To establish an estimation procedure for reliable catch amount of illegal, unreported and unregulated (IUU) fishing, light-gathering fishing operations in the northwestern Pacific were analyzed based on the Visible Infrared Imaging Radiometer Suite (VIIRS) day/night band (DNB) data provided by the Suomi National Polar Partnership (SNPP) satellite. The estimated fishing activities were compared with the navigation tracks of vessels obtained from the automatic identification system (AIS). As a model case, the fishing activities of Chinese fishing boats using fish aggregation lights outside the Japanese EEZ in the northwestern Pacific were analyzed from mid-June to early-September 2016. Integration analyses of VIIRS DNB data and AIS information provided reliable data for estimating the fishing activities of Chinese fishing boats and suggested the importance of estimating fish carrier ship movements. The total amount of the chub mackerel (Scomber japonicus) catch during this period was independently estimated from three angles: 1) the fishing capacity of the fishing boats, 2) the freezing capacity of refrigeration factory ships ;and 3) the fish hold capacity of the fish carrier ships, based on information obtained from interviews with Chinese fisheries companies. These estimates indicated that the total amount of mackerel catch by Chinese fisheries was more than 80% of the allowable biological catch (ABC) of Japan in this area in 2016. This suggests that Pacific high seas fishing has a significant impact on the future of fish abundance. Our proposed procedure raises the possibility of evaluating the fishing impact of some forms of IUU fisheries independently from conventional statistical reports.
Human Impacts on the Environment
Understanding cumulative effects of multiple threats is key to guiding effective management to conserve endangered species. The critically endangered, Southern Resident killer whale population of the northeastern Pacific Ocean provides a data-rich case to explore anthropogenic threats on population viability. Primary threats include: limitation of preferred prey, Chinook salmon; anthropogenic noise and disturbance, which reduce foraging efficiency; and high levels of stored contaminants, including PCBs. We constructed a population viability analysis to explore possible demographic trajectories and the relative importance of anthropogenic stressors. The population is fragile, with no growth projected under current conditions, and decline expected if new or increased threats are imposed. Improvements in fecundity and calf survival are needed to reach a conservation objective of 2.3% annual population growth. Prey limitation is the most important factor affecting population growth. However, to meet recovery targets through prey management alone, Chinook abundance would have to be sustained near the highest levels since the 1970s. The most optimistic mitigation of noise and contaminants would make the difference between a declining and increasing population, but would be insufficient to reach recovery targets. Reducing acoustic disturbance by 50% combined with increasing Chinook by 15% would allow the population to reach 2.3% growth.
Land-based activities, including deforestation, agriculture, and urbanisation, cause increased erosion, reduced inland and coastal water quality, and subsequent loss or degradation of downstream coastal marine ecosystems. Quantitative approaches to link sediment loads from catchments to metrics of downstream marine ecosystem state are required to calculate the cost effectiveness of taking conservation actions on land to benefits accrued in the ocean. Here we quantify the relationship between sediment loads derived from landscapes to habitat suitability of seagrass meadows in Moreton Bay, Queensland, Australia. We use the following approach: (1) a catchment hydrological model generates sediment loads; (2) a statistical model links sediment loads to water clarity at monthly time-steps; (3) a species distribution model (SDM) factors in water clarity, bathymetry, wave height, and substrate suitability to predict seagrass habitat suitability at monthly time-steps; and (4) a statistical model quantifies the effect of sediment loads on area of seagrass suitable habitat in a given year. The relationship between sediment loads and seagrass suitable habitat is non-linear: large increases in sediment have a disproportionately large negative impact on availability of seagrass suitable habitat. Varying the temporal scale of analysis (monthly vs. yearly), or varying the threshold value used to delineate predicted seagrass presence vs. absence, both affect the magnitude, but not the overall shape, of the relationship between sediment loads and seagrass suitable habitat area. Quantifying the link between sediment produced from catchments and extent of downstream marine ecosystems allows assessment of the relative costs and benefits of taking conservation actions on land or in the ocean, respectively, to marine ecosystems.
Interactions between marine mammals and plastic debris have been the focus of studies for many years. Examples of interactions include entanglement in discarded fishing items or the presence of ingested debris in digestive tracts. Plastics, including microplastics, are a form of marine debris globally distributed in coastal areas, oceanic waters and deep seas. Cetaceans which strand along the coast present a unique opportunity to study interactions between animals with macro- and microplastics. A combination of novel techniques and a review of historical data was used to complete an extensive study of cetaceans interacting with marine debris within Irish waters. Of the 25 species of marine mammals reported in Irish waters, at least 19 species were reported stranded between 1990 and 2015 (n = 2934). Two hundred and forty-one of the stranded cetaceans presented signs of possible entanglement or interactions with fisheries. Of this number, 52.7% were positively identified as bycatch or as entangled in fisheries items, 26.6% were classified as mutilated and 20.7% could not be related to fisheries but showed signs of entanglement. In addition, 274 cetaceans were recorded as by-catch during observer programmes targeting albacore tuna. Post-mortem examinations were carried out on a total of 528 stranded and bycaught individuals and 45 (8.5%) had marine debris in their digestive tracts: 21 contained macrodebris, 21 contained microdebris and three had both macro- and microdebris. Forty percent of the ingested debris were fisheries related items. All 21 individuals investigated with the novel method for microplastics contained microplastics, composed of fibres (83.6%) and fragments (16.4%). Deep diving species presented more incidences of macrodebris ingestion but it was not possible to investigate this relationship to ecological habitat. More research on the plastic implications to higher trophic level organisms is required to understand the effects of these pollutants.
