Over two million leisure boats use the coastal areas of the Baltic Sea for recreational purposes. The majority of these boats are painted with toxic antifouling paints that release biocides into the coastal ecosystems and negatively impact non-targeted species. Regulations concerning the use of antifouling paints differ dramatically between countries bordering the Baltic Sea and most of them lack the support of biological data. In the present study, we collected data on biofouling in 17 marinas along the Baltic Sea coast during three consecutive boating seasons (May–October 2014, 2015 and 2016). In this context, we compared different monitoring strategies and developed a fouling index (FI) to characterise marinas according to the recorded biofouling abundance and type (defined according to the hardness and strength of attachment to the substrate). Lower FI values, i.e. softer and/or less abundant biofouling, were consistently observed in marinas in the northern Baltic Sea. The decrease in FI from the south-western to the northern Baltic Sea was partially explained by the concomitant decrease in salinity. Nevertheless, most of the observed changes in biofouling seemed to be determined by local factors and inter-annual variability, which emphasizes the necessity for systematic monitoring of biofouling by end-users and/or authorities for the effective implementation of non-toxic antifouling alternatives in marinas. Based on the obtained results, we discuss how monitoring programs and other related measures can be used to support adaptive management strategies towards more sustainable antifouling practices in the Baltic Sea.
Lionfish (Pterois volitans) have rapidly invaded the tropical Atlantic and spread across the wider Caribbean in a relatively short period of time. Because of its high invasion capacity, we used it as a model to identify the connectivity among nine marine protected areas (MPAs) situated in four countries in the Gulf of Mexico and the Caribbean Sea. This study provides evidence of local genetic differentiation of P. volitans in the Gulf of Mexico and the Caribbean Sea. A total of 475 lionfish samples were characterized with 12 microsatellites, with 6–20 alleles per locus. Departures from Hardy–Weinberg equilibrium (HWE) were found in 10 of the 12 loci, all caused by heterozygous excess. Moderate genetic differentiation was observed between Chiriviche, Venezuela and Xcalak, México localities (FST = 0.012), and between the Los Roques and the Veracruz (FST = 0.074) sites. STRUCTURE analysis found that four genetic entities best fit our data. A unique genetic group in the Gulf of Mexico may imply that the lionfish invasion unfolded both in a counterclockwise manner in the Gulf of Mexico. In spite of the notable dispersion of P. volitans, our results show some genetic structure, as do other noninvasive Caribbean fish species, suggesting that the connectivity in some MPAs analyzed in the Caribbean is limited and caused by only a few source individuals with subsequent genetic drift leading to local genetic differentiation. This indicates that P. volitans dispersion could be caused by mesoscale phenomena, which produce stochastic connectivity pulses. Due to the isolation of some MPAs from others, these findings may hold a promise for local short‐term control of by means of intensive fishing, even in MPAs, and may have regional long‐term effects.
In the first decades of 2000s, several Italian sites affected by strong anthropogenic impact were recognized as Sites of National Interest (SINs) for a successive reclamation project, some of which also including marine sectors. These coastal areas are characterized by high complexity and diversity as regards the natural setting as well as for extent, history, type, and degree of contamination. For this, the Italian Ministry of Environment charged its scientific research Institute (earlier ICRAM, now ISPRA) with planning a flexible, adaptable, and large-scale environmental characterization. In this context, the investigation of marine sediments was identified as the primary target to assess the environmental status, because of their conservative capacity with respect to contaminants and their role in the exchange processes with other environmental matrices, such as water column and aquatic organisms. A multidisciplinary, chemical–physical, and ecotoxicological survey was identified as the most appropriate and objective criterion for assessing the sediment quality associated, when necessary, with integrative studies. The results derived from this multidisciplinary approach highlighted the main sources of contamination, together with size and extent of the environmental impact on the coastal marine areas, strictly correlated with the kind of anthropogenic activities and coastal morphology. In order to underline how the different environmental setting influences the degree of anthropogenic impact, four different case studies, selected among the more complex by geochemical and geomorphological viewpoints and more extensively studied, were considered. A comprehensive evaluation of these case studies allowed to deduce some general principles concerning the effects of anthropogenic impact, which can be applicable to other transitional and marine coastal areas.
