Over the last 20 years, marine/maritime spatial planning (MSP)1 has gained a strong political presence in Europe and elsewhere. Before 2006, only a hand- ful of countries had begun to spatially plan sea areas, such as China, where marine functional zoning was first proposed by government in 1998. In Europe, efforts began in 2002 as part of the EU-funded BaltCoast project involving Germany, Sweden, Estonia, Poland, Latvia, Denmark and Finland. Belgium, Germany and the Netherlands then became forerunners of MSP in Europe, approving integrated management plans for their waters in 2005. By 2017, the number of countries with MSP initiatives of some type had grown to about 60, the majority of which are in Europe but also some in Central America, Africa and Asia (Ehler 2017; Santos et al. 2019).2
Juvenile scallops of Pecten maximus were studied to see the capability to clear out and incorporate salmon feed and feces (30 μg L-1). Algae were also given, in a low and high concentration in addition to feed and feces, to mimic a winter and summer situation in Norwegian waters. Rhodomonas baltica and Chaetoseris muelleri were provided in a concentration of 50 μg L-1 and 300 μg L-1. The feeding trial lasted for 27 days. Clearance rate was measured to study filtration characteristics, while fatty acid profiling and stable isotopes of nitrogen and carbon were used to trace the uptake of salmon feed and feces in the digestive gland and muscle of juvenile scallops (30–35 mm shell height). The results show that the scallops could clear out and retain both salmon feed and feces particles, although at a statistically lower clearance rate than the algae. Fatty acid profiling revealed that the scallops assimilated and incorporated the consumed salmon feed and feces, given with either high or low algae concentrations, in their tissues, where the fatty acid C18:1n9 was used as a tracer fatty acid. The digestive gland of the scallops that were fed salmon feed and feces contained a higher share of C18:1n9 than those that were only fed algae. The digestive gland reflected the fatty acid composition of the diet, while the fatty acid composition of the muscle, which also changed, reflected a more complex relation between diet and metabolic processes in the tissue. The use of stable isotopes of carbon and nitrogen to trace food sources was inconclusive in this study due to low differences between samples fed different feeds. Fatty acid profiling was a more sensitive method for tracing low concentrations of salmon feed and feces in the algae diet of scallops. Our results suggest that P. maximus could be a candidate for integrated multitrophic aquaculture (IMTA) and that scallops have the potential to utilize small particles of wasted salmon feed and feces during a winter situation with low phytoplankton concentration and during an algal bloom in Norwegian waters.
Caribbean coral reefs are undergoing massive degradation, with local increases of macroalgae and reduction of architectural complexity associated with loss of reef-building corals. We explored whether reef degradation affects the feeding ecology of two co-occurring spiny lobsters: Panulirus guttatus, which is an obligate reef-dweller, and Panulirus argus, which uses various benthic habitats including coral reefs. We collected lobsters of both species from the back-reef zones of two large reefs similar in length (∼1.5 km) but differing widely in level of degradation, at the Puerto Morelos Reef National Park (Mexico). We measured the carapace length (CL) and weight (W) of lobsters, estimated three condition indices (hepatosomatic index, HI; blood refractive index, BRI; and W/CL ratio), and analyzed their stomach contents and stable isotope values (δ15N and δ13C). All lobsters tested negative for the presence of the virus PaV1, which can affect nutritional condition. Stomach contents yielded 72 animal taxa, mainly mollusks and crustaceans, with an average of 35 taxa per species per reef, but with much overlap. In P. guttatus, CL, HI, BRI, and W/CL did not vary with reef, but mean isotopic values did. The isotopic niche of P. guttatus showed little overlap between reefs, reflecting differences in local carbon sources and underlining the habitat specialization of P. guttatus, which exhibited a higher trophic position on the more degraded reef. Overall, the trophic position of P. guttatus was higher than that of P. argus. In P. argus, none of the variables differed between reefs and the isotopic niche was wide and with great overlap between reefs, reflecting the broader foraging ranges of P. argus compared to P. guttatus. Additional isotopic values from 16 P. arguscaught at a depth of 25 m in the fore reef suggest that these larger lobsters forage over different habitats and have a higher trophic position than their smaller conspecifics and congeners from the back reef. The feeding ecology of P. argus appears to be less influenced by coral reef degradation than that of P. guttatus, but our results suggest a buffering effect of omnivory against habitat degradation for both lobster species.
