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Patterns of reproductive ontogeny in four species of coral reef wrasses (F: Labridae) Hemigymnus melapterus, Hemigymnus fasciatus, Cheilinus fasciatus and Oxycheilinus digramma were investigated. Populations of each species were sampled from two island groups of the central Great Barrier Reef (GBR), Australia, and from coral reefs in the central Philippines. These three sampling locations span 30° of latitude. The GBR and Philippine reefs experience biologically significant differences in water temperature, geography and human activity. The studied wrasses are effectively unfished in Australia but heavily fished in the Philippines. Gonad weights, histology and demographic data were obtained across the entire size and age range of H. melapterus, C. fasciatus and O. digramma from all locations. Analysis identified three processes of male recruitment: functional gonochorism and both forms of protogynous hermaphroditism, monandry and diandry. The expression of these distinct sexual ontogenies was locality dependent. Populations of H. melapterus, H. fasciatus, C. fasciatus and O. digramma on the GBR showed consistently uniform patterns of sexual ontogeny, with all species being exclusively monandric. H. melapterus, C. fasciatus and O. digramma in the Philippines displayed complex sexual ontogenies, with all species showing histological evidence of both diandry and functional gonochorism. Reproductive investment in gonadal tissue, and population sex structure, also differed between GBR and Philippine coral reefs. Philippine populations had substantially lower gonado-somatic indices than populations on the GBR. Nonetheless, Philippine populations matured more rapidly and displayed a protracted timing of sex change over a large size and age range. Thus, mature females appeared earlier and persisted later into ontogeny in the Philippines than on GBR reefs. Protracted timing of sex change on Philippine reefs is likely linked to the presence of primary males in the population, which is known to reduce the strength of selection for mature females to undergo sex change and become male. Hypotheses based on social structure of fish populations, environmental factors and evolutionary history were developed to account for the different patterns of sexual ontogeny in the focal wrasses.

Nonreef habitats such as mangroves, seagrass, and macroalgal beds are important for foraging, spawning, and as nursery habitat for some coral reef fishes. The spatial configuration of nonreef habitats adjacent to coral reefs can therefore have a substantial influence on the distribution and composition of reef fish. We investigate how different habitats in a tropical seascape in the Philippines influence the presence, density, and biomass of coral reef fishes to understand the relative importance of different habitats across various spatial scales. A detailed seascape map generated from satellite imagery was combined with field surveys of fish and benthic habitat on coral reefs. We then compared the relative importance of local reef (within coral reef) and adjacent habitat (habitats in the surrounding seascape) variables for coral reef fishes. Overall, adjacent habitat variables were as important as local reef variables in explaining reef fish density and biomass, despite being fewer in number in final models. For adult and juvenile wrasses (Labridae), and juveniles of some parrotfish taxa (Chlorurus), adjacent habitat was more important in explaining fish density and biomass. Notably, wrasses were positively influenced by the amount of sand and macroalgae in the adjacent seascape. Adjacent habitat metrics with the highest relative importance were sand (positive), macroalgae (positive), and mangrove habitats (negative), and fish responses to these metrics were consistent across fish groups evaluated. The 500‐m spatial scale was selected most often in models for seascape variables. Local coral reef variables with the greatest importance were percent cover of live coral (positive), sand (negative), and macroalgae (mixed). Incorporating spatial metrics that describe the surrounding seascape will capture more holistic patterns of fish–habitat relationships on reefs. This is important in regions where protection of reef fish habitat is an integral part of fisheries management but where protection of nonreef habitats is often overlooked., How do multiple habitats in a seascape influence the presence, density, and biomass of coral reef fishes? Although local coral reef habitat is the major influence, non‐reef habitats within 500 m can strongly affect reef fish distributions, especially juvenile fish and wrasses.

Environmental disturbances and fishing are well known drivers of coral reef fish population size, length-frequency, and assemblage structure. However, few studies have partitioned the spatial and temporal impacts of multiple disturbance events and long-term no-take marine reserve (NTMR) protection on the biomass of juvenile and adult reef-fishes based on the known size of sexual maturity. Here, we document responses in the biomass of juvenile and adult wrasses (Labridae) Hemigymnus melapterus, H. fasciatus, Cheilinus fasciatus, and Oxycheilinus digramma, to environmental disturbance events, NTMR protection, and predator density on inshore fringing coral reefs at the Palm and Whitsunday Island groups, Great Barrier Reef (GBR), Australia from 2007 to 2018 (12 years). The biomass of juvenile and adult wrasses on inshore GBR reefs were driven predominantly by benthic habitat associations, rather than by NTMR protection or density of wrasse predators (Plectropomus spp.). Despite similar species-specific associations of juvenile and adult wrasses with benthic cover, juvenile wrasse biomass consistently declined following coral bleaching and cyclone events. Conversely, adult wrasses had variable responses to disturbance events, including some increases in biomass. Disturbance-mediated declines in the biomass of juvenile wrasses are likely to generate ongoing reductions in the abundance of these species on inshore GBR reefs. Our findings provide further evidence that habitat loss impacts a range of coral reef fishes beyond those that are directly reliant upon live coral. Shifts in assemblage structure, loss of biodiversity, and reductions in fishery productivity will become increasingly apparent in coral reef ecosystems if anthropogenic global warming continues unabated.

Empirical evidence for increases in the reproductive potential (egg output per unit area) of coral reef fish in no-take marine reserves (NTMRs) is sparse. Here, we inferred the development of reproductive potential in two species of protogynous reef fishes, Chlorurus bleekeri (Labridae: Scarinae) and Cephalopholis argus (Epinephelidae) inside and outside of Philippine NTMRs. We estimated key reproductive parameters and applied these to species-specific density and length data from 17 NTMRs (durations of protection: 0-11 years) and paired fished sites (controls) in a space-for-time substitution approach. For C. argus, we also used density and length data collected almost annually over 29 years from a NTMR and an adjacent control at Apo Island. Results suggested that C. bleekeri can develop 6.0 times greater reproductive potential in NTMRs than controls after 11 years of protection, equivalent to approximately 582,000 more eggs produced 500 m-2 inside NTMRs. Enhancement of reproductive potential in C. argus was not evident after 11 years in the space-for-time substitution. At Apo Island NTMR, reproductive potential of C. argus increased approximately 6-fold over 29 years but NTMR/control ratios in reproductive potential decreased through time (from 3.2 to 2.4) probably due to spillover of C. argus from the NTMR to the control. Cephalopholis argus was estimated to produce approximately 113,000 more eggs 500 m-2 inside Apo Island NTMR at the 29th year of protection. Ratios of reproductive potential between NTMR and controls in C. bleekeri and C. argus were often greater than corresponding ratios in density or biomass. The study underscores the importance of species-specific reproductive life history traits that drive variation in the development of larval fish subsidies that originate from NTMRs. This article is protected by copyright. All rights reserved.

