A holistic basis for achieving ecosystem‐based management is needed to counter the continuing degradation of coral reefs. The high variation in recovery rates of fish, corresponding to fisheries yields, and the ecological complexity of coral reefs have challenged efforts to estimate fisheries sustainability. Yet, estimating stable yields can be determined when biomass, recovery, changes in per area yields and ecological change are evaluated together. Long‐term rates of change in yields and fishable biomass‐yield ratios have been the key missing variables for most coral reef assessments. Calibrating a fishery yield model using independently collected fishable biomass and recovery data produced large confidence intervals driven by high variability in biomass recovery rates that precluded accurate or universal yields for coral reefs. To test the model's predictions, I present changes in Kenyan reef fisheries for >20 years. Here, exceeding yields above 6 tonnes km−2 year−1 when fishable biomass was ~20 tonnes/km2 (~20% of unfished biomass) resulted in a >2.4% annual decline. Therefore, rates of decline fit the mean settings well and model predictions may therefore be used as a benchmark in reefs with mean recovery rates (i.e. r = 0.20–0.25). The mean model settings indicate a maximum sustained yield (MSY) of ~6 tonnes km−2 year−1 when fishable biomass was ~50 tonnes/km2. Variable reported recovery rates indicate that high sustainable yields will depend greatly on maintaining these rates, which can be reduced if productivity declines and management of stocks and functional diversity are ineffective. A number of ecological state‐yield trade‐off occurs as abrupt ecological changes prior to biomass levels that produce MSY.
Ecosystem-based Management (EBM)
Many climate change adaptation scholars recognise the complexities in the governance of adaptation. Most have used the concept of ‘barriers to adaptation’ in an attempt to describe why governance of adaptation is challenging. However, these studies have recently been critiqued for over simplifying complex governance processes by referring to the static concept of barriers, thereby ignoring dynamic complexity as a root explanatory cause. This paper builds the argument that how barriers are currently used in the literature is insufficient to explain why the governance of adaptation often proves difficult. We adopt a so-called mechanism-based approach to investigate how and why the governance of ecosystem-based adaptation (EbA) reaches impasses in five cases in Thailand and the Netherlands. Our findings show six causal mechanisms that explain impasses in the five case studies: (1) frame polarisation, (2) timing synchronisation, (3) risk innovation, (4) rules of the game, (5) veto players and (6) lost in translation. Several of these causal mechanisms are recurring and emerge under specific contextual conditions or are activated by other mechanisms. Our findings provide valuable insights into the impasses in the governance of EbA and allow for critical reflections on the analytical value of the mechanism-based approach in explaining why the governance of adaptation proves difficult and how this can be overcome.
Managing diverse ecosystems is challenging because structuring drivers are often processes having diffuse impacts that attenuate from the people who were “managed” to the expected ecosystem-wide outcome. Coral reef fishes targeted for management only indirectly link to the ecosystem’s foundation (reef corals). Three successively weakening interaction tiers separate management of fishing from coral abundance. We studied 12 islands along the 700-km eastern Caribbean archipelago, comparing fished and unfished coral reefs. Fishing reduced biomass of carnivorous (snappers and groupers) and herbivorous (parrotfish and surgeonfish) fishes. We document attenuating but important effects of managing fishing, which explained 37% of variance in parrotfish abundance, 20% of variance in harmful algal abundance, and 17% of variance in juvenile coral abundance. The explained variance increased when we quantified herbivory using area-specific bite rates. Local fisheries management resulted in a 62% increase in the archipelago’s juvenile coral density, improving the ecosystem’s recovery potential from major disturbances.
Effective ecosystem-based fishery management involves assessment of foraging interactions among consumers, including upper level predators such as marine birds and humans. Of particular value is information on predator energetic and consumption demands and how they vary in response to the often volatile dynamics of forage populations, as well as the factors that affect forage availability and potential prey switching. We examined the prey requirements of common murre (Uria aalge), Brandt's cormorant (Phalacrocorax penicillatus), and rhinoceros auklet (Cerorhinca monocerata) in the central California Current over a 30-year period, 1986–2015. We developed a bioenergetics model that incorporates species-specific values for daily basic energy needs, diet composition, energy content of prey items and assimilation efficiency, and then projected results relative to stock size and levels of commercial take of several species. The most common forage species consumed were juvenile rockfish (Sebastesspp.), northern anchovy (Engraulis mordax), smelt (Osmeridae), and market squid (Doryteuthis opalescens). Total biomass of forage species consumed during the breeding season varied annually from 8500 to >60,000 metric ton (t). Predator population size and diet composition had the greatest influence on overall prey consumption. The most numerous forage species consumed in a given year was related to abundance estimates of forage species derived from an independent ecosystem assessment survey within the central place foraging range of breeding avian predators. The energy density of dominant prey consumed annually affected predator energy expenditure during chick rearing and whether prey switching was required. Increased forage species take by predators, as revealed by seabirds, may be adding consumptive pressure to key forage fish populations, regardless of the potential additional impacts of commercial fisheries. Improving estimates of consumption by predators and fisheries will promote more effective management from an ecosystem perspective.