Information on the spatial ecology of reef sharks is critical to understanding life-history patterns, yet gaps remain in our knowledge of how these species move and occupy space. Previous studies have focused on offshore reefs and atolls with little information available on the movement and space use of sharks utilising reef habitats closer to shore. Cross-shelf differences in physical and biological properties of reefs can alter regional ecosystem processes resulting in different movement patterns for resident sharks. Passive acoustic telemetry was used to examine residency, space use and depth use of 40 blacktip reef sharks, Carcharhinus melanopterus, on an inshore reef in Queensland, Australia, and assess temporal or biological influences. All sharks showed strong site-attachment to inshore reefs with residency highest among adult females. Sharks exhibited a sex-based, seasonal pattern in space use where males moved more, occupied more space and explored new areas during the reproductive season, while females utilised the same amount of space throughout the year, but shifted the location of the space used. A positive relationship was also observed between space use and size. There was evidence of seasonal site fidelity and long-distance movement with the coordinated, annual migration of two adult males to the study site during the mating season. Depth use was segregated with some small sharks occupying shallower depths than adults throughout the day and year, most likely as refuge from predation. Results highlight the importance of inshore reef habitats to blacktip reef sharks and provide evidence of connectivity with offshore reefs, at least for adult males.
Securing economically and ecologically significant molluscs, as our oceans warm due to climate change, is a global priority. South eastern Australia receives warm water in a strengthening East Australia Current and so resident species are vulnerable to elevated temperature and marine heat waves. This study tested whether prior exposure to elevated temperature can enhance resilience of oysters to ocean warming. Two Australian species, the flat oyster, Ostrea angasi, and the Sydney rock oyster, Saccostrea glomerata, were obtained as adults and “heat shocked” by exposure to a dose of warm water in the laboratory. Oysters were then transferred to elevated seawater temperature conditions where the thermal outfall from power generation was used as a proxy to investigate the impacts of ocean warming. Shell growth, condition index, lipid content and survival of flat oysters and condition of Sydney rock oysters were all significantly reduced by elevated seawater temperature in the field. Flat oysters grew faster than Sydney rock oysters at ambient temperature, but their growth and survival was more sensitive to elevated temperature. “Stress inoculation” by heat shock did little to ameliorate the negative effects of increased temperature, although the survival of heat-shocked flat oysters was greater than non-heat shocked oysters. Further investigations are required to determine if early exposure to heat stress can enhance resilience of oysters to ocean warming.
As a hotspot of species diversity and fishing pressure, Indonesia is a global priority for the conservation of sharks, rays and their cartilaginous relatives (herein “sharks”). The high value marine tourism industry in Indonesia can create economic incentives for protecting and sustainably managing marine ecosystems and species, including sharks. This study estimates the economic value of shark and ray tourism in Indonesia and explores tourist preferences and local community perceptions of the tourism industry to understand the current and potential future role of this industry in shark and ray conservation. We identified 24 shark tourism hotspots across 14 provinces, with primary data collected from 365 tourists and 84 local community members over six case study sites. We use Purchasing Power Parity (PPP) and travel efforts to extrapolate expenditures to other tourism sites. We estimate that at least 188,931 dedicated or partially dedicated shark tourists visit Indonesia each year. The median annual expenditures of these shark tourists is estimated at USD 22 million (for 2017), accounting for at least 7% of the total USD 1 billion marine tourism revenue in Indonesia in 2017 and 1.45× the value of annual shark exports in the country (inflation-adjusted to 2017 values). If sharks were absent from the surveyed sites, Indonesia’s tourism industry could lose ∼25% of these dive tourist expenditures. Despite this considerable value, our study indicates a mismatch between the absolute economic value of shark and ray tourism and its role in providing an incentive for conservation. Results from interviews with local communities in or near shark and ray tourism sites indicate that shark fishers are not well placed to receive direct economic benefits from shark and ray tourism. Since overfishing is the primary threat to shark populations, failure to engage with and appropriately incentivize these stakeholders will be detrimental to the success of Indonesia’s shark conservation efforts. If shark populations continue to decline due to insufficient conservation actions, the tourism industry could suffer economic losses from shark and ray tourism of more than USD 121 million per annum by 2027, as well as detrimental impacts on species, marine ecosystems, fisheries and people.
