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Networks of marine protected areas (MPAs) are being increasingly implemented worldwide as conservation management tools. We report here on MPA effectiveness using data from a 17‐year long remotely operated vehicle (ROV) monitoring program spanning mesophotic (~ 20–130 m) depths in 26 MPAs across California's MPA network. We utilize a spatial modeling approach that includes important environmental covariates as well as spatial dependence in the data, and allows the separation of statewide and regional trends in the abundance of focal species from additional trends specific to MPAs. We demonstrate that there have been statewide and/or regional recoveries in abundance for the majority of our 10 focal demersal fish species, with all four statewide species assessments and 18 out of 22 species‐region combinations assessed displaying positive trends. We also demonstrate that MPA protection has had an additional positive effect on the abundance of the majority of these focal species inside MPAs compared with reference areas, with positive effects for all four statewide species, and 18 out of 22 statewide/regions assessed showing positive effects, four showing no statistically detectable differences, and no negative MPA effects found. Comparisons with theoretical expectations of MPA recovery for our focal species showed that 2 out of 4 statewide, and 11 out of 17 species‐region combinations assessed displayed higher mean MPA effects than expected. Our results highlight strong trajectories of increasing abundance and additional MPA effects for many of our focal species, demonstrating that MPAs are having positive effects in mesophotic depths across the network as well as at previously reported shallower depths, and that image‐based platforms such as ROVs provide an important tool to support timely reporting on the effectiveness of MPA networks. [ABSTRACT FROM AUTHOR]

This paper proposes a fishery model with price fluctuations and predators. Under the assumption that the price changes much faster than other variables in the system, the fishery model can be considered as a fast–slow system. Using the approximate aggregation method, a simplified three-dimensional model is used for further research. The results indicate that due to overfishing by fishermen and the presence of predators, fish populations may become extinct, which is also known as catastrophic equilibrium. To avoid this situation, we propose two solutions. The first is to establish marine protected areas (MPAs) that prohibit fishing. We propose a fish population dynamics model with MPA, assuming that fish and predators move freely in protected areas and fishing areas. The results show that it is necessary to establish MPA. The second type is that regulatory agencies can control overfishing by fishermen by increasing taxes, thereby avoiding a catastrophic equilibrium. The ultimate goal is to achieve maximum economic benefits while maintaining balanced development of the ecosystem. [ABSTRACT FROM AUTHOR]

Estuarine and adjacent inshore habitats have long been recognised as important nursery areas for fishes before they disperse to coastal habitats. Assessing nursery function supports spatial and fisheries management, yet work commonly focusses on singular habitat types. Re-considering how juvenile fish connect habitats may improve our understanding of nursery function and the scales that recruits are supplied to coastal fisheries. This study quantified the juvenile movements of two harvested fishes in south-eastern Australia, luderick (Girella tricuspidata) and yellowfin bream (Acanthopagrus australis). Acoustic tags were used to track 33 luderick and 20 yellowfin bream from seagrass meadows for up to ~400 days in Jervis Bay Marine Park. Both species had relatively small home ranges (< 7 km2) and exhibited site attachment to seagrass meadows where they were released. Most luderick and yellowfin bream were detected moving 100's metres to kilometres to reefs adjacent to seagrass, although these movements were not habitat shifts. Rather, reef-ward movements represented repeated visits that lasted days to months before fish returned to seagrass, suggesting that these movements may be explorations in search of suitable adult habitat. Strong retention within an existing marine reserve was observed, with only five of 33 fish tagged within reserves crossing the boundary into fished waters. Overall, our results demonstrate that juvenile fish use and connect multiple habitat types during their movements. These findings support the broadening of the nursery concept from single habitats to a mosaic of functionally connected habitat patches (dubbed 'seascape nurseries'). [ABSTRACT FROM AUTHOR]

We present a bioeconomic fishery model with variable price based on supply and demand. The model considers three variables: resource biomass, fishing effort, and market price. Rapid price changes classify the fishery system as a slow–fast system. Two main cases arise: catastrophic equilibrium (CE) with overexploitation and fish extinction, and a sustainable fishery equilibrium. We aim to determine conditions for maximum sustainable yield by optimizing cost per unit of fishing effort. Additionally, we explore conditions to prevent extinction and restore sustainable fishing. Marine protected areas (MPAs) can restore fish stocks by destabilizing the CE and maintaining a stable positive equilibrium. A model incorporating an MPA and fish movement is proposed, suggesting a small carrying capacity-to-surface area ratio in the fishing zone. Optimal total catch can be achieved by selecting the appropriate MPA surface area. [ABSTRACT FROM AUTHOR]

Mangrove forests are broadly recognized to support a variety of ecosystem services on coastal margins worldwide. These services may significantly contribute to the wellbeing of millions of people, but there is limited information about their importance in the Global South. This study mapped for the first time the flow of ecosystem services in Brazilian Amazon mangroves, which represent over 700,000 ha of mangroves in the country. We also identified the spatial changes in the flow of services across coastal landscapes, including urban, agricultural upland areas and coastal natural protected areas. Our matrix model indicated that mangroves, waterbodies, sandflats and mudflats are critical to the flow of multiple ecosystem services, including provisioning (fish, mariculture), cultural (historical and intrinsic value, research, and education), and regulation (climate, flood control, nursery, and breeding grounds). Social economic context, occupation, education, and residence time are important factors influencing villagers to identify the flow of ecosystem services, which could be compared across other coastal marine reserves in South America that have similar management of natural resources. Adjacent coastal upland habitats such as forests and croplands are important to support many provisioning ecosystem services to coastal villagers that would otherwise be obtained from mangroves, suggesting that protecting these connected habitats and supporting small-scale agriculture may help to avoid deforestation of mangrove forests. As over 80% of the mangroves in the country are managed as extractive reserves and may support communities with comparable socio-economic characteristics, we provide a foundation for the development and replication of ecosystem services assessments in Brazilian mangroves, which cover an area of over 1 million hectares. Our work highlights the importance of mangrove forests in providing food, and cultural services and to increase local climate resilience of coastal villages in the Amazon coast.

Trophic downgrading destabilizes ecosystems and can drive large‐scale shifts in ecosystem state. While restoring predatory interactions in marine reserves can reverse anthropogenic‐driven shifts, empirical evidence of increased ecosystem stability and persistence in the presence of predators is scant. We compared temporal variation in rocky reef ecosystem state in New Zealand's oldest marine reserve to nearby fished reefs to examine whether protection of predators led to more persistent and stable reef ecosystem states in the marine reserve. Contrasting ecosystem states were found between reserve and fished sites, and this persisted over the 22‐year study period. Fished sites were predominantly urchin barrens but occasionally fluctuated to short‐lived turfs and mixed algal forests, while reserve sites displayed unidirectional successional trajectories toward stable kelp forests (Ecklonia radiata) taking up to three decades following protection. This provides empirical evidence that long‐term protection of predators facilitates kelp forest recovery, resists shifts to denuded alternate states, and enhances kelp forest stability. [ABSTRACT FROM AUTHOR]

In this work, we examine a predator–prey model that considers the implicit marine reserve in prey species and a linear function of critical biomass level. The model's basic properties (existence, uniqueness, positivity, boundedness, and permanence) and equilibrium points are determined. We obtain three equilibrium points: the trivial equilibrium point, the equilibrium point where there is no harvest, and the co-existing equilibrium point. The local and global stability of each equilibrium point of the model is explored. Moreover, the interior equilibrium point is always globally asymptotically stable, and the system experiences no limit cycles around the interior equilibrium point. Numerical simulations are conducted to illustrate the theoretical results obtained. Finally, we find overlapping conditions regarding the dynamics between the model we developed and a model that considers a constant critical biomass level for certain parameters. [ABSTRACT FROM AUTHOR]

