No-take Zones Research Articles

When the Light Goes Out: Distribution and Sleeping Habitat Use of Parrotfishes at Night

Understanding the diurnal and nocturnal activity of organisms is a key topic in behavioral ecology, with implications for population structure and management strategies. In reef systems, parrotfishes play crucial roles as nominal herbivores, but overfishing has led to population collapses with detrimental effects on reef functions. Parrotfish are good models to study diel rhythms, as they are often easily observed while sleeping at night. We assessed the distribution, sleeping substrate selectivity and sleeping areas of parrotfishes during the night in a subtropical rocky reef of the Southwestern Atlantic. We performed replicated visual censuses (50 × 2 m) at different depths to estimate parrotfish abundance, while quantifying the structural complexity of sleeping sites. Among the seven recorded parrotfish species, we focused on the four most abundant to determine their sleeping habitat selectivity. Active telemetry was used for the two most abundant species to define their sleeping site areas and sleeping hotspots. All four species exhibited a preference for sediment as a sleeping substrate, while avoiding zoanthids. Species distribution was influenced by depth, with Scarus zelindae predominantly sleeping in high-complexity substrate at intermediate depths and Sparisoma tuiupiranga sleeping in the rock–sand interface at deeper depths. Tagged Sparisoma axillare and Sparisoma frondosum exhibited similar sleeping areas in terms of size and geographical locations; showing high site fidelity, they returned to the same sleeping sites over consecutive nights. These results represent the first assessment of parrotfish distribution and habitat use at night in the Atlantic. This information is crucial for guiding management actions, particularly in the planning of no-take zones for fishing control and population recovery.

Commercial fishery no-take zones for African penguins minimize fisheries losses at the expense of conservation gains

Abstract The African penguin population has declined precipitously in recent decades, and if current rates of decline persist, this species could become extinct in the wild by 2035. Resource extraction of small pelagic fish prey by the purse-seine fishery around African penguin breeding colonies has been identified as a demographically meaningful threat to African penguins. Consequently, long-term, effective no-take zones around breeding colonies have been endorsed by an expert panel of scientists constituted by the South African government. Here, we consider the six largest South African penguin colonies that currently hold 76% of the global population. We evaluate the adequacy of different no-take zone options using a trade-off mechanism recommended by the expert panel. For all six colonies except Bird Island, Algoa Bay, which is subject to the least fishing pressure, the current no-take zone delineations are assessed as having little benefit to the African penguin and little to no cost to the purse-seine fishery. Four of the six current no-take zones include ≤50% of the African penguins’ core foraging areas. Alternative no-take zones that approximate a more balanced trade-off offer more impactful alternatives to the current fisheries restrictions. Given the urgent need to implement evidence-based conservation interventions for the endangered African penguin, we recommend the substitution of the current no-take zones with those proposed herein.

Study on the relationship between economic input growth in Marine protected areas and environmental governance in the North Pacific Coast of Costa Rica: Based on reef fish assemblages

Reef fish communities under fishing pressure often experience reduced biomass, abundance, and altered size structure. The establishment of marine protected areas (MPAs) can help mitigate these declines. However, the success of MPAs, especially in developing countries with financial and socioeconomic challenges, largely hinges on effective enforcement. This study utilized underwater visual surveys (UVS) and baited remote underwater video stations (BRUVS) to evaluate population density, size distribution, and biomass of both economically valuable (e.g., target and ornamental species) and ecologically important (e.g., small/large predators and herbivores) fish groups within and outside a no-take MPA on the northern Pacific coast of Costa Rica.The results indicated that protective measures did not significantly affect the biomass of economically valuable fish species. However, there were notable differences in fish abundance and size distribution between no-take zones (where fishing is prohibited) and open-fishing zones. This suggests that, despite potential illegal fishing activities within the MPA, certain fish community components benefit from the protective measures.Specifically, herbivores and ornamental fish, which are often targeted by artisanal compressor fishing and the aquarium trade, exhibited higher biomass and abundance levels within the MPA. Additionally, significant shark species such as Galeocerdo cuvier, Carcharhinus leucas, and Carcharhinus limbatus were exclusively found within the MPA.The study also highlighted the crucial role of habitat quality, particularly high coral cover, in enhancing the biomass of ornamental fish.This research contributes to the growing body of evidence that MPAs, even with limited enforcement, consistently offer ecological benefits for reef fish communities

Deep learning for detection and counting of Nephrops norvegicus from underwater videos

Abstract The Norway lobster (Nephrops norvegicus) is one of the most important fishery items for the EU blue economy. This paper describes a software architecture based on neural networks, designed to identify the presence of N. norvegicus and estimate the number of its individuals per square meter (i.e. stock density) in deep-sea (350–380 m depth) Fishery No-Take Zones of the northwestern Mediterranean. Inferencing models were obtained by training open-source networks with images obtained from frames partitioning of in submarine vehicle videos. Animal detections were also tracked in successive frames of video sequences to avoid biases in individual recounting, offering significant success and precision in detection and density estimations.