Patterns of reproductive ontogeny in four species of coral reef wrasses (F: Labridae) Hemigymnus melapterus, Hemigymnus fasciatus, Cheilinus fasciatus and Oxycheilinus digramma were investigated. Populations of each species were sampled from two island groups of the central Great Barrier Reef (GBR), Australia, and from coral reefs in the central Philippines. These three sampling locations span 30° of latitude. The GBR and Philippine reefs experience biologically significant differences in water temperature, geography and human activity. The studied wrasses are effectively unfished in Australia but heavily fished in the Philippines. Gonad weights, histology and demographic data were obtained across the entire size and age range of H. melapterus, C. fasciatus and O. digramma from all locations. Analysis identified three processes of male recruitment: functional gonochorism and both forms of protogynous hermaphroditism, monandry and diandry. The expression of these distinct sexual ontogenies was locality dependent. Populations of H. melapterus, H. fasciatus, C. fasciatus and O. digramma on the GBR showed consistently uniform patterns of sexual ontogeny, with all species being exclusively monandric. H. melapterus, C. fasciatus and O. digramma in the Philippines displayed complex sexual ontogenies, with all species showing histological evidence of both diandry and functional gonochorism. Reproductive investment in gonadal tissue, and population sex structure, also differed between GBR and Philippine coral reefs. Philippine populations had substantially lower gonado-somatic indices than populations on the GBR. Nonetheless, Philippine populations matured more rapidly and displayed a protracted timing of sex change over a large size and age range. Thus, mature females appeared earlier and persisted later into ontogeny in the Philippines than on GBR reefs. Protracted timing of sex change on Philippine reefs is likely linked to the presence of primary males in the population, which is known to reduce the strength of selection for mature females to undergo sex change and become male. Hypotheses based on social structure of fish populations, environmental factors and evolutionary history were developed to account for the different patterns of sexual ontogeny in the focal wrasses.

Juvenile fish often use alternative habitats distinct from their adult phases. Parrotfishes are an integral group of coral reef fish assemblages, are targeted in fisheries, are sensitive to reef disturbances, and have been documented as multiple-habitat users. Considering the abundance of research conducted on parrotfishes, very little is known about their juvenile ecology at the species level due to their cryptic and variable coloration patterns. We collected juvenile parrotfishes in non-reef habitats (macroalgal beds, seagrass beds, and lagoons) in the Philippines and used DNA analysis to determine species composition. The results were then compared with data on adult parrotfish abundance from underwater visual census (UVC) surveys in coral reef and non-reef habitats. Collections identified 15 species of juvenile parrotfishes in non-reef habitats, and of these, 10 were also recorded in UVCs as adults. Informed by adult surveys, 42% of the 19 parrotfish species observed as adults were classified as multi-habitat users based on their presence in coral reef and non-reef habitats. When accounting for the occurrence of species as juveniles in non-reef habitats, 93% of the species collected as juveniles would be considered multi-habitat users. Species identified as juveniles in non-reef habitats comprised 50% of the average adult parrotfish density on coral reefs and 58&ndash, 94% in non-reef habitats. The species richness of juveniles in non-reef habitats was greater than that of adults occupying the same habitats, and the most common adult species observed in UVCs was not collected as juveniles in non-reef habitats. Finally, UVC suggested that 97% of juvenile parrotfish &lt, 10-cm total length was present in non-reef habitats compared to coral reefs. These results provide further evidence for ontogenetic movement across habitat boundaries for parrotfish species in a diverse and highly connected tropical seascape. This is one of the few studies to quantify links between nursery and adult habitat in parrotfishes, highlighting the importance of including non-reef habitats in ecological studies of an iconic group of coral reef fish.