Corallivory is the predation of coral mucus, tissue, and skeleton by fishes and invertebrates, and a source of chronic stress for many reef-building coral species. Corallivores often prey on corals repeatedly, and this predation induces wounds that require extensive cellular resources to heal. The effects of corallivory on coral growth, reproduction, and community dynamics are well-documented, and often result in reduced growth rates and fitness. Given the degree of anthropogenic pressures that threaten coral reefs, it is now imperative to focus on understanding how corallivory interacts with anthropogenic forces to alter coral health and community dynamics. For example, coral bleaching events that stem from global climate change often reduce preferred corals species for many corallivorous fishes. These reductions in preferred prey may result in declines in populations of more specialized corallivores while more generalist corallivores may increase. Corallivory may also make corals more susceptible to thermal stress and exacerbate bleaching. At local scales, overfishing depletes corallivorous fish stocks, reducing fish corallivory and bioerosion, whilst removing invertivorous fishes and allowing population increases in invertebrate corallivores (e.g., urchins, Drupella spp.). Interactive effects of local stressors, such as overfishing and nutrient pollution, can alter the effect of corallivory by increasing coral-algal competition and destabilizing the coral microbiome, subsequently leading to coral disease and mortality. Here, we synthesize recent literature of how global climate change and local stressors affect corallivore populations and shape the patterns and effect of corallivory. Our review indicates that the combined effects of corallivory and anthropogenic pressures may be underappreciated and that these interactions often drive changes in coral reefs on scales from ecosystems to microbes. Understanding the ecology of coral reefs in the Anthropocene will require an increased focus on how anthropogenic forcing alters biotic interactions, such as corallivory, and the resulting cascading effects on corals and reef ecosystems.
The Ocean Observatories Initiative (OOI) is a United States National Science Foundation-funded major research facility that provides continuous observations of the ocean and seafloor from coastal and open ocean locations in the Atlantic and Pacific. Multiple cycles of OOI infrastructure deployment, recovery, and refurbishment have occurred since operations began in 2014. This heterogeneous ocean observing infrastructure with multidisciplinary sampling in important but challenging locations has provided new scientific and engineering insights into the operation of a sustained ocean observing system. This paper summarizes the challenges, successes, and failures experienced to date and shares recommendations on best practices that will be of benefit to the global ocean observing community.
Recently, marine reserves have become a widely advocated approach to marine conservation. However, these studies beg the question as to how the selection imposed by harvesting and the dispersal rates between two patches influence stock abundance and the maximum fishery yield from the perspective of mathematical model. In this paper, a prey–predator model with selective harvesting by incorporating two discrete state delays in age and size for both the species in unreserve area has been established. Considering the resources exploitation and ecological observation, a hybrid optimal problem with Lagrange function and state delays together with characteristic times is formulated. We then develop an efficient numerical method by the lights of optimal state delay control method and Pontryagin-type minimum (maximum) principle. Finally, we discuss the impacts of selection for harvesting ages and efforts as well as migration coefficients on the fishery abundance and maximal yield by a series of simulations. Our results manifest: (1) after establishing protected areas, the oscillating amplitudes of prey and predator in unprotected areas are lessened and the stocks of predator in both areas are greatly enhanced with increasing of dispersal rates. (2) selective harvest tactics is appropriate for the strong intensity harvest in order to increase the abundance of all populations; (3) at the specific ages, optimal harvest efforts can enhance greatly fishery yield for the harvested population. However, the too late harvest for populations can reduce fishery sustainable yield, and this undesirable effects should be considered alongside harvest efforts when developing hunting regulations or policies; (4) the appropriate age selections will bring about the higher yield when the over-exploitation is implemented; (5) creating reserved areas only for preys greatly enhances fishery stocks and the sustainable yield than the other two patterns. However, setting reserved areas merely for the predator population is undesirable for increasing the fishery stock and yield.