Cape Rodney–Ōkakari Point Marine Reserve (North Island, New Zealand/ Te Ika-a-Māui, Aotearoa), is New Zealand's oldest marine reserve and includes one of the most visited beaches in the country. The reserve's effect on both target species and biogenic habitats is well-documented. It is less well-known, however, how protection affects other taxa. Here, we present two surveys, made nearly 50 years apart, of encrusting, intertidal bryozoans from Echinoderm Reef, quantify their relative abundance and species richness, and discuss possible reasons for the changes between 1971 and 2019. Prior to protection, encrusting bryozoans were common under boulders on Echinoderm Reef, a rocky intertidal mudstone terrace within the reserve. Since the reserve designation, however, there has been a decline in both abundance and species richness within this intertidal bryozoan community. Inconsistent sampling of the reserve's bryozoans makes it difficult to correlate changes in the bryozoan community with changes in the reserve's biotic and abiotic characteristics. Despite monitoring shortcomings, there is still value in the ad hoc biological surveys that have been performed, as they provide a snapshot of what communities were like at the time of collection. In the future, however, more research is needed to understand change within this bryozoan community. [ABSTRACT FROM AUTHOR]

South Africa sought to implement an ecologically representative Marine Protected Area (MPA) network to achieve biodiversity and fisheries management goals with least impact on offshore stakeholders. The result was the declaration of a spatially efficient network representing 131 of 150 marine ecosystem types (87%) in 5.4% of ocean area. We outline the 15‐year process from planning to implementation of 20 new MPAs, including contentious areas recognized as important for conservation decades ago. Systematic Conservation Planning (SCP) supported by 532 data layers and an inclusive stakeholder process identified priority areas, reduced conflict and guided complex trade‐offs. Multiple scenarios and iterative improvements increased transparency, supported ocean zonation and achieved balanced compromises while maintaining conservation objectives. Key challenges, enabling factors and lessons are shared. We demonstrate that flexible, evidence‐based SCP together with adaptive social processes that are alert to opportunities can support implementation of representative MPA networks aligned to ocean economy goals. South Africa used systematic planning and inclusive stakeholder engagement to protect 87% of its 150 marine ecosystem types in just 5% ocean area [ABSTRACT FROM AUTHOR]

Widespread degradation of marine ecosystems and ecosystem services, coupled with national and global commitments to improve protection of the oceans, has led to a proliferation of efforts to designate new marine protected areas (MPAs) and MPA networks. A range of design features must be considered when designating MPAs, including MPA size and shape, level of protection, and the species and habitats protected, and evidence suggests these design elements can be crucial in determining MPA effectiveness. Over the past several decades, expansive literature has emerged providing recommendations for MPA design, and yet collectively these recommendations can be overwhelming and even contradictory for MPA planners. To address this barrier, we reviewed and synthesized 307 unique MPA design recommendations across 56 peer‐reviewed and gray literature publications. We created a new set of 24 condensed design guidelines grouped by conservation objectives: ecological spatial connectivity (e.g., genetic, larval, community); habitat representation; species or population persistence; mitigation of and complementarity to human activities; and permanence and adaptability. We then discuss examples of datasets, models, and tools that can be utilized to implement specific guidelines. Our review and novel synthesis can help decision‐makers understand and apply MPA design recommendations to achieve desired conservation objectives. [ABSTRACT FROM AUTHOR]

The populations of two iconic fish species, the dusky grouper Epinephelus marginatus and the brown meagre Sciaena umbra, were recorded at 13 sites inside and outside the marine reserve of Scandola, Corsica (NW Mediterranean), according to three levels of protection (integral reserve, buffer zone and unprotected zones) in summer 2012 and 2018. No change in mean abundance with protection level was recorded for E. marginatus between years but relocation of individuals was observed among sites. In contrast, S. umbra mean abundance decreased in the integral reserve in 2018. A particular abundance decline was recorded in 2018 at certain sites in the integral reserve for both species (dusky grouper: -63%; brown meagre: -88%). Different hypotheses explaining the changes observed are discussed (depth refuge, disease, poaching, artisanal fisheries and boat tourism). The increase in marine noise pollution generated by motorboats in summer during these species' reproduction period, by disturbing their acoustic communication and mating behaviour, could be a cause of depopulation at certain sites. [ABSTRACT FROM AUTHOR]

The relative roles of top-down (consumer-driven) and bottom-up (resource-driven) forcing in exploited marine ecosystems have been much debated. Examples from a variety of marine systems of exploitation-induced, top-down trophic forcing have led to a general view that human-induced predator perturbations can disrupt entire marine food webs, yet other studies that have found no such evidence provide a counterpoint. Though evidence continues to emerge, an unresolved debate exists regarding both the relative roles of top-down versus bottom-up forcing and the capacity of human exploitation to instigate top-down, community-level effects. Using time-series data for 104 reef communities spanning tropical to temperate Australia from 1992 to 2013, we aimed to quantify relationships among long-term trophic group population density trends, latitude, and exploitation status over a continental-scale biogeographic range. Specifically, we amalgamated two long-term monitoring databases of marine community dynamics to test for significant positive or negative trends in density of each of three key trophic levels (predators, herbivores, and algae) across the entire time series at each of the 104 locations. We found that trophic control tended toward bottom-up driven in tropical systems and top-down driven in temperate systems. Further, alternating long-term population trends across multiple trophic levels (a method of identifying trophic cascades), presumably due to top-down trophic forcing, occurred in roughly fifteen percent of locations where the prerequisite significant predator trends occurred. Such alternating trophic trends were significantly more likely to occur at locations with increasing predator densities over time. Within these locations, we found a marked latitudinal gradient in the prevalence of long-term, alternating trophic group trends, from rare in the tropics (

With the increasingly imperilled status of shark populations, there is a pressing need to evaluate management solutions. Given the threats posed by fishing, marine reserves (MRs) present a promising option.Ata Whenua (Fiordland) in the South Island of Aotearoa/New Zealand is an ideal location to investigate this phenomenon owing to the presence of several shark species in coastal MRs.One‐hundred and sixty‐seven baited remote underwater video deployments were made in five MRs. A multi‐model inference approach using generalized linear modelling was used to assess the combined effect of the MRs on two trophic groups of coastal sharks.Generalized linear modelling was used to assess the effect of protection on, firstly, the presence of broadnose sevengill sharks (Notorynchus cepedianus), while accounting for variations in environmental variables, and secondly, the combined relative abundance of mesopredatory sharks detected (spiny dogfish, Squalus acanthias; school shark, Galeorhinus galeus; and carpet shark, Cephaloscyllium isabellum).Mesopredators had a higher relative abundance in MRs by a factor of 2.5 and there was a strong significant effect of protection, suggesting that MRs have led to an increase in their abundance or a change in distribution. In contrast, there was no effect of protection detected for sevengill sharks.It is concluded that the relatively small (<40 km2) MRs sampled do not provide conservation benefits for a large, mobile shark, but that they are potentially large enough to offer protection for mesopredatory sharks with smaller home ranges.To be effective for shark conservation, we therefore recommend that MRs need to be appropriately sized for the ranging behaviour of the target species for protection. [ABSTRACT FROM AUTHOR]

