Dynamic energy budget (DEB) theory offers a comprehensive framework for understanding the overall physiological performance (growth, development, respiration, reproduction, etc.) of an organism over the course of its life cycle. We present here a simplified DEB model for the swimming crab Liocarcinus depurator. To the best of our knowledge, this is the first to be presented for this species. Most applications of the standard DEB model assume continuous growth in all size metrics (length, wet mass, carbon content) of the modelled species. However, in crustaceans growth, measured as an increase of carapace length/width, occurs periodically via moult. To account for this, we have extended the model to track the continuous increase in carbon mass as well as the episodic increase in physical size. Model predictions were consistent with the patterns in the observed data, predicting both the moult increment and the intermoult period of an individual. In addition to presenting the model itself, we also make recommendations for further development, and evaluate the potential applications of such a model, both at the individual level (e.g. aquaculture) and as a potential tool for population level dynamics (e.g. fisheries stock assessment).
In this period of environmental change, understanding how resource users respond to such changes is critical for effective resource management and adaptation planning. Extensive work has focused on natural resource responses to environmental changes, but less has examined the response of resource users to such changes. We used an interdisciplinary approach to analyse changes in resource use among commercial trawl fishing communities in the northwest Atlantic, a region that has shown poleward shifts in harvested fish species. We found substantial community-level changes in fishing patterns since 1996: southern trawl fleets of larger vessels with low catch diversity fished up to 400 km further north, while trawl fleets of smaller vessels with low catch diversity shrank or disappeared from the data set over time. In contrast, trawl fleets (of both large and small vessels) with higher catch diversity neither changed fishing location dramatically or nor disappeared as often from the data set. This analysis suggests that catch diversity and high mobility may buffer fishing communities from effects of environmental change. Particularly in times of rapid and uncertain change, constructing diverse portfolios and allowing for fleet mobility may represent effective adaptation strategies.
Most reporting of stock status accumulated at a national or regional level gives statistics on what proportion of the stocks are below some abundance threshold or above some fishing mortality rate threshold. This approach does not convey useful information on the performance of the fisheries management system in maximizing long-term sustainable yield, which is the primary objective of most national and international fisheries legislation. In this paper, I present a graphical approach for representing how much yield is being lost as a consequence of current suboptimal abundance and fishing pressure. Using the EU stocks assessed by ICES as an example, I show how traditional criteria for overfished and overfishing fail to display realistic information about the performance of the fishery. This approach provides much more useful information for the public and policy makers.
Mandates to execute ecosystem-based management exist but are not implemented sufficiently enough to reap the benefits of a growing blue economy.
The production of marine habitat maps typically relies on the use of habitat classification schemes (HCSs). The choice of which HCS to use for a mapping study is often related to familiarity, established practice, and national desires. Despite a superficial similarity, HCSs differ greatly across six key properties, namely, purpose, environmental and ecological scope, spatial scale, thematic resolution, structure, and compatibility with mapping techniques. These properties impart specific strengths and weaknesses for each HCS, which are subsequently transferred to the habitat maps applying these schemes. This review has examined seven HCSs (that are commonly used and widely adopted for national and international mapping programmes), over the six properties, to understand their influence on marine habitat mapping. In addition, variation in how mappers interpret and apply HCSs introduces additional uncertainties and biases into the final maps. Recommendations are provided for improving HCSs for marine habitat mapping as well as for enhancing the working practices of mappers using habitat classification. It is hoped that implementation of these recommendations will lead to greater certainty and usage within mapping studies and more consistency between studies and adjoining maps.
