The Arctic faces high expectations of Blue Growth due to future projections of easier access and increased biological productivity. These expectations are, however, often based on global and regional climate change projections and largely ignore the complexity of social-ecological interactions taking place across different temporal and spatial scales. This paper illustrates how such cross-scale interactions at, and across, different dimensions (e.g., ecological, socioeconomic and governance) can affect the development of Arctic fisheries; and potentially create uncertainties for future Blue Growth projections. Two Arctic marine systems, The Barents Sea and the Central Arctic Ocean (CAO), are used as focus areas. The former hosts productive fisheries and is mostly covered by the EEZs of Norway and Russia, while the latter is still mainly covered by sea-ice and is a high seas area with no multilevel governance system in place. The examples show that, both systems are affected by a number of processes, beyond the environmental change, spanning a wide range of dimensions, as well as spatial and temporal scales. To address the complexity of the Arctic marine systems calls for an increase in holistic scientific understanding together with adaptive management practices. This is particularly important in the CAO, where no robust regional management structures are in place. Recognizing how cross-scale dynamics can cause uncertainties to the current fisheries projections and implementing well-functioning adaptive management structures across different Arctic sub-systems can play a key role in whether the Blue Growth potential in Arctic fisheries is realized or lost.
Our human-dominant world can be viewed as being built up in two parts, social and ecological systems, each consisting of multi-level organizations that interact in a complex manner. However, there are knowledge gaps among those interactions. In this paper, we focus on studies filling two types of gaps in the socioecological system, some of which are case studies in the East Asia region and others are discussed in a more general context. First, we address the gaps between different levels of organizations in ecological systems, namely, (1) the importance of plant trait plasticity in bridging evolution and ecology, (2) linking primary producer diversity and the dynamics of blue carbon in coastal ecosystems in the Asia–Pacific region, and (3) research direction of climate change biology to fill the gaps across evolution, community, and ecosystem. Also included is (4) the gap between ecological monitoring programs and theories, which also addresses the potential of citizen science. Second, we illustrate the gaps between ecological and social systems through ongoing development of an ecosystem management framework, i.e., ecosystem-based disaster risk reduction. Finally, we summarize the benefits of filling the gaps for ecologists and society.
Since the Third U.S. National Climate Assessment (NCA3) was published in May 2014, new observations along multiple lines of evidence have strengthened the conclusion that Earth’s climate is changing at a pace and in a pattern not explainable by natural influences. While this report focuses especially on observed and projected future changes for the United States, it is important to understand those changes in the global context.
Systematic conservation planning has become a standard approach globally, but prioritization of conservation efforts hardly considers species traits in decision making. This can be important for species persistence and thus adequacy of the conservation plan. Here, we developed and validated a novel approach of incorporating trophic information into a systematic conservation planning framework. We demonstrate the benefits of this approach using fish data from Europe's second largest river, the Danube. Our results show that adding trophic information leads to a different spatial configuration of priority areas at no additional cost. This can enhance identification of priority refugia for species in the lower position of the trophic web while simultaneously identifying areas that represent a more diverse species pool. Our methodological approach to incorporating species traits into systematic conservation planning is generally applicable, irrespective of realm, geographical area, and species composition and can potentially lead to more adequate conservation plans.
Nutrient limitation of oceanic primary production exerts a fundamental control on marine food webs and the flux of carbon into the deep ocean1. The extensive boundaries of the oligotrophic sub-tropical gyres collectively define the most extreme transition in ocean productivity, but little is known about nutrient limitation in these zones1,2,3,4. Here we present the results of full-factorial nutrient amendment experiments conducted at the eastern boundary of the South Atlantic gyre. We find extensive regions in which the addition of nitrogen or iron individually resulted in no significant phytoplankton growth over 48 hours. However, the addition of both nitrogen and iron increased concentrations of chlorophyll a by up to approximately 40-fold, led to diatom proliferation, and reduced community diversity. Once nitrogen–iron co-limitation had been alleviated, the addition of cobalt or cobalt-containing vitamin B12 could further enhance chlorophyll a yields by up to threefold. Our results suggest that nitrogen–iron co-limitation is pervasive in the ocean, with other micronutrients also approaching co-deficiency. Such multi-nutrient limitations potentially increase phytoplankton community diversity.