'La Rinconada Marine' Reserve (MR), Chile was created in 1997 to preserve the genetic stock of the scallop Argopecten purpuratus and eventually to supply seed to areas outside of the reserve and support aquaculture activities. Data from biological and fisheries monitoring of A. purpuratus as well as environmental conditions in the MR are available for the period from 1993 to 2009.The continuous extraction of A. purpuratus from La Rinconada MR in Chile, without a science‐based exploitation plan, has not only decreased the abundance and population structure of the species but has also significantly affected seed settlement in artificial collectors and population recruitment. Therefore, the goals of the MR have not been achieved.This review of biological and fishing studies of A. purpuratus in La Rinconada MR provides a basis for the implementation of a sustainable programme for the natural collection of A. purpuratus seed for population recovery.A. purpuratus recruitment varies substantially between years and is not strongly related to the size of the parental population. Larval collection and recruitment depend on environmental events (El Niño‐Southern Oscillation) and biological substrate availability (Rhodymenia red algae). These factors produce a bentho‐pelagic decoupling between parental abundance, larval production and subsequent recruitment of A. purpuratus that limits stock recovery in the MR.To address the poor population status of A. purpuratus in the MR, recovery of the adult population is needed. Therefore, an assisted collection and recruitment strategy is proposed to increase the population and enable the generation of surplus seed, fulfilling the initial aims of La Rinconada MR. [ABSTRACT FROM AUTHOR]

Abstract South Africa sought to implement an ecologically representative Marine Protected Area (MPA) network to achieve biodiversity and fisheries management goals with least impact on offshore stakeholders. The result was the declaration of a spatially efficient network representing 131 of 150 marine ecosystem types (87%) in 5.4% of ocean area. We outline the 15‐year process from planning to implementation of 20 new MPAs, including contentious areas recognized as important for conservation decades ago. Systematic Conservation Planning (SCP) supported by 532 data layers and an inclusive stakeholder process identified priority areas, reduced conflict and guided complex trade‐offs. Multiple scenarios and iterative improvements increased transparency, supported ocean zonation and achieved balanced compromises while maintaining conservation objectives. Key challenges, enabling factors and lessons are shared. We demonstrate that flexible, evidence‐based SCP together with adaptive social processes that are alert to opportunities can support implementation of representative MPA networks aligned to ocean economy goals.

Abstract Widespread degradation of marine ecosystems and ecosystem services, coupled with national and global commitments to improve protection of the oceans, has led to a proliferation of efforts to designate new marine protected areas (MPAs) and MPA networks. A range of design features must be considered when designating MPAs, including MPA size and shape, level of protection, and the species and habitats protected, and evidence suggests these design elements can be crucial in determining MPA effectiveness. Over the past several decades, expansive literature has emerged providing recommendations for MPA design, and yet collectively these recommendations can be overwhelming and even contradictory for MPA planners. To address this barrier, we reviewed and synthesized 307 unique MPA design recommendations across 56 peer‐reviewed and gray literature publications. We created a new set of 24 condensed design guidelines grouped by conservation objectives: ecological spatial connectivity (e.g., genetic, larval, community); habitat representation; species or population persistence; mitigation of and complementarity to human activities; and permanence and adaptability. We then discuss examples of datasets, models, and tools that can be utilized to implement specific guidelines. Our review and novel synthesis can help decision‐makers understand and apply MPA design recommendations to achieve desired conservation objectives.

Marine Protected Areas (MPAs) are being implemented worldwide, yet there are few cases where managers make specific predictions of the response of previously harvested populations to MPA implementation. Such predictions are needed to evaluate whether MPAs are working as expected, and if not, why. This evaluation is necessary to perform adaptive management, identifying whether and when adjustments to management might be necessary to achieve MPA goals. Using monitoring data and population models, we quantified expected responses of targeted species to MPA implementation and compared them to monitoring data. The model required two factors to explain observed responses in MPAs: (a) pre‐MPA harvest rates, which can vary at local spatial scales, and (b) recruitment variability before and after MPA establishment. Low recruitment years before MPA establishment in our study system drove deviations from expected equilibrium population size distributions and introduced an additional time lag to response detectability. Synthesis and applications. We combined monitoring data and population models to show how (a) harvest rates prior to Marine Protected Area (MPA) implementation, (b) variability in recruitment, and (c) initial population size structure determine whether a response to MPA establishment is detectable. Pre‐MPA harvest rates across MPAs plays a large role in MPA response detectability, demonstrating the importance of measuring this poorly known parameter. While an intuitive expectation is for response detectability to depend on recruitment variability and stochasticity in population trajectories after MPA establishment, we address the overlooked role of recruitment variability before MPA establishment, which alters the size structure at the time of MPA establishment. These factors provide MPA practitioners with reasons whether or not MPAs may lead to responses of targeted species. Our overall approach provides a framework for a critical step of adaptive management.

On the 100-year anniversary of the Australian Coral Reef Society (ACRS), previously known as the Great Barrier Reef Committee (GBRC), we provide an overview of ACRS activities throughout its history, with a detailed account of key milestones in the last 40 years. We outline how the ACRS as promoted the protection and conservation of reefs, through expert advice, reviews, and submissions to enquiries. Examples are provided under the following themes: ACRS consultancy on zoning the Great Barrier Reef (GBR) Marine Park, marine protected area design, water quality on the GBR, port expansions along the Queensland coastline and environmental reform for the offshore oil and gas industry. We illustrate how scientists over recent decades have worked to better understand and encourage policy responses to the impacts of climate change on Australia's coral reefs. For a hundred years, the GBRC-ACRS has provided an avenue for Australian coral reef scientists, managers and conservationists to influence reef governance through policy. While these unique avenues for delivering timely and targeted expertise have helped to reduce proximate threats to reefs at local scales, their outcome in relation to climate change, arguably the largest threat to Australia's coral reefs, remains to be seen. We review ACRS activities under the following themes: consulting on the Capricorn Bunker Group to zone the Great Barrier Reef Marine Park, marine protected area design, water quality on the GBR, Queensland port expansions, environmental reform for the offshore oil and gas industry and the impacts of climate change on Australian reefs. We outline how the ACRS has promoted the exchange of scientific information to protect and conserve Australian reefs for a 100 years. [ABSTRACT FROM AUTHOR]

Marine Protected Areas (MPAs) are increasingly used as a management and conservation strategy. However, the effects of MPA implementation (i.e. restrictions on extractive use) on recreational fishers' spatial behaviour are often not considered. Spatial shifts in fishing pressure and which port fishers choose to fish from can have ecological and economic impacts. Therefore, it is critical that MPA impacts on recreational fishers are adequately investigated and weighed against potential conservation benefits from MPA designation.The State of Oregon, USA, has a system of five no‐take marine reserves (MRs) with adjacent limited‐take MPAs. This study used an interrupted time series approach to investigate how fishing licence sales were impacted by MR implementation.This study found that recreational fishers near only one MR were potentially adversely impacted by MR implementation. The proportion of coastal licence sales near Redfish Rocks MR displayed an immediate sustained 47.1% proportional decrease following reserve implementation. Conversely, there was a 0.5% proportional increase in monthly demand for licence sales near Otter Rock and Cascade Head MRs.This study suggests that most MRs in Oregon were designated in a manner that limited significant adverse impacts to some ocean users, a specified MR objective. The process of MR planning in Oregon, which involved considerable public input, could be used as an example for MR designation in other similar settings. However, when a potential MR site and adjacent town's conditions match those at Redfish Rocks MR, there may be adverse socio‐economic impacts that should be weighed against potential ecological benefits.This study also demonstrates the application of an interrupted time series approach. When sufficient data are available, this is a robust approach that addresses numerous shortfalls of traditional MPA impact evaluations. [ABSTRACT FROM AUTHOR]