Understanding whether assemblages of species respond more strongly to bottom-up (availability of trophic resources or habitats) or top-down (predation pressure) processes is important for effective management of resources and ecosystems. We determined the relative influence of environmental factors and predation by humans in shaping the density, biomass, and species richness of 4 medium-bodied (10-40 cm total length [TL]) coral reef fish groups targeted by fishers (mesopredators, planktivores, grazer and detritivores, and scrapers) and the density of 2 groups not targeted by fishers (invertivores, small fish ≤10 cm TL) in the central Philippines. Boosted regression trees were used to model the response of each fish group to 21 predictor variables: 13 habitat variables, 5 island variables, and 3 fishing variables (no-take marine reserve [NTMR] presence or absence, NTMR size, and NTMR age). Targeted and nontargeted fish groups responded most strongly to habitat variables, then island variables. Fishing (NTMR) variables generally had less influence on fish groups. Of the habitat variables, live hard coral cover, structural complexity or habitat complexity index, and depth had the greatest effects on density, biomass, and species richness of targeted fish groups and on the density of nontargeted fishes. Of the island variables, proximity to the nearest river and island elevation had the most influence on fish groups. The NTMRs affected only fishes targeted by fishers; NTMR size positively correlated with density, biomass, and species richness of targeted fishes, particularly mesopredatory, and grazing and detritivorous fishes. Importantly, NTMRs as small as 15 ha positively affected medium-bodied fishes. This finding provides reassurance for regions that have invested in small-scale community-managed NTMRs. However, management strategies that integrate sound coastal land-use practices to conserve adjacent reef fish habitat, strategic NTMR placement, and establishment of larger NTMRs will be crucial for maintaining biodiversity and fisheries.Influencia Relativa de los Factores Ambientales y la Pesca sobre el Ensamblaje de Peces en los Arrecifes de Coral Resumen Es importante entender si el ensamblaje de especies responde con mayor fuerza al proceso de abajo-arriba (disponibilidad de recursos tróficos o hábitats) o al de arriba-abajo (presión de depredadores) para el manejo efectivo de los recursos y los ecosistemas. Determinamos la influencia relativa de los factores ambientales y la depredación humana en la configuración de la densidad, la biomasa y la riqueza de especies de cuatro peces de arrecife de coral con un tamaño corporal mediano (10-40 cm de longitud total [LT]) que son preferidos por los pescadores (mesodepredadores, planctívoros, forrajeros y detritívoros, y raspadores) y también determinamos la densidad de dos grupos que no son blanco de los pescadores (invertívoros y peces de talla pequeña ≤10 cm LT) en la región central de las Filipinas. Usamos árboles de regresión amplificados para modelar la respuesta de cada grupo de peces a 21 variables de predicción: trece variables de hábitat, cinco variables de isla y tres variables de pesca (ausencia o presencia de una reserva marina vedada [RMV], tamaño y antigüedad de la NTMR). Los grupos de peces preferidos y no preferidos por los pescadores respondieron con mayor fuerza a las variables de hábitat que a las variables de isla. Las variables de pesca (RMV) en general tuvieron una menor influencia sobre los grupos de peces. De las variables de hábitat, la cobertura de coral duro vivo, la complejidad estructural o el índice de complejidad del hábitat y la profundidad tuvieron el mayor efecto sobre la densidad, la biomasa y la riqueza de especies de los peces preferidos por los pescadores y sobre la densidad de los peces no preferidos por los pescadores. De las variables de isla, la proximidad al río más cercano y la elevación de la isla tuvieron la mayor influencia sobre los grupos de peces. Las RMVs afectaron sólo a los peces preferidos por los pescadores; el tamaño de la NTMR tuvo una correlación positiva con la densidad, la biomasa y la riqueza de especies de los peces preferidos por los pescadores, particularmente los peces mesodepredadores, forrajeros y detritívoros. De manera importante, las RMVs con un tamaño mínimo de 15 ha afectaron positivamente a los peces de talla mediana. Este hallazgo proporciona seguridad para las regiones que han invertido en RMVs de pequeña escala y manejadas por la comunidad. Sin embargo, las estrategias de manejo que integran prácticas firmes de uso de suelo costero para conservar el hábitat adyacente de peces, la ubicación estratégica de RMV y el establecimiento de RMVs más grandes serán cruciales para el mantenimiento de la biodiversidad y las pesquerías.了解物种群聚对自下而上 (营养资源或栖息地的可用性) 还是自上而下 (捕食压力) 的过程反应更为强烈, 对于有效管理资源和生态系统十分重要。本研究确定了环境因素和人类捕捞在决定菲律宾中部四类作为渔民捕捞目标物种的中等体型 (总长度 10-40 厘米) 珊瑚鱼类 (中等捕食者、食浮游生物鱼类、食草及食腐鱼类、刮食鱼类) 的密度、生物量和物种丰富度, 以及两类非目标物种 (食无脊椎动物鱼类, 总长度小于 10 厘米的小鱼) 的密度中的相对影响。我们使用了增强回归树来模拟每个类别的鱼类对 21 个预测变量的响应, 包含13 个栖息地相关变量、 5 个岛屿相关变量和 3 个捕捞相关的变量 (是否存在禁捕海洋保护区、禁捕海洋保护区大小及建立时长)。目标和非目标鱼类对栖息地变量的反应最为强烈, 其次是岛屿变量。捕捞相关变量 (禁捕海洋保护区) 对鱼群的影响一般较小。在栖息地变量中, 存活硬珊瑚的覆盖、结构复杂性或栖息地复杂性指数和深度对目标鱼类种群密度、生物量、物种丰富度及非目标鱼类密度的影响最大。此外, 禁捕海洋保护区只影响渔民的目标捕捞物种;禁捕海洋保护区的大小与目标鱼类的密度、生物量和物种丰富度呈正相关关系, 特别是对于中等捕食者、食草及食腐鱼类而言。另一重要结果是, 即使只有 15 公顷大小的禁捕海洋保护区也能对中等体型的鱼类产生积极影响。这一发现为投资小型社区管理禁捕海洋保护区的地区提供了保障。然而, 在管理战略中纳入健全的沿海土地利用实践以保护相邻珊瑚礁鱼类栖息地、战略性地设置禁捕海洋保护区, 以及建立更大的禁捕海洋保护区, 也将对维持生物多样性和渔业产生重要作用。【翻译: 胡怡思; 审校: 聂永刚】.

No-take marine reserves (NTMR) are increasingly being implemented to mitigate the effects of fishing on coral reefs, yet determining the efficacy of NTMRs depends largely on partitioning the effects of fishing from the effect of benthic habitat. Species of coral-reef fishes typically decline in density when subjected to fishing or benthic disturbances, but this is not always the case. This study documents the long-term (8-31 years) response of six species of detritivorous surgeonfishes (family Acanthuridae) to NTMR protection and benthic habitat change at four islands (Apo, Sumilon, Mantigue, Selinog) in the central Philippines, each island with a NTMR and a monitored fished site. Despite being subject to moderate fishing pressure, these species did not increase in density with NTMR protection. However, density of these surgeonfishes had a strong negative relationship with cover of live hard coral and a strong positive relationship with cover of dead substratum (sand, rubble, hard dead substratum). These surgeonfishes typically feed over dead substrata and thus probably increase in density following large environmental disturbances that substantially reduce live hard coral cover. Here, we describe effects of environmental disturbance events (e.g., use of explosives, typhoons) that reduced live hard-coral cover and subsequent large increases (up to 25 fold) in surgeonfish densities, which then slowly (over 5-15 years) decreased in density as live hard coral recovered. Density of these functionally important surgeonfish species was influenced more by changes to benthic cover than by NTMR protection. Thus, we highlight the greater importance of bottom-up controls (i.e., benthic changes to food availability) than top-down control (i.e., fishing) on a functionally important group of coral-reef fishes.

Baseline ecological studies of mesophotic coral ecosystems are lacking in the equatorial Indo-West Pacific region where coral reefs are highly threatened by anthropogenic and climate-induced disturbances. Here, we used baited remote underwater video to describe benthic habitat and fish assemblage structure from 10 to 80 m depth at Apo Island, a well-managed marine protected area in the Philippines. We conducted surveys 2 yr after two storms (in 2011 and 2012) caused severe damage to shallow coral communities within the no-take marine reserve (NTMR) of Apo Island, which led to declines in fish populations that had built up over three decades. We found that hard coral cover was restricted to 30 m) was dominated by sand/rubble and rock (dead coral) with low cover of soft corals, sponges and macroalgae. Storm damage appeared to have reached the deepest limit of the fringing reef (40 m) and reduced variability in benthic structure within the NTMR. Species richness and/or abundance of most trophic groups of fish declined with increasing depth regardless of storm damage. There were differences in taxonomic and trophic structure and degree of targeting by fisheries between shallow and mesophotic fish assemblages. Threatened shark species and a fish species previously unreported in the Philippines were recorded at mesophotic depths. Our findings provide a first glimpse of the benthic and fish assemblage structure of Philippine coral reef ecosystems across a wide depth gradient. This work also underscores how a combination of limited coral reef development at mesophotic depths close to shallow reefs and severe habitat loss caused by storms would result in minimal depth refuge for reef fish populations.