An ecological coherence assessment of the Wider Caribbean Region marine protected area network

Marine protected areas (MPA) are area-based management tools that serve as the cornerstone for marine conservation and sustainable use. There has been a recent shift from establishing MPAs on an individual basis to establishing networks of connected MPAs to better reflect the transient dynamics of marine species and to ensure they are acting synergistically to deliver their intended outcomes in a coherent manner. This study employs innovative geospatial analysis to assess the ecological coherence of the MPA network comprising 846 sites within the Wider Caribbean Region, a global hotspot of marine biodiversity. Evaluating four main criteria widely used in policy—representativity, replicability, connectivity, and adequacy—through 14 tests, our findings indicate that the current MPA network is unlikely to have achieved ecological coherence across all criteria. To improve ecological coherence, regional management could focus on expanding coverage of ecologically important areas, encompassing a broader range of biogeographic zones, and protecting the full spectrum of marine habitats in the region. Efforts should also be directed towards establishing larger MPAs and increasing the number of MPAs with no-take zones, while ensuring the protection of indigenous and local communities' rights to sustainable marine resource use.

Combined Use of Fatty Acid Profiles and Elemental Fingerprints to Trace the Geographic Origin of Live Baits for Sports Fishing: The Solitary Tube Worm (Diopatra neapolitana, Annelida, Onuphidae) as a Case Study.

Diopatra neapolitana Delle Chiaje, 1841 (Annelida, Onuphidae) is one of the most exploited polychaete species in European waters, particularly in Ria de Aveiro, a coastal lagoon in mainland Portugal, where the overexploitation of this resource has led to a generalized decline of local populations. In an attempt to reduce the impact of harvesting, several management actions were implemented, but illegal poaching still fuels a parallel economy that threatens the sustainable use of this marine resource. The present study evaluated the combination of fatty acid profiles and elemental fingerprints of the whole body and jaws, respectively, of D. neapolitana collected from four harvesting locations within Ria de Aveiro in order to determine if their geographic origin could be correctly assigned post-harvesting. Results showed that both fatty acid profiles and elemental fingerprints differ significantly among locations, discriminating the geographic origin with higher accuracy when combining these two natural barcodes than when employing each individually. The present work can, therefore, contribute to the implementation of an effective management plan for the sustainable use of this marine resource, making it possible to detect if D. neapolitana was sourced from no-take zones and if it was collected from the place of origin claimed by live bait traders.

The bumpy road to conservation: Challenges and opportunities in updating the Galapagos zoning system

In 2014, the Galapagos National Park Directorate, sponsored by various international non-governmental organizations, initiated a comprehensive marine and terrestrial spatial planning process to improve the management effectiveness of Galapagos’ protected areas. This effort aimed to reconfigure management areas by expanding or redistributing no-take zones to protect Key Biodiversity Areas and ensure the conservation of at least 30% of terrestrial and marine ecosystems in the Galapagos. However, this process encountered significant challenges, notably the erosion of fishers' trust following the implementation of a "Marine Sanctuary". This top-down decision resulted in socio-political tension, compelling the Ecuadorian government to delay the implementation of the new marine zoning until there was conclusive scientific data on its socio-economic impact on local small-scale fishers’ livelihoods. This paper examines the achievements and shortcomings of the Galapagos zoning update process, highlighting the successful integration of scientific zoning criteria and the enhanced protection of critical biodiversity areas, together with the reduced support from fishers and legal disputes. To move forward, we recommended a bottom-up approach centered on rebuilding trust among the fishing community via innovative engagement strategies and the introduction of market incentives to promote sustainable practices. Assessing the long-term impact of no-take zones is essential for refining management approaches. Additionally, the application of cutting-edge technology within an adaptive co-management model is recommended to improve fisheries and ecological data gathering and analysis, facilitating proactive and well-informed management decisions. Our suggestions aim to reconcile conservation objectives with the needs and aspirations of the local communities in this iconic archipelago.