Aotearoa New Zealand is the last major landmass settled by people, and therefore provides a recent record of ecological legacy effects in the coastal zone. Large‐scale land clearances of forests accelerated over the last century, affecting the concentration of suspended sediments, light environment, and nutrient composition on rocky reefs, and consequently the distribution, abundance, and composition of algal forests. The environmental effects were compounded in many places by overfishing and long‐term declines of large predatory species, often leading to proliferation and extensive grazing by sea urchins. In this study, we examine these processes in three biogeographic regions that have been differentially affected by ecological legacy effects. The study was based on the depth‐specific associations between sea urchins (Evechinus chloroticus) and the common kelp (Ecklonia radiata) from multiple sites within each region, some of which were sampled over two decades within no‐take marine reserves and in actively fished areas. Satellite‐derived estimates of water‐column properties were used as proxies for the relative effects of coastal sedimentation on kelp forest habitats. We then used an information‐theoretic framework to assess the relative factor weightings of marine reserve effects on urchin density, total suspended solids (TSS), and regional urchin density on the depth‐specific density of Ecklonia radiata. The fishing effects were significant within and outside of reserves in the northern and central regions, but the effect sizes were by far strongest in the northern region. In the central region characterized by extensive land clearance and forestry combined with high coastal retention of water, the concentration of TSS had a major influence on the depth distribution of kelp, confining it to shallow water (<10‐m depth) in small patches where urchins did not overgraze. These patterns are in sharp contrast to the small marine reserve effects and deep distribution of Ecklonia radiata in the southern region, which has intact native forested catchments, comparatively low fishing pressure, and a large regional network of marine reserves. The results highlight important differences in how centuries‐old legacies of land clearance and exploitation affect regional‐scale dynamics of sea urchins and kelp and define the appropriate spatial scale of ecosystem‐based management of critical kelp forest habitats. [ABSTRACT FROM AUTHOR]

In this work, we examine a predator–prey model that considers the implicit marine reserve in prey species and a linear function of critical biomass level. The model’s basic properties (existence, uniqueness, positivity, boundedness, and permanence) and equilibrium points are determined. We obtain three equilibrium points: the trivial equilibrium point, the equilibrium point where there is no harvest, and the co-existing equilibrium point. The local and global stability of each equilibrium point of the model is explored. Moreover, the interior equilibrium point is always globally asymptotically stable, and the system experiences no limit cycles around the interior equilibrium point. Numerical simulations are conducted to illustrate the theoretical results obtained. Finally, we find overlapping conditions regarding the dynamics between the model we developed and a model that considers a constant critical biomass level for certain parameters.

Abstract Aotearoa New Zealand is the last major landmass settled by people, and therefore provides a recent record of ecological legacy effects in the coastal zone. Large‐scale land clearances of forests accelerated over the last century, affecting the concentration of suspended sediments, light environment, and nutrient composition on rocky reefs, and consequently the distribution, abundance, and composition of algal forests. The environmental effects were compounded in many places by overfishing and long‐term declines of large predatory species, often leading to proliferation and extensive grazing by sea urchins. In this study, we examine these processes in three biogeographic regions that have been differentially affected by ecological legacy effects. The study was based on the depth‐specific associations between sea urchins (Evechinus chloroticus) and the common kelp (Ecklonia radiata) from multiple sites within each region, some of which were sampled over two decades within no‐take marine reserves and in actively fished areas. Satellite‐derived estimates of water‐column properties were used as proxies for the relative effects of coastal sedimentation on kelp forest habitats. We then used an information‐theoretic framework to assess the relative factor weightings of marine reserve effects on urchin density, total suspended solids (TSS), and regional urchin density on the depth‐specific density of Ecklonia radiata. The fishing effects were significant within and outside of reserves in the northern and central regions, but the effect sizes were by far strongest in the northern region. In the central region characterized by extensive land clearance and forestry combined with high coastal retention of water, the concentration of TSS had a major influence on the depth distribution of kelp, confining it to shallow water (

Sequential hermaphroditic species, such as blue cod (Parapercis colias), are particularly vulnerable to selective harvesting as it can directly influence the sex ratio, timing of sex change, and consequentially recruitment success. We analyzed the population structure, at which males dominate the populations, and modeled fecundity of blue cod from the Marlborough Sounds in the north of New Zealand's South Island, and compared these results with previously collected data from a blue cod population in Fiordland on the southwest coast of the South Island. In addition to the geographical difference, there were differences in the time the two populations were sampled, and the fisheries management regime between regions. Within the Marlborough Sounds population, the length‐frequency distribution was skewed toward high numbers of smaller individuals with an average length of 290 ± 59 mm. In Fiordland, the average length of blue cod was 380 ± 78 mm. Larger proportions of males within each length class were observed in the Marlborough Sounds, whereas females were the dominant sex in the Fiordland population. The estimated length at which males dominate the population was significantly smaller for the Marlborough Sounds population (182 mm) than for blue cod from the Fiordland population (419 mm). Geographical and temporal differences in sampling likely played important roles in the observed life history differences, particularly in the observed differences in growth. However, when compared to length and age data from national surveys, the life history traits of both sampled populations have remained relatively stable over the past 15 years, indicating that differences in population management and fishing pressure are the most likely explanation for the observed differences in length frequency and length‐at‐sex‐change. For effective and sustainable management of species with sequential hermaphroditism, size‐sensitive management, particularly protecting larger individuals, is required to avoid declines in length structure and recruitment limitations. [ABSTRACT FROM AUTHOR]

The description of diagnostic morphological characters and DNA barcoding of fish larvae from nine species of the carangid family are provided from specimens collected during a weekly zooplankton time-series (2016-2017) at Cabo Pulmo National Park, Gulf of California, Mexico. Five nominal species ( Caranxsexfasciatus , C.caballus , Naucratesductor , Selarcrumenophthalmus , and Seleneperuviana ) and three morphotypes of Decapterus spp. and one of Caranx spp. were identified and separated based on morphological, meristic, and pigmentary diagnostic characters. All larvae were genetically sequenced for a fragment of the cytochrome c oxidase subunit I mitochondrial gene. Sequences of larval Caranx and Decapterus showed high genetic similarity (> 99%), low intraspecific divergence (< 1%), and an interspecific divergence between 6% and 11%, allowing the discrimination of diagnostic pigmentation patterns of fish larvae among three sibling species from each genus: Caranx ( C.caballus , C.caninus , and C.sexfasciatus ) and Decapterus ( D.macarellus , D.macrosoma , and D.muroadsi ). DNA barcoding supported the presence of Caranxcaballus , C.caninus , C.sexfasciatus , Decapterusmacarellus , D.muroadsi , Selarcrumenophthalmus , and Seleneperuviana , and for the first time Naucratesductor and D.macrosoma at the CPNP. Abundance of these nine species (confirmed molecularly) was estimated throughout the 2016-2017 weekly time series. Decapterusmacarellus and Caranxcaninus were the most abundant species. The morphological and molecular taxonomic methods allowed us to infer the species number and abundance of these commercial species at the CPNP to improve conservation in protected areas and fishery management., Competing Interests: The authors have declared that no competing interests exist., (Claudia A. Silva-Segundo, René Funes-Rodríguez, Eduardo Anaya-Godínez, Jaime Gómez-Gutiérrez.)

