practitioners would like to collaborate with geneticists at universities or other institutes, but do not necessarily know who to talk to or fully understand how genetics might benefit them. We contend these barriers or similar likely exist at an international level, suggest ways they might be overcome, and emphasise the need for clearer communication between geneticists and practitioners.
Blue whales Balaenoptera musculus occur seasonally in the St. Lawrence Estuary, Canada, where they spend most of their time foraging. Their recurrent presence has stimulated the development of a large whale-watching industry. Here, we examine the effect of vessel distance on blue whale foraging behaviour by measuring changes in surface and diving patterns. Vessels were within 2000 m of blue whales during 70% of 33 follows, and 59% of total observation time. At vessel distances ≤400 m, surface and dive times were on average 49 and 36% shorter, respectively, and the number of breaths taken by the whales was reduced by 51% compared to control observations without vessel presence within 2000 m of whales. The consequent reduction in foraging time was likely greater than 36%, given that transit time is incompressible and foraging depth is dictated by where krill densities are located. We showed that the relative proportion of lost foraging time from vessel exposure increased exponentially with prey depth. Whales were unable to compensate for lost feeding opportunities by increasing diving rate or swim speed, except when feeding within 10 to 15 m of the surface. Our results indicate that preventing vessels from entering within a 400 m radius around blue whales can help reduce the negative effects of marine recreational activities on blue whale foraging.
Environmental pollution caused by inert anthropogenic stressors such as microplastics in aquatic media is constantly increasing. Through the proliferating use of plastic products in daily life, more and more plastic particles enter waters as primary microplastics. Even though large scale plastic items such as plastic bottles and bags represent the highest percentage of plastic waste, their degeneration also generates microparticles and nanoparticles (secondary microplastics). Modern sewage treatment plants require innovative ideas in order to deal with this man-made problem. State-of-the-art technology offers approaches to minimise the amount of microplastics in aquatic systems. These technologies, however, are either insufficient or very costly, as well as time-consuming in both cases. The conceptual idea presented here is to apply innovative inorganic-organic hybrid silica gels which provide a cost-effective and straightforward approach. Currently, the synthesis of preorganised bioinspired compounds is advancing in order to produce functionalised hybrid silica gels in a further step. These gels have the ability to remove stressors such as microplastics from waste water. By means of the sol-gel process, bioinspired silane compounds are currently being permuted to macromolecules and examined with respect to their properties as fixation and filter material in order to remove the hydrophobic anthropogenic stressors sustainably. Here, the reproduction of biological systems plays a significant role. In particular in material sciences, this approach is becoming increasingly important. Among other concepts, new biomimetic molecules form the basis for the investigation of innovative host-guest relationships for anthropogenic stressors in the environment and their implementation in technical processes.
Marine debris is one of the most significant issues facing oceans worldwide. The sources of this debris vary depending on proximity to urban centres and the nature of activities within an area. This paper examines the influence of tourism in the southern Great Barrier Reef (GBR), and its contribution to litter levels in the region. By conducting beach debris surveys on occupied and unoccupied islands, this study found that debris was prevalent throughout the region with significant differences in material types between locations. The greatest source of debris from publically accessible islands was tourist-related, with this source also influencing debris loads on nearby uninhabited islands. A focus on debris at Heron Island, showed that sites close to amenities had greater levels of tourist-sourced items like cigarette butts. These findings indicate the contribution of tourists to this problem and that working with operators and managers is needed to minimise visitor impacts.
Space is political. The sphere of politics is spatial. Every political order is relational to space. It applies in space (and time)—and may change with it. For most of the time, the world has been understood as the way in which its territories were delineated and used. Today, the popular term to frame such changes is “power shifts”. The most fundamental geopolitical dichotomy, however, is as old as human civilization: land-based power versus sea-based power. Since the days of ancient Greece the issue has been relevant. In the twenty-first century, the spaces of the world are divided among 193 UN member states, to which have to be added around three dozen dependent territories and states of lesser recognition. Yet, territorial acquisition has not lost its appeal and the notion of state sovereignty remains tied to the factual control of land. Residual states or failed states have become a prominent feature of global narratives while the complexity of the maritime agenda, beyond the single issue of climate change and its impact on survival in atoll states and coastal areas, is often underestimated in the international political and academic debate. Together, territorial spaces and maritime spheres frame the future of the global economy and, most likely, also all possible dimensions of geopolitics and the troubles it can bring about.
