Mineral extraction from the seabed has experienced a recent surge of interest from both the mining industry and marine scientists. While improved methods of geological investigation have enabled the mapping of new seafloor mineral reserves, the ecological impacts of mining in both the deep sea and the shallow seabed are poorly known. This paper presents a synthesis of the empirical evidence from experimental seabed mining and parallel industries to infer the effects of seabed mineral extraction on marine ecosystems, focusing on polymetallic nodules and ferromanganese concretions. We use a problem-structuring framework to evaluate causal relationships between pressures caused by nodule extraction and the associated changes in marine ecosystems. To ensure that the rationale behind impact assessments is clear, we propose that future impact assessments use pressure-specific expert elicitation. We further discuss integrating ecosystem services in the impact assessments and the implications of current methods for environmental risk assessments.
There is great interest and rapid progress around the world in developing sets of indicators of marine ecosystem integrity for assessment and management. However, the complexity of coastal marine ecosystems can challenge such efforts. To address this challenge, an expert-based, hierarchical, and adaptive approach was developed with the objectives of healthy marine ecosystems and community partnerships in monitoring and management. Small sets of the top-ranked indicators of ecosystem integrity and associated human pressures were derived from expert-rankings of lists of identified candidate indicators of the status of, and pressures on, each of 17 ecosystem features, organized within 8 elements in turn within 3 overlapping aspects of ecosystem health. Over 200 experts played a role in rating the relative value of 1035 candidate indicators. A panel of topic experts was assigned to each of the 17 ecosystem features to apply 21 weighted indicator selection criteria. Selection criteria and candidate indicators were identified through literature reviews, expert panels, and surveys, and they were evaluated in terms of the experts' judgements of importance to the health of Canada's Pacific marine ecosystems. This produced a flexible, robust, and adaptable approach to identifying representative sets of indicators for any scale and for any management unit within Canada's Pacific. At the broadest scale, it produced a top 20 list of ecosystem state and pressure indicators. These top indicators, or other sets selected for smaller regions, can then guide the development of both regional and nested local monitoring programs in a way that maximizes continuity while including locally unique values. This hierarchical expert-based approach was designed to address challenges of complexity and scale and to enable efficient selection of useful and representative sets of indicators of ecosystem integrity while also enabling the participation of broad government and stakeholder communities.
The valuation of nature is an inbuilt component of validating environmental management decisions and an important research field for different disciplines related to conservation, economy and ethics. Here, biodiversity was valued using an ecological approach based on the intrinsic value incorporated in biodiversity per se, regardless of any human association. The Marine Biological Valuation protocol was drawn upon the methodology of terrestrial valuation maps, to support the European MSFD environmental status assessment (descriptor 1 – biodiversity) and national marine spatial planning approaches. To apply the protocol on the Portuguese continental shelf we compiled and analyzed national biological databases for a wide taxonomic range of ecosystem components (seabirds, demersal fish, macrobenthos, marine mammals and sea turtles) and assessed the spatial overlap with existing and proposed conservation areas (Natura 2000 network). The resultant maps described patterns of biological value consistent with the physical and biological oceanographic conditions as well as local hydrodynamics of the Portuguese continental shelf. The results of our approach confirm previously identified valuable areas for protection (particularly in the northern and central regions), but also highlights the value of currently unprotected sites, mainly in the southern region. Biological valuation maps showed to be comprehensive tool to compile and spatially analyze biological datasets. By drawing attention to subzones of biological importance, it constitutes a valuable instrument in making appropriate-scale decisions on the spatial allocation of human activities in the context of the Portuguese marine spatial planning, currently facing the pressure and impacts of increased maritime exploitation.
The assessment of ecosystem services, the benefits humans obtain from ecosystems, is a worldwide topic of growing interest, but examples addressing coastal and marine waters are still a small minority. In this study, we carry out an expert based ecosystem service assessment for a concrete case study, the Szczecin (Oder) Lagoon located at the German/Polish border in the Baltic Sea region. We analyze to what extent, in which step and how it can be applied for supporting Integrated Coastal Zone Management (ICZM), the ecological-social-economic assessment within System Approach Frameworks (SAF), and Marine Spatial Planning (MSP). The large, shallow Szczecin Lagoon is heavily eutrophied. Therefore, several alternative measures (scenarios) are under discussion to improve its water quality and its ecological status. Scenarios include a large-scale mussel farm; the establishment of a local mussel farm that removes nutrients via harvest and increases water transparency; artificial mussel beds; groins to reduce coastal current velocities, favor sediment accumulation, and promote the enlargement of macrophyte beds and other measures to enlarge macrophyte belts and coverage. We adapt and apply a computer aided ecosystem service assessment and visualization tool (ESAT). Eight experts and two student groups apply this tool and carry out an assessment of each scenario compared to the present state of the lagoon. The results show that the scenario assuming measures to enlarge macrophyte belts is perceived as the one that generates the highest additional ecosystem service output. However, more importantly our approach can serve as tool to catch the views of experts, can extract disagreements between experts and misunderstandings in the setup of scenarios as well as services that have highest priority for further consideration. Further, the results are useful for preparing stakeholder discussions and workshops. However, the expert assessments are influenced by the spatial scale of the assessed scenarios. As consequence, the assessment results itself cannot be regarded as a reliable basis for decision making. Today, Integrated Coastal Zone Management ideas and approaches are well reflected and integrated into Marine Spatial Planning and we show that a comparative ecosystem service assessment can be applied in different steps of each concept.
