Introduction to the development of models with dynamic structure for marine ecosystems

Underprotected Marine Protected Areas in a Global Biodiversity Hotspot

Marine protected areas (MPAs) are increasingly implemented as a conservation tool worldwide. In many cases, they are managed adaptively: the abundance of target species is monitored, and observations are compared to some model-based expectation for the trajectory of population recovery to ensure that the MPA is achieving its goals. Most previous analyses of the transient (short-term) response of populations to the cessation of fishing inside MPAs have dealt only with gonochore (fixed-sex) species. However, many important fishery species are protogynous hermaphrodites (female-to-male sex-changing). Because size-selective harvest will predominantly target males in these species, harvesting not only reduces abundance but also skews the sex ratio toward females. Thus the response to MPA implementation will involve changes in both survival and sex ratio, and ultimately reproductive output. We used an age-structured model of a generic sex-changing fish population to compare transient population dynamics after MPA implementation to those of an otherwise similar gonochore population and examine how different features of sex-changing life history affect those dynamics. We examined both demographically open (most larval recruitment comes from outside the MPA) and demographically closed (most larval recruitment is locally produced) dynamics. Under both scenarios, population recovery of protogynous species takes longer when fishing was more intense pre-MPA (as in gonochores), but also depends heavily on the mating function, the degree to which the sex ratio affects reproduction. If few males are needed and reproduction is not affected by a highly female-biased sex ratio, then population recovery is much faster; if males are a limiting resource, then increases in abundance after MPA implementation are much slower than for gonochores. Unfortunately, the mating function is largely unknown for fishes. In general, we expect that most protogynous species with haremic mating systems will be in the first category (few males needed), though there is at least one example of a fish species (though not a sex-changing species) for which males are limiting. Thus a better understanding of the importance of male fish to population dynamics is needed for the adaptive management of MPAs.

The expansion of marine protected areas (MPAs) is a core focus of global conservation efforts, with the "30x30" initiative to protect 30% of the ocean by 2030 serving as a prominent example of this trend. We consider a series of proposed MPA network expansions of various sizes, and we forecast the impact this increase in protection would have on global patterns of fishing effort. We do so by building a predictive machine learning model trained on a global dataset of satellite-based fishing vessel monitoring data, current MPA locations, and spatiotemporal environmental, geographic, political, and economic features. We then use this model to predict future fishing effort under various MPA expansion scenarios compared to a business-as-usual counterfactual scenario that includes no new MPAs. The difference between these scenarios represents the predicted change in fishing effort associated with MPA expansion. We find that regardless of the MPA network objectives or size, fishing effort would decrease inside the MPAs, though by much less than 100%. Moreover, we find that the reduction in fishing effort inside MPAs does not simply redistribute outside-rather, fishing effort outside MPAs would also decline. The overall magnitude of the predicted decrease in global fishing effort principally depends on where networks are placed in relation to existing fishing effort. MPA expansion will lead to a global redistribution of fishing effort that should be accounted for in network design, implementation, and impact evaluation.

The implementation of large-scale marine protected areas (MPAs) depends upon scarce conservation resources, while their effects on biodiversity conservation are rarely assessed to date. Quantitative evaluations are necessary to assess the effectiveness of large-scale MPAs in enhancing ecosystem resilience, protecting biodiversity, and mitigating expanding threats. In this study, the effectiveness of large-scale MPAs, which are remotely managed and in offshore areas of the southwestern Atlantic Ocean (Brazil), was assessed concerning the occurrence of fishing activities within their boundaries before and after their implementation. Two sets of MPAs surrounding the São Pedro and São Paulo archipelago (SPSP) and the Trindade-Martin Vaz Islands (TMV) were established in early 2018, each comprising one no-take (i.e., fully-protected) and one multiple-use (i.e., partially-protected) area. For this assessment, I used satellite detections of Vessel Monitoring System transmission to quantify the fishing pressure (i.e., “likely fishing days”) from commercial fisheries spanning 5 years (2015–2019). I then derived three metrics – fishing area, intensity, and density – to compare fishing activity within each MPA and year. The results showed that the effectiveness of the multiple-use MPAs was variable and contrasting, with SPSP experiencing a reduction in the fishing intensity and area and TMV experiencing an increase in both measures. An inverted pattern was evident for the no-take MPAs: while the one in the SPSP region experienced an increase in the fishing density after its establishment following a squeeze factor, the no-take MPA in the TMV region observed a decrease in the fishing density when comparing years before and after MPA implementation. These outputs can support managers in planning the implementation of further conservation strategies, such as monitoring and enforcement plans, and the analyses here also contribute to enhancing our understanding on the implications and challenges of adopting large-scale MPAs in the offshore environment as a high-profile strategy of ocean conservation.