Ecological carrying capacity (ECC) is an important indicator in evaluating sustainable development in an ecosystem. However, a standard method to systematically evaluate an ecosystem's carrying capacity, particularly marine ecosystems, is rarely existent. This study proposes a general conceptual model for systematic evaluation of the carrying capacity of marine ecosystems. The proposed model involves (1) identification of carriers, (2) determination of carrying objects and (3) construction of evaluation index framework. An index system was developed based on a case study conducted in Dongtou Islands in China. Moreover, this case study demonstrates the application of the conceptual model in ECC evaluation.
Our aim was to quantify microplastic ingestion by fish assemblages in two tropical Brazilian estuaries and to evaluate whether biological and ecological factors influence the ingestion of microplastics by fish species. Of 2233 fish from both estuaries (from 69 species) examined in this study, 9% of the individuals (24 species) had microplastics in their gut contents. Microplastic ingestion occurred irrespective of fish size and functional group. The diet of fish species was analyzed based on prey items identified in the fish's full stomach contents and five feeding guilds were defined. Microplastics were common throughout all feeding guilds. Low (average ingestion values 1.06 ± 0.30 items/total fish) but widespread occurrence among estuaries also indicates proliferation of microplastic pollution. Our findings highlight the need to focus on assemblage level studies to understand the real magnitude of the problem and emphasize the urgency of mitigation measures directed at microplastic pollution in estuarine ecosystems.
Filamentous plastic litter collected from two beaches in south west England has been characterized by FTIR and XRF. The majority of samples were constructed of polyethylene and consisted of twisted or braided strands of a variety of colours that appeared to be derived from commercial fishing nets. A number of different elements were detected among the samples but, from an environmental perspective, the regular occurrence of Cr and Pb and the occasional or isolated occurrence of Br, Cd and Se were of greatest concern. The highest total concentrations of Br (2420 μg g−1), Cd (1460 μg g−1), Cr (909 μg g−1), Pb (3770 μg g−1) and Se (240 μg g−1) were always encountered among orange samples and are attributed to the presence of lead chromates and cadmium sulphoselenide as colourants and to brominated compounds as flame retardants. Element bioaccessibility was evaluated by ICP-MS following an acidic extraction test that mimics the digestive tract of seabirds, with maximum values after a seven-day incubation period and relative to respective total concentrations of 0.2–0.4% for Cd, Cr and Pb and about 7% for Br. In addition to the well-documented impacts on wildlife through entrapment, filamentous plastic waste may act as a significant source of hazardous chemicals into the marine foodchain through ingestion.
The conservation outcomes of a protected area depend on management actions. The effectiveness of protected area management remains a concern for donors and policy-makers. However, very few feasible methods assessing the ability and performance of management teams have been developed. Behavioral shifts in habitat usage, direct and sensitive wildlife responses to threats, have been ignored in the evaluation of protected area management. To address the technical limitations, we developed a method that uses the behavioral dynamics of target species as indicators of the efficacy of threat reduction, control, and overall management effort. By comparing wildlife behavior with threat avoidance distances and patterns we can examine threat mitigation efficacy as a proxy for overall reserve management effectiveness. Using evidence of giant panda habitat utilization in eleven reserves across Qinling Mountains from 2000 to 2012, we built a model of behavior based on the avoidance of four types of anthropogenic threat. We stratified the eleven reserves into five efficacies, of which Changqing reserve was deemed to have the highest management effectiveness. Our approach was validated and supported by changes in suitable habitat and population size across reserves. Focusing on the end result of all threats and management effort means that our framework is straightforward for reserve staff to implement, produces easily interpreted results, and is worthy of application. This study highlights the value of behavioral dynamics when making a full and scientific assessment of the effectiveness of protected area management, and helps investors and policy-makers realize the efficacy of conservation inputs.