Marine protected areas (MPAs) are a widely used marine conservation tool designed to preserve marine biodiversity and improve fisheries management. Although the environmental benefits of MPAs are well established, evaluating the social and economic impacts of MPAs is challenging. In this paper we quantitatively identify the economic and social differences between communities based on whether or not the community has a tabu area in their local fishing ground. This is an area permanently closed to fishing within a locally managed marine area (LMMA), a form of MPA in the Pacific region. To do this we analyse survey data at both the household and village level in Kadavu, an administrative province of Fiji. We find there are differences in economic activity and diet between the communities but little difference in overall income and wealth. Our study shows that villages with an active tabu area have more positive social outcomes in terms of perceptions of LMMAs. However, there are some notable negative social outcomes as well. In particular, we find that households not engaged in commercial fishing perceive conflict around the management of marine resources. We also find that households engaged in commercial fishing believe penalties for violating LMMA rules are high. Together, these results could potentially impede the adoption of LMMAs and tabu areas. Overall, our survey results do not indicate that tabu areas are detrimental or beneficial on the whole, either economically and socially.
Microplastic occurrence and composition were investigated along the Polish coast (southern Baltic Sea) on 12 beaches differing in terms of intensity of their touristic exploitation, urbanisation and sediment characteristics. Their mean concentrations varied between 76 and 295 items per kg dry sediment. Fibres and plastic fragments were the dominant microplastic types. Overall, no relationship was found between their concentrations and sediment characteristics. Fine sediments were not identified as microplastic pollution traps. The highest microplastic concentrations were recorded at some urban beaches indicating that population density and the level of coastal infrastructure development are important factors affecting microplastic pollution level on beaches. On the other hand, microplastic concentrations in national parks did not differ substantially from the other beaches. Our results suggest that sediment accumulation processes may exceed microplastic accumulation, and overcome the effect of tourism and/or urbanisation, highlighting the role of the beach hydrodynamic status in structuring beach microplastic pollution.
Seafood mislabelling is a global issue that affects consumers, target species, and the ability to manage fisheries. Due to their high demand and value, groupers (Epinephelinae spp.) are frequent targets for fraudulent substitution on the world's major seafood markets. Yet, little is known on the prevalence of grouper mislabelling in the Wider Caribbean Region. We conducted the first ‘grouper’ authentication survey in the Turks and Caicos Islands (TCI), a luxury tourist destination where the locally caught but critically endangered Nassau grouper (Epinephelus striatus) features prominently on menus. DNA barcoding was used to assess mislabelling of market samples and simultaneously to gauge compliance with the Nassau grouper closed season. Our genetic analyses did not detect banned Nassau grouper, but only 18% of samples from restaurants and stores were confirmed as Epinephelinae (i.e. groupers), and 96% were mislabelled in some way. Substitutes for grouper mostly comprised freshwater catfish (Pangasianodon hypophthalmus; 57% of samples) and snappers (Lutjanidae; 25%), whereas samples sold as ‘local grouper’ were from Indo-Pacific or Asian inland waters. Only 22% of samples were matched to species found locally, all being cubera snapper (Lutjanus cyanopterus). Our study suggests that (i) mislabelling is motivated predominantly by financial incentives and/or driven by low supplies of groupers, (ii) local fishers are not the main source of mislabelled grouper into the supply chain, and (iii) the primary victims are consumers, fishing communities, and ultimately fragile fish stocks. Our findings can be used to help improve transparency, traceability and accountability in local seafood supply chains.