No-take marine reserves (NTMRs) are expected to benefit fisheries via the net export of eggs and larvae (recruitment subsidy) from reserves to adjacent fished areas. Quantifying egg production is the first step in evaluating recruitment subsidy potential. We calculated annual egg production per unit area (EPUA) from 2004 to 2013 for the commercially important common coral trout, Plectropomus leopardus, on fished and NTMR reefs throughout the Great Barrier Reef (GBR), Australia. Geographic region, NTMR status, fish size, and population density were all found to affect EPUA. The interactions among these factors were such that, EPUA on NTMR reefs compared to reefs open to fishing was 21% greater in the southern GBR, 152% greater in the central GBR, but 56% less in the northern GBR. The results show that while NTMRs can potentially provide a substantial recruitment subsidy (central GBR reefs), they may provide a far smaller subsidy (southern GBR), or serve as recruitment sinks (northern GBR) for the same species in nearby locations where demographic rates differ. This study highlights the importance of considering spatial variation in EPUA when assessing locations of NTMRs if recruitment subsidy is expected from them.

Networks of no-take marine reserves (NTMRs) are a widely advocated strategy for managing coral reefs. However, uncertainty about the strength of population connectivity between individual reefs and NTMRs through larval dispersal remains a major obstacle to effective network design. In this study, larval dispersal among NTMRs and fishing grounds in the Philippines was inferred by conducting genetic parentage analysis on a coral-reef fish (Chaetodon vagabundus). Adult and juvenile fish were sampled intensively in an area encompassing approximately 90 km of coastline. Thirty-seven true parent-offspring pairs were accepted after screening 1978 juveniles against 1387 adults. The data showed all types of dispersal connections that may occur in NTMR networks, with assignments suggesting connectivity among NTMRs and fishing grounds (n = 35) far outnumbering those indicating self-recruitment (n = 2). Critically, half (51%) of the inferred occurrences of larval dispersal linked reefs managed by separate, independent municipalities and constituent villages, emphasising the need for nested collaborative management arrangements across management units to sustain NTMR networks. Larval dispersal appeared to be influenced by wind-driven seasonal reversals in the direction of surface currents. The best-fit larval dispersal kernel estimated from the parentage data predicted that 50% of larvae originating from a population would attempt to settle within 33 km, and 95% within 83 km. Mean larval dispersal distance was estimated to be 36.5 km. These results suggest that creating a network of closely spaced (less than a few tens of km apart) NTMRs can enhance recruitment for protected and fished populations throughout the NTMR network. The findings underscore major challenges for regional coral-reef management initiatives that must be addressed with priority: (1) strengthening management of NTMR networks across political or customary boundaries; and (2) achieving adequate population connectivity via larval dispersal to sustain reef-fish populations within these networks.

Effective conservation depends upon people's compliance with regulations, yet non-compliance (eg poaching) is often the rule rather than the exception. Poaching is often clandestine and socially undesirable, requiring specialized, multidisciplinary approaches for assessment and management. We estimated poaching by recreational fishers in no-fishing reserves of Australia's Great Barrier Reef Marine Park (GBRMP) by conducting social surveys and quantifying derelict (lost or discarded) fishing gear. Our study revealed that (1)between 3-18% of fishers admitted to poaching within the past year, (2) poaching activities were often concentrated at certain times (holidays) and in specific places (poaching hotspots), and (3) fishers' primary motivations to poach were the perception of higher catches in reserves and a low probability of detection. Our results suggest that extolling certain ecological benefits of marine reserves where enforcement capacity is low could lead to the perverse outcome of encouraging non-compliance. Our combined social-ecological approach revealed that even in an iconic marine park such as the GBRMP, poaching levels are higher than previously assumed, which has implications for effective management.

Quantifying the role of biophysical and anthropogenic drivers of coral reef ecosystem processes can inform management strategies that aim to maintain or restore ecosystem structure and productivity. However, few studies have examined the combined effects of multiple drivers, partitioned their impacts, or established threshold values that may trigger shifts in benthic cover. Inshore fringing reefs of the Great Barrier Reef Marine Park (GBRMP) occur in high-sediment, high-nutrient environments and are under increasing pressure from multiple acute and chronic stressors. Despite world-leading management, including networks of no-take marine reserves, relative declines in hard coral cover of 40–50% have occurred in recent years, with localized but persistent shifts from coral to macroalgal dominance on some reefs. Here we use boosted regression tree analyses to test the relative importance of multiple biophysical drivers on coral and macroalgal cover using a long-term (12–18 yr) data set collected from reefs at four island groups. Coral and macroalgal cover were negatively correlated at all island groups, and particularly when macroalgal cover was above 20%. Although reefs at each island group had different disturbance-and-recovery histories, degree heating weeks (DHW) and routine wave exposure consistently emerged as common drivers of coral and macroalgal cover. In addition, different combinations of sea-surface temperature, nutrient and turbidity parameters, exposure to high turbidity (primary) floodwater, depth, grazing fish density, farming damselfish density, and management zoning variously contributed to changes in coral and macroalgal cover at each island group. Clear threshold values were apparent for multiple drivers including wave exposure, depth, and degree heating weeks for coral cover, and depth, degree heating weeks, chlorophyll a, and cyclone exposure for macroalgal cover, however, all threshold values were variable among island groups. Our findings demonstrate that inshore coral reef communities are typically structured by broadscale climatic perturbations, superimposed upon unique sets of local-scale drivers. Although rapidly escalating climate change impacts are the largest threat to coral reefs of the GBRMP and globally, our findings suggest that proactive management actions that effectively reduce chronic stressors at local scales should contribute to improved reef resistance and recovery potential following acute climatic disturbances.