Isolation by disturbance: a pattern of genetic structure of the coral Pocillopora grandis in the Gulf of California

Genetic differentiation within species can be influenced by the distance between populations (isolation by distance, IBD) or by differences in the habitats they occupy (isolation by environment, IBE). Understanding the population structure and dynamics that influence genetic diversity within small (<100 km2) multi-use marine protected areas (MPAs) and varying disturbances or protections is relevant to better designing and managing them. Pocillopora grandis communities were studied at 10 different sites in the Gulf of California, Mexico. The comparison between sites inside and outside an MPA or whether the population structure followed IBD or IBE was investigated with the genetic marker HSP70B. Environmental heterogeneity was used to test for IBE, and was measured by comparing the present benthic communities by site and through analysis of satellite images, while distance was used to test for IBD. Mantel tests found that the population of P. grandis did not follow IBD or IBE. Instead, cluster analysis grouped low (no-take zones) and high (crown-of-thorns starfish outbreaks and highly visited by tourists) disturbance sites together with the remaining sites within and outside of the MPA in another cluster (ΦRT = 0.082, p = 0.007). Furthermore, lower genetic diversity was found at sites with low and high disturbance. Our results suggest that instead of IBE or IBD influencing the population structure, the protection and disturbance levels could have a correlation with genetic patterns (i.e. isolation by disturbance, ID). These findings will be valuable for MPAs in terms of efficient management of genetic diversity objectives by considering the appropriate spacing and protections, depending on how vulnerable a species is to disturbance.

Use and management of seagrass ecosystems in southwestern Madagascar

Madagascar’s seagrass meadows are among the least-studied ecosystems in the western Indian Ocean region. To facilitate sustainable management, understanding the traditional uses of seagrass areas in relation to current management policies is necessary. This study assessed the uses of, and policies relevant to, seagrass ecosystems off southwestern Madagascar. We interviewed 131 community members in five coastal villages around the Bay of Ranobe in Toliara Province. Answers to the survey revealed a good level of awareness of seagrass, though 55% of respondents perceived the status of the seagrass areas as deteriorating. Opinions varied on the source or degree of threats to seagrass, but 74.8% of respondents suggested destructive fishing methods or other factors, including natural phenomena and animal grazing. The responses highlight that seagrass meadows serve as areas important for fishing, seaweed cultivation or sea cucumber farming, and the passage of boat/pirogue transportation. There are currently no tangible policies that directly protect or manage the seagrass areas regarding these activities, although some national regulations and local management initiatives are indirectly relevant, notably no-take zones and the local-level codes known as Dina. Development and implementation of a national management plan for seagrass ecosystems is a key gap. This demands the collection of scientific data to support decision-making to ensure long-term provision of the services provided by seagrass meadows. The involvement of coastal communities in the management of seagrass ecosystems will be necessary for the success of any new policies.

Intertidal gleaning fisheries: Recognising local-scale contributions and management scenarios

Intertidal gleaning is a widespread means through which women participate in the fishery harvest sector. However, the fishery is often under recognised in management and policy-making. Accordingly, there is a need to further our understanding of the fishery, and how local factors may help or hinder effective management. This study focuses on Zanzibar, Tanzania, using focus group discussions (FGDs) and interviews to investigate local-scale contributions from gleaning in seagrass dominated areas – which are particularly frequented gleaning grounds locally, and more widely in the Indo-Pacific region. The study also gathered insight into how gleaners perceived different management scenarios used elsewhere within the small-scale fishery sector. Despite being typically viewed as a sustenance means, gleaning was found to be primarily an economic activity, mainly through catching the bivalve, Anadara antiquata, and commercial gastropod species (Chicoreus ramosus and Pleuroploca spp). FGD respondents held positive pre-conceived ideas about rotating no-take zone scenarios as a management strategy, as well as indicating preferences for community-based measures. In order for no-take zones to have a higher chance of success, further investigation is needed to understand the life histories of commonly gleaned species in order to inform rotation periods, as well as developing means of cross-community cooperation due to the shared, open access nature of intertidal zones. These results demonstrate the economic importance of gleaning for coastal women in Zanzibar, who have invaluable insights, built on lived experience and local knowledge, which could enable and benefit a more inclusive management system.

