A commonly cited reason for the failure of time-area closures to achieve fisheries management goals is the displacement of fishing effort from inside the closure into the surrounding area still open to fishing. Designing time-area closures that are predicted to achieve management goals under multiple spatial patterns of effort redistribution will increase chances of success. Using data from an estuarine gill net fishery, we tested if there are time-area closures predicted to reduce bycatch of two protected species groups while maintaining target catch under four simulated effort redistribution patterns. We found that the pattern of effort redistribution had a substantial impact on the amount of predicted bycatch in each closure scenario. Multiple closures were predicted to reduce bycatch of these species under all four simulations of effort redistribution. However, some combinations of closure and effort redistribution pattern resulted in estimated bycatch being higher than without a closure. We did not find any time-area closures that resulted in a predicted reduction in bycatch while maintaining target catch at original levels. We demonstrate a simple way for fisheries managers to account for the uncertainty in fishers' behavior by designing time-area closures that are predicted to reduce bycatch under multiple potential patterns of spatial redistribution of fishing effort.
The recreational, catch and release fishery for fishes that inhabit shallow-water, coastal marine habitats in tropical and sub-tropical regions (called the flats fishery) is economically valuable and increasingly perceived as a sustainable ecotourism pursuit. However, knowledge of many aspects of target species (such as bonefish, tarpon and permit) ecology is incomplete, and fishery- and non-fishery-related threats to the fish and habitats are numerous and often poorly understood. The International Bonefish and Tarpon Symposium is convened every three years to share new knowledge and to chart directions for future research, with a focus on research that informs conservation and management. Most of the articles in this Special Issue focus on the flats fishery in the Caribbean Sea, Gulf of Mexico, and western North Atlantic ocean, but the findings presented here provide guidance for similar work in other regions. Conservation and management of flats fisheries present a challenge because the fisheries are typically data poor; they occur in locations that lack resources and there are scant data on the target species and their habitats. Since earlier symposia, much has been accomplished to fill knowledge gaps and contribute actionable knowledge to conservation. Studies are being replicated across a wider geographic range, and connectivity is being studied at local and regional scales. Citizen science and local ecological knowledge have contributed to a better understanding of historical trends and ongoing processes. In some instances, data have been applied to proactive habitat protections, as in the Bahamas, and to habitat restoration, as in Florida. In other instances, though much data have been gathered, additional information is needed before a comprehensive conservation strategy is possible, as in the Florida Keys. As the articles contained in this Special Issue demonstrate, a mixed-methods approach that uses complementary sources of information to construct a broad understanding of the flats fishery is necessary to guide research and inform conservation and management.
The intensive harvest of wild populations for food can pose a risk to food security and to conservation goals. While ecosystem approaches to management offer a potential means to balance those risks, they require a method of assessment that is commensurate across multiple objectives. A major challenge is conducting these assessments in a way that considers the priorities and knowledge of stakeholders. In this study, we co-developed an ecological risk assessment (ERA) for fisheries in California (USA) with scientists, managers, and stakeholders. This ERA was intended to meet the requirements of existing policy mandates in the state of California and provide a systematic, efficient, and transparent approach to prioritize fisheries for additional management actions, including the development of fisheries management plans fully compliant with California laws. We assessed the relative risk posed to target species, bycatch, and habitats from nine state-managed fisheries and found risk to target species was not necessarily similar to risks to bycatch and habitat groups. In addition, no single fishery consistently presented the greatest risk for all bycatch or habitat groups. However, considered in combination, the greatest risk for target species, bycatch groups, and habitats emerged from two commercial fisheries for California halibut. The participatory process used to generate these results offers the potential to increase stakeholders' trust in the assessment and therefore its application in management. We suggest that adopting similar processes in other management contexts and jurisdictions will advance progress toward ecosystem-based fisheries management that simultaneously satisfies fisheries, conservation, and relationship-building objectives.
Marine litter is a global threat to marine biodiversity. However, there is a key knowledge gap on the impacts of marine litter in the Philippines – a country of high marine biodiversity and large exclusive economic zone. This gap is addressed here by using information shared on the internet by citizen scientists and conservation groups to assess the impacts of marine litter on megafauna. Facebook, presently the largest social media platform, was scanned for posts concerning the interaction between litter and marine species in the Philippines. Results showed thirty-two individuals from 17 species were affected by marine litter in the country. Furthermore, ingestion (61%) was the most frequent interaction reported. Mindanao was also identified as a hotspot for marine litter interactions. The study highlights the utility of social media in providing data to create an inventory of marine species adversely affected by litter and the spatial distribution of these interactions.
To verify weather mangroves act as sinks for marine litter, we surveyed through visual census 20 forests along the Red Sea and the Arabian Gulf, both in inhabited and remote locations. Anthropogenic debris items were counted and classified along transects, and the influence of main drivers of distribution were considered (i.e. land-based and ocean-based sources, density of the forest and properties of the object). We confirmed that distance to major maritime traffic routes significantly affects the density of anthropogenic debris in Red Sea mangrove forests, while this was independent of land-based activities. This suggests ocean-based activities combined with surface currents as major drivers of litter in this basin. Additionally, litter was more abundant where the mangrove density was higher, and object distribution through the mangrove stand often depended on their shape and dimension. We particularly show that pneumatophores act as a sieve retaining large plastic objects, leading to higher plastic mass estimates in mangroves compared to those of beaches previously surveyed in the Red Sea.