An influential paradigm in coral reef ecology is that fishing causes trophic cascades through reef fish assemblages, resulting in reduced herbivory and thus benthic phase shifts from coral to algal dominance. Few long‐term field tests exist of how fishing affects the trophic structure of coral reef fish assemblages, and how such changes affect the benthos. Alternatively, benthic change itself may drive the trophic structure of reef fish assemblages. Reef fish trophic structure and benthic cover were quantified almost annually from 1983 to 2014 at two small Philippine islands (Apo, Sumilon). At each island a No‐Take Marine Reserve (NTMR) site and a site open to subsistence reef fishing were monitored. Thirteen trophic groups were identified. Large planktivores often accounted for >50% of assemblage biomass. Significant NTMR effects were detected at each island for total fish biomass, but for only 2 of 13 trophic components: generalist large predators and large planktivores. Fishing‐induced changes in biomass of these components had no effect on live hard coral (HC) cover. In contrast, HC cover affected biomass of 11 of 13 trophic components significantly. Positive associations with HC cover were detected for total fish biomass, generalist large predators, piscivores, obligate coral feeders, large planktivores, and small planktivores. Negative associations with HC cover were detected for large benthic foragers, detritivores, excavators, scrapers, and sand feeders. These associations of fish biomass to HC cover were most clear when environmental disturbances (e.g., coral bleaching, typhoons) reduced HC cover, often quickly (1–2 yr), and when HC recovered, often slowly (5–10 yr). As HC cover changed, the biomass of 11 trophic components of the fish assemblage changed. Benthic and fish assemblages were distinct at all sites from the outset, remaining so for 31 yr, despite differences in fishing pressure and disturbance history. HC cover alone explained ~30% of the variability in reef fish trophic structure, whereas fishing alone explained 24%. Furthermore, HC cover affected more trophic groups more strongly than fishing. Management of coral reefs must include measures to maintain coral reef habitats, not just measures to reduce fishing by NTMRs.

Coral reefs are periodically impacted by disturbance events that reduce live coral cover and habitat complexity, with concomitant effects on fish assemblage structure. While the density of some fish species may increase following coral loss, most species decline. Determining which species are ‘winners’ and ‘losers’ following disturbances is fundamental to inform projections of future reef community structure, biodiversity, and productivity. Here, we analyse a long-term (2006–2018), spatially extensive (≈ 700 km) ‘natural experiment’ in which the responses of 11 wrasse taxa to acute disturbance events and no-take marine reserve (NTMR) protection were quantified on fringing coral reefs in the Palm (18°34′ S, 146°29′ E), Whitsunday (20°08′ S, 148°56′ E), and Keppel Island (23°10′ S, 150°57′ E) groups, Great Barrier Reef, Australia. The responses of wrasse densities to benthic habitat change were taxa specific and temporally consistent. Disturbance-mediated reductions in live hard coral cover and/or habitat complexity resulted in density declines for Hemigymnus melapterus, Hemigymnus fasciatus, Cheilinus fasciatus, Labroides spp., Oxycheilinus digramma, and Thalassoma spp. Conversely, Halichoeres spp. densities correlated positively with increased relative cover of sand and rubble, while Stethojulis spp., Anampses spp., Epibulus insidiator, and Bodianus spp. displayed variable responses to habitat changes. No wrasses exhibited an NTMR effect and predator density, irrespective of NTMR status, only influenced five taxa across all island groups. The lack of NTMR effects and variable top-down predator effects suggest that taxa-specific benthic habitat associations were the predominant drivers of wrasse densities on inshore GBR reefs.

Marine protected areas are increasingly being implemented to attain a variety of conservation and fisheries management objectives. Although rarely considered, protection of targeted species within these areas may also conserve behaviours (e.g. boldness) that are often the first removed by human exploitation. Here we examine fish behaviour in fished, no-take, and no-entry management zones for a highly targeted reef fish species (coral trout; Plectropomus leopardus) on coral reefs in two regions of the Great Barrier Reef Marine Park, Australia. Using three behavioural metrics (flight-initiation distance, pre-flight behaviour, and escape trajectories), we demonstrate how protected areas, particularly no-entry zones, can effectively conserve naive or bold behavioural traits in fish populations. Flight-initiation distance was consistently highest in fished zones, but the effects of protection afforded by no-take and no-entry zones varied by study region. Flight-initiation distance was consistently higher for fish above the minimum legal retention size limit, except in no-entry zones of the southern region. This indicates that no-entry zones may be maintaining near-natural, pre-exploitation behaviour, which could have considerable implications for the genetic and social structures of a highly valuable commercial species. Conservation and fisheries management would therefore benefit from an increased understanding of how fish behaviour can influence population structures, and how these populations may be influenced by fishing and other human interactions.

Cross-shelf differences in coral reef benthic and fish assemblages are common, yet it is unknown whether these assemblages respond uniformly to environmental disturbances or whether local conditions result in differential responses of assemblages at different shelf positions. Here, we compare changes in the taxonomic and functional composition, and associated traits, of herbivorous reef fish assemblages across a continental shelf, five years before and six months after two severe cyclones and a thermal bleaching event that resulted in substantial and widespread loss of live hard coral cover. Each shelf position maintained a distinct taxonomic assemblage of fishes after disturbances, but the assemblages shared fewer species among shelf positions. There was a substantial loss of species richness following disturbances within each shelf position. Total biomass of the herbivorous fish assemblage increased after disturbances on mid- and outer-shelf reefs, but not on inner-shelf reefs. Using trait-based analyses, we found there was a loss of trait richness at each shelf position, but trait specialisation and originality increased on inner-shelf reefs. This study highlights the pervasiveness of extreme environmental disturbances on ecological assemblages. Whilst distinct cross-shelf assemblages can remain following environmental disturbances, assemblages have reduced richness and are potentially more vulnerable to chronic localised stresses.

Developing networks of no-take marine reserves is often hindered by uncertainty in the extent to which local marine populations are connected to one another through larval dispersal and recruitment (connectivity). While patterns of connectivity can be predicted by larval dispersal models and validated by empirical methods, biogeographic approaches have rarely been used to investigate connectivity at spatial scales relevant to reserve networks (10's–100's of km). Here, species assemblage patterns in coral reef fish were used together with an individual-based model of dispersal of reef fish larvae to infer patterns of connectivity in a ∼300 km wide region in the Philippines that included the Bohol Sea and adjacent bodies of water. A dominant current flows through the study region, which may facilitate connectivity among >100 no-take reserves. Connectivity was first investigated by analysing data on the presence/absence of 216 species of reef fish and habitat variables across 61 sites. Hierarchical clustering of sites reflecting species assemblage patterns distinguished a major group of sites in the Bohol Sea (Bray–Curtis similarity >70%) from sites situated in adjacent bodies of water (bays, channels between islands and a local sea). The grouping of sites could be partly explained by a combination of degree of embayment, % cover of sand and % cover of rubble (Spearman rank correlation, ρw = 0.42). The individual-based model simulated dispersal of reef fish larvae monthly for three consecutive years in the region. The results of simulations, using a range of pelagic larval durations (15–45 days), were consistent with the species assemblage patterns. Sites in the model that showed strongest potential connectivity corresponded to the majority of sites that comprised the Bohol Sea group suggested by hierarchical clustering. Most sites in the model that exhibited weak connectivity were groups of sites which had fish assemblages that were least similar to those in the Bohol Sea group. Concurrent findings from the two approaches suggest a strong influence of local oceanography and geography on broad spatial patterns of connectivity. The predictions can be used as an initial basis to organise existing reserves to form ecologically meaningful networks. This study showed that species assemblage patterns could be a viable supplementary indicator of connectivity if used together with predictions from a larval dispersal model and if the potential effect of habitat on the structuring of species assemblages is taken into consideration.