The appetite for ecosystem-based fisheries management (EBFM) approaches has grown, but the perception persists that implementation is slow. Here, we synthesize progress toward implementing EBFM in the United States through one potential avenue: expanding fish stock assessments to include ecosystem considerations and interactions between species, fleets, and sectors. We reviewed over 200 stock assessments and assessed how the stock assessment reports included information about system influences on the assessed stock. Our goals were to quantify whether and how assessments incorporated broader system-level considerations, and to explore factors that might contribute to the use of system-level information. Interactions among fishing fleets (technical interactions) were more commonly included than biophysical interactions (species, habitat, climate). Interactions within the physical environment (habitat, climate) were included twice as often as interactions among species (predation). Many assessment reports included ecological interactions only as background or qualitative considerations, rather than incorporating them in the assessment model. Our analyses suggested that ecosystem characteristics are more likely to be included when the species was overfished (stock status), the assessment is conducted at a science centre with a longstanding stomach contents analysis program, and/or the species life history characteristics suggest it is likely to be influenced by the physical environment, habitat, or predation mortality (short-lived species, sessile benthic species, or low trophic-level species). Regional differences in stomach contents analysis programs may limit the inclusion of predation mortality in stock assessments, and more guidance is needed on best practices for the prioritization of when and how biophysical information should be considered. However, our results demonstrate that significant progress has been made to use best available science and data to expand single-species stock assessments, particularly when a broad definition of EBFM is applied.
The debate over Brexit and the fisheries question has focused very largely on the expected benefits for the UK's fishing industry to the virtual exclusion of potential implications for the seafood supply chain. This paper refocuses attention on a supply chain now heavily dependent on both imports and exports of fish and fish products mainly to EU markets. Brexit could pose potentially significant problems arising from the imposition of tariff and non-tariff restrictions on trade and limitation on future movements of semi-skilled and unskilled EU migrants into the UK labour market. Three elements of the supply chain are likely to be directly affected: the shellfish and small scale fisheries sectors impacted by tariff and non-tariff restrictions and perhaps most significantly the fish processing industry, similarly affected by trade restrictions and heavily dependent on EU labour. Brexit has also been the catalyst for renewed pressures in Scotland for further devolution of powers relating to the fishing industry that at some future date could see the development of two distinctive seafood supply chains within the UK.
The ability to perceive and recognise a reflected mirror image as self (mirror self-recognition, MSR) is considered a hallmark of cognition across species. Although MSR has been reported in mammals and birds, it is not known to occur in any other major taxon. Potentially limiting our ability to test for MSR in other taxa is that the established assay, the mark test, requires that animals display contingency testing and self-directed behaviour. These behaviours may be difficult for humans to interpret in taxonomically divergent animals, especially those that lack the dexterity (or limbs) required to touch a mark. Here, we show that a fish, the cleaner wrasse Labroides dimidiatus, shows behaviour that may reasonably be interpreted as passing through all phases of the mark test: (i) social reactions towards the reflection, (ii) repeated idiosyncratic behaviours towards the mirror, and (iii) frequent observation of their reflection. When subsequently provided with a coloured tag in a modified mark test, fish attempt to remove the mark by scraping their body in the presence of a mirror but show no response towards transparent marks or to coloured marks in the absence of a mirror. This remarkable finding presents a challenge to our interpretation of the mark test—do we accept that these behavioural responses, which are taken as evidence of self-recognition in other species during the mark test, lead to the conclusion that fish are self-aware? Or do we rather decide that these behavioural patterns have a basis in a cognitive process other than self-recognition and that fish do not pass the mark test? If the former, what does this mean for our understanding of animal intelligence? If the latter, what does this mean for our application and interpretation of the mark test as a metric for animal cognitive abilities?
An operational framework to assess the value of fisheries restricted areas (FRAs) for marine conservation was developed. Such a framework contributes to the wider concept of considering other effective area-based conservation measures (OECMs), as complementing conservation efforts and substantially contributing to effectively and equitably achieving Aichi biodiversity Target 11. A tailor-made multi-criteria decision analysis was designed and applied, for potential OECMs to be carefully assessed on a case-by-case basis and categorized according to their effectiveness in terms of contributing to marine biodiversity conservation. The official documentation and guidance provided by the IUCN were fully respected and made operational, providing a paradigm to managers and decision makers for assessing the contribution of FRAs to marine conservation under the OECM concept. The study also constitutes a review of the conservation status of the Aegean Sea and provides scientific documentation to the managers and decision makers in the area to address spatial conservation targets. By considering Natura 2000 sites as effective marine protected areas (MPAs), the Aichi Target 11 is attained (14.94%) at national level (i.e. within the Greek territorial waters). At ecoregional level (i.e. including international waters of the Aegean Sea) the target is not achieved (6.66%). It is proposed that, by adding all effective FRAs and a number of less effective FRAs, under the condition of increasing their effectiveness for conservation, to the network of MPAs in the area and designating them as OECMs, the conservation target can be attained also at ecoregional level.