Sustainable Development Goal (SDG) no. 15 addresses the protection of terrestrial ecosystems and sustainable forest management, and Target 15.2 encourages countries to sustainably manage forests, and halt deforestation by 2020. SDG indicator 15.1.1 proposes tracking forest area as an indicator for achieving that SDG. Though mangrove forests represent only about 5% of Belize's overall forest cover, the critical ecosystem services they provide are recognized in the country's Forests Act, which regulates the modification of mangrove ecosystems. Preceding the SDGs, from 2008 to 2009, the Government of Belize piloted a complete moratorium on mangrove removal, building on the Forests Act. As Earth Observation (EO) systems provide a means to track effectiveness of Belize's management of its mangrove forests, this paper examines historic and recent changes in mangrove cover across all of Belize, applying statistical adjustments to rates of change derived from Landsat satellite data. Particular attention was paid to the country's only World Heritage Site, the Belize Barrier Reef Reserve System (BBRRS), where mangrove clearing was prohibited since the site's designation in December 1996. The data indicate that within the BBRRS, approximately 89 ha of mangroves were lost from 1996 to 2017, compared to the estimated loss of 2703 ha outside the BBRRS during the same period, and nationwide loss of almost 4100 ha from 1980 to 2017. Thus, compared to the mangroves outside of the BBRRS, the annual rate of mangrove loss within the BBRRS over the period 1996–2017 was merely 4.24 ha per year, versus 129.11 ha per year outside the BBRRS. Furthermore, almost 75% of the 1996–2017 mangrove loss outside the BBRRS were concentrated in three particular geographic zones associated with tourism infrastructure. It was also estimated that Belize's overall mangrove cover declined 5.4% over 36 years, from 76,250 ha in 1980 to 72,169 ha in 2017. In terms of its implications, in addition to contributing to SDG 15, this work also addresses SDG Target 14.2 regarding sustainable management of marine and coastal ecosystems. This study serves as a use case of how EO data can contribute to monitoring changes in baseline data and thus tracking of progress toward SDG Targets.
Water sampling and filtration of environmental DNA (eDNA) analysis have been performed by several different methods, and each method may yield a different species composition or eDNA concentration. Here, we investigated the eDNA of seawater samples directly collected by SCUBA to compare two widely used filtration methods: open filtration with a glass filter (GF/F) and enclosed filtration (Sterivex). We referred to biomass based on visual observation data collected simultaneously to clarify the difference between organism groups. Water samples were collected at two points in the Sea of Japan in May, September and December 2018. The respective samples were filtered through GF/F and Sterivex for eDNA extraction. We quantified the eDNA concentration of five fish and two cnidarian species by quantitative polymerase chain reaction (qPCR) using species-specific primers/probe sets. A strong correlation of eDNA concentration was obtained between GF/F and Sterivex; the intercepts and slopes of the linear regression lines were slightly different in fish and jellyfish. The amount of eDNA detected using the GF/F filtration method was higher than that detected using Sterivex when the eDNA concentration was high; the opposite trend was observed when the eDNA concentration was relatively low. The concentration of eDNA correlated with visually estimated biomass; eDNA concentration per biomass in jellyfish was approximately 700 times greater than that in fish. We conclude that GF/F provides an advantage in collecting a large amount of eDNA, whereas Sterivex offers superior eDNA sensitivity. Both filtration methods are effective in estimating the spatiotemporal biomass size of target marine species.
Widespread and ever-increasing anthropogenic impacts in the marine environment are driving a need to develop more efficient survey methods for monitoring changes in marine biodiversity. There is a particular urgent need for survey methods that could more rapidly and effectively detect change in species richness, abundance and community composition. Here, test the suitability of the Mackinnon Lists Technique for use in the marine environment by testing its effectiveness for rapid assessment of fish communities. The MacKinnon Lists Technique is a time-efficient and cost-effective sampling method developed for studying avian tropical biodiversity, in which several list samples of species can be collected from a single survey. Using the well-established MaxN approach on data from deployments of a Baited Remote Underwater Video Systems for comparison, we tested the suitability of the MacKinnon Lists Technique for use in marine environments by analysing tropical reef fish communities. Using both methods for each data set, differences in community composition between depths and levels of protection were assessed. Both methods were comparable for diversity and evenness indices with similar ranks for species. Multivariate analysis showed that the MacKinnon Lists Technique and MaxN detected similar differences in community composition at different depths and protection status. However, the MacKinnon Lists Technique detected significant differences between factors when fewer videos (representing reduced survey effort) were used. We conclude that the MacKinnon Lists Technique is at least as effective as the widely used MaxN method for detecting differences between communities in the marine environment and suggest can do so with lower survey effort. The MacKinnon Lists Technique has the potential to be widely used as an effective new tool for rapid conservation monitoring in marine ecosystems.