Parks and protected areas have been instrumental in reducing anthropogenic sources of damage in terrestrial and aquatic environments. Pathogen invasion often succeeds physical wounding and injury, yet links between the reduction of damage and the moderation of disease have not been assessed. Here, we examine the utility of no-take marine reserves as tools for mitigating diseases that affect reef-building corals. We found that sites located within reserves had fourfold reductions in coral disease prevalence compared to non-reserve sites (80 466 corals surveyed). Of 31 explanatory variables assessed, coral damage and the abundance of derelict fishing line best explained differences in disease assemblages between reserves and non-reserves. Unexpectedly, we recorded significantly higher levels of disease, coral damage, and derelict fishing line in non-reserves with fishing gear restrictions than in those without gear restrictions. Fishers targeting stocks perceived to be less depleted, coupled with enhanced site access from immediately adjacent boat moorings, may explain these unexpected patterns. Significant correlations between the distance from mooring sites and prevalence values for a ciliate disease known to infest wounded tissue (r = −0.65), coral damage (r = −0.64), and the abundance of derelict fishing line (r = −0.85) corroborate this interpretation. This is the first study to link disease with recreational use intensity in a park, emphasizing the need to evaluate the placement of closures and their direct relationship to ecosystem health. Since corals are modular, ecological processes that govern reproductive and competitive fitness are frequently related to colony surface area therefore, even low levels of cumulative tissue loss from progressing diseases pose significant threats to reef coral persistence. Disease mitigation through reductions in physical injury in areas where human activities are concentrated is another mechanism by which protected areas may improve ecosystem resilience in a changing climate.

It has become almost paradigmatic in the coral reef literature that fishing-induced reductions of parrotfish abundance cause benthic phase shifts from coral to macroalgal dominance. This study examined the alternatives of top-down control of the benthos by parrotfish density and bottom-up control of parrotfish density by the benthos at four Philippine islands in a long-term (7.5–30 years) “natural experiment”. No-take marine reserves (NTMRs) demonstrated that fishing reduced parrotfish density significantly at two islands (Sumilon, Mantigue), but not significantly at two other islands (Apo, Selinog). There was no evidence that cover of hard coral decreased, nor macroalgal cover increased, in fished areas relative to NTMRs, no evidence that parrotfish density affected hard coral cover significantly, and thus no evidence of top-down, fishing-induced benthic phase shifts at all four islands. There was, however, compelling evidence that benthos (cover of dead substrata and hard coral) exerted strong bottom-up control on parrotfish density. This bottom-up control was demonstrated most clearly by major environmental disturbances (e.g. typhoons, coral bleaching) that changed benthic habitat and, subsequently, parrotfish density. As hard coral cover declined (and cover of dead substratum increased), parrotfish density increased and vice versa. This response occurred in both major parrotfish feeding guilds (scrapers and excavators). This long-term study on heavily fished coral reefs suggests that the benthos drives the parrotfish, not the other way around. The paradigm of fishing-induced benthic phase shifts may not apply to all coral reefs at all times. Multiple drivers of benthic change on coral reefs should always be considered.

Peaks in the reproduction of coral reef fish in equatorial regions are hypothesised to usually coincide with periods of the year when winds are weaker, presumably to minimise larval transport and maximise recruitment. The annual patterns of spawning of four species of reef fish in the central Philippines (9.201355°N, 123.327421°E) were investigated over 11–22 months. On an annual basis, the study area experiences two windy monsoon seasons and two monsoon transition periods when winds are weaker. Protracted breeding seasons were evident, but the timing of inferred spawning peaks varied among species. Spawning peaks of Pterocaesio pisang (Caesionidae) coincided with the first monsoon transition period of the year (April–June) and the north-east monsoon (November–March). Caesio caerulaurea (Caesionidae) showed a spawning peak during the south-west monsoon (July–September) extending to the following monsoon transition period (October). In Naso minor (Acanthuridae), an annual pattern was difficult to discern due to insufficient data, but there was some suggestion of higher spawning activity during the north-east monsoon. Spawning in Pomacentrus moluccensis (Pomacentridae) was inferred to occur year-round except during the north-east monsoon. These results suggest that conditions favourable to the survival of pelagic larvae are not restricted to monsoon transition periods. Alternatively, the results indicate direct or indirect effects of temperature, rainfall, wind or wave action on the reproduction of adults. Variable annual patterns of reproduction in reef fish pose a further challenge to fisheries management interventions in the region. This variability is possibly being influenced in complex ways by environmental factors that change with the monsoons.

Recent research has demonstrated that, despite a pelagic larval stage, many coral reef fishes disperse over relatively small distances, leading to well-connected populations on scales of 0–30 km. Although variation in key biological characteristics has been explored on the scale of 100–1000 s of km, it has rarely been explored at the scale relevant to actual larval dispersal and population connectivity on ecological timescales. In this study, we surveyed the habitat and collected specimens (n = 447) of juvenile butterflyfish, Chaetodon vagabundus, at nine sites along an 80-km stretch of coastline in the central Philippines to identify variation in key life history parameters at a spatial scale relevant to population connectivity. Mean pelagic larval duration (PLD) was 24.03 d (SE = 0.16 d), and settlement size was estimated to be 20.54 mm total length (TL; SE = 0.61 mm). Both traits were spatially consistent, although this PLD is considerably shorter than that reported elsewhere. In contrast, post-settlement daily growth rates, calculated from otolith increment widths from 1 to 50 d post-settlement, varied strongly across the study region. Elevated growth rates were associated with rocky habitats that this species is known to recruit to, but were strongly negatively correlated with macroalgal cover and exhibited negative density dependence with conspecific juveniles. Larger animals had lower early (first 50 d post-settlement) growth rates than smaller animals, even after accounting for seasonal variation in growth rates. Both VBGF and Gompertz models provided good fits to post-settlement size-at-age data (n = 447 fish), but the VBGF’s estimate of asymptotic length (L ∞ = 168 mm) was more consistent with field observations of maximum fish length. Our findings indicate that larval characteristics are consistent at the spatial scale at which populations are likely well connected, but that site-level biological differences develop post-settlement, most likely as a result of key differences in quality of recruitment habitat.