The emergence of ecosystem-based fisheries management (EBFM) has broadened the policy scope of fisheries management by accounting for the biological and ecological connectivity of fisheries. Less attention, however, has been given to the economic connectivity of fisheries. If fishers consider multiple fisheries when deciding where, when, and how much to fish, then management changes in one fishery can generate spillover impacts in other fisheries. Catch-share programs are a popular fisheries management framework that may be particularly prone to generating spillovers given that they typically change fishers’ incentives and their subsequent actions. We use data from Alaska fisheries to examine spillovers from each of the main catch-share programs in Alaska. We evaluate changes in participation—a traditional indicator in fisheries economics—in both the catch-share and non–catch-share fisheries. Using network analysis, we also investigate whether catch-share programs change the economic connectivity of fisheries, which can have implications for the socioeconomic resilience and robustness of the ecosystem, and empirically identify the set of fisheries impacted by each Alaska catch-share program. We find that cross-fishery participation spillovers and changes in economic connectivity coincide with some, but not all, catch-share programs. Our findings suggest that economic connectivity and the potential for cross-fishery spillovers deserve serious consideration, especially when designing and evaluating EBFM policies.
The ingestion of plastic marine litter (PML) by sea turtles is widespread and concerning, and the five species that occur in the southwestern Atlantic – green, loggerhead, olive ridley, leatherback and hawksbill – are vulnerable to this pollution. Here, we quantified and characterized PML ingested by these species in southern Brazil, and observed PML ingestion in 49 of 86 sampled individuals (~57.0%). Green turtles presented the highest rates and variety of ingested plastics, and such ingestion has been high at least since 1997. Omnivorous turtles presented higher PML ingestion than carnivorous ones. Loggerheads displayed a negative correlation between body size and number of ingested items. Green turtles ingested mostly flexible transparent and flexible/hard white plastics; loggerheads ate mainly flexible, hard and foam fragments, in white and black/brown colors. These results help us better understand PML ingestion by sea turtles, highlighting the seriousness of this threat and providing information for prevention and mitigation strategies.
Plastic pollution is a modern tragedy of the commons, with hundreds of species affected by society's waste. Birds in particular mistake plastic for prey, and millions of wild birds carry small plastic loads in their stomach and are exposed to potential toxicological effects. It is currently unknown how severely the toxicological and endocrine disrupting chemicals in plastic affect avian development, reproduction and endocrine function. To address this question, we conducted multi-generational plastic feeding experiments to test the toxicological consequences of plastic ingestion at environmentally relevant loads in Japanese quail, Coturnix japonica, investigating parental and two filial generations. Contrary to expectations, we found no evidence of lasting toxicological effects on mortality, adult body weight, organ histology, hormone levels, fertility, hatch rates and eggshell strength in birds experimentally fed plastic. However, we found plastic ingestion causes higher frequencies of male reproductive cysts and minor delays in chick growth and sexual maturity, though without affecting ultimate survival or reproductive output. We report that although plastic ingestion causes detectable endocrine effects in our model species, our lack of finding mortality, morbidity and adverse reproductive outcomes may challenge the common hypothesis of severe toxicological harm and population-level effects when environmentally relevant loads of plastic are ingested.