Abstract Sequential hermaphroditic species, such as blue cod (Parapercis colias), are particularly vulnerable to selective harvesting as it can directly influence the sex ratio, timing of sex change, and consequentially recruitment success. We analyzed the population structure, at which males dominate the populations, and modeled fecundity of blue cod from the Marlborough Sounds in the north of New Zealand's South Island, and compared these results with previously collected data from a blue cod population in Fiordland on the southwest coast of the South Island. In addition to the geographical difference, there were differences in the time the two populations were sampled, and the fisheries management regime between regions. Within the Marlborough Sounds population, the length‐frequency distribution was skewed toward high numbers of smaller individuals with an average length of 290 ± 59 mm. In Fiordland, the average length of blue cod was 380 ± 78 mm. Larger proportions of males within each length class were observed in the Marlborough Sounds, whereas females were the dominant sex in the Fiordland population. The estimated length at which males dominate the population was significantly smaller for the Marlborough Sounds population (182 mm) than for blue cod from the Fiordland population (419 mm). Geographical and temporal differences in sampling likely played important roles in the observed life history differences, particularly in the observed differences in growth. However, when compared to length and age data from national surveys, the life history traits of both sampled populations have remained relatively stable over the past 15 years, indicating that differences in population management and fishing pressure are the most likely explanation for the observed differences in length frequency and length‐at‐sex‐change. For effective and sustainable management of species with sequential hermaphroditism, size‐sensitive management, particularly protecting larger individuals, is required to avoid declines in length structure and recruitment limitations.

In this paper, we propose to study a fishery model with variable price. We assume that the price evolves much faster than the rest of the system. Under certain assumptions, this makes it possible to consider the fishery system as a slow–fast system, on two time scales, and to study it with a reduced model of dimension two. Two main cases can occur. The first one which we called catastrophic equilibrium corresponds to over-exploitation leading to fish extinction and a booming price. The second case corresponds to a sustainable fishery equilibrium which is stable. The possible effects of the creation of marine protected areas (MPAs), sites where fishing is prohibited, on the fish stock and fishery are evaluated. We show that MPAs can have a positive effect on the restoration of depleted fish stocks by destabilizing the catastrophic equilibrium and keeping only one positive equilibrium which will be globally asymptotically stable. This problem is addressed by proposing a model with MPA for the fish dynamics. Fish are assumed to move between MPA and fishing area and are subject to harvesting through fishing. We show that to avoid the extinction of the stock and stabilize the fishery in the long term, it is necessary to define a fishing zone such that the ratio of its carrying capacity to its surface is small enough. We further show that with a judicious choice of the surface area of the MPA, it is possible to optimize the total capture. [ABSTRACT FROM AUTHOR]

Due to the remarkable ecological value of the Ross Sea, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) adopted a large-scale Ross Sea region marine protected area (RSRMPA) in 2016. Since then, many CCAMLR Members have conducted research and monitoring in the region. In 2021, the U.S. Ross Sea science community convened a workshop to collate, synthesize, and coordinate U.S. research and monitoring in the RSRMPA. Here we present workshop results, including an extensive synthesis of the peer-reviewed literature related to the region during the period 2010–early 2021. From the synthesis, several things stand out. First, the quantity and breadth of U.S. Ross Sea research compares to a National Science Foundation Long Term Ecological Research project, especially involving McMurdo Sound. These studies are foundational in assessing effectiveness of the RSRMPA. Second, climate change and fishing remain the two factors most critical to changing ecosystem structure and function in the region. Third, studies that integrate ecological processes with physical oceanographic change continue to be needed, especially in a directed and coordinated research program, in order to effectively separate climate from fishing to explain trends among designated indicator species. [ABSTRACT FROM AUTHOR]

Marine protected areas (MPAs) are considered key tools for achieving the sustainability of coastal fisheries by allowing habitat and species conservation by means of use regulations and active management. The effects of protection are more visible in slow-growing, high site fidelity and late-maturing species such as dusky grouper, a flagship species for all the fishermen and divers in the Mediterranean Sea. We studied the reproductive behavior of dusky grouper at Tabarca Island Marine Protected Area (TIMPA) in order to: (a) describe its temporal pattern; (b) evaluate the relationships among reproductive behavior and environmental factors and (c) verify the effects of social structure on reproductive activity. We observed all the behavior patterns previously reported in other studies besides the final spawn event. Our results evidenced that the monthly average density of dusky groupers tended to increase when temperature rose close to the seabed and without defined temporal limits for reproductive behavior. Among the environmental factors considered, visibility exhibited a very strong effect on the reproductive behavior of dusky grouper, interacting significantly with seabed temperature and thermocline. Regarding the effects of social structure, reproductive activity was positively correlated with the presence of large-sized individuals. We have discussed the differential facts of the reproductive activity of dusky groupers observed at TIMPA relating the results to the biogeographical location, the patterns of the environmental drivers (such as the seabed temperature per day, the thermocline, the visibility, the stream force, the photoperiod and the divers per day) and the structure of the habitat. These negative results contrast with the existing knowledge and generate new working hypotheses useful to improve the efficiency of MPAs and the sustainability of coastal fisheries. [ABSTRACT FROM AUTHOR]

From 1999-2001, the Argopecten purpuratus population at La Rinconada was directly evaluated by monitoring larvae and their subsequent settlement on artificial collectors to determine their density, size structure, and abundance. An increase in specimens, doubling the number observed in 1997, occurred in 1999. However, reductions in the distribution area, specimens, and average size occurred in 2000 and 2001, reflecting anthropogenic impacts. Application of the growth parameters to the annual size structure indicated losses of 5.7 million individuals between 1999 and 2000 and 5 million between 2000 and 2001. The specimens increase over 90 mm, from 130,000 in 1997 to 2.6 million in 2001, explains the high larvae numbers found, with records of 17,667 and 21,756 in 1999; 16,100 in 2000; and 34,175 and 21,700 in 2001. A relationship between larval presence and postlarval settling could not be established; only the relationships between periods of larval abundance and those of maximum fixation could be observed. In conclusion, a viable solution to illegal fishing affecting the reserve with complementary or substitute measures for local fishers is urgently required. [ABSTRACT FROM AUTHOR]

Preserving biodiversity over time is a pressing challenge for conservation science. A key goal of marine protected areas (MPAs) is to maintain stability in species composition, via reduced turnover, to support ecosystem function. Yet, this stability is rarely measured directly under different levels of protection. Rather, evaluations of MPA efficacy generally consist of static measures of abundance, species richness, and biomass, and rare measures of turnover are limited to short‐term studies involving pairwise (beta diversity) comparisons. Zeta diversity is a recently developed metric of turnover that allows for measurement of compositional similarity across multiple assemblages and thus provides more comprehensive estimates of turnover. We evaluated the effectiveness of MPAs at preserving fish zeta diversity across a network of marine reserves over 10 years in Batemans Marine Park, Australia. Snorkel transect surveys were conducted across multiple replicated and spatially interspersed sites to record fish species occurrence through time. Protection provided by MPAs conferred greater stability in fish species turnover. Marine protected areas had significantly shallower decline in zeta diversity compared with partially protected and unprotected areas. The retention of harvested species was four to six times greater in MPAs compared with partially protected and unprotected areas, and the stabilizing effects of protection were observable within 4 years of park implementation. Conversely, partial protection offered little to no improvement in stability, compared with unprotected areas. These findings support the efficacy of MPAs for preserving temporal fish diversity stability. The implementation of MPAs helps stabilize fish diversity and may, therefore, support biodiversity resilience under ongoing environmental change. [ABSTRACT FROM AUTHOR]