Marine heatwaves (MHWs) have occurred in all ocean basins with severe negative impacts on coastal and ocean ecosystems. The northeast Pacific 2013–2015 MHW in particular received major societal concerns. Yet, our knowledge about how MHWs impact fish stocks is limited. Here, we combine outputs from a large ensemble simulation of an Earth system model with a fish impact model to simulate responses of major northeast Pacific fish stocks to MHWs. We show that MHWs cause biomass decrease and shifts in biogeography of fish stocks that are at least four times faster and bigger in magnitude than the effects of decadal-scale mean changes throughout the 21st century. With MHWs, we project a doubling of impact levels by 2050 amongst the most important fisheries species over previous assessments that focus only on long-term climate change. Our results underscore the additional challenges from MHWs for fisheries and their management under climate change.
There is a reluctance to incorporate Fishers’ Ecological Knowledge (FEK) into the evidence base used to underpin marine management decisions. FEK has proved to be useful as an alternative reference of biological changes in data-poor scenarios. Yet, recreational fisher knowledge has rarely been included in scientific studies despite being a source of FEK. Here, the use of recreational FEK to assess the conservation status of marine ecosystems in Galicia (NW Spain) was evaluated. Galicia has a highly complex marine socioecological system that includes both a large global commercial fleet and a powerful recreational sector, alongside other important stakeholders (e.g., tourism, aquaculture). Anglers and spear fishers were asked to provide their perceptions of the conservation status of fish stocks and the impacts on marine ecosystems. Face-to-face interviews were transcribed into text and analyzed using text mining tools. Key concepts were used to quantify fishers’ perceptions of changes in their target fish stocks and quantify the main impacts on marine ecosystems. Overfishing and habitat loss, followed by reduction in biodiversity, pollution, and warming temperatures were considered to be the main drivers of the poor status of cephalopods and finfish stocks. Perceived temporal declines in fish stocks were consistent with available biological data, highlighting the potential for recreational FEK to be used to assess long-term ecological changes. It was important to seek opinions from different users, including fishers from traditional commercial and recreational fisheries, as these groups had good knowledge of the impacts on natural and cultural community heritage. The poor status of ballan wrasse (Labrus bergylta) and kelp beds was identified, which was of concern due to it being a key species in coastal ecosystems. Use of FEK is a good approach to develop knowledge of these systems, but broader monitoring programs are needed to protect the future of these ecosystems.
The Arctic Ocean is an early warning system for indicators and effects of climate change. We use a novel combination of experimental and time-series data on effects of ocean warming and acidification on the commercially important Northeast Arctic cod (Gadus morhua) to incorporate these physiological processes into the recruitment model of the fish population. By running an ecological-economic optimization model, we investigate how the interaction of ocean warming, acidification and fishing pressure affects the sustainability of the fishery in terms of ecological, economic, social and consumer-related indicators, ranging from present day conditions up to future climate change scenarios. We find that near-term climate change will benefit the fishery, but under likely future warming and acidification this large fishery is at risk of collapse by the end of the century, even with the best adaptation effort in terms of reduced fishing pressure.
Global threats to ocean biodiversity have generated a worldwide movement to take actions to improve conservation and management. Several international initiatives have recommended the adoption of marine protected areas (MPAs) in national and international waters. National governments and the Commission for the Conservation of Antarctic Marine Living Resources have successfully adopted multiple MPAs in the Southern Ocean despite the challenging nature of establishing MPAs in international waters. But are these MPAs representative of Southern Ocean biodiversity? Here we answer this question for both existing and proposed Antarctic MPAs, using benthic and pelagic regionalizations as a proxy for biodiversity. Currently about 11.98% of the Southern Ocean is protected in MPAs, with 4.61% being encompassed by no-take areas. While this is a relatively large proportion of protection when compared to other international waters, current Antarctic MPAs are not representative of the full range of benthic and pelagic ecoregions. Implementing additional protected areas, including those currently under negotiation, would encompass almost 22% of the Southern Ocean. It would also substantially improve representation with 17 benthic and pelagic ecoregions (out of 23 and 19, respectively) achieving at least 10% representation.