No-take marine reserves (NTMRs) are advocated as tools to enhance or maintain density and assemblage structure of coral reef fishes. These reef fish population and assemblage attributes may be affected by both NTMR protection and benthic habitat change. Before-after-control-impact-pair (BACIP) sampling designs and long-term (8-30 yr) monitoring at 4 Philippine NTMRs were used to examine the relative effects of NTMR protection and benthic habitat change on densities and assemblage structures of fishery-targeted (Lethrinidae and Lutjanidae) and non-targeted (Pomacentridae) reef fishes. Targeted fish density increased significantly in NTMRs relative to fished control sites at all reserves over time. Non-targeted fish density and hard coral cover displayed a variety of patterns of change over time (unrelated to NTMR protection), but closely mirrored each other. Targeted fish were considered potential predators of non-targeted fish. Availability of potential prey for predators had a larger influence than the effect of potential predators on prey, with both processes much weaker than effects of habitat change. Multivariate analyses of long-term temporal data indicated that 65.8% of the variance in assemblage structure of non-targeted pomacentrids was explained by benthic habitat variables (structural complexity, cover of dead substrate) whereas NTMR protection alone explained only 9.7%. In contrast, 36.2% of assemblage structure of targeted lethrinids/lutjanids was explained by duration of NTMR protection (42.2% excluding effects of typhoons at one reserve), with habitat variables alone explaining 24.7%. These results help clarify the relative effects of NTMR protection, benthic habitat change, and potential trophic interactions on reef fishes targeted and non-targeted by fishing.

Reef fish populations can be affected by both fishing and changes in benthic habitat. Yet, partitioning these effects is often difficult, usually requiring an appropriate sampling design and long-term monitoring. Here we quantify, over a 30-yr period, the effects of benthic habitat change and no-take marine reserve (NTMR) protection on the density and species richness of a lightly harvested benthic-feeding reef fish family, the Mullidae (goatfish), at four Philippine islands. Boosted regression trees demonstrated that goatfish density and species richness had strong negative associations with hard coral cover and strong positive associations with cover of dead substratum. No-take marine reserve protection had no effect on the density or species richness of goatfish over 19 and 30 yr at Sumilon and Apo islands, respectively. However, environmental disturbances (e.g., typhoons, coral bleaching) that reduced hard coral cover subsequently led to increases in goatfish numbers for periods ranging from 2 to 8 yr. After initial increases due to benthic disturbance, goatfish populations decreased during coral recovery, occurring on timescales of 10–20 yr. This long-term, “natural experiment” demonstrated that changes to benthic habitat (bottom-up control) had a far greater effect on Philippine goatfish populations than protection from fishing (a top-down effect) in NTMRs. Given the strong positive response of goatfish populations to loss of live hard coral cover, this group of fishes may be a valuable indicator species for habitat degradation on coral reefs.

Saura () claims that studies using the Probability of Connectivity metric (PC) had already demonstrated the importance of including node self-connections in network metrics. As originally defined and used, PC cannot test the importance of self-connections. However, with key terms redefined, PC could be a useful tool in future work.

Fishing is altering aquatic ecosystems through changes in the abundance, species composition and behavior of target species. Changes in fish behavior have received relatively little attention, despite significant evidence of behavioral change driven by human impacts mediating function and processes in terrestrial ecosystems, and emerging evidence that the same is true in marine systems even within marine reserves. Here, we measured the wariness of two families of coral reef fishes in both fished areas and marine reserves embedded within a fished seascape along an exploitation gradient ranging from wilderness sites (Chagos) to heavily fished areas (the Philippines). We used linear mixed effect models to identify relationships between fish flight initiation distance (FID) and fishing pressure, fish size, habitat complexity and life-history stage. Critically, fish FID increased with fishing pressure both in fished areas and inside marine reserves. These results imply that as fishing pressure increases in adjacent areas, progressively greater fish wariness may reduce the magnitude of some ecosystem functions within small marine reserves.

The effects of no-take marine reserve (NTMR) protection and changes in benthic habitat on fusiliers (family Caesionidae) were investigated at four small Philippine offshore islands on time scales of 10–31 years. Fusiliers are highly mobile, schooling, medium-sized planktivorous fish that generally feed “off-reef.” For these reasons, and given the small size of the NTMRs (3.6–37.5 ha) in this study, it was predicted that fusilier density would be unlikely to show clear effects of NTMR protection, or to respond to changes in benthic habitat. In contrast to predictions, clear NTMR effects were observed on fusilier density at three of the four NTMRs, with durations of protection from 14 to 31 years. Furthermore, the study provided strong evidence that benthic variables, specifically cover of live hard coral and dead substratum, affect the density of fusiliers. This effect of benthic habitat on density was highlighted by several major environmental disturbances that caused shifts in the benthic habitat from live hard coral to dead substratum. For two of the three most abundant species of fusiliers individually, and for all three of them combined (Pterocaesio pisang + Caesio caerulaurea + Pterocaesio digramma/tessellata), as live hard coral cover decreased, fish density decreased. It is hypothesized that these “off-reef” daytime feeders may have such a strong association with live hard coral cover because they use this habitat as nocturnal sleeping sites. Multivariate analyses indicated that, across all sites and times sampled, cover of live hard coral and dead substratum accounted for 38% of the variation in fish assemblage structure. These results are important as there are very few reports in the published literature of strong effects of NTMR protection or changes in benthic habitat on the density and assemblage structure of fusiliers.

Network analysis is gaining increasing importance in conservation planning. However, which network metrics are the best predictors of metapopulation persistence is still unresolved. Here, we identify a critical limitation of graph theory-derived network metrics that have been proposed for this purpose: their omission of node self-connections. We resolve this by presenting modifications of existing network metrics, and developing entirely new metrics, that account for node self-connections. Then, we illustrate the performance of these new and modified metrics with an age-structured metapopulation model for a real-world marine reserve network case study, and we evaluate the robustness of our findings by systematically varying particular features of that network. Our new and modified metrics predict metapopulation persistence much better than existing metrics do, even when self-connections are weak. Existing metrics become good predictors of persistence only when self-connections are entirely absent, an unrealistic scenario in the overwhelming majority of metapopulation applications. Our study provides a set of novel tools that can substantially enhance the extent to which network metrics can be employed to understand, and manage for, metapopulation persistence.

