Ecological indicators are widely used to characterise ecosystem health. In the marine environment, indicators have been developed to assess the ecosystem effects of fishing to support an ecosystem approach to fisheries. However, very little work on the performance and robustness of ecological indicators has been carried out. An important aspect of robustness is that indicators should respond specifically to changes in the pressures they are designed to detect (e.g. fishing) rather than changes in other drivers (e.g. environment). We adopted a multi-model approach to compare and test the specificity of commonly used ecological indicators to capture fishing effects in the presence of environmental change and under different fishing strategies. We tested specificity in the presence of two types of environmental change: “random”, representing interannual climate variability and “directional”, representing climate change. We used phytoplankton biomass as a proxy of the environmental conditions, as this driver was comparable across all ecosystem models, then applied a signal-to-noise ratio analysis to test the specificity of indicators with random environmental change. For directional change, we used mean gradients to apportion the quantity of change in the indicators due to fishing and the environment. We found that depending on the fishing strategy and environmental change, ecological indicators could range from high to low specificity to fishing. As expected, the specificity of indicators to fishing almost always decreased as environmental variability increased. In 55–76% of the scenarios run with directional change in phytoplankton biomass across fishing strategies and ecosystem models, indicators were significantly more responsive to changes in fishing than to changes in phytoplankton biomass. This important result makes the tested ecological indicators good candidates to support fisheries management in a changing environment. Among the indicators, the catch over biomass ratio was most often the most specific indicator to fishing, whereas mean length was most often the most sensitive to change in phytoplankton biomass. However, the responses of indicators were highly variable depending on the ecosystem and fishing strategy under consideration. We therefore recommend that indicators should be tested in the particular ecosystem before they are used for monitoring and management purposes.
The aim of this study was to determine the recreational value of the three major coral reefs in the Mexican Pacific: Cabo Pulmo, Islas Marietas and Huatulco. 488 and 455 domestic and international tourists respectively were interviewed, and their socioeconomic profile and perception of the coral reef they visited were determined. Using the dichotomous choice contingent valuation method, a willingness to pay of US$ 5.79 for conservation activities was determined, as well as a net annual benefit from the reef of US$1.4 million. The results of the study show that the tourists are willing to pay a higher entrance fee than that established by the federal government. Therefore, if a new entrance fee policy is implemented for entering to marine national parks, the federal government could increase its limited budget for monitoring and research activities in these ecosystems.
Conservation often focuses on “critical habitat” including areas important for the reproduction of threatened taxa. As for many aquatic species a priority of shark conservation is the protection of nurseries, yet few countries can support the costly fieldwork required to identify these according to strict criteria. Alternative approaches are therefore required where resource, capacity and security constraints exist. This study collates low-resolution data from alternative, remotely collected and inexpensive existing sources (fish market surveys, literature, museums, anecdotal accounts), to evaluate a possible nursery for the regionally Endangered bull shark (Carcharhinus leucas) in the Tigris-Euphrates system and adjacent northwestern Persian/Arabian Gulf (Iraq, Iran, Kuwait), a data-poor area long characterised by conflict and inaccessibility. Evidence is presented that aligns with two of the three nursery definition criteria (abundance and repeated use), along with other data supporting known C. leucas reproductive behaviour. While the necessarily low resolution data cannot answer the full suite of strict nursery criteria nor identify precise nursery locations, they nevertheless collectively provide compelling evidence for a broad area of importance to young and juvenile C. leucas. This area is both highly threatened (e.g. by damming, climate change, fisheries) and of potential major significance, given the apparent absence of similar estuary habitat for thousands of kilometres of arid northwestern Indian Ocean coast. The inexpensive desk-based approach to identifying critical habitat provides another toolkit option for conservationists and could best be applied to distinctive threatened aquatic taxa, especially in the developing world where conservation is often resource-limited.
The advancement and expansion of a scientific field depends on its ability to organize its findings and establish a basis in the professional literature. In late 2015, a review was undertaken to examine the body of literature regarding the Large Marine Ecosystems (LMEs) of the world. Trends in the literature were studied to explore this approach as a means for implementing ecosystem-based management of coastal and marine resources, with the objective of providing guidance for filling gaps in the scientific literature supporting this concept. Since 1995, there has been an increase in the number of peer-reviewed, scientific journal articles related to the LME approach, termed “LME articles.” Based on this review, we observed that between 1983 and early 2016, 392 LME journal articles were published. In the examined literature, there is a strong focus on fisheries and fisheries-related considerations and concerns, with 59% of the most relevant journal articles focused on fish or fisheries. Future publications should draw on the experience of past and current LME projects to inform and provide tools for future projects to address the socioeconomic aspects of implementing ecosystem-based management. This review also highlights a connection between investments in LME projects by the Global Environment Facility and the amount of corresponding publications regarding the supported LMEs.
Shoreline armoring is prevalent around the world with unprecedented human population growth and urbanization along coastal habitats. Armoring structures, such as riprap and bulkheads, that are built to prevent beach erosion and protect coastal infrastructure from storms and flooding can cause deterioration of habitats for migratory fish species, disrupt aquatic–terrestrial connectivity, and reduce overall coastal ecosystem health. Relative to armored shorelines, natural shorelines retain valuable habitats for macroinvertebrates and other coastal biota. One question is whether the impacts of armoring are reversible, allowing restoration via armoring removal and related actions of sediment nourishment and replanting of native riparian vegetation. Armoring removal is targeted as a viable option for restoring some habitat functions, but few assessments of coastal biota response exist. Here, we use opportunistic sampling of pre- and post-restoration data for five biotic measures (wrack % cover, saltmarsh % cover, number of logs, and macroinvertebrate abundance and richness) from a set of six restored sites in Puget Sound, WA, USA. This broad suite of ecosystem metrics responded strongly and positively to armor removal, and these results were evident after less than one year. Restoration responses remained positive and statistically significant across different shoreline elevations and temporal trajectories. This analysis shows that removing shoreline armoring is effective for restoration projects aimed at improving the health and productivity of coastal ecosystems, and these results may be widely applicable.