Coral reef ecosystems are among the first to fundamentally change in structure due to climate change, which leads to questioning of whether decades of knowledge regarding reef management is still applicable. Here we assess ecological responses to no-take marine reserves over two decades, spanning a major climate-driven coral bleaching event. Pre-bleaching reserve responses were consistent with a large literature, with higher coral cover, more species of fish, and greater fish biomass, particularly of upper trophic levels. However, in the 16 years following coral mortality, reserve effects were absent for the reef benthos, and greatly diminished for fish species richness. Positive fish biomass effects persisted, but the groups of fish benefiting from marine reserves profoundly changed, with low trophic level herbivores dominating the responses. These findings highlight that while marine reserves still have important roles on coral reefs in the face of climate change, the species and functional groups they benefit will be substantially altered.
Ocean health is critical for human well-being but is threatened by multiple stressors. Parties to the Convention on Biological Diversity agreed to protect 10% of their waters by 2020. The scientific evidence supporting the use of marine protected areas (MPAs) to conserve biodiversity stems primarily from knowledge on fully protected areas, but most of what is being established is partially protected. Here, we assess the protection levels of the 1,062 Mediterranean MPAs. While 6.01% of the Mediterranean is covered by protection, 95% of this area shows no difference between the regulations imposed inside the MPAs compared with those outside. Full and high levels of protection, the most effective for biodiversity conservation, represent only 0.23% of the basin and are unevenly distributed across political boundaries and eco-regions. Our current efforts are insufficient at managing human uses of nature at sea, and protection levels should be increased to deliver tangible benefits for biodiversity conservation.
The characteristics of coral reef sampling and monitoring are highly variable, with numbers of units and sampling effort varying from one study to another. Numerous works have been carried out to determine an appropriate effect size through statistical power; however, these were always from a univariate perspective. In this work, we used the pseudo multivariate dissimilarity-based standard error (MultSE) approach to assess the precision of sampling scleractinian coral assemblages in reefs of Venezuela between 2017 and 2018 when using different combinations of number of transects, quadrats and points. For this, the MultSE of 36 sites previously sampled was estimated, using four 30m-transects with 15 photo-quadrats each and 25 random points per quadrat. We obtained that the MultSE was highly variable between sites and is not correlated with the univariate standard error nor with the richness of species. Then, a subset of sites was re-annotated using 100 uniformly distributed points, which allowed the simulation of different numbers of transects per site, quadrats per transect and points per quadrat using resampling techniques. The magnitude of the MultSE stabilized by adding more transects, however, adding more quadrats or points does not improve the estimate. For this case study, the error was reduced by half when using 10 transects, 10 quadrats per transect and 25 points per quadrat. We recommend the use of MultSE in reef monitoring programs, in particular when conducting pilot surveys to optimize the estimation of the community structure.
Satellites collecting optical data offer a unique perspective from which to observe the problem of plastic litter in the marine environment, but few studies have successfully demonstrated their use for this purpose. For the first time, we show that patches of floating macroplastics are detectable in optical data acquired by the European Space Agency (ESA) Sentinel-2 satellites and, furthermore, are distinguishable from naturally occurring materials such as seaweed. We present case studies from four countries where suspected macroplastics were detected in Sentinel-2 Earth Observation data. Patches of materials on the ocean surface were highlighted using a novel Floating Debris Index (FDI) developed for the Sentinel-2 Multi-Spectral Instrument (MSI). In all cases, floating aggregations were detectable on sub-pixel scales, and appeared to be composed of a mix of seaweed, sea foam, and macroplastics. Building first steps toward a future monitoring system, we leveraged spectral shape to identify macroplastics, and a Naïve Bayes algorithm to classify mixed materials. Suspected plastics were successfully classified as plastics with an accuracy of 86%.