Baltic amber, adored for its beauty already in Homer's Odyssey (ca. 800 B.C.E), has its material density close to that of wide-spread plastics like polyamide, polystyrene, or acrylic. Migrations of amber stones in the sea and their massive washing ashore have been monitored by Baltic citizens for ages. Based on the collected information, we present the hypothesis on the behaviour of microplastic particles in sea coastal zone. Fresh-to-strong winds generate surface waves, currents and roll-structures, whose joint effect washes ashore from the underwater slope both amber stones and plastics – and carries them back to the sea in a few days. Analysis of underlying hydrophysical processes suggests that sea coastal zone under stormy winds plays a role of a mill for plastics, and negatively buoyant pieces seem to repeatedly migrate between beaches and underwater slopes until they are broken into small enough fragments that can be transported by currents to deeper areas and deposited out of reach of stormy waves. Direct observations on microplastics migrations are urged to prove the hypothesis.
Plastic pollution and its environmental effects has received global attention the recent years. However, limited attention has so far been directed towards how plastics are regulated in a life cycle perspective and how regulatory gaps can be addressed in order to limit and prevent environmental exposure and hazards of macro- and microplastics. In this paper, we map European regulation taking outset in the life cycle perspective of plastic carrier bags: from plastic bag production to when it enters the environment. Relevant regulatory frameworks, directives and authorities along the life cycle are identified and their role in regulation of plastics is discussed. Most important regulations were identified as: the EU chemical Regulation, the Packaging and Packaging Waste Directive including the amending Directive regarding regulation of the consumption of lightweight plastic carrier bags, the Waste Framework Directive and the Directive on the Landfill of Waste. The main gaps identified relate to lack of clear definitions of categories of polymers, unambitious recycling rates and lack of consideration of macro- and microplastics in key pieces of legislation. We recommend that polymers are categorized according to whether they are polymers with the same monomer constituents (homopolymers) or with different monomer constituents (copolymers) and that polymers are no longer exempt from registration and evaluation under REACH. Plastics should furthermore have the same high level of monitoring and reporting requirements as hazardous waste involving stricter requirements to labelling, recordkeeping, monitoring and control over the whole lifecycle. Finally, we recommend that more ambitious recycle and recovery targets are set across the EU. Regulation of the consumption of lightweight plastic carrier bags should also apply to heavyweight plastic carrier bags. Last, the Marine and Water Framework Directives should specifically address plastic waste affecting water quality.
A conceptual model was constructed for the functioning the algae-dominated rocky reef ecosystem of the Mediterranean Sea. The Ecosystem-Based Quality Index (reef-EBQI) is based upon this model. This index meets the objectives of the EU Marine Strategy Framework Directive. It is based upon (i) the weighting of each compartment, according to its importance in the functioning of the ecosystem; (ii) biological parameters assessing the state of each compartment; (iii) the aggregation of these parameters, assessing the quality of the ecosystem functioning, for each site; (iv) and a Confidence Index measuring the reliability of the index, for each site. The reef-EBQI was used at 40 sites in the northwestern Mediterranean. It constitutes an efficient tool, because it is based upon a wide set of functional compartments, rather than upon just a few species; it is easy and inexpensive to implement, robust and not redundant with regard to already existing indices.
For almost 50 years scientists have been drawing attention to marine plastics, working to increase what we know about their incidence and impacts. However, how we come to know things is just as important as what we know. How do oceanic plastics become understood and how does this influence what we decide to do about them? Drawing upon discard studies and cultural geographies, this paper details processes of understanding and problematising marine debris by considering the practices of: an activist working with Indigenous communities to track and manage discarded fishing gear, a scientist investigating the influence of plastics in the lives of sea turtles, and Indigenous artists using oceanic debris as their material. Rather than categorising these knowledge as either lay or scientific, creating a sense of opposition, the concept of traces – material, immaterial, methodological – is employed to foreground the contingency and multiplicity involved. In this way, insight is gained about the materials, embodiments, affects and techniques involved in producing knowledge about oceanic plastics, as well as about how responses to this detritus become articulated and shared with wider publics.