Since the Third U.S. National Climate Assessment (NCA3) was published in May 2014, new observations along multiple lines of evidence have strengthened the conclusion that Earth’s climate is changing at a pace and in a pattern not explainable by natural influences. While this report focuses especially on observed and projected future changes for the United States, it is important to understand those changes in the global context.
Better mitigation of anthropogenic stressors on marine ecosystems is urgently needed to address increasing biodiversity losses worldwide. We explore opportunities for stressor mitigation using whole-of-systems modelling of ecological resilience, accounting for complex interactions between stressors, their timing and duration, background environmental conditions and biological processes. We then search for ecological windows, times when stressors minimally impact ecological resilience, defined here as risk, recovery and resistance. We show for 28 globally distributed seagrass meadows that stressor scheduling that exploits ecological windows for dredging campaigns can achieve up to a fourfold reduction in recovery time and 35% reduction in extinction risk. Although the timing and length of windows vary among sites to some degree, global trends indicate favourable windows in autumn and winter. Our results demonstrate that resilience is dynamic with respect to space, time and stressors, varying most strongly with: (i) the life history of the seagrass genus and (ii) the duration and timing of the impacting stress.
The states and federal agencies that comprise the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force (Hypoxia Task Force or HTF) continue to work collaboratively to implement the Gulf Hypoxia Action Plan 2008 (2008 Action Plan). Since the release of the plan, each HTF state has developed a nutrient reduction strategy through stakeholder participation that serves as a road map for implementing nutrient reductions in that state; these strategies serve as the cornerstone for reaching the HTF’s goals. The federal members of the HTF issued an updated unified federal strategy in December 2016 to guide assistance to states and continued scientific support (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2016a). In furtherance of its goals, the HTF is also expanding partnerships with organizations with the same or similar goals. In May 2014, the HTF entered into an agreement with 12 land grant universities (LGUs) to reduce gaps in research and outreach/extension needs in the Mississippi/Atchafalaya River Basin (MARB). In February 2016, the HTF released its first Report on Point Source Progress in Hypoxia Task Force States (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2016b). This report documents the nitrogen and phosphorus monitoring data and discharge limits for major sewage treatment plants within the 12 HTF states. The Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2014 (HABHRCA) directs the U.S. Environmental Protection Agency (EPA) Administrator, through the HTF, to submit a progress report biennially to the appropriate congressional committees and the President. In 2015 EPA submitted the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force: 2015 Report to Congress; this report is the second biennial report to Congress (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2015). This 2017 report highlights specific examples of progress achieved by the HTF and its members. The report also discusses strategies for meeting the HTF’s goals, as well as key lessons the HTF has learned, including the importance of: planning and targeting at a watershed scale; identifying the critical pollutants, their sources, and means of transport; using appropriate models to plan and evaluate implementation; using appropriate monitoring designs to evaluate conservation outcomes; understanding farmers’ attitudes toward conservation practices and working with them through appropriate messengers to offer financial and technical assistance; and sustaining engagement with the agricultural community following adoption of conservation systems. As new research and information have become available and systems of conservation practices are implemented on vulnerable lands across this large basin, the HTF has gained a better understanding of the complexities of hypoxia in the Gulf and the efforts and time that will be needed to achieve its goals. In February 2015, the HTF announced that it would retain its goal of reducing the areal extent of the Gulf of Mexico hypoxic zone to less than 5,000 km2 by the year 2035. The HTF agreed on an interim target of a 20 percent nutrient load reduction by the year 2025 as a milestone toward achieving the final goal in 2035. The HTF also agreed to adopt quantitative measures to track progress in reducing point and nonpoint source inputs. To accelerate the reduction of nutrient pollution, the HTF will: • Target vulnerable lands and quantify nutrient load reductions achieved through federal programs, subject to future appropriations. 2 • Implement state nutrient reduction strategies, including targeting vulnerable lands and quantifying nutrient reductions. • Expand and build new partnerships and alliances with universities, the agricultural community, cities, and others. • Track progress towards the interim target and long-term goal, with intent to understand whether the current actions are appropriate to meet the goal. The Hypoxia Task Force looks forward to continuing to use its biennial reports to Congress to report on progress toward reducing nutrient loads to the northern Gulf of Mexico, summarize lessons learned in implementing nutrient reduction strategies, and describe any adjustments to its strategies for reducing Gulf hypoxia.