The Larkin lectures are held every two years at the University of British Columbia in recognition of Dr. Peter Larkin's contributions to fisheries science. The lecture I presented in November 2015 coincided with an announcement that the Institute of Fisheries that Peter Larkin founded in the 1960s would be restructured as the “Institute for Oceans and Fisheries” with an emphasis on fisheries and oceans issues important to British Columbia as well as the rest of the world. I decided to look back at research issues that Peter Larkin thought would be important for Pacific salmon (Oncorhynchus spp.) in the future and see what has happened as a way of identifying the complexity that the Institute for Oceans and Fisheries in particular and the science community in general will face. I chose five themes from Peter Larkin's talks: 1 understanding marine survival, 2 ocean carrying capacity, 3 aquaculture, 4 climate, Pacific salmon and climate change and 5 informing the public, and then added my opinion about research priorities for the future. Peter Larkin recognized the future relevance of these examples, but he probably could not have imagined how these and related issues will challenge his renamed institute and the rest of the research community over the next 50 years.
Reconciling food security, economic development and biodiversity conservation is a key challenge, especially in the face of the demographic transition characterizing many countries in the world. Fisheries and marine ecosystems constitute a difficult application of this bio-economic challenge. Many experts and scientists advocate an ecosystem approach to manage marine socio-ecosystems for their sustainability and resilience. However, the ways by which to operationalize ecosystem-based fisheries management (EBFM) remain poorly specified. We propose a specific methodological framework—viability modelling—to do so. We show how viability modelling can be applied using four contrasted case-studies: two small-scale fisheries in South America and Pacific and two larger-scale fisheries in Europe and Australia. The four fisheries are analysed using the same modelling framework, structured around a set of common methods, indicators and scenarios. The calibrated models are dynamic, multispecies and multifleet and account for various sources of uncertainty. A multicriteria evaluation is used to assess the scenarios’ outcomes over a long time horizon with different constraints based on ecological, social and economic reference points. Results show to what extent the bio-economic and ecosystem risks associated with the adoption of status quo strategies are relatively high and challenge the implementation of EBFM. In contrast, strategies called ecoviability or co-viability strategies, that aim at satisfying the viability constraints, reduce significantly these ecological and economic risks and promote EBFM. The gains associated with those ecoviability strategies, however, decrease with the intensity of regulations imposed on these fisheries.
Escape incidents of farmed fish involve economic losses to fish farms, interactions with local fisheries and environmental impacts to coastal ecosystems. More attention should clearly be paid to preventive measures. It is also essential to develop and establish contingency plans in case of escapes, to mitigate potentially negative socioeconomic and environmental impacts. Three mark-and-recapture experiments simulating escape incidents of sea bass (N = 1000 ind.), sea bream (N = 1000 ind.) and meagre (N = 1000 ind.) were carried out at three coastal fish farms located along the Mediterranean Coast of Spain. First, targeted experimental fishing trials in collaboration with artisanal netters were attempted at each location as potential fast-response contingency plans for recapturing escapees. Targeted fishing was successful on meagre (N = 38 ind., CPUE: 2.2 ind 10 m−2 h−1) and sea bream (N = 8 ind., CPUE: 1.3 ind 10 m−2 h−1), while no sea bass were recaptured. Secondly, recaptures reported from local fishermen (professional and recreational) during the study period were also considered. Altogether, total recapture rates were similar among the three species (sea bass: 5.4%; sea bream: 7.1%; meagre: 8.7%), although the spatial and temporal observations of recaptures varied among species. Recreational fishermen were the only contributors, recapturing 54 tagged sea bass (angling: 85%; spear-fishing: 15%) in mainly shallow coastal waters and about three km distance from the fish-farm during the weeks after release. A total of 71 escaped sea bream were recaptured by both recreational and artisanal fishermen, contributing similarly (recapture rates: 47.9% and 40.8% of total, respectively). Most sea bream recaptures were during the first nine days after release (86% of total recaptures), mainly near the farm facilities (<3 km). The bulk of meagre recaptures were during the first two days after release (>95%), mainly by experimental and artisanal netting (38 and 47 individuals respectively) again near the facility. In parallel, an underwater visual census was carried out at coastal locations and Natura 2000 sites in each study area, to assess the presence of escapees in marine habitats of special interest. Neither escaped sea bass nor escaped meagre were observed during underwater surveys, and only three tagged sea bream were found together at artificial reefs. Given that recaptures of tagged fish differed among fish species and fishing techniques following simulated escape incidents at W-Mediterranean coastal facilities, diverse potential contingency plans are here discussed.