Comparisons of six selected Mediterranean MPAs were conducted to find similarities and site-specific differences in coastline fluxes and sources of plastic marine litter. Output from the recently developed 2D Lagrangian model for the Mediterranean was post-processed to study (1) the National Park of ses Salines d’Eivissa i Formentera, (2) Nature Reserve of Bouches de Bonifacio, (3) North-East Malta MPA, (4) Specially Protected Area of Porto Cesareo, (5) Community Importance Site of Torre Guaceto, and (6) Ethniko Thalassio Parko Alonnisou Voreion Sporadon. Model coastline fluxes of plastic ranged from 0.4 to3.6 kg (km day)−1, which is relatively low compared to the average flux of 6.2 ± 0.8 kg (km day)−1 calculated over the Mediterranean 2013–2017. Shipping was identified as a major source of plastic litter in all MPAs studied, contributing 55%–88% of total plastic. Site-specific rankings of the top 5 land-based plastic sources revealed that sea surface kinematics control plastic drift.
Ocean acidification (OA) is a major emergent stressor of marine ecosystems with global implications for biodiversity conservation, sustainable development and economic prosperity. International action is imperative for addressing it. This paper builds a science-based governing framework, identifying three overarching policy objectives and six areas for action that should be pursued so as to minimise this global problem. No unifying OA treaty or legal instrument with the explicit task of addressing OA currently exists and it looks highly unlikely that any will eventuate. A more pragmatic approach is to use existing multilateral agreements. However, taking on OA as a unified problem seems to be beyond the scope of existing agreements, due to structural limitations and the willingness of Parties. Given this, it is more likely that OA will be addressed by a network of agreements, each responding to discrete elements of the problem of OA within their capabilities. However, it is unclear how existing MEA capabilities extend to addressing OA. This paper therefore offers an analytical framework through existing governance structures can be explored for their capabilities to respond to OA.
Mangroves provide many benefits to human welfare, but they are disappearing rapidly; Ecuador and countries within the Tropical Eastern Pacific (TEP) region have lost over 40% of their mangrove coverage in the last 40 years. One reason for this destruction is that the benefits of mangroves have not been valued in a way that policymakers and markets can understand. Here, we present the first economic valuation of multiple ecosystem services (ES) for Ecuador and the TEP using the Galapagos mangroves as a case study. We focused on three ES of high value and policy relevance: carbon storage, support for small-scale fisheries, and mangrove-based tourism. Our data suggest that over 778,000 tons of carbon are stored in Galapagos mangroves, with mean belowground carbon being 211.03 ± 179.65 Mg C/ha, valued at $2940/ha or $22,838/ha depending on the valuation methodology. We identified mangrove-dependent fish targeted by the local finfish fishery, with net benefits of $245 ha−1, making this fishery the second most profitable in the Archipelago. The value of mangrove-based recreation was estimated at $16,958/ha, contributing $62 million to the industry. By accounting for stakeholders and existing property rights, our results allow for the discussion of institutionalizing ES payments for the Galapagos Islands.
The territorial waters and the EEZ of the Netherlands form a part of the southern North Sea. The area is intensely used and for several of these uses considerable growth is forecast. For years, industrial freedom and market forces prevailed during discussions on marine spatial planning in the Netherlands. But in 2005 it became clear that this might lead to increasing conflicts with the environment and between users. The introduction of a new spatial planning framework was in response to an increasing interest in new developments and a growing demand for governmental coordination of these developments. During the years after, societal demands changed rapidly, especially with regard to renewable energy and demand for sand to strengthen the coast. At a regular interval of 6 years, revised Marine Spatial Plans have been developed which are adapted to the new knowledge and experience acquired and the new societal demands. Each cycle has a strong stakeholder involvement, both informal and formal.
Long-distance (>40-km) dispersal from marine reserves is poorly documented; yet, it can provide essential benefits such as seeding fished areas or connecting marine reserves into networks. From a meta-analysis, we suggest that the spatial scale of marine connectivity is underestimated due to the limited geographic extent of sampling designs. We also found that the largest marine reserves (>1000 km2) are the most isolated. These findings have important implications for the assessment of evolutionary, ecological, and socio-economic long-distance benefits of marine reserves. We conclude that existing methods to infer dispersal should consider the up-to-date genomic advances and also expand the spatial scale of sampling designs. Incorporating long-distance connectivity in conservation planning will contribute to increase the benefits of marine reserve networks.