Tragedy of the Commons in a Mediterranean MPA: The Case of Gyaros Island Marine Reserve

Gyaros Island (Aegean Sea) is a recently (2019) established MPA in the Mediterranean Sea, allowing spatiotemporal small-scale fishing (SSF) activities with specific access rules. However, due to the inability of the state authorities to establish any fishing permit process, Gyaros MPA initially functioned as a No-Take Zone (NTZ), offering a rare opportunity for scientific monitoring. Significant political pressure by fisher organizations led to the opening of the MPA in June 2022 without any fishing permit restriction. The unprecedented ‘race for fish’ that followed led to a significant deterioration of the MPA status, as confirmed by scientific monitoring before and after the opening. Outcry from national media, based on concerns raised by the scientific community and NGOs, resulted in lifting access to fishing in September 2022, upgrading Gyaros MPA to a full NTZ. This study aimed to assess if and how the MPA functioning was impacted based on a series of experimental fishing trials and questionnaire surveys conducted with local fishers. Although a substantial part of the fishing community’s mindset is embracing MPAs, our results also suggest that the self-interests of a fishers’ minority, along with non-science-based policy by the national authorities, have led to overfishing and deterioration of MPA status.

Stakeholders’ perception on consumption, fishing, and conservation of Red grouper, Epinephelus morio, off the northern coast of the Yucatan Peninsula, Mexico

The fishery of Red grouper, Epinephelus morio, is one of the most commercially important in Yucatan, Mexico. However, catch trends declined from more than 14,000 t in 1970 to less than 6500 t in 2019. Consequently, the fishery authority (CONAPESCA) declared this fishery overexploited. Stakeholders may play a fundamental role regulating catch trends of Red grouper adopting responsible fishing and consumption. This work aimed to evaluate perceptions of stakeholders (fishers and fish consumers) on consumption, fishing status, and conservation of Red grouper in Yucatan using interviews and web-based questionnaires. Results revealed stakeholders regularly consume Red grouper, with fishing and consumption influenced by economic, social, and cultural factors. Stakeholders were aware of the fishery management in place, such as a seasonal, fishing ban and the minimum catch size, established by the federal government for Red grouper. Differences emerged regarding perception on fishery management between fishers and fish consumers. All stakeholders showed a willingness to follow regulations and responsible consumption during the ban, and proposed alternatives for protection through enhancing fishery regulatory measures, updating the ban and establishing spatial restrictions, such as zones for fishery protection (no-take zones). Understanding stakeholder perceptions is utmost because identifying this knowledge could provide a clearer scenario and more focused fishery management approaches for managers to promote the recovery of the Red grouper fishery. We recommend implementing a precautionary management scheme based on a combination of a management strategic evaluation and a renovated fishery strategy, along with other community-based approaches, for the Red grouper fishery in Yucatan

Blue Swimming Crab’s Conservation Area Determination in The North of Java Sea Using Reproductive Indicator

Despite being operated on a small scale, Blue Swimming Crab (BSC), Portunus pelagicus fishery substantially contributes to Indonesia's fisheries as the country's third-largest export commodity after tuna and shrimp. The high of BSC’s demand led to pressure on its stock. Hence a conservation area is needed to be set up, in this study, was proposed using reproduction indicators. with the case study of BSC Stock in Keboromo Waters, Pati Regency, North Central Java. The samples were collected from 38 sampling points at a distance of 2-12 miles from the coastline during November-December 2022 using collapsible crab traps. A reproduction observation on female crabs was carried out on their carapace width and gonad maturity stage. The data then were analyzed for the percentage of egg-berried females (EBF), size at first maturity (Lm) and first captured (Lc), and their spawning potential Ratio (SPR). This study found that the mature crabs (GMS2) in November and December were higher than in other stages while the proportion of ovigerous females (EBF) in December was higher than in November. At several sampling points, the size at first captures (Lc) was higher than that at first maturity (Lm) indicating a decrease in resource stocks due to a delay in the recruitment process. SPR of 19% showed that reproductive potential should be maintained before recruitment is limited, therefore based on the existence of EBF in particular sampling points it is recommended three conservation areas as a temporary no-take zone in BSC fishing ground in Keboromo Watres, Pati Regency.