Sustained observations of marine biodiversity and ecosystems focused on specific conservation and management problems are needed around the world to effectively mitigate or manage changes resulting from anthropogenic pressures. These observations, while complex and expensive, are required by the international scientific, governance and policy communities to provide baselines against which the effects of human pressures and climate change may be measured and reported, and resources allocated to implement solutions. To identify biological and ecological essential ocean variables (EOVs) for implementation within a global ocean observing system that is relevant for science, informs society, and technologically feasible, we used a driver‐pressure‐state‐impact‐response (DPSIR) model. We (1) examined relevant international agreements to identify societal drivers and pressures on marine resources and ecosystems, (2) evaluated the temporal and spatial scales of variables measured by 100+ observing programs, and (3) analysed the impact and scalability of these variables and how they contribute to address societal and scientific issues. EOVs were related to the status of ecosystem components (phytoplankton and zooplankton biomass and diversity, and abundance and distribution of fish, marine turtles, birds and mammals), and to the extent and health of ecosystems (cover and composition of hard coral, seagrass, mangrove and macroalgal canopy). Benthic invertebrate abundance and distribution and microbe diversity and biomass were identified as emerging EOVs to be developed based on emerging requirements and new technologies. The temporal scale at which any shifts in biological systems will be detected will vary across the EOVs, the properties being monitored and the length of the existing time‐series. Global implementation to deliver useful products will require collaboration of the scientific and policy sectors and a significant commitment to improve human and infrastructure capacity across the globe, including the development of new, more automated observing technologies, and encouraging the application of international standards and best practices.
U.S. fisheries management has made tremendous strides under the current management framework, which centers on single stocks rather than ecosystems. However, conventional management focuses on one fishing sector at a time, considers a narrow range of issues, and is separated into individual fishery management plans often leaving little opportunity to consider overarching management goals across fisheries. Ecosystem-based Fisheries Management (EBFM) provides mechanisms to address these but has not been widely adopted. Here, we review and analyze the development of Fisheries Ecosystem Plans (FEPs) as a means to implement EBFM. In doing so, we provide a blueprint for next-generation FEPS that have the potential to translate EBFM to action. We highlight FEPs as a structured planning process that uses adaptive management to operationalize EBFM. This “FEP Loop” process starts by identifying the key factors that shape a fishery system and considering them simultaneously, as a coherent whole. It then helps managers and stakeholders delineate their overarching goals for the system and refine them into specific, realistic projects. And it charts a course forward with a set of management actions that work in concert to achieve the highest-priority objectives. We conclude that EBFM is feasible today using existing science tools, policy instruments, and management structures. Not only that, nearly all of the steps in the proposed “FEP Loop” process are presently being carried out by U.S. fishery managers. The process of reviewing regional experiences in developing and applying the FEP loop will lead to adaptations and improvements of the process we propose.
Ecosystem-based management (EBM) should lead to policy that effectively addresses major negative impacts on the ecosystem in order to solve the problems identified. So far, there is little empirical knowledge about what is conducive to the formulation and implementation of such policies. The article suggests that implementation theory is an appropriate theoretical platform for acquiring such knowledge. General implementation theory is a starting point that gradually can be specified for implementation of EBM through carefully selected case studies. The article describes the theory and demonstrates its applicability by analysing the implementation of the measures in the Barents Sea Management Plan. Despite a policy design that violated several traditional recommendations for successful implementation, most measures in the plan were actually put into practice. The explanation lies in the Norwegian political-administrative system, the mobilization of knowledge, the collaboration created by involving a group of ministries and the authoritative handling of conflicts by the cabinet. All these explanations refer to processes occurring during the formulation of the policy, thus illustrating the need for a broader focus than the implementation process itself when studying policy implementation. The political leadership of the Norwegian government was decisive, demonstrating that EBM can be effectively implemented in a top-down fashion.
Climate change effects have the potential of affecting both ocean and atmospheric processes. These changes pose serious threats to the millions of people that live by the coast. Thus, the objective of the present review is to discuss how climate change is altering (and will continue to alter) atmospheric and oceanic processes, what are the main implications of these alterations along the coastline, and which are the ecosystem-based management (EBM) strategies that have been proposed and applied to address these issues. While ocean warming, ocean acidification and increasing sea level have been more extensively studied, investigations on the effects of climate change to wind and wave climates are less frequent. Coastal ecosystems and their respective natural resources will respond differently according to location, environmental drivers and coastal processes. EBM strategies have mostly concentrated on improving ecosystem services, which can be used to assist in mitigating climate change effects. The main challenge for developing nations regards gaps in information and scarcity of resources. Thus, for effective management and adaptive EBM strategies to be developed worldwide, information at a local level is greatly needed.
In this paper, I argue that we have at hand what is needed to provide scientific advice for ecosystem-based management of small pelagics and other species groups now. The ingredients for this advice are (i) large marine ecosystems as spatial management units; (ii) maintaining ecosystem productivity and exploiting at multispecies maximum yield as overarching management objectives; (iii) assessment of ecosystems by evaluating changes in primary productivity; (iv) an operational management procedure in which single-species catch proposals are adjusted to ecosystem productivity using a set of control rules. Inspection of historic landings for small pelagics and other small species in the Northeast Atlantic (ICES area) reveals that most likely fisheries exploitation does not, and never did, exceed system productivity in most LMEs and is therefore overall sustainable, although not necessarily for individual stocks.
The Government of Indonesia, through the Ministry of Marine Affairs and Fisheries, considers an ecosystem approach to fisheries management (EAFM) to be the preferred option and best practice for the long-term sustainability of fisheries and the ecosystem services provided to society. Recognizing that an appropriate legal, policy and institutional framework must be in place for an EAFM, this paper presents a review of current Indonesian laws and policies for an EAFM; an assessment to identify gaps, challenges and opportunities for an EAFM; and recommendations for EAFM implementation. A strong co-management structure of the fishery management area (FMA) governance is at the heart of EAFM implementation. It is also critical to mention the governance or institution structure of Fishery Management Council of FMA in Indonesian waters in the new proposed fishery law.