The Persian/Arabian Gulf (hereafter, ‘the Gulf’) is an environmentally extreme sea that is being increasingly affected by climate change and anthropogenic stressors, and concern is growing about the future of marine biodiversity in the region. However, identification of species and habitats most in need of conservation is challenging as comprehensive information on species-specific threats and population statuses is lacking. Through application of the International Union for Conservation of Nature (IUCN)Red List methodology – the global accepted standard for classifying extinction risk at the species level – we evaluated the regional conservation status of 471 species of marine bony fishes in the Gulf. The best estimate of the proportion of regionally threatened marine bony fishes, based on all species for which sufficient data were available for assessment, is 8.2%; this is at least twice the proportion of other regions where such assessments have been undertaken. Primary threats include those related to fisheries and& harvesting and those related to coastal development and loss of habitat, impacting 47% and 32% of marine bony fishes, respectively. Such threats are particularly acute in nearshore areas where spatial analyses indicated high species richness. The future of Gulf ecosystems, and the survival of the marine bony fishes, will depend on concerted, collaborative efforts among all Gulf States to develop efficient and effective local and regional marine conservation practices and policies, particularly for species assessed as regionally threatened.
A major problem worldwide is the rapid change in species abundance and distribution, which is rapidly restructuring the biological communities of many ecosystems under changing climates. Tracking these transformations in the marine environment is crucial but our understanding is often hampered by the absence of historical data and by the practical challenge of survey large geographical areas. Here we focus on the Mediterranean Sea, a region which is warming faster than the rest of the global ocean, tracing back the spatio-temporal dynamic of species, which are emerging the most in terms of increasing abundances and expanding distributions. To this aim, we accessed the Local Ecological Knowledge (LEK) of small-scale and recreational fishers reconstructing the dynamics of fish perceived as ‘new’ or increasing in different fishing area. Over 500 fishers across 95 locations and 9 different countries were interviewed and semi-quantitative information on yearly changes in species abundance was collected. Overall, 75 species were mentioned by the respondents, being the most frequent citations related to warm-adapted species of both, native and exotic origin. Respondents belonging to the same biogeographic sectors described coherent spatio-temporal dynamics, and gradients along latitudinal and longitudinal axes were revealed. This information provides a more complete understanding of recent bio-geographical changes in the Mediterranean Sea and it also demonstrates that adequately structured LEK methodology might be applied successfully beyond the local scale, across national borders and jurisdictions. Acknowledging this potential through macro-regional coordination, could pave the ground for future large-scale aggregations of individual observations, increasing our potential for integrated monitoring and conservation planning at the regional or even global level.
Park managers call for cost-effective and innovative solutions to handle a wide variety of environmental problems that threaten biodiversity in protected areas. Recently, drones have been called upon to revolutionize conservation and hold great potential to evolve and raise better-informed decisions to assist management. Despite great expectations, the benefits that drones could bring to foster effectiveness remain fundamentally unexplored. To address this gap, we performed a literature review about the use of drones in conservation. We selected a total of 256 studies, of which 99 were carried out in protected areas. We classified the studies in five distinct areas of applications: “wildlife monitoring and management”; “ecosystem monitoring”; “law enforcement”; “ecotourism”; and “environmental management and disaster response”. We also identified specific gaps and challenges that would allow for the expansion of critical research or monitoring. Our results support the evidence that drones hold merits to serve conservation actions and reinforce effective management, but multidisciplinary research must resolve the operational and analytical shortcomings that undermine the prospects for drones integration in protected areas.
In the Pacific Northwest, residents are mobilizing to prevent the coastal export of fossil fuels and protect unique ecosystems and place-based communities. This paper examines the diverse groups, largely from the Bellingham area, and how they succeeded in blocking construction of what was to be the largest coal-shipping port in North America, the Gateway Pacific Terminal (GPT). Tribes, environmental organizations, faith-based groups, and other citizen groups used a multitude of approaches to prevent development, both independently and in concert. This paper reviews the various ways in which the groups collaborated and supported one another to resist the neoliberalization of the coast and support local sovereignty, unique ecosystems, and place-based communities. Groups like Power Past Coal, Protect Whatcom, and Coal-Free Bellingham fought for important and protective changes and evidenced communitywide political support, but the sovereign rights of the Lummi Nation were the legal bar to constructing the coal terminal.