Marine protected areas are a useful tool to protect coral reef fishes but not representative to conserve their functional role

Anthropogenic actions have direct and indirect impacts on natural systems, leading to significant alterations in marine ecosystems worldwide. One of the most notable problems is species loss, as the disappearance of species from an area can compromise ecological functions. This is at the core of a severe biodiversity crisis. To address and reverse these processes, marine protected areas (MPAs) have been utilized as a crucial tool to mitigate species loss, increase biomass, and serve as a fisheries management tool. However, there is a lack of information assessing MPAs from the perspective of their contribution to maintaining ecological functions. In recent decades, functional diversity (FD) indices have been widely used to assess ecosystem functioning. In this paper, we conducted an assessment using a global database of reef fish abundance to analyze the effect of No-Take Zones (NTZ) on the FD and “true” diversity (TD) indices of tropical reef fish assemblages in seven tropical biogeographic regions. We found a significant protective effect for some indices, although these responses were dependent on the bioregion. At the bioregional level, NTZs included lower numbers of species and functional entities than open access areas. Consequently, the functional richness protected within these zones partially represented the functional diversity in each biogeographic province. However, smaller-scale functional diversity indices responded to NTZ protection depending on the bioregion. Therefore, these results reinforce that the assessed NTZs are responsive to the protection of functional diversity, although they are not sufficient for safeguarding ecosystem functions in tropical reefs. This highlights the importance of expanding the number of protection entities worldwide with management strategies focused on coral reef fish functionality, as well as effective local/regional assessments. Thus, a new paradigm is necessary in the planning and creation of MPAs to safeguard ecosystem functions, with a priority given to the protection of ecosystem functions and habitats.

Contrasting management regimes indicative of mesopredator release in temperate coastal fish assemblages.

The absence of functional top predators has been proposed as a mechanism acting to shape fish assemblages in temperate marine ecosystems, with cascading effects on lower trophic levels. We explore this scenario by comparing the trophic and functional status of fish assemblages in Norwegian marine national parks, open to fishing, to a nearby coastal seascape that harbors a system of marine protected areas (MPAs) including a no-take zone. Demersal fish assemblages were sampled using fyke nets over three consecutive seasons. Atlantic cod (Gadus morhua) is potentially a dominant top predator in this ecosystem, and historically, this and other gadids have been targeted by the full range of former and present fisheries. In the present study, we find that average body size of the Atlantic cod was significantly larger in the zoned seascape compared to the unprotected areas (mean ± SD: 36.6 cm ± 14.38 vs. 23.4 ± 7.50; p < .001) and that the unprotected seascape was characterized by a higher abundance of mesopredator fish species. These observations are consistent with the hypothesis that the protection of top predators within MPAs aids to control the mesopredator populations and provides empirical support to the notion that the present state of many coastal fish assemblages is driven by mesopredator release linked to functional depletion of large top predators.

A data-driven approach to multiple-stressor impact assessment for a marine protected area.

The coastal environment is not managed in a way that considers the impact of cumulative threats, despite being subject to threats from all realms (marine, land, and atmosphere). Relationships between threats and species are often nonlinear; thus, current (linear) approaches to estimating the impact of threats may be misleading. We developed a data-driven approach to assessing cumulative impacts on ecosystems and applied it to explore nonlinear relationships between threats and a temperate reef fish community. We used data on water quality, commercial fishing, climate change, and indicators of recreational fishing and urbanization to build a cumulative threat map of the northern region in New South Wales, Australia. We used statistical models of fish abundance to quantify associations among threats and biophysical covariates and predicted where cumulative impacts are likely to have the greatest impact on fish. We also assessed the performance of no-take zones (NTZs), to protect fish from cumulative threats across 2 marine protected area networks (marine parks). Fishing had a greater impact on fish than water quality threats (i.e., percent increase above the mean for invertivores was 337% when fishing was removed and was 11% above the mean when water quality was removed inside NTZs), and fishing outside NTZs affected fish abundances inside NTZs. Quantifying the spatial influence of multiple threats enables managers to understand the multitude of management actions required to address threats.

Coral predation and implications for restoration of Kenyan reefs: The effects of site selection, coral species and fisheries management

Active coral reef restoration is increasingly applied for local reef management, but remains hampered by biological interactions such as coral predation (corallivory). To determine factors that drive corallivory and develop more ecology-based restoration approaches, coral and corallivore communities were characterized and fish bite mark densities quantified on natural coral colonies and fragments outplanted on small artificial structures. Six study sites were distributed equally among three levels of fisheries management at southern Kenyan reefs (fished < reserve < no-take). Obligate corallivorous fish densities strongly correlated with coral cover regardless of fisheries management level, whereas facultative corallivorous fish (mainly parrotfish) were most abundant in no-take zones. High corallivorous snail densities were associated with low coral diversity and corallivorous sea stars were scarce. Bite mark densities on natural reefs were clearly higher for branching corals, but did not correlate to coral cover, coral diversity or corallivorous fish densities. Compared to natural colonies, predation pressure was up to 24-fold greater on outplanted coral fragments and especially fierce inside no-take zones. This high predation pressure correlated with low live tissue cover of outplanted fragments. These results demonstrate that reefs with low coral cover, often targeted for restoration, do not necessarily experience greater coral predation and that improved outplanting methods and species considerations are needed to address high predation pressure on outplanted fragments. The interplay between fisheries management, reef restoration and corallivory warrants further scrutiny: while obligate corallivorous fish are unlikely detrimental to reef recovery, high densities of facultative corallivorous fish could hamper restoration efforts.