Knowledge of the spatial distribution and habitat preferences of marine top‐predators is essential for monitoring their populations. The summertime abundance of male sperm whales (parāoa, Physeter macrocephalus) at the Kaikōura Canyon (New Zealand) has almost halved over the last three decades, possibly reflecting a shift in distribution away from this foraging ground. To better understand the seasonal drivers of habitat use by sperm whales, we recorded presence and absence locations of foraging whales during acoustic‐visual surveys, in conjunction with water‐column oceanographic sampling. Season‐specific generalized additive models (GAM) indicated that whale distribution was best predicted by seafloor depth, thermal stratification in the water‐column, and slope gradient and orientation. Habitat use differed between summer and winter, consistent with patterns in diving behavior and stable isotope ratios, suggesting seasonal fluctuations in prey targeted by sperm whales. Our results advance understanding of fine‐scale habitat use by sperm whales, with new insights into the ecological drivers of seasonal fluctuations in foraging distribution. Our study demonstrates the importance of quantifying water‐column processes in the study of habitat preferences by deep‐diving predators. We also identify thermal stratification as an oceanographic feature susceptible to climate change, which could contribute to the decline in sperm whale abundance at Kaikōura. [ABSTRACT FROM AUTHOR]

Complex ecological interactions are widely utilized to deliver conservation benefits but their efficacy is often debated. Using a coral reef trophic cascade as an example, we reveal that outcomes can be surprisingly difficult to detect. Even important impacts of marine reserves can go undetected (20% more coral with power < 0.5). This evidentiary challenge is compounded by misinterpretation of "nonsignificant" results as evidence of failed conservation practice. We illustrate a more appropriate analytical approach using a Bayesian Region of Practical Equivalence (ROPE) whereby many tests of conservation practice would be interpreted correctly as "undecided" rather than "negative." Practitioners working with ecological cascades will increasingly be faced with "undecided" evidence of conservation benefits. Since one solution is to consider a wider diversity of evidence, we provide a hierarchy of evidentiary quality. In this way, even reductionist evidence of the component ecological interactions can be utilized, which is far easier to collect and evaluate. [ABSTRACT FROM AUTHOR]

Abstract The relative roles of top‐down (consumer‐driven) and bottom‐up (resource‐driven) forcing in exploited marine ecosystems have been much debated. Examples from a variety of marine systems of exploitation‐induced, top‐down trophic forcing have led to a general view that human‐induced predator perturbations can disrupt entire marine food webs, yet other studies that have found no such evidence provide a counterpoint. Though evidence continues to emerge, an unresolved debate exists regarding both the relative roles of top‐down versus bottom‐up forcing and the capacity of human exploitation to instigate top‐down, community‐level effects. Using time‐series data for 104 reef communities spanning tropical to temperate Australia from 1992 to 2013, we aimed to quantify relationships among long‐term trophic group population density trends, latitude, and exploitation status over a continental‐scale biogeographic range. Specifically, we amalgamated two long‐term monitoring databases of marine community dynamics to test for significant positive or negative trends in density of each of three key trophic levels (predators, herbivores, and algae) across the entire time series at each of the 104 locations. We found that trophic control tended toward bottom‐up driven in tropical systems and top‐down driven in temperate systems. Further, alternating long‐term population trends across multiple trophic levels (a method of identifying trophic cascades), presumably due to top‐down trophic forcing, occurred in roughly fifteen percent of locations where the prerequisite significant predator trends occurred. Such alternating trophic trends were significantly more likely to occur at locations with increasing predator densities over time. Within these locations, we found a marked latitudinal gradient in the prevalence of long‐term, alternating trophic group trends, from rare in the tropics (

Abstract Complex ecological interactions are widely utilized to deliver conservation benefits but their efficacy is often debated. Using a coral reef trophic cascade as an example, we reveal that outcomes can be surprisingly difficult to detect. Even important impacts of marine reserves can go undetected (20% more coral with power

Excessive human waste nutrients, which usually consist of nitrogenous and phosphate compounds, are known as the major environmental stresses in coastal waters. Therefore, monitoring of nutrients level is very important in marine reserve park. This study presents an application of multi-metric index in accessing the spatial and temporal level of a nutrient in surface water at Batam City Marine Reserve Park, Indonesia. Research had been done with seasonal and spatial zones on three major islands namely Petong, Abang, and Dedep. Water samples from each station were taken from the surface water. Phosphate, nitrate, nitrite, and ammonia, were analyzed in situ and chlorophyll was conducted in the laboratory by spectrophotometric method. Statistical multi-metric detected the average eutrophication index (EI) value between 0.2-0.7, which is mesotrophic to eutrophic. Petong and Abang zones were categorized as eutrophic, and Dadap was mesotrophic. Continuous nutrients contamination throughout seasonal may be derived from sedimentation and domestic run-off from human-populated islands in the middle and northern region. Therefore, ecosystem rehabilitation and mitigation of anthropogenic run-off are needed to optimise the conservation management. Moreover, Dadap zone as the area with the least anthropogenic pressures is potential to be the core of conservation area in Batam City marine reserve park.

Fisheries in developing countries are often confronted with the problem of excessive harvesting of the marine resources as a result of lax management practices. This study formulates an optimal control problem involving a predator-prey model with partial harvesting of the prey species and a critical biomass level below which the fishery is not economically viable. The region of boundedness and the equilibrium points of the system are determined and discussed. Stability analysis of the model shows that the interior equilibrium point is both locally and globally asymptotically stable. The Bendixson–Dulac criterion establishes that the system does not possess any limit cycles or periodic orbits. Pontryagin’s maximum principle is employed to determine the necessary conditions for optimality of the model. Singularity analysis of the model, with the aid of the generalized Legendre–Clebsch condition, indicates that the existence of singular arcs cannot be ruled out. Therefore, the characterization of the optimal control gives rise to both bang-bang and singular controls. Furthermore, the relationship between the shadow price of fish stock, the shadow price of fishing effort and the price of landed fish as it relates to the optimal reserve area is explored. Numerical simulations are performed to validate the established theoretical results using empirical data on the Ghana sardinella fishery. The study reveals that the fishery can sustain an effort rate of more than twice the maximum sustainable (MSY) rate, provided that 40% of the current fish stock is in a marine reserve and the operational fish population is at least 30% of the carrying capacity of the ecosystem.