The invasion of Indo-Pacific lionfish is one of the most pressing concerns in the context of coral reef conservation throughout the Caribbean. Invasive lionfish threaten Caribbean fish communities by feeding on a wide range of native prey species, some of which have high ecological and economic value. In Roatan (Honduras) a local non-governmental organisation (i.e. Roatan Marine Park) trains residents and tourists in the use of spears to remove invasive lionfish. Here, we assess the effectiveness of local removal efforts in reducing lionfish populations. We ask whether reefs subject to relatively frequent removals support more diverse and abundant native fish assemblages compared to sites were no removals take place. Lionfish biomass, as well as density and diversity of native prey species were quantified on reefs subject to regular and no removal efforts. Reefs subject to regular lionfish removals (two to three removals month−1) with a mean catch per unit effort of 2.76 ± 1.72 lionfish fisher−1 h−1 had 95% lower lionfish biomass compared to non-removal sites. Sites subject to lionfish removals supported 30% higher densities of native prey-sized fishes compared to sites subject to no removal efforts. We found no evidence that species richness and diversity of native fish communities differ between removal and non-removal sites. We conclude that opportunistic voluntary removals are an effective management intervention to reduce lionfish populations locally and might alleviate negative impacts of lionfish predation. We recommend that local management and the diving industry cooperate to cost-effectively extend the spatial scale at which removal regimes are currently sustained.
Winnowing of poorly-adapted species from local communities causes shifts/declines in species richness, making ecosystems increasingly ecologically depauperate. Low diversity can be associated with marginality of environments, which is increasing as climate change impacts ecosystems globally. This paper demonstrates the demographic mechanisms (size-specific mortality, growth, fertility; and metapopulation connectivity) associated with population-level changes due to thermal stress extremes for five zooxanthellate reef-coral species. Effects vary among species, leading to predictable changes in population size and, consequently, community structure. The Persian/Arabian Gulf (PAG) is an ecologically marginal reef environment with a subset of Indo-Pacific species, plus endemics. Local heating correlates with changes in coral population dynamics and community structure. Recent population dynamics of PAG corals were quantified in two phases (medium disturbed MD 1998–2010 and 2013–2017, severely disturbed SD 1996/8, 2010/11/12) with two stable states of declining coral frequency and cover. The strongest changes in life-dynamics, as expressed by transition matrices solved for MD and SD periods were in Acropora downingiand Porites harrisoni, which showed significant partial and whole-colony mortality (termed “shrinkers”). But in Dipsastrea pallida, Platygyra daedalea, Cyphastraea microphthalma the changes to life dynamics were more subtle, with only partial tissue mortality (termed “persisters”). Metapopulation models suggested recovery predominantly in species experiencing partial rather than whole-colony mortality. Increased frequency of disturbance caused progressive reduction in coral size, cover, and population fecundity. Also, the greater the frequency of disturbance, the more larval connectivity is required to maintain the metapopulation. An oceanographic model revealed important local larval retention and connectivity primarily between adjacent populations, suggesting that correlated disturbances across populations will lead to winnowing of species due to colony, tissue, and fertility losses, with resultant insufficient dispersal potential to make up for losses—especially if disturbances increase under climate change. Variable extinction thresholds exist based on the susceptibility of species to disturbance (“shrinkers” vs. “persisters”), determining which species will be winnowed from the community. Besides projected changes in coral community and population structure, no species are projected to increase in cover. Increased marginality due to climate change will lead to a net loss of coral cover and novel communities in PAG.
Population genomic surveys suggest that climate-associated genetic variation occurs widely across species, but whether it is sufficient to allow population persistence via evolutionary adaptation has seldom been quantified. To ask whether rapid adaptation in reef-building corals can keep pace with future ocean warming, we measured genetic variation at predicted warm-adapted loci and simulated future evolution and persistence in a high-latitude population of corals from Rarotonga, Cook Islands. Alleles associated with thermal tolerance were present but at low frequencies in this cooler, southerly locality. Simulations based on predicted ocean warming in Rarotonga showed rapid evolution of heat tolerance resulting in population persistence under mild warming scenarios consistent with low CO2 emission plans, RCP2.6 and RCP4.5. Under more severe scenarios, RCP6.0 and RCP8.5, adaptation was not rapid enough to prevent extinction. Population adaptation was faster for models based on smaller numbers of additive loci that determine thermal tolerance and for higher population growth rates. Finally, accelerated migration via transplantation of thermally tolerant individuals (1 to 5%/year) sped adaptation. These results show that cool-water corals can adapt to warmer oceans but only under mild scenarios resulting from international emissions controls. Incorporation of genomic data into models of species response to climate change offers a promising method for estimating future adaptive processes.