Marine protected areas (MPAs) have been advocated as a solution to the challenges of both conservation and modern fishery management, but their application remains controversial, partly because there are only general guidelines for evaluating their effectiveness. We propose a framework to specifically evaluate established MPAs in six steps. We tested the approach by reviewing published research and unpublished information on the Goukamma MPA in the centre of the South African temperate south coast. Information reviewed included effects on the structure of fish populations, catch and abundance indices of fish species, and ecosystem effects. We investigated factors that determine the usefulness of a MPA in fisheries management, including the movement behaviour of adult fishes, larval dispersal and fisher-displacement patterns. We found that differences in the rates of exploitation across the MPA border resulted in differences in abundance, size and condition of the main target species, roman (Chrysoblephus laticeps). The diversity and abundance of non-target fish species, and the composition of the benthic invertebrate community, were affected by the cessation of fishing. The potential for ‘spillover’ of adult roman might be limited to the vicinity of the MPA by their small home range, but there is potential for self-seeding and dispersal of roman eggs and larvae over wider areas. These theoretical considerations were confirmed by an analysis of catch data from before and after MPA implementation. The framework presented here may help to identify and fill gaps in the knowledge of established MPAs along South Africa’s temperate south coast.

Marine conservation is a complex challenge and its success is generally determined by social factors. Consequently, before promoting the creation of marine protected areas (MPAs), it is necessary to consider the stakeholder’s vision upon them, their perceptions, interests and expectations, in order to minimize conflicts and achieve the necessary support for their implementation and effective management. In this context, and considering the project to propose the creation of a Multiple-Use Coastal Marine Protected Area (AMCP-MU) in the Almirantazgo Sound, we evaluated the perception of artisanal fishermen from the Magallanes region on the topics of biodiversity conservation, MPAs and the project to create a new AMCP-MU. Thirty-five fishermen were interviewed in different coves from Porvenir, Punta Arenas and Puerto Natales cities. In general, the interviewees demonstrated basic knowledge about the aforementioned topics, which, in general, was obtained through different means. Forty three percent of the fishermen interviewed, perceived MPAs as closed areas, intended to protect species and were human activities represent a threat to them, while 23% indicated that MPAs are not necessarily closed areas, allowing the development of some activities. Regarding the creation of an AMCP-MU in the Almirantazgo Sound, 68% of the fishermen stated that it should not generate restrictions for the development of their activities, nor for those of other sectors (e.g. tourism sector). In regards of the fishermen’s perception upon the stakeholders linked to biodiversity conservation in the region, 54% of the fishermen showed some apprehension towards public services, due to their regulating and supervising role, while the tourism sector and Non-governmental organization were viewed more positively. The results of this work contribute to the understanding of the human dimension of marine conservation in Magallanes, highlight the importance of communication to find a common ground between diverse actors with different cultural interests and experiences, and provide contextual background for the process of creation and implementation of MPAs.

Ecosystem‐based management and conservation approaches such as marine protected areas (MPAs) require large amounts of ecological data to be implemented and adaptively managed. Recently, many citizen science programs have endeavored to help provide these much‐needed data. Implementation of MPAs under the Marine Life Protection Act (MLPA) Initiative in Southern California was followed by a monitoring program to establish a comprehensive baseline of the ecological conditions of several marine ecosystems at the time of MPA implementation. This baseline monitoring consortium involved several citizen science monitoring programs alongside more traditional academic monitoring programs, creating an opportunity to evaluate the potential for citizen scientists to become more involved in future long‐term monitoring efforts. We investigated different citizen science models, their program goals, and contributions to MPA baseline monitoring, including their respective monitoring protocols and data quality assurance measures, in the context of the goals of the MLPA baseline monitoring program. We focused on three very different case studies: (i) commercial fishermen and other volunteers collaborating with researchers to study the California spiny lobster, (ii) volunteer divers monitoring rocky reefs with the Reef Check California (RCCA) program and (iii) middle and high school students monitoring the inter‐tidal life of rocky shore and sandy beach ecosystems with the National Marine Sanctuaries’ Long‐term Monitoring Program and Experiential Training for Students (LiMPETS) program. We elucidate capacities and potential of citizen science approaches for MPA baseline monitoring and for building capacity towards sustainable long‐term monitoring of MPAs. Results from this study will be relevant and timely as the monitoring of California's MPAs transitions from baseline to long‐term monitoring, and as citizen science continues to become more prevalent in California and elsewhere.

