Marine plastic pollution is a major environmental issue. Given their ubiquitous nature and small dimensions, ingestion of microplastic (MP) and nanoplastic (NP) particles and their subsequent impact on marine life are a growing concern worldwide. Transfers along the trophic chain, including possible translocation, for which the hazards are less understood, are also a major preoccupation. Effects of MP ingestion have been studied on animals through laboratory exposure, showing impacts on feeding activity, reserve depletion and inflammatory responses, with consequences for fitness, notably reproduction. However, most experimental studies have used doses of manufactured virgin microspheres that may not be environmentally realistic. As for most ecotoxicological issues, the environmental relevance of laboratory exposure experiments has recently been debated. Here we review constraints and priorities for conducting experimental exposures of marine wildlife to microplastics based on the literature, feedback from peer reviewers and knowledge gained from our experience. Priorities are suggested taking into account the complexity of microplastics in terms of (i) aggregation status, surface properties and interactions with organic and inorganic materials, (ii) diversity of encountered particles types and concentrations, (iii) particle bioavailability and distribution in experimental tanks to achieve reproducibility and repeatability in estimating effects, and (iv) strict experimental procedures to verify the existence of genuine translocation. Relevant integrative approaches encompass a wide spectrum of methods from -omics to ecophysiological approaches, including modeling, are discussed to provide novel insights on the impacts of MP/NP on marine ecosystems from a long-term perspective. Knowledge obtained in this way would inform stakeholders in such a way as to help them mitigate impacts of the micro- and nano-plastic legacy.
Assessment of mangrove ecosystem services (ES) is essential to understand and manage the contribution of these ecosystems to the well-being of local communities. They are the primary beneficiaries but their experience, knowledge, and information are frequently ignored in ES assessment and mapping. In this study, a participatory resource mapping (PRM) approach was applied using local knowledge and experience to analyze geo-referenced information on mangrove ecosystem services. Local communities were involved from the beginning in method selection, application, evaluation, and verification. This “inclusive participatory ES mapping” was conducted in two villages (Bedono and Timbulsloko, Central Java, Indonesia) from 2014 to 2015. Participants representing different community elements were involved in the mapping process. They first created a historical map of the situation in their villages roughly between 1980 and 1999 (before rehabilitation) and then described the subsequent environmental changes. The mapping exercise also documented different mangrove resources that are utilized by communities and identified key areas, such as harvesting zones, biodiversity hotspots, erosion zones, different fishing grounds, and newly rehabilitated areas. The maps reveal that integrating PRM and indigenous geo-referenced information can elicit past and contemporary information on (changes in) ecosystem service availability and use. The results show that by involving local communities from the beginning, the participatory ES mapping can facilitate social learning, provide the foundation for the creation of social capital, and equip the community with sufficient spatial information to improve local mangrove management. The participatory ES mapping approach presented in this paper can be used as a model to support local and regional decision-making processes and to enhance community-based mangrove management in other coastal regions in Indonesia and beyond.
Corals are multipartite sedentary organisms, which have evolved complex, physiological networks in order to survive perturbations and environmental fluctuations. However, climate change is warming tropical waters, pushing the limits of coral tolerance and driving global declines. Coral susceptibility to thermal anomalies is variable among species and through time, and directly relates to constituent immunity. Constituent immunity refers to immune activities required to ensure homeostasis, whereas an immune response is acutely heightened immune activity to a perturbation. Understanding the mechanisms behind coral health, and sustained health through adverse conditions, is increasingly important for establishing effective reef conservation and restoration projects. However, most experimental studies of coral health use species that are highly susceptible to thermal events, potentially skewing our understanding. To determine the influence of warmer water on immunity, activities of key coral immune pathways and an antioxidant were compared under ambient (27°C) and warmer water (32°C), and between injured and uninjured (control) branches of the tolerant reef coral Porites cylindrica. Three types of phenoloxidase, mono-phenoloxidase, ortho-diphenoloxidase and para-diphenloxidase, indicative of two melanin synthesis pathways (the tyrosinase and laccase-type), and peroxidase were measured at 0 (control), 1, 6, 24, 48, and 168 h post-injury. All four enzymes demonstrated consistent levels of activity under ambient conditions (27°C), indicating constituent immunity. Upon injury at ambient temperature, all enzyme activities were significantly higher 1 h post-injury as compared to uninjured controls, demonstrating a comprehensive immune response to tissue disruption. Under warmer water, constituent immunity increased through time indicative of immune modulation to maintain homeostasis. However, warmer water, within the non-bleaching summer range, suppressed the immune response to injury, delaying it by 24 h. Therefore, upon the environmental cue of warmer water, the tolerant coral P. cylindrica may divert resources away from immune responses (immunosuppression) while enhancing constituent immunity (immune modulation) so as to maintain health through sub-optimal conditions. These changes in immunity with warmer water demonstrate that temperature affects coral immunity and, for this tolerant coral, triggers immune-modulation that may provide cross-tolerance to perturbations more frequent in summer months, such as bleaching and disease.