This research examines the donation behavior of tourists who are asked to donate to coastal conservation aimed at addressing a bundled mix of land and sea issues. Historically, the governance and financing of land and sea conservation have been separated; yet coastal tourism directly involves a mix of activities and development challenges which link land and sea together on the coast. Marine parks, and numerous studies examining their funding schemes, have typically focused on mandatory user fees targeting specific types of activities. For example, many studies focus only on scuba divers' willingness to pay (WTP) for marine conservation. Alternative funding mechanisms, such as voluntary contributions, may be preferred, or even necessary, to traditional government imposed fees, but much less is known about effective implementation. Relatively few studies focus on bundled cross-boundary conservation activities (i.e., land and sea conservation) from all visitors of a marine park (i.e., beachgoers, surfers, boaters, snorkelers) and its encompassing coastal area. In this study we target tourists visiting a popular island and employ field experimental methods to explore the optimal donation request mechanism and pricing levels that influence real voluntary payments for conservation. The field experiment examines voluntary payments under the treatment conditions: open-ended, a set of several suggested donation amounts, and default opt-in and opt-out at two price levels. The field experiment was conducted with tourists on the island of Gili Trawangan, Indonesia. Results reveal that tourists are willing to donate to bundled land-sea conservation issues and that there is a significantly higher propensity to donate in all treatment conditions compared to the open-ended condition. The default opt-out conditions garnered the highest rate of donations at 75% and 62% respectively for the lower and higher set amounts. The mean donation amount was largest in the higher default opt-out condition. Our results suggest that the optimal method of requesting voluntary donations is a set default amount requiring users to opt-out if they do not wish to donate. Implementing a default opt-out eco-donation targeting all types of visitors represents a significant source of funding and illustrates the potential for donations to finance land and sea conservation efforts, an important avenue for future investigation in many interconnected systems that have been historically governed and financed separately.
Assessing coral reef resilience is an increasingly important component of coral reef management. Existing coral reef resilience assessments are not practical, especially for developing countries. South-east Asian countries have been using line-intercept-transect (LIT) in coral reef monitoring for a long time. The present study proposes an index for assessing coral reef resilience based on data collected from the LIT method. The resilience index formula was modified from an existing resilience index for soil communities developed by Orwin and Wardle. We used an ideal resilient coral reef community as a reference point for the index. The ideal coral reef was defined from data collected from 1992 to 2009. Six variables were statistically selected for the resilience indicators: coral functional group (CFG), coral habitat quality (CHQ), sand-silt cover (SSC), coral cover (COC), coral small-size number (CSN), and algae-other-fauna (AOF) cover. Maximum values of five variables were determined as the best state, while the maximum value of CSN was determined from 1240 data-sets of Indonesian reefs. The resilience index performed well in relation to changes in COC, AOF, and SSC variables. Managers can use this tool to compare coral reef resilience levels among locations and times. This index would be applicable for global coral reef resilience assessment.
Implementing a governance transformation entails the creation of a new institutional system when ecological, economic, or social structures make the existing system untenable. It involves building capacities, establishing viable formal and informal institutions, and triggering major societal changes. Early assessments (EAs) provide a mechanism to fine-tune and support institutional learning processes, which are needed to provide legitimacy and political acceptability of transformational change. We performed an EA of a governance transformation aimed at implementing ecosystem-based, multilevel participatory fisheries management in Chile. We performed individual interviews and workshops and synthesized existing reports to assess the main challenges of the institutionalization of the new policy. Results showed that successful implementation of the governance transformation would need to address key issues related to building trust and improving transparency, including clear protocols for cocreating knowledge and securing resources and capacities. The EA allowed us to define specific recommendations associated with legal reforms, issuing of new executive orders to clarify implementation, and improvement in operational standards by government agencies. EAs provide a fundamental tool that helps build legitimacy and sustainability of new governance systems. They bring a sense of reality, informed by social science, that allows us to understand progress in the implementation of governance transformations, by identifying rigidities that fail to accommodate emerging realities.