Here we provide a broad overview of the Great Amazon Reef System (GARS) based on the first-ever video surveys of the region. This footage supports four major hypotheses: (1) the GARS area may be six times larger than previously suggested (up to 56,000 km2); (2) the GARS may extend deeper than previously suggested (up to 220 m); (3) the GARS is composed of a greater complexity and diversity of habitats than previously recognized (e.g., reef platforms, reef walls, rhodolith beds, and sponge bottoms); and (4) the GARS represents a useful system to test whether a deep corridor connects the Caribbean Sea to the Southwest Atlantic Ocean. We also call attention to the urgent need to adopt precautionary conservation measures to protect the region in the face of increasing threats from extractive oil and gas practices. With less than 5% of the potential area of the GARS surveyed so far, more research will be required to inform a systematic conservation planning approach and determine how best to establish a network of marine protected areas. Such planning will be required to reconcile extractive activities with effective biodiversity conservation in the GARS.
Indonesia's marine ecosystems form a fundamental part of the world's natural heritage, representing a global maxima of marine biodiversity and supporting the world's second largest production of seafood. Seagrasses are a key part of that support. In the absence of empirical data we present evidence from expert opinions as to the state of Indonesia's seagrass ecosystems, their support for ecosystem services, with a focus on fisheries, and the damaging activities that threaten their existence. We further draw on expert opinion to elicit potential solutions to prevent further loss. Seagrasses and the ecosystem services they support across the Indonesian archipelago are in a critical state of decline. Declining seagrass health is the result of shifting environmental conditions due largely to coastal development, land reclamation, and deforestation, as well as seaweed farming, overfishing and garbage dumping. In particular, we also describe the declining state of the fisheries resources that seagrass meadows support. The perilous state of Indonesia's seagrasses will compromise their resilience to climate change and result in a loss of their high ecosystem service value. Community supported management initiatives provide one mechanism for seagrass protection. Exemplars highlight the need for increased local level autonomy for the management of marine resources, opening up opportunities for incentive type conservation schemes.
We review the status of marine shellfish ecosystems formed primarily by bivalves in Australia, including: identifying ecosystem-forming species, assessing their historical and current extent, causes for decline and past and present management. Fourteen species of bivalves were identified as developing complex, three-dimensional reef or bed ecosystems in intertidal and subtidal areas across tropical, subtropical and temperate Australia. A dramatic decline in the extent and condition of Australia’s two most common shellfish ecosystems, developed by Saccostrea glomerata and Ostrea angasi oysters, occurred during the mid-1800s to early 1900s in concurrence with extensive harvesting for food and lime production, ecosystem modification, disease outbreaks and a decline in water quality. Out of 118 historical locations containing O. angasi-developed ecosystems, only one location still contains the ecosystem whilst only six locations are known to still contain S. glomerata-developed ecosystems out of 60 historical locations. Ecosystems developed by the introduced oyster Crasostrea gigas are likely to be increasing in extent, whilst data on the remaining 11 ecosystem-forming species are limited, preventing a detailed assessment of their current ecosystem-forming status. Our analysis identifies that current knowledge on extent, physical characteristics, biodiversity and ecosystem services of Australian shellfish ecosystems is extremely limited. Despite the limited information on shellfish ecosystems, a number of restoration projects have recently been initiated across Australia and we propose a number of existing government policies and conservation mechanisms, if enacted, would readily serve to support the future conservation and recovery of Australia’s shellfish ecosystems.
Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.
Nature conservation and fisheries management often focus on particular seabed features that are considered vulnerable or important to commercial species. As a result, individual seabed types are protected in isolation, without any understanding of what effect the mixture of seabed types within the landscape has on ecosystem functions. Here we undertook predictive seabed modelling within a coastal marine protected area using observations from underwater stereo-video camera deployments and environmental information (depth, wave fetch, maximum tidal speeds, distance from coast and underlying geology). The effect of the predicted substratum type, extent and heterogeneity or the diversity of substrata, within a radius of 1500 m around each camera deployment of juvenile gadoid relative abundance was analysed. The predicted substratum model performed well with wave fetch and depth being the most influential predictor variables. Gadus morhua (Atlantic cod) were associated with relatively more rugose substrata (Algal-gravel-pebble and seagrass) and heterogeneous landscapes, than Melanogrammus aeglefinus (haddock) or Merlangius merlangus (whiting) (sand and mud). An increase in M. merlangus relative abundance was observed with increasing substratum extent. These results reveal that landscape effects should be considered when protecting the seabed for fish and not just individual seabed types. The landscape approach used in this study therefore has important implications for marine protected area, fisheries management and monitoring advice concerning demersal fish populations.
Sharp declines in numerous shark populations around the world have generated considerable interest in better understanding and characterising their biology, ecology and critical habitats. The scalloped hammerhead shark (SHS, Sphyrna lewini) is subject to a multitude of natural and anthropogenic threats that are often exacerbated within the coastal embayments and estuaries used during SHS early life stages. In this study, we describe the temporal and spatial distribution, age class composition, and reproductive biology of SHS in the Rewa Delta (RD), Fiji. A total of 1054 SHS (including 796 tagged individuals; 101 of which were recaptured) were captured from September 2014 to March 2016 in the RD. A majority of the captures in this area were neonates and young-of-the-year (YOY) (99.8%). Significant seasonality in patterns of occurrence of both neonates and YOY individuals suggests a defined parturition period during the austral summer. Between the seven sampling sites in the RD we also found significant differences in SHS neonate catch per unit of effort, and average total length of individuals. According to the data, the RD is likely to represent an important nursery area for SHS up to one year of age.