The use of unoccupied aircraft systems (UASs, also known as drones) in science is growing rapidly. Recent advances in microelectronics and battery technology have resulted in the rapid development of low-cost UASs that are transforming many industries. Drones are poised to revolutionize marine science and conservation, as they provide essentially on-demand remote sensing capabilities at low cost and with reduced human risk. A variety of multirotor, fixed-wing, and transitional UAS platforms are capable of carrying various optical and physical sampling payloads and are being employed in almost every subdiscipline of marine science and conservation. This article provides an overview of the UAS platforms and sensors used in marine science and conservation missions along with example physical, biological, and natural resource management applications and typical analytical workflows. It concludes with details on potential effects of UASs on marine wildlife and a look to the future of UASs in marine science and conservation.
Many broadly distributed migratory species exhibit fidelity to fine-scale areas that support vital life history requirements (e.g., resource acquisition, reproduction). Thus, such areas are critical for population dynamics and are of high conservation priority. Leatherback sea turtles are among the world’s most widely distributed species, and their breeding and feeding areas are typically separated by thousands of kilometres. In this study, we analysed turtle-borne video data on daytime feeding rates and energy acquisition in Nova Scotia, Canada, to quantify the importance of this discrete, seasonal foraging area for leatherback energy requirements. Based on daytime foraging only, we estimate that a single foraging season in Nova Scotia could support 59% of a non-breeding leatherback’s annual energy budget, and 29% of energetic requirements for a female on a typical 2-year reproductive cycle. However, maximum energy intake rates for leatherbacks are nearly four times lower than those of mammals and birds due the low energy content of leatherbacks’ gelatinous zooplankton prey. These results illustrate that high quality, local-scale foraging areas such as Nova Scotia are critically important to the stability and future growth of the leatherback population in the Northwest Atlantic Ocean. Thus, as with other migratory species, efforts to reduce threats and maintain habitat quality in such areas should be high conservation priorities.
Cold-water corals form high biodiversity habitats in the deep sea. They are generally long-lived, slow-growing, and thus particularly vulnerable to anthropogenic impact. We used high-definition imagery to quantify the impact and assess the recovery of deep-sea corals that were affected by the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. Over three hundred Paramuricea spp. colonies were imaged yearly between 2011 and 2017 at five sites, and the images were digitized to quantify health, hydroid overgrowth, identify branch loss, and track recovery patterns. Although the median level of impact decreased after 2011 at all impacted sites, it has been stable since then and remained higher than at the reference sites. Recovery depended on the initial level of impact to the colonies, which negatively affected the ability of individual branches to recover or remain healthy. The effect of initial impact on recovery between consecutive years was still visible seven years after the spill, indicating a long-term, non-acute, impact on the colonies. Injured corals were also more likely to lose branches, and branch loss was still significantly higher at some of the impacted sites between 2016 and 2017, indicating an ongoing effect of the spill, which may eventually lead to delayed mortality. The methodology we employed allows us to successfully detect small changes in the health of corals. We suggest the establishment of image-based coral-monitoring sites to collect baseline data on coral biology, assess the efficacy of Marine Protected Areas, and detect future anthropogenic impact to these vulnerable deep-sea ecosystems.
Sharks and rays are often caught as bycatch by commercial fisheries, and high incidences of bycatch are partially to blame for the declines in many populations of elasmobranchs. In an effort to reduce rates of bycatch, researchers have tested various deterrents that could benefit fisheries. Permanent magnets are one promising form of bycatch reduction device, yet their efficacy has only been tested for hook-and-line fisheries with variable results. Here, we examined the potential benefits of permanent magnets on an ocean fish trap fishery targeting snapper (Pagrus auratus) where more than 10% of the total catch is comprised of unwanted elasmobranchs and the presence of elasmobranchs reduces the catch of target species. Over 1000 fish traps were deployed in a fishery-dependent survey in New South Wales, Australia. Standardised catch rates indicate that the incorporation of magnets into fish traps significantly reduced incidences of elasmobranch bycatch (mainly Brachaelurus waddi) by over a third, while increasing the amount of target fish caught by an equivalent amount. Together these results suggest that magnets can be used as an effective bycatch reduction device that reduces incidences of elasmobranch bycatch while increasing the profitability of fish traps for fishermen. Future studies should aim to replicate these results in areas where different species of elasmobranchs occur.