Social impacts of marine protected areas in South Africa on coastal fishing communities

Marine protected areas (MPAs) are increasingly being used globally to conserve marine resources. However, whether many MPAs are being effectively and equitably managed, and how MPA management influences substantive outcomes remain unknown. We developed a global database of management and fish population data (433 and 218 MPAs, respectively) to assess: MPA management processes; the effects of MPAs on fish populations; and relationships between management processes and ecological effects. Here we report that many MPAs failed to meet thresholds for effective and equitable management processes, with widespread shortfalls in staff and financial resources. Although 71% of MPAs positively influenced fish populations, these conservation impacts were highly variable. Staff and budget capacity were the strongest predictors of conservation impact: MPAs with adequate staff capacity had ecological effects 2.9 times greater than MPAs with inadequate capacity. Thus, continued global expansion of MPAs without adequate investment in human and financial capacity is likely to lead to sub-optimal conservation outcomes.

As Marine Protected Areas (MPAs) expand in size and number, it is critical that we understand how they are impacting local communities. However, social impact evaluations on MPAs are often conducted with limited data points before and after MPA implementation, which can weaken the reliability of their results. To address this gap, we collected longitudinal American Community Survey (ACS) socioeconomic data on coastal communities and counties adjacent to marine reserves in Oregon. Oregon has both limited-take MPAs and stricter no-take marine reserves. This study focused solely on the marine reserves. We compared treatment and control units before and after marine reserve implementation using both difference-in-differences (DID) and synthetic control approaches. Each approach yielded different results, potentially providing a more complete picture of marine reserve impacts and long-term trends while also highlighting the need to consider the variability of ACS data collected from small communities. The percent of the population employed in tourism-related industries was the only significant model in both the DID and synthetic control approaches. Tourism employment increased post marine reserve implementation more in communities adjacent to the marine reserves than in more distant coastal communities. This result could indicate that marine reserves are bringing more visitors to the coast, thereby increasing the need for a more tourism-based economy. However, this may not be the case since most coastal visitors are unaware of Oregon's marine reserves and fewer than 10% of business owners think the reserves have impacted their business. An alternative hypothesis is that the marine reserves were placed near communities with a prominent land-sea connection that were already shifting their economic base to focus more on tourism. This study contributes to the literature by demonstrating how secondary data sources can be used to aid in a more comprehensive MPA impact evaluation, how two different impact evaluation approaches (i.e., synthetic control and DID) can result in differing conclusions, and how the robust synthetic control approach can be easily applied to improve MPA impact evaluations. As one element of a large-scale assessment of marine reserve impacts, this study also broadens our understanding of underlying trends on the Oregon coast and how the recently implemented marine reserves may be impacting nearby communities.

Coral reefs and associated fish populations have experienced rapid decline in the Caribbean region and marine protected areas (MPAs) have been widely implemented to address this decline. The performance of no-take MPAs (i.e., marine reserves) for protecting and rebuilding fish populations is influenced by the movement of animals within and across their boundaries. Very little is known about Caribbean reef fish movements creating a critical knowledge gap that can impede effective MPA design, performance and evaluation. Using miniature implanted acoustic transmitters and a fixed acoustic receiver array, we address three key questions: How far can reef fish move? Does connectivity exist between adjacent MPAs? Does existing MPA size match the spatial scale of reef fish movements? We show that many reef fishes are capable of traveling far greater distances and in shorter duration than was previously known. Across the Puerto Rican Shelf, more than half of our 163 tagged fish (18 species of 10 families) moved distances greater than 1 km with three fish moving more than 10 km in a single day and a quarter spending time outside of MPAs. We provide direct evidence of ecological connectivity across a network of MPAs, including estimated movements of more than 40 km connecting a nearshore MPA with a shelf-edge spawning aggregation. Most tagged fish showed high fidelity to MPAs, but also spent time outside MPAs, potentially contributing to spillover. Three-quarters of our fish were capable of traveling distances that would take them beyond the protection offered by at least 40–64% of the existing eastern Caribbean MPAs. We recommend that key species movement patterns be used to inform and evaluate MPA functionality and design, particularly size and shape. A re-scaling of our perception of Caribbean reef fish mobility and habitat use is imperative, with important implications for ecology and management effectiveness.