No-take marine protected areas (MPAs) are an important tool for conserving marine biodiversity and managing fisheries. However, with increasing environmental change driven by local and global stressors, it is critical to understand whether MPAs can continue to provide social, economic and conservation benefits in the long-term. Here, we compare coral reef benthic and fish assemblages across 17 paired MPA-fished control sites on three heavily populated, high elevation “mainland” islands, and four lowly populated, low elevation “offshore” islands that differed in their exposure to recent typhoons. Despite lower cover of macroalgae in MPAs compared to fished areas, especially on mainland islands, there were no consistent differences in benthic assemblages or total hard coral cover between paired MPA and fished reefs. Typhoons had severe negative effects on live hard coral cover, regardless of island type or MPA protection, and typhoon impacted reefs supported different fish assemblages and lower total biomass of fish, compared to non-impacted reefs. Although fish assemblage structure and total biomass differed between mainland and offshore islands, MPAs consistently supported a higher total biomass of fish than fished areas, with the magnitude of the MPA effect lower on typhoon impacted reefs. Our findings suggest that despite inherent differences in environmental conditions between mainland and offshore island coral reefs, MPAs can provide benefits to fish biomass, even when reefs are affected by typhoons. The development of management strategies that incorporate sound coastal land-use practices, while positioning MPAs in areas less prone to typhoon impact, will provide MPAs the best chance of success if climatic extremes increase.

No-take marine reserves (NTMRs) are promoted extensively as conservation and fisheries management tools in response to marine ecosystem degradation and fisheries decline, but their use remains controversial. Numerous studies indicate that NTMRs result in higher abundances of fishery-targeted marine species, but few studies utilised robust sampling designs. Comparisons of NTMRs and fished sites must account for potential confounding of habitat type and quality in heterogeneous marine environments. In a review of 164 NTMR studies, many studies failed to adequately account for habitat effects, with no apparent improvement in the literature through time (1983–2013). Five methods employed to partition reserve and habitat effects were used in conjunction with three basic sampling designs: single-point-in-time comparisons, temporal monitoring, and before-after-control-impact (BACI) studies. Researchers evaluating NTMRs: a) ignored habitat or described sites as broadly similar (28.7%); b) constrained sampling to similar habitats (43.9%); c) explicitly tested for habitat differences among sites (12.8%); d) used statistical methods to partition habitat and reserve effects (26.2%); and e) examined changes in habitat caused by reserve protection (17.1%). Over half of the studies (54.3%) made no statistical attempt to account for habitat effects. Robust studies, utilising methods (c-e) within BACI designs, are needed to accurately differentiate NTMR from habitat effects and permit managers to more accurately assess the benefits of NTMRs.

Coral reef fishes differ in their intrinsic vulnerability to fishing and rates of population recovery after cessation of fishing. We reviewed life history-based predictions about the vulnerability of different groups of coral reef fish and examined the empirical evidence for different rates of population recovery inside no-take marine reserves to (1) determine if the empirical data agree with predictions about vulnerability and (2) show plausible scenarios of recovery within fully protected reserves and periodically-harvested fishery closures. In general, larger-bodied carnivorous reef fishes are predicted to be more vulnerable to fishing while smaller-bodied species lower in the food web (e.g., some herbivores) are predicted to be less vulnerable. However, this prediction does not always hold true because of the considerable diversity of life history strategies in reef fishes. Long-term trends in reef fish population recovery inside no-take reserves are consistent with broad predictions about vulnerability, suggesting that moderately to highly vulnerable species will require a significantly longer time (decades) to attain local carrying capacity than less vulnerable species. We recommend: (1) expanding age-based demographic studies of economically and ecologically important reef fishes to improve estimates of vulnerability; (2) long term (20–40 years), if not permanent, protection of no-take reserves to allow full population recovery and maximum biomass export; (3) strict compliance to no-take reserves to avoid considerable delays in recovery; (4) carefully controlling the timing and intensity of harvesting periodic closures to ensure long-term fishery benefits; (5) the use of periodically-harvested closures together with, rather than instead of, permanent no-take reserves.

A scarcity of life-history data currently exists for many exploited coral reef fishes, hindering our ability to interpret fishery dynamics and develop sound conservation policies. In particular, parrotfishes (Family Labridae) represent a ubiquitous and ecologically important group that is increasingly prevalent in commercial and artisanal fisheries worldwide. We used both fishery-dependent and fishery-independent data to examine the effect of life histories on vulnerability to overexploitation in parrotfishes. Vulnerability for each species was derived from independent measures associated with both temporal (20-year catch records) and spatial datasets. Most life-history traits examined were significant predictors of vulnerability across species, but their relative utility differed considerably. Length-based traits (e.g., lengths at maturity and sex change, maximum length) were generally superior to age-based traits (e.g., life span), but one age-based trait, age at female maturation, was the best predictor. The results suggest that easily derived metrics such as maximum length can be effective measures of sensitivity to exploitation when applied to phylogenetically related multispecies assemblages, but more holistic and comprehensive age-based demographic data should be sought, especially in data-deficient and heavily impacted regions. Given the increasing prevalence of parrotfishes in the global coral reef harvest, species-specific responses demonstrate the capacity for heavy fishing pressure to alter parrotfish assemblages considerably.

Batch fecundity of female Plectropomus leopardus, a coral reef fish targeted by commercial and recreational fishing, was compared between reefs open to fishing and reefs within no-take marine reserves within three regions of the Great Barrier Reef (GBR), Australia. Length, weight, and age had positive effects on batch fecundity of spawners from northern and central reefs but negligible effects on spawners from southern reefs. Females were least fecund for a given length, weight, and age in the southern GBR. Batch fecundity of a 500-mm fork length female was 430 % greater on central reefs and 207 % greater on northern reefs than on southern reefs. The effects of length and age on batch fecundity did not differ significantly between reserve and fished reefs in any region, but weight-specific fecundity was 100 % greater for large 2.0 kg females on reserve reefs compared with fished reefs in the central GBR. We hypothesize that regional variation in batch fecundity is likely driven by water temperature and prey availability. Significant regional variation in batch fecundity highlights the need for understanding spatial variation in reproductive output where single conservation or fishery management strategies cover large, potentially diverse, spatial scales.

The effects of size and age on reproductive dynamics of common coral trout Plectropomus leopardus populations were compared between coral reefs open or closed (no-take marine reserves) to fishing and among four geographic regions of the Great Barrier Reef (GBR), Australia. The