The Pacific coast of Colombia has some of the most extensive mangrove forests in South America. As an isolated region and one of the country's poorest, coastal communities rely on fishing as a main source of animal protein and income. In an attempt to reverse declining trends of fisheries resources, in 2008, an Exclusive Zone of Artisanal Fishing closed to industrial fishing, was established by stakeholders in the Northern Chocó region. Here we present a case study to investigate the effects of this area-based management on fisheries productivity and catch composition. Fishery landings data from 2010 to 2013 are compared to those of a neighbouring region with no fisheries management. Catch per unit effort, mean weight landed, and number of landed individuals were calculated for mangrove and non-mangrove associated species by boat type and fishing gear. A set of mixed effects models were used to unpack the effects of multiple factors and their interactions on response variables. Results show that across fishing gears and time, mean catch per unit effort increased by 50% in the Exclusive Zone of Artisanal Fishing within 3 years. Fisheries here focused on offshore resources with 61% more fishing trips associated with motorised boats than in the unmanaged region, where fishing was predominantly in mangroves and close to the coast. This suggests that fisheries management may have played a role in reducing pressure on mangrove resources. However, area-based management may have also driven the displacement of fishing effort by excluding industrial trawlers, which then concentrated their activity in neighbouring areas.
The Earth′s climate is warming, especially in the mid- and high latitudes of the Northern Hemisphere. The northern elephant seal (Mirounga angustirostris) breeds and haul-outs on islands and the mainland of Baja California, Mexico, and California, U.S.A. At the beginning of the 21st century, numbers of elephant seals in California are increasing, but the status of Baja California populations is unknown, and some data suggest they may be decreasing. We hypothesize that the elephant seal population of Baja California is experiencing a decline because the animals are not migrating as far south due to warming sea and air temperatures. Here we assessed population trends of the Baja California population, and climate change in the region. The numbers of northern elephant seals in Baja California colonies have been decreasing since the 1990s, and both the surface waters off Baja California and the local air temperatures have warmed during the last three decades. We propose that declining population sizes may be attributable to decreased migration towards the southern portions of the range in response to the observed temperature increases. Further research is needed to confirm our hypothesis; however, if true, it would imply that elephant seal colonies of Baja California and California are not demographically isolated which would pose challenges to environmental and management policies between Mexico and the United States.
The seascapes on which many millions of people make their living and secure food have complex and dynamic spatial features—the figurative hills and valleys—that influence where and how people work at sea. Here, we quantify the physical mosaic of the surface ocean by identifying Lagrangian Coherent Structures for a whole seascape—the U.S. California Current Large Marine Ecosystem—and assess their impact on the spatial distribution of fishing. We observe that there is a mixed response: some fisheries track these physical features, and others avoid them. These spatial behaviors map to economic impacts, in particular we find that tuna fishermen can expect to make three times more revenue per trip if fishing occurs on strong Lagrangian Coherent Structures. However, we find no relationship for salmon and pink shrimp fishing trips. These results highlight a connection between the biophysical state of the oceans, the spatial patterns of human activity, and ultimately the economic welfare of coastal communities.
The increased frequency of publications concerning trophic ecology of coral reefs suggests a degree of interest in the role species and functional groups play in energy flow within these systems. Coral reef ecosystems are particularly complex, however, and assignment of trophic positions requires precise knowledge of mechanisms driving food webs and population dynamics. Competent analytical tools and empirical analysis are integral to defining ecosystem processes and avoiding misinterpretation of results. Here we examine the contribution of trophodynamics to informing ecological roles and understanding of coral reef ecology. Applied trophic studies of coral reefs were used to identify recent trends in methodology and analysis. Although research is increasing, clear definitions and scaling of studies is lacking. Trophodynamic studies will require more precise spatial and temporal data collection and analysis using multiple methods to fully explore the complex interactions within coral reef ecosystems.
In spite of the growing attention towards the overall quality of Marine Protected Areas (MPAs), most empirical studies so far have narrowly focused their assessments on specific natural or social features and governing structures. In response, this study analyzed multi-use MPAs in the eelgrass restoration site in Hinase, Okayama, Japan in their environmental, economic and social dimensions. Considering changes in time and space as well as internal and external influences, the study faced many difficulties in dealing with the dynamics of MPA environments. At the same time, it showed clearly the control over development and fishery activities by several MPA relevant regulations, improvements of the ecological function by the regrowth of eelgrass, an increase in some fish species due to the same regrowth, and expansion of social networks deriving from the restoration activity. The study also revealed convincing evidence that self-motivated MPA management practice by fishers under the Territorial Use Rights for Fisheries (TURFs), in conjunction with other mixed management systems such as Satoumi, could lead to flexible and long-term efforts for improving food security, livelihoods, and the marine environment. This study highlights the importance of comprehensive research to deepen the understanding of the structure and functions of complex and diverse marine ecosystems and social systems.