Overfishing and destructive fishing practices are major threats to marine biodiversity in the Philippines, where over 1.9 million small-scale fishers are supported by these biodiverse marine communities. Nearly 50% of all marine fish capture in the Philippines is from artisanal fisheries, with much of it not reported or under-reported. Marine reserves, where fishing is prohibited have been created in many local government units to help restore and preserve this biodiversity. The success of these marine reserves is still under serious debate with effective management still representing a significant challenge. The lack of a governance system to centrally managed marine reserves has resulted in non-governmental organizations developing community-based management schemes. Using independent fisheries data from Rare’s Fish Forever program, we applied PERMANOVA, SIMPER and biodiversity index analyses to evaluate the community structure of reef fish in 20 sites within the Philippines. We analyzed the differences in fish assemblage inside and outside of these marine reserves, before and after community-based management had been implemented. We provide evidence that: (i) fish community structure changes within marine reserves after community-based management strategies are implemented; and (ii) community-based management of marine fisheries resources protects and promotes biodiversity inside, and in some cases, outside marine reserves. Variability across sites suggests that other social or ecological factors may be influencing the ability of marine reserves to fully protect biodiversity and marine resources. Small-scale fishers in the Philippines participate in mixed-catch harvests and depend on biodiversity and reef community structure for their livelihoods. Thus, this work has implications on how community-based management strategies for marine reserves and adjacent waters may be beneficial for the sustainability of small-scale fishers.

One of today’s greatest conservation challenges is balancing policies, laws, and management strategies established to achieve economic goals that depend on extracting ocean resources with those established to conserve marine biodiversity. We use the Northeast Canyons and Seamounts Marine National Monument (NCSM) as a case study to explore the consequences of changing from a policy that prevents fishing to a fisheries management policy. We found that opening the NCSM to commercial fishing reduces species protections. Fishing with pelagic and bottom tending fixed gear exposes species inhabiting the sea surface and midwater regions to entanglement and bycatch risk. Fishing with bottom tending fixed gear also exposes deep-sea coral habitat to gear known to have detrimental impacts. The NCSM was designated as a marine national monument due to the area’s unique ecological resources that are a subject of scientific interest. Our case study demonstrates that a fisheries management policy is insufficient to protect these ecological resources.

This article reviews a suite of studies conducted in a network of coastal Marine Protected Areas (MPAs) in Skagerrak, Southeast Norway. In 2006, Norway’s first lobster reserves were implemented, with the aim of protecting European lobster (Homarus gammarus) through a ban on fixed gear. A before–after control-impact paired series (BACIPS) monitoring program was initiated to evaluate effects of protection on depleted lobster populations. Experimental trapping and capture-recapture techniques were combined to track demography of populations, also including movement of individuals within and beyond MPAs and adjacent control areas. Further, population genetics and parentage studies were applied, allowing for estimation of gene flow, and novel work on sexual selection in lobsters. Additional studies have evaluated MPA effects on coastal cod (Gadus morhua), and on commercially harvested labrids (Ctenolabrus rupestris and Symphodus melops) and anadromous brown trout (Salmo trutta). Together, these studies reported effects of protection pertaining to increased population density, survival, body size and phenotypic diversity, changes in emigration and interaction with surrounding fisheries, and alteration of selection pressure on morphological- and behavioral traits. Designation of MPAs in close collaboration with fishers and managers, long-term monitoring, inclusion of citizen science and evolving research protocols—also including fisheries data—have revealed novel effects of protection and harvesting on marine populations, thus providing substantial contributions to conservation science. Moreover, knowledge of MPA effects on coastal species has impacted harvest regulations showing the utility of MPAs as empirically documented management tools in Norway.

Background: Conservation activities and natural resource management interventions have often aimed to tackle the dual challenge of improving nature conservation and human well-being. However, there is concern over the extent to which this dual goal has been achieved, and an increasing recognition of trade-offs and synergies within and between aspects of each of the goals. The amount and scope of the available evidence on the success of conservation and management interventions in both arenas has lacked documentation, for a number of reasons, including limited resources for monitoring and evaluation and the difficulty in bringing together a disparate evidence base. This systematic map focuses on the interaction between marine conservation management and the health and well-being of coastal communities in South East Asia. Method: We searched bibliographic databases to find published literature, and identified grey literature through institutional and organisational website searches and key stakeholders. Eligibility criteria were applied in two stages, title and abstract and full text, with consistency checks. We extracted meta-data on the design and characteristics of each study, from which we produced an interactive database and map, and a narrative summary. Results: We assessed 42,894 records at title and abstract from the main searches. 1,331 articles were assessed at full text (30 articles were not retrievable). 287 articles (281 studies) were included in the systematic map. Most studies were peer-reviewed publications (90%), and from the Philippines and Indonesia (72%). 31% of studies were solely qualitative, 45% were solely quantitative and 24% included both qualitative and quantitative research. Only 24% (31/127) of quantitative studies included a comparator.We identified knowledge clusters where studies investigated the links between the marine conservation interventions: Site Protection, Economic or Livelihood Incentives or Alternatives, or Habitat Management, and the human health and well-being outcomes: Economic Living Standards, Governance and Empowerment, or Social Relations. In addition, qualitative research clusters were identified exploring the links between the intervention Habitat Management, and the outcome Governance and Empowerment, and between the intervention Economic or Livelihood Incentives or Alternatives, and the outcomes of Governance and Empowerment, and Social Relations.We identified major knowledge gaps in evidence for the effect of marine conservation interventions on the outcomes Freedom of Choice and Action, Security and Safety, Subjective Well-being, Health, and Culture and Spirituality. There was a lack of studies involving Education, Awareness and Activism interventions that reported any human health and well-being outcomes. Conclusion: We present the first updatable, interrogable and comprehensive evidence map on this topic for South East Asia. Our work supports further, detailed investigation of knowledge clusters using systematic review and also serves to identify understudied topic areas. The lack of comparative, quantitative studies suggests that future research should include counterfactuals to strengthen the robustness of evidence base. Users of this systematic map should recognise that much evidence may be national or locally specific, and that we did not undertake an assessment of study quality. Thus, when considering implications for policy and decision-making, users should carefully consider the heterogeneity of available evidence and refer to original research articles to gain a full depth of understanding and context.

Sperm whales have occupied the waters off the Galápagos Islands, Ecuador, for at least the past 200 years. During the 19th century, they were the target of intensive whaling that severely depleted the population. In recent times, after commercial whaling ended, sperm whales in the region remain vulnerable to multiple threats, especially potential entanglement in fishing gear, which may hinder their ability to recover from the whaling era.As a highly mobile, long‐lived species, long‐term analysis of the habitat use of sperm whales is necessary to establish effective conservation and management strategies. Here, contemporary (1985–2014) and historical (1830–1850) sperm whale habitat use off the Galápagos Islands was analysed and contrasted to the extent of the Galápagos Marine Reserve (GMR). Contemporary habitat use and its variability over time were modelled as a function of geographic, oceanographic, and topographic variables using generalized additive models.The fine‐scale habitat (<50 km) used by sperm whales was associated with topographic (i.e. depth and slope) and oceanographic characteristics (i.e. relative sea surface temperature and standard deviation of sea surface temperature), but these preferences varied over time.While historical and contemporary data indicate that sperm whale habitat primarily occurred within the boundaries of the GMR, in recent years, whales were found up to 30.1% of the time outside the GMR, potentially overlapping with commercial fisheries operating in the area.The dynamic nature of the relationship of this nomadic species with its habitat highlights the need of large‐scale conservation efforts across the Eastern Tropical Pacific region, including the wide‐scale enforcement of regulations requiring the use of Automatic Identification System in fishing vessels, the promotion of on‐board fisheries observer programmes, the development of adaptive management strategies, and international collaboration to identify and mitigate threats. [ABSTRACT FROM AUTHOR]