Better mitigation of anthropogenic stressors on marine ecosystems is urgently needed to address increasing biodiversity losses worldwide. We explore opportunities for stressor mitigation using whole-of-systems modelling of ecological resilience, accounting for complex interactions between stressors, their timing and duration, background environmental conditions and biological processes. We then search for ecological windows, times when stressors minimally impact ecological resilience, defined here as risk, recovery and resistance. We show for 28 globally distributed seagrass meadows that stressor scheduling that exploits ecological windows for dredging campaigns can achieve up to a fourfold reduction in recovery time and 35% reduction in extinction risk. Although the timing and length of windows vary among sites to some degree, global trends indicate favourable windows in autumn and winter. Our results demonstrate that resilience is dynamic with respect to space, time and stressors, varying most strongly with: (i) the life history of the seagrass genus and (ii) the duration and timing of the impacting stress.
The role of commercial harbours as sink and source habitats for non-indigenous species (NIS) and the role of recreational boating for their secondary spread were investigated by analysing the fouling community of five Italian harbours and five marinas in the western Mediterranean Sea. It was first hypothesised that NIS assemblages in the recreational marinas were subsets of those occurring in commercial harbours. However, the data did not consistently support this hypothesis: the NIS pools of some marinas significantly diverged from harbours even belonging to the same coastal stretches, including NIS occurring only in marinas. This study confirms harbours as hotspots for marine NIS, but also reveals that numbers of NIS in some marinas is higher than expected, suggesting that recreational vessels effectively facilitate NIS spread. It is recommended that this vector of NIS introduction is taken into account in the future planning of sustainable development of maritime tourism in Europe.
The impact of environmental change and anthropogenic stressors on coastal marine systems will strongly depend on changes in the magnitude and composition of organic matter exported from the water column to the seafloor. Knowledge of vertical export in the Baltic Sea is synthesised to illustrate how organic matter deposition will respond to climate warming, climate-related changes in freshwater runoff, and ocean acidification. Pelagic heterotrophic processes are suggested to become more important in a future warmer climate, with negative feedbacks to organic matter deposition to the seafloor. This is an important step towards improved oxygen conditions in the near-bottom layer that will reduce the release of inorganic nutrients from the sediment and hence counteract further eutrophication. The evaluation of these processes in ecosystem models, validated by field observations, will significantly advance the understanding of the system’s response to environmental change and will improve the use of such models in management of coastal areas.
The future is uncertain for Antarctica, with many possibilities – some more plausible, others more preferable. Indeed, the region and its governance regime may be reaching (or may have reached) a crossroads moment as a result of a series of challenges, including the changing Antarctic climate and environment, increasing human activity, shifting values among Antarctic states and a low-cost, somewhat benign governance regime (the Antarctic Treaty System). Within this context there are a number of interdependent drivers that are likely to influence Antarctica's future over, say, 25 years: global environmental and socio-economic developments; Antarctic governance; Antarctic research, including national Antarctic programme operations; and Antarctic tourism. The research presented here involved a thorough examination of Antarctic literature on current Antarctic developments and challenges, and an assessment of global trends. Scenarios were developed through a facilitated workshop process. From these, four future scenarios were developed based on interactions between these drivers. The resulting scenarios provide a dynamic, evolving possibility space to be explored as a means of understanding where Antarctic issues might evolve, depending on the growth or diminishing importance of drivers. In turn these suggest that more structured polar futures are needed based on formal quantitative and qualitative data.