Anthropogenic impacts on coastal areas have led to an increased degradation of marine environments globally. Eelgrass ecosystems are particularly susceptible to human induced stressors as they are sensitive to low light conditions and usually grow in shallow protected areas where pressure from coastal development is high. The extensive decline in coverage of eelgrass along the Swedish Northwest coast since the 1980s has largely been attributed to the effects of coastal eutrophication and overfishing. However, the impact on eelgrass from small-scale coastal development (docks and marinas) has never been investigated in this area. The aim of this study was to assess the local and large-scale effect of shading by docks and marinas on eelgrass habitats along the Swedish NW coast and to investigate the decision process behind small-scale exploitation to identify problems with the current legislation, which allows for continued exploitation of eelgrass. Through field assessments of eelgrass around docks and analysis of available data on eelgrass and dock distribution along the coast, the present study demonstrates that shading from docks reduced eelgrass coverage with on average 42–64% under and adjacent to the docks, and that floating docks affected larger areas and caused a much stronger reduction in eelgrass coverage (up to 100% loss) compared to docks elevated on poles (up to 70% reduction in coverage). The total eelgrass area negatively affected by docks and marinas along the NW coast was estimated to approximately 480 ha, an area corresponding to over 7% of the present areal coverage of eelgrass in the region. The analysis of decisions for dock construction showed that eelgrass was generally not assessed or considered in the decision process and that 69–88% of the applications were approved also in areas where eelgrass was present. Furthermore, marine protected areas only marginally reduced the approval of applications in eelgrass habitats. The continued small-scale development along the Swedish NW coast constitutes a significant threat to the already decimated coverage of eelgrass along the coast and changes in the management practices are needed in order to achieve both national and international goals on environmental status.
Studies of oil spills on sand beaches have focused traditionally on the effects of short-term oil exposure, with recovery of sand beach macrobenthic communities occurring within several weeks to several years. The Deepwater Horizon spill resulted in chronic, multi-year re-oiling and up to 4 yr of extensive and often intensive treatments. Of the 965 km of sand beaches that were oiled, shoreline treatment was documented on 683 km. Intensive mechanical treatment was conducted from 9 to 45 mo after the initial oiling on 32.4 km of shoreline in Louisiana, and deep beach excavation/sifting and tilling was conducted along 60.5 km in Louisiana, Alabama, and Florida, often along contiguous lengths of beach. Recovery of sand beach invertebrate communities from the combined effects of oiling and treatment would likely be delayed by 2 to 6 yr after the last response action was completed. We introduce the concept of ‘Response Injury’ categories that reflect both intensity and frequency of beach treatment methods. We use the literature on similar types of disturbances to sand beach communities (foot traffic, vehicular traffic, wrack removal, beach nourishment) to describe the expected impacts. Temporal patterns of response-related disturbances can affect seasonal recruitment of organisms and the overall rate of ecosystem recovery from both oil exposure and treatment disturbance. This concept provides a framework for specifically assessing response-related impacts in future spills, which has not been considered in previous injury assessments.
- The application of deicing road salts began in the 1940s and has increased drastically in regions where snow and ice removal is critical for transportation safety. The most commonly applied road salt is sodium chloride (NaCl). However, the increased costs of NaCl, its negative effects on human health, and the degradation of roadside habitats has driven transportation agencies to seek alternative road salts and organic additives to reduce the application rate of NaCl or increase its effectiveness. Few studies have examined the effects of NaCl in aquatic ecosystems, but none have explored the potential impacts of road salt alternatives or additives on aquatic food webs.
- We assessed the effects of three road salts (NaCl, MgCl2 and ClearLane™) and two road salts mixed with organic additives (GeoMelt™ and Magic Salt™) on food webs in experimental aquatic communities, with environmentally relevant concentrations, standardized by chloride concentration.
- We found that NaCl had few effects on aquatic communities. However, the microbial breakdown of organic additives initially reduced dissolved oxygen. Additionally, microbial activity likely transformed unusable phosphorus from the organic additives to usable phosphorus for algae, which increased algal growth. The increase in algal growth led to an increase in zooplankton abundance. Finally, MgCl2 – a common alternative to NaCl – reduced compositional differences of zooplankton, and at low concentrations increased the abundance of amphipods.
- Synthesis and applications. Our results indicate that alternative road salts (to NaCl), and road salt additives can alter the abundance and composition of organisms in freshwater food webs at multiple trophic levels, even at low concentrations. Consequently, road salt alternatives and additives might alter ecosystem function and ecosystem services. Therefore, transportation agencies should use caution in applying road salt alternatives and additives. A comprehensive investigation of road salt alternatives and road salt additives should be conducted before wide-scale use is implemented. Further research is also needed to determine the impacts of salt additives and alternatives on higher trophic levels, such as amphibians and fish.