Sea noise collected over 2003 to 2017 from the Perth Canyon, Western Australia was analysed for variation in the South Eastern Indian Ocean pygmy blue whale song structure. The primary song-types were: P3, a three unit phrase (I, II and III) repeated with an inter-song interval (ISI) of 170–194 s; P2, a phrase consisting of only units II & III repeated every 84–96 s; and P1 with a phrase consisting of only unit II repeated every 45–49 s. The different ISI values were approximate multiples of each other within a season. When comparing data from each season, across seasons, the ISI value for each song increased significantly through time (all fits had p<< 0.001), at 0.30 s/Year (95%CI 0.217–0.383), 0.8 s/Year (95%CI 0.655–1.025) and 1.73 s/Year (95%CI 1.264–2.196) for the P1, P2 and P3 songs respectively. The proportions of each song-type averaged at 21.5, 24.2 and 56% for P1, P2 and P3 occurrence respectively and these ratios could vary by up to ± 8% (95% CI) amongst years. On some occasions animals changed the P3 ISI to be significantly shorter (120–160 s) or longer (220–280 s). Hybrid song patterns occurred where animals combined multiple phrase types into a repeated song. In recent years whales introduced further complexity by splitting song units. This variability of song-type and proportions implies abundance measure for this whale sub population based on song detection needs to factor in trends in song variability to make data comparable between seasons. Further, such variability in song production by a sub population of pygmy blue whales raises questions as to the stability of the song types that are used to delineate populations. The high level of song variability may be driven by an increasing number of background whale callers creating ‘noise’ and so forcing animals to alter song in order to ‘stand out’ amongst the crowd.
Collective action of resource users is essential for sustainability. Yet, often user groups are socioculturally heterogeneous, which requires cooperation to be established across salient group boundaries. We explore the effect of this type of heterogeneity on resource extraction in lab-in-the-field Common Pool Resource (CPR) experiments in Zanzibar, Tanzania. We create heterogeneous groups by mixing fishers from two neighbouring fishing villages which have distinct social identities, a history of conflict and diverging resource use practices and institutions. Additionally, we analyse between-village differences in extraction behaviour in the heterogeneous setting to assess if out-group cooperation in a CPR dilemma is associated with a community’s institutional scope in the economic realm (e.g., degree of market integration). We find no aggregate effect of heterogeneity on extraction. However, this is because fishers from the two villages behave differently in the heterogeneity treatment. We find support for the hypothesis that cooperation under sociocultural heterogeneity is higher for fishers from the village with larger institutional scope. In line with this explanation, cooperation under heterogeneity also correlates with a survey measure of individual fishers’ radius of trust. We discuss implications for resource governance and collective action research.
The U.S. Endangered Species Act (ESA) is a powerful environmental law protecting imperiled plants and animals, and a growing number of marine species have been protected under this law as extinction risk in the oceans has increased. Marine mammals and sea turtles comprise 38% of the 163 ESA-listed marine “species”, which includes subspecies and distinct population segments, yet analyses of recovery trends after listing are lacking. Here we gathered the best available annual abundance estimates for geographically delimited populations of all 62 marine mammal and sea turtle species listed under the ESA. Of these, we chose representative populations of species that were listed before 2012, occur and reproduce in U.S. waters, and have data of sufficient quality and timespan for trend analyses. Thus, we quantitatively analyzed population trends, magnitude of population change, and recovery status for 23 and 8 representative populations of 14 marine mammal and 5 sea turtle species, respectively. Using generalized linear and non-linear models, we found that 18 marine mammal (78%) and 6 sea turtle (75%) populations significantly increased after listing; 3 marine mammal (13%) and 2 sea turtle (25%) populations showed non-significant changes; while 2 marine mammal (9%), but no sea turtle populations declined after ESA protection. Overall, the 24 populations that increased in abundance were from species listed for 20 years or more (e.g., large whales, manatees, and sea turtles). Conservation measures triggered by ESA listing such as ending exploitation, tailored species management, and fishery regulations, and other national and international measures, appear to have been largely successful in promoting species recovery, leading to the delisting of some species and to increases in most populations. These findings underscore the capacity of marine mammal and sea turtle species to recover from substantial geographical population declines when conservation actions are implemented in a timely and effective manner.
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.