Using an international dataset compiled from 121 sites in 87 marine protected areas (MPAs) globally (Edgar et al., 2014), I assessed how various configurations of design and management conditions affected MPA ecological performance, measured in terms of fish species richness and biomass. The set-theoretic approach used Boolean algebra to identify pathways that combined up to five ‘NEOLI’ (No-take, Enforced, Old, Large, Isolated) conditions and that were sufficient for achieving positive, and negative, ecological outcomes. Ecological isolation was overwhelming the most important condition affecting ecological outcomes but Old and Large were also conditions important for achieving high levels of biomass among large fishes (jacks, groupers, sharks). Solution coverage was uniformly low (<0.35) for all models of positive ecological performance suggesting the presence of numerous other conditions and pathways to ecological success that did not involve the NEOLI conditions. Solution coverage was higher (>0.50) for negative results (i.e., the absence of high biomass) among the large commercially-exploited fishes, implying asymmetries in how MPAs may rebuild populations on the one hand and, on the other, protect against further decline. The results revealed complex interactions involving MPA design, implementation, and management conditions that affect MPA ecological performance. In general terms, the presence of no-take regulations and effective enforcement were insufficient to ensure MPA effectiveness on their own. Given the central role of ecological isolation in securing ecological benefits from MPAs, site selection in the design phase appears critical for success.

Evaluation of the effects on rockfish and kelp artisanal fisheries of the proposed Mejillones Peninsula marine protected area (northern Chile, SE Pacific coast)

Marine protected areas (MPAs) have become a popular tool utilised across global oceans to achieve a variety of conservation goals. Because the reasons for MPA implementation can differ, it is imperative that resource managers design and execute management strategies that allow them to effectively assess MPA performance relative to the goals they set. We compared three MPA monitoring techniques commonly utilised to survey groundfish populations across different depth strata of temperate rocky reef habitat: underwater visual census (0–20 m), scientific hook and line fishing (10–50 m) and baited remote underwater video (30–100 m). We compared the strength and direction of standardised metrics, including response ratios, diversity indices and community structure, examining results through the lens of MPA performance. While each of our monitoring techniques detected similar MPA effects on groundfish biomass and density aggregated across species, MPA effects for individual species varied across methods. Each technique was shown to survey distinct groundfish community assemblages with varying levels of species diversity and richness. Synthesis and applications. While each technique was found to measure similar general trends in marine protected area (MPA) performance over time, we found compelling evidence that the utilization of multiple techniques allows managers to create the most comprehensive, effective and inclusive MPA monitoring regimes.

Marine Protected Areas (MPAs) are a tool to safeguard marine natural systems, yet their effectiveness depends on how well they are integrated into the existing socioeconomic context. Stakeholder engagement in MPA design can contribute to increasing integration. This study focuses on the co-design of an MPA between researchers, public administration, the private sector, and non-governmental organizations. The proposed MPA is in Portugal and includes an area that is a hotspot for biodiversity and economic activities. This is the first MPA proposal in mainland Portugal co-designed using a participatory approach. This study highlights the steps of the zoning process and synthesizes the eight main lessons learned, useful for other cases, particularly for relatively small coastal MPAs with multiple socioeconomic activities. Three zoning proposals were developed and discussed within the participatory process. The proposals considered the best scientific and local knowledge available and were defined using ecological, socioeconomic, and shape-area guiding principles. In an iterative manner and following a participatory approach, compromises with stakeholders were achieved, and a final proposal, scientifically sound and socially accepted by most stakeholders, was delivered to the government. The final zoning plan will achieve ambitious conservation goals, including the largest fully protected area to be declared in mainland Portugal, while minimizing the impacts on the existing economic activities and promoting its sustainability. This process resulted in valuable lessons that may be applied elsewhere and guide future MPA implementation or rezoning of existing ones. These transdisciplinary and participatory processes can be time and resource-consuming but are vital for ensuring MPA effectiveness.