Determination of coral reef health status using social indicators

The Lamawan Pony Marine Protected Area (MPA) in San Jose de Buenavista, Antique, Philippines, was created to improve marine conservation and fisheries management. The socio-cultural component of this study deployed primarily Key Informant Interviews (KIIs), Focus Group Discussions (FGDs), and face-to-face surveys in four fishing communities. Findings from the surveys revealed that the MPA status is poor due to anthropogenic impacts. The knowledge of MPA presence is high (86%); however, the local perception of MPA sustainability is low (26%), due to fishing challenges. Despite these conditions, results suggest that increasing the no-take zone area to at least 20% of the total MPA size is necessary to achieve the goals set for an MPA. The data in this study are imperative for improving sustainable fishery management in the future that balances the economic needs of its coastal populace.

Intertidal Gleaning Exclusion as a Trigger for Seagrass Species and Fauna Recovery and Passive Seagrass Rehabilitation

This study evaluates gleaning exclusion as an approach for the rehabilitation of seagrass ecosystems and as an option for important intertidal resource management that contributes to the social well-being of communities. The monitoring of seagrass plant and invertebrate recovery after the implementation of gleaning exclusion was conducted over 50 plots of 5 m × 5 m each, which were settled in the seagrass meadow of NW Maputo Bay, Mozambique. The exclusion experiment was designed to compensate for the important loss of seagrass in the area due to gleaning activity characterized mainly by digging and revolving sediments to collect mostly clams. Results showed that, in general, seagrass plant shoot density started having significant positive recovery after five months: three months for Halophila ovalis, five months for Halodule uninvervis, and much more time (&gt;six months) for the IUCN Red List endangered Zostera capensis. For invertebrates, 194 individual invertebrates were collected belonging to 13 species. Solen cylindraceus was the most dominant edible invertebrate species in the local community, and Dosinia hepatica for non-edible species. The result of the experiment showed a positive recovery in the abundance and diversity of invertebrates. The results support previous findings, suggesting that the installation of a no-take zone can enhance the health of an ecosystem. Therefore, to limit the violation and conflicts of the no-take zones, the creation of alternative activities for harvesters and the flexibility of restrictions are vital. Further investigation should be considered to obtain an effective management of the zones, including documentation of species, gleaning practices, and an effective restoration of seagrass meadows.

Conservation for sustaining livelihoods: Adaptive co-management of fish no-take zones in the Mekong River

A major challenge in natural resource management in developing countries is to pursue conservation objectives while avoiding negative impacts on local livelihoods. Inland capture fisheries provide opportunities to demonstrate an integration of conservation and livelihood objectives when managed as a social-ecological system. While numerous marine no-take reserves have been found effective for the recovery of fisheries, few well-documented examples exist in the freshwater realm. Research gaps also remain in the role of co-management in balancing various management objectives and resolving conflicts. This paper offers critical reflection on adaptive co-management of fish conservation zones (FCZs) in the Mekong River in Cambodia and its social-ecological outcomes as perceived by local stakeholders. The management approach was found generally effective for the local stakeholders to negotiate between conservation and livelihood objectives at key stages of the implementation, and resolve conflicts; however, the lessons learned were not uniform across all sites. The degree of difficulty in conflict resolution was mainly a function of the fishing dependency of local communities on the protected site, the prevalence of severe poverty in adjacent villages, and the availability of livelihood options other than fishing. Growing stakeholder perception over time, of the FCZs as yielding positive outcomes—for both conservation and livelihood—motivated the local communities to create more FCZs. We argue clear recognition by local stakeholders of the achievements and the fairness in the FCZ management, facilitated through participatory approaches, can improve their acceptance of conservation rules and enhance their effectiveness. However, long-term mechanisms to support these community initiatives technically and financially are needed. Simple yet scientifically robust approaches for tropical freshwater fisheries monitoring, including periodical assessments of indicator species, are also needed to facilitate performance evaluation of specific management measures locally.