The ecosystem services afforded by coastal wetlands are threatened by climate change and other anthropogenic stressors. The Kennedy Space Center and Merritt Island National Wildlife Refuge in east central Florida offer a representative site for investigating how changes to vegetation distribution interact with management to impact coastal protection. Here, salt marshes are converting to mangroves, and mosquito impoundment structures are being modified. The resulting changes to vegetation composition and topography influence coastal protection services in wetlands. We used a model-based assessment of wave attenuation and erosion to compare vegetation (mangrove, salt marsh) and impoundment state (intact, graded). Our findings suggest that the habitat needed to attenuate 90% of wave height is significantly larger for salt marshes than mangroves. Erosion prevention was significantly higher (470%) in scenarios with mangroves than in salt marshes. Intact berms attenuated waves over shorter distances, but did not significantly reduce erosion. Differences in coastal protection were driven more by vegetation than by impoundment state. Overall, our findings reveal that mangroves provide more coastal protection services, and therefore more coastal protection value, than salt marshes in east central Florida. Other coastal regions undergoing similar habitat conversion may also benefit from increased coastal protection in the future.
Monitoring and managing fisheries bycatch is increasingly recognized as a critical component of robust fisheries management frameworks. This review, addressing this subject, begins by defining bycatch and analyzing the reasons it happens, from accidental to intentional discarding. It identifies the most common species composing bycatch of the main tuna fisheries using purse seine and longline gear. Considerations of options available to estimate bycatch, their potential biases and uncertainties, and ways to address these issues are discussed. The formulas used to estimate bycatch also point to the options to reduce them, lowering bycatch per unit of effort or lowering effort itself. It shows that a mean can be reduced by reducing all its component figures, or by eliminating the high values at the extreme of the distribution (i.e., where a small proportion of events causes a large proportion of the problem), a common issue in bycatch. A generic strategy is described that can be applied to all gears and fisheries, and it is then described for the fisheries of interest, showing examples of its application. These cover many mitigation actions based on gear and operational changes. Management options aiming at reducing bycatch are also mentioned. A detailed description of the ways the strategy has been implemented for purse seiners and longliners is provided. Finally, market strategies, education and awareness of stakeholders, mainly fishers, and some potential future developments are briefly described.
Bivalve aquaculture has become increasingly important for marine protein production and is an alternative to exploiting natural resources. Its further and sustainable development should follow an ecosystem approach, to maintain both biodiversity and ecosystem functioning. The identification of critical thresholds to development remains difficult. The present work aims at combining the calculation of the system’s ecological carrying capacity (ECC) with the ecosystem view of resilience for a bay system exposed to bivalve (scallop) aquaculture. Using a trophic food-web model, a stepwise further expansion of culture activities was simulated, and the impact on the system was evaluated twofold: First, a recently developed approach to estimating ECC was used, and second, a resilience indicator was calculated, which is based on the distribution of consumption flows within the trophic network (sensu Arreguín-Sanchez in Ecol Model 272: 27–276, 2014). Results suggest that a culture expansion beyond present-day scale would (a) cause a shift in community composition towards a system dominated by secondary consumers, (b) lead to the loss of system compartments, affecting ecosystem functioning, and (c) result in a decrease in resilience, emphasizing the need to regulate aquaculture activities. The applicability and potential of this presented method in the context of an ecosystem-based approach to aquaculture is discussed. This work aims at adding to the ongoing discussion on sustainable bivalve aquaculture and is expected to help guide aquaculture management.
After being displaced, juvenile reef fishes are able to return home over large distances. This strong homing behaviour is extraordinary and may allow insights into the longer-term spatial ecology of fish communities. For example, it appears intuitive that strong homing behaviour should be indicative of long-term site fidelity. However, this connection has rarely been tested. We quantified the site fidelity of juvenile fishes of four species after returning home following displacement. Two species, parrotfishes and Pomacentrus moluccensis, showed significantly reduced site fidelity after returning home. On average, they disappeared from their home sites almost 3 d earlier than expected. Mortality or competitive exclusion does not seem to be the main reasons for their disappearance. Rather, we suggest an increased propensity to relocate after encountering alternative reef locations while homing. It appears that some juvenile fishes may have a higher innate spatial flexibility than their strict homing drive suggests.
How do technologies of power make the world governable? The understanding of how management techniques create governability remains rather poor. In this article, I analyse how spatial regulation in Norwegian fisheries direct human behaviour towards scientific, political, and administrative objectives. Like other fisheries’ regulations, they contribute to governmentalisation and governability, and this article illustrate how this happens. Governance aims towards specific outcomes, but in the attempt to make the world governable, the governing and those who are governed are changed and new social orders may be the result. Thus, governing instruments are not only instruments for the direction of behaviour, but also instruments for social change.