Coastal resource management (CRM) programs have been implemented in the Philippines since the 1980s with the specific intent to protect and rehabilitate coastal habitats and enhance the sustainability of coastal communities. However, the implementation of these programs alone does not guarantee the success of program objectives. Monitoring and evaluation of program outcomes is essential for determining if programs are effective in reaching management goals. The purpose of this research was to evaluate long-term CRM programs using community perceptions of coastal resource condition, management practices, and program outcomes. Coastal residents in Baybay City, Leyte were surveyed and asked to rank a series of questions related to resource condition and 20 previously described management performance indicators. Respondents reported a decline in coastal resource condition over the past decade, even though they perceive positive outcomes of management programs aimed at enhancing resource condition. The sustainability and efficiency of management outcomes were perceived positively, with mixed views on equity outcomes. Results suggest that lack of full inclusion, low management oversight, and threat to coastal resources are concerns of the coastal community. Socioeconomic data collected from respondents yielded a pattern indicating that gender, self-reported level of environmental knowledge, and management cluster were significant contextual variables associated with perceptions of respondents. Overall, CRM programs are perceived to have a positive impact and there is a high level of interest for participating in future management activities. This study exemplifies how perceptions and associated contextual information of the community provides invaluable insights into the effectiveness of coastal resource management and be incorporated into the adaptive management cycle.
To effectively tackle the challenge of biological invasions through targeted strategies and mitigation measures, managers and policy makers require adequate reporting and flow of information. For this reason, the European ‘Natura 2000’ network of protected areas, which is the main conservation tool of the European Union, is supported by a standardized database. All threats to biodiversity are supposed to be reported in sufficient detail through that database. We compared the reported threats by ‘invasive non-native species’ in the Natura 2000 database with the actual cumulative impacts of invasive alien species on marine habitats in the Mediterranean using the CIMPAL index (Cumulative IMPacts of invasive ALien species). CIMPAL estimates cumulative impact scores on the basis of the distributions of invasive species and ecosystems, and both the documented magnitude of negative ecological impacts and the strength of such evidence. We showed that the threat of invasive alien species is substantially under-reported in the official documentation. Specifically, among the 1455 marine sites of the network, no threat was officially reported in one third of the sites. The threat of biological invasions was only reported in 154 sites, despite negative impacts by invasive alien species being predicted for 98% of all sites when using CIMPAL. In fact, in the subgroup of sites where no threats have been officially reported, the impacts predicted by CIMPAL were the highest. Such, inadequate and insufficient reporting of threats in the Mediterranean marine Natura 2000 sites presents a significant obstacle to the flow of accurate information needed to support conservation policies and marine management.
Effective management of natural resources involves a multidisciplinary perspective to address complex issues in data poor-environments. With mobile species that do not conform to human-defined borders a cross-boundary approach is essential. There is a continuing concern of ecological sustainability of marine environments, which demands monitoring of ecosystem indicators. Such indicators are increasingly derived from monitoring sentinel species. Harbour porpoises (Phocoena phocoena) are included as indicator species in several national and international agreements. Increasing exposure to anthropogenic stressors may impact harbour porpoise populations. To investigate these risks, a better understanding of threats and their effect is required. This study aimed to identify current knowledge gaps, to predict future pressures or threats, and to define useful conservation indicators to facilitate future research on harbour porpoises in the North Sea, through expert elicitation gained in a two-round Delphi approach. The three most important knowledge gaps addressed were bycatch, population dynamics, and the cumulative effects of multiple stressors. Bycatch was predicted as the highest concern for porpoises in the next 20 years, followed by chemical and noise pollution, respectively. A list of essential indicators aiming to increase understanding of harbour porpoises’ health status was established and studying causes of death, distribution, abundance, habitat use and diet composition were scored as most relevant. These results should guide research focus and management objectives of harbour porpoise populations and the study design could be translated to serve managers in other geographical areas aiming to identify knowledge gaps and defining research priorities for other wildlife species.