The objective of this study is to analyse, from a legal point of view, the influence of the transposition of Marine Spatial Planning Directive into both Spanish and Portuguese domestic laws on the development of marine renewable energies in both countries. This article concludes that the Portuguese legal system is more favourable for the development of marine renewable energies than the Spanish legal regime, since the former establishes a more flexible planning system, sets criteria for the prioritisation of marine uses, incorporates trade-off mechanisms, introduces an electronic single-window system and regulates a pilot zone. These measures can help streamline licensing processes, avoid and resolve conflicts with other sea users, and adapt planning instruments to the rapid development of new marine renewable technologies. However, both legal regimes lack specific legal mechanisms aimed at offering effective protection of the marine environment against negative effects arising from the installation of such devices. Similarly, there is a lack of coordination between maritime spatial planning instruments and land planning instruments, and between the Central Government and the autonomous regions. This may hinder the installation of marine renewable energies. This study has implications in relation to the EU integrated marine policy aimed at achieving a balance between blue growth and the conservation of the marine environment, as well as an inter-administrative coordination improvement in decision-making.
The offshore renewable energy sector has challenging requirements related to the physical simulation of the ocean environment for the purpose of evaluating energy generating technologies. In this paper the demands of the wave and tidal energy sectors are considered, with measurement and characterisation of the environment explored and replication of these conditions described. This review examines the process of advanced ocean environment replication from the sea to the tank, and rather than an exhaustive overview of all approaches it follows the rationale behind projects led, or strongly connected to, the late Professor Ian Bryden. This gives an element of commonality to the motivations behind marine data acquisition programmes and the facilities constructed to take advantage of the resulting datasets and findings. This review presents a decade of flagship research, conducted in the United Kingdom, at the interfaces between physical oceanography, engineering simulation tools and industrial applications in the area of offshore renewable energy. Wave and tidal datasets are presented, with particular emphasis on the novel tidal measurement techniques developed for tidal energy characterisation in the Fall of Warness, Orkney, UK. Non-parametric wave spectra characterisation methodologies are applied to the European Marine Energy Centre's (EMEC) Billia Croo wave test site, giving complex and highly realistic site-specific directional inputs for simulation of wave energy sites and converters. Finally, the processes of recreating the resulting wave, tidal, and combined wave-current conditions in the FloWave Ocean Energy Research Facility are presented. The common motivations across measurement, characterisation, and test tank are discussed with conclusions drawn on the strengths, gaps and challenges associated with detailed site replication.
Microplastic (MP) pollution is an emerging issue in aquatic sciences. Little comparative information currently exists about the problem in coastal systems exposed to different levels of human impact. Here we report a year-long study on the abundance of MP in the water column of three estuaries on the east-coast of Australia. The estuaries are subject to different scales of human impact; the Clyde estuary has little human modification, the Bega estuary has a small township and single wastewater treatment works discharging to its waters, and the Hunter estuary which has multiple townships, multiple wastewater treatment plants, and heavy industry. MP abundance followed an expected pattern with the lowest abundance in the low-impact Clyde estuary (98 part. m3), moderate levels of MP in the moderately impacted Bega estuary (246 part. m3), and high MP abundance in the highly impacted Hunter estuary (1,032 part. m3). The majority of particles were < 200 μm and fragment-like rather than fiber-like. MP abundance was positively related to maximum antecedent rainfall in the Bega estuary, however there are no clear environmental factors that could explain MP variation in the other systems. MP were generally higher in summer and following freshwater inflow events. On the Hunter estuary MP abundance was at times as high as zooplankton abundance, and within the range of numbers reported in other highly impacted systems globally. The results confirm that higher levels of human impact lead to greater plastic pollution and highlight the need to examine aquatic ecosystems under a range of conditions in order to adequately characterize the extent of MP pollution in rivers and coastal systems.
As petroleum development and other activities move further north, the potential for oil spills in ice-covered waters is of great concern. As a tool for contingency planning and forecasting during response, oil spill models play a key role. With the development of new, high-resolution coupled ice-ocean models, better predictions of sea ice are becoming available. We have updated the OSCAR oil spill model to use sea-ice velocity and coverage fields from coupled ice-ocean models to improve simulation of oil fate and transport in ice-covered waters.
We describe the implementation of oil transport in the presence of ice, and demonstrate the improvement by considering three case studies. We find clear improvement when taking ice velocity from a coupled ice-ocean model into account, compared to a heuristic model that uses surface current and wind velocity. The difference is found to be especially important in a response situation near the marginal ice zone.
While ballast water has long been linked to the global transport of invasive species, little is known about its microbiome. Herein, we used 16S rRNA gene sequencing and metabarcoding to perform the most comprehensive microbiological survey of ballast water arriving to hub ports to date. In total, we characterized 41 ballast, 20 harbor, and 6 open ocean water samples from four world ports (Shanghai, China; Singapore; Durban, South Africa; Los Angeles, California). In addition, we cultured Enterococcus and E. coli to evaluate adherence to International Maritime Organization standards for ballast discharge. Five of the 41 vessels – all of which were loaded in China – did not comply with standards for at least one indicator organism. Dominant bacterial taxa of ballast water at the class level were Alphaproteobacteria, Gammaproteobacteria, and Bacteroidia. Ballast water samples were composed of significantly lower proportions of Oxyphotobacteria than either ocean or harbor samples. Linear discriminant analysis (LDA) effect size (LEfSe) and machine learning were used to identify and test potential biomarkers for classifying sample types (ocean, harbor, ballast). Eight candidate biomarkers were used to achieve 81% (k nearest neighbors) to 88% (random forest) classification accuracy. Further research of these biomarkers could aid the development of techniques to rapidly assess ballast water origin.