The anchovy (Engraulis ringens) fishery in central-southern Chile, like many fisheries worldwide, is overexploitation mainly due to poor and short-term management by fishing authorities and communities. This study proposes and evaluates marine reserves as a possible tool to apply since there is a current marine reserve law in Chile. The study's methodology is the simulation of a bioeconomic model that includes two areas: one is the protected, and the other is the artisanal fishing, in which the protected area transfers biomass to the artisanal fishing area. The reserve is incorporated as a decision variable in the management of this resource. It is determined as a percentage of protection of the total fish population related to fishing effort, which quantifies and evaluates the impact of protecting a stock of parental fish on the fishery's sustainability. Biomass data used is from 2000-2006, during which the anchovy fishery was fully exploited. The carrying capacity and intrinsic growth rate are estimated, and biomass is projected at different protection and effort levels. Results show that if a marine reserve with a protection level of 30% had been applied as a management policy in the anchovy fishery of central-southern Chile in the early 2000s, the fishing activity would be in a state of full exploitation rather than overexploitation as it is today. This model's fundamental contribution is that it makes possible fishery evaluation with real data from the same fishing activity. [ABSTRACT FROM AUTHOR]

The queen conch (Strombus gigas) provides important economic, ecological, and societal benefits to local communities throughout the Caribbean. The species, however, has fallen victim to commercial exploitation and overfishing in many areas. In Belize, even with restricted harvesting seasons, size restrictions, and regulations set by the Convention on International Trade in Endangered Species (CITES), harvesting practices have significantly depleted populations. Marine reserves, including the Glover's Reef Marine Reserve, were established to protect biodiversity and maintain populations of Belize's natural coral reefs. Utilizing size, frequency, and evidence of harvesting (shell notches), the 2018 Tropical Marine Biology (BSC 3355) course analyzed the effectiveness of this reserve on protecting populations of S. gigas. Conch inside the reserve were significantly larger than those outside the reserve, a trait important for reproductive capacity. Population abundance, however, was similar, with few live conch in either area. This finding provides evidence that queen conch populations in Glover's Reef Marine Reserve are still threatened by harvesting. It is suggested that further precautions, regulations, and educational programs be put into place to protect and increase S. gigas populations in this reserve and throughout Belize. [ABSTRACT FROM AUTHOR]

The Chañaral Island Marine Reserve (CIMR) is a protected area in north-central Chile that is a feeding area for large cetaceans such as fin, blue and humpback whales. However, a number of studies indicate that a large proportion of whale sightings occur outside this protected area. Thus, an increase in the size (or dimension) of the protected area has been suggested. This requires ensuring compatibility of the protected area with economic activities which take place there, especially fishing, tourism and diving. This study proposes a strategic plan for expanding the CIMR area developed using the decision-making algorithm MARXAN. We proposed three conservation scenarios: Scenario 0 divided the proposed area into planning units (PU) classed as either "obligatory" or "available"; Scenario 1 in which all PUs were "available" and Scenario 2 with the PUs "obligatory", "available" and "suggested". The results suggest that Scenario 2 is the most favorable for conservation, since it supports increasing the current area of the reserve, adding a second nautical mile around the island. This would create an area sufficient to fulfill the conservation goals for the three whale species (30% of the feeding areas for blue and fin whales and 10% for humpback whale) without producing an impact on the current activities in the CIMR. This zoning proposal provides a roadmap for the development of protected areas based on scientific baseline, including the participation of local communities that ultimately should validate the proposal to successfully support its implementation. [ABSTRACT FROM AUTHOR]

Achieving the UN SD Goals requires the conservation of keystone marine species. As top predators, many sharks play a crucial role in balancing marine ecosystems; yet, they have been experiencing severe population declines. Overfishing is indisputably the main threat to shark populations, but little is known about the impact of non-extractive human pressure. This study tests the effect of varied human presence on shark behavior at an insular marine reserve. In 2020, humans were virtually absent from Fernando de Noronha (FEN), Brazil, during a 211-days lockdown period prompted by the COVID-19 pandemics. A local shark tracking program rendered nearly 280000 acoustic detections in coastal waters from 2016 through 2021. Lemon sharks, Negaprion brevirostris , showed a 43% increase in detection rate during the lockdown which was ascribed to the concomitant decrease in human presence. In contrast, the detection rate of tiger sharks, Galeocerdo cuvier , decreased by 67% during the lockdown, but this trend was likely related to seasonality in tiger shark behavior. After the lockdown, both species' detection rates tended to return to previous levels. Further, lemon sharks increased diurnal coastal residency and made more use of areas less restrictive to human use during the lockdown, whilst tiger sharks increased nocturnal coastal residency during and after the lockdown period. Contrasting trends might relate with lemon sharks completing their life cycle in FEN and tiger sharks being migrants arriving to FEN at older ages and being less exposed to local anthropogenic stimuli across ontogeny. This study demonstrates that non-extractive human disturbance can induce significant changes in the way marine predators explore crucial habitats for accomplishing trophic, reproductive, and ontogenetic functions. Ascertaining the ecological impacts of marine-based human development should thus consider cryptic responses by keystone megafauna to the anthropogenic landscape produced by an ever-growing coastal population. The designation of human exclusion marine areas could emerge as the single solution to endow shark populations with suitable habitats for optimizing their resilience to human pressure. [Display omitted] • Knowledge of shark responses to human pressure is crucial for ensuring their conservation. • The COVID-19 lockdown drastically reduced human presence at a touristic marine protected area. • Acoustic tracking revealed significant effects of human disturbance on shark behavior. • Interspecific differences in shark behavioral responses to varied human presence were observed. • Non-extractive human pressure may prompt harmful impacts on lemon shark fitness. [ABSTRACT FROM AUTHOR]

Abstract The recovery of communities of predatory fishes within a no‐take marine reserve after the eradication of illegal fishing provides an opportunity to examine the role of sharks and other large‐bodied mesopredatory fishes in structuring reef fish communities. We used baited remote underwater video stations to investigate whether an increase in sharks was associated with a change in structure of the mesopredatory fish community at Ashmore Reef, Western Australia. We found an almost fourfold increase in shark abundance in reef habitat from 0.64 hr−1 ± 0.15 SE in 2004, when Ashmore Reef was being fished illegally, to 2.45 hr−1 ± 0.37 in 2016, after eight years of full‐time enforcement of the reserve. Shark recovery in reef habitat was accompanied by a two and a half‐fold decline in the abundance of small mesopredatory fishes (≤50 cm TL) (14.00 hr−1 ± 3.79 to 5.6 hr−1 ± 1.20) and a concomitant increase in large mesopredatory fishes (≥100 cm TL) from 1.82 hr−1 ± 0.48 to 4.27 hr−1 ± 0.93. In contrast, near‐reef habitats showed an increase in abundance of large mesopredatory fishes between years (2.00 hr−1 ± 0.65 to 4.56 hr−1 ± 1.11), although only smaller increases in sharks (0.67 hr−1 ± 0.25 to 1.22 hr−1 ± 0.34) and smaller mesopredatory fishes. Although the abundance of most mesopredatory groups increased with recovery from fishing, we suggest that the large decline of small mesopredatory fish in reef habitat was mostly due to higher predation pressure following the increase in sharks and large mesopredatory fishes. At the regional scale, the structure of fished communities at Ashmore Reef in 2004 resembled those of present day Scott Reefs, where fishing still continues today. In 2016, Ashmore fish communities resembled those of the Rowley Shoals, which have been protected from fishing for decades.