Marine deposits of sunken wood provide an important habitat for deep-sea biota, including an extensive wood-endemic invertebrate fauna. These habitats are important in their own right; many species on organic falls are not able to survive in other deep sea ecosystems. Evolutionary transitions of species among various chemosynthesis-based ecosystems does not proceed deliberately from organic falls toward hydrothermal vents. Polyplacophoran molluscs (chitons) are generally rare in deep-sea systems but are found in comparatively high diversity and abundance on tropical sunken wood. A new time-calibrated phylogeny for the predominantly deep-sea order Lepidopleurida shows the chiton lineages found in sunken wood habitats do not comprise a single clade or radiation, but represents a minimum of three independent radiations in the Pacific alone. Most marine invertebrate groups diversified in the deep sea following the end Cretaceous extinction event; by contrast, sunken-wood chitons may have persisted in these habitats for longer than other animals. Fossil chitons from the early Carboniferous (ca. 350 Mya) have strong similarities to modern wood-endemic taxa, yet the common ancestor of living Lepidopleurida occurred much later in the Triassic and did not apparently rely on woodfall. Clades within Lepidopleurida that occupy wood habitats in the tropical Pacific probably arose in the Jurassic, which corresponds to evidence from the fossil record, but with an additional separate colonisation more recently in the early Paleogene. Wood-endemic chiton species encompass multiple independent evolutionary origins of co-occurring wood species, and these separate lineages correspond to differences in micohabitat and feeding strategies. These patterns demonstrate the ongoing evolutionary linkages between terrestrial and deep marine environments, and the opportunistic adaptations of deep-sea organisms.
The island nations and territories of the South Pacific are facing a number of pressing environmental concerns, including solid waste management and coastal pollution. Here we provide baseline information on the presence and concentration of heavy metals and selected organic contaminants (pesticides, PAHs, phthalates) in 7 coastal streams and in surface waters adjacent to the Futiga landfill in American Samoa. All sampled stream sediments contained high concentrations of lead, and some of mercury. Several coastal stream waters showed relatively high concentrations of diethyl phthalate and of organophosphate pesticides, above chronic toxicity values for fish and other aquatic organisms. Parathion, which has been banned by the US Environmental Protection Agency since 2006, was detected in several stream sites. Increased monitoring and initiatives to limit non-point source land-based pollution will greatly improve the state of freshwater and coastal resources, as well as reduce risks to human health in American Samoa.
Global climate change poses a serious threat to the future health of coral reef ecosystems. This calls for management strategies that are focused on maximizing the evolutionary potential of coral reefs. Fundamental to this is an accurate understanding of the spatial genetic structure in dominant reef-building coral species. In this study, we apply a genotyping-by-sequencing approach to investigate genome-wide patterns of genetic diversity, gene flow, and local adaptation in a reef-building coral, Pocillopora damicornis, across 10 degrees of latitude and a transition from temperate to tropical waters. We identified strong patterns of differentiation and reduced genetic diversity in high-latitude populations. In addition, genome-wide scans for selection identified a number of outlier loci putatively under directional selection with homology to proteins previously known to be involved in heat tolerance in corals and associated with processes such as photoprotection, protein degradation, and immunity. This study provides genomic evidence for both restricted gene flow and local adaptation in a widely distributed coral species, and highlights the potential vulnerability of leading-edge populations to rapid environmental change as they are locally adapted, reproductively isolated, and have reduced levels of genetic diversity.
Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45–2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02–2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems.
Microplastics (<5 mm) are contaminants of emerging global concern. They have received considerable attention in scientific research, resulting in an increased awareness of the issue among politicians and the general public. However, there has been significant variation in sampling and extraction procedures used to quantify microplastics levels. The difference in extraction procedures can especially impact study outcomes, making it difficult, and sometimes impossible, to directly compare results among studies. To address this, we recently developed a standard operating procedure (SOP) for sampling microplastics on beaches. We are now assessing regional and global variations in beach microplastics using this standardized approach for 2 research projects. Our first project involves the general public through citizen science. Participants collect sand samples from beaches using a basic protocol, and we subsequently extract and quantify microplastics in a central laboratory using the SOP. Presently, we have 80+ samples from around the world and expect this number to further increase. Second, we are conducting 2, in-depth, regional case studies: one along the Dutch coast (close to major rivers, a known source of microplastic input into marine systems), and the other on the Lesser Antilles in the Caribbean (in the proximity to a hotspot of plastics in the North Atlantic Ocean). In both projects, we use our new SOP to determine regional variation in microplastics, including differences in physicochemical characteristics such as size, shape, and polymer type. Our research will provide, for the first time, a systematic comparison on levels of microplastics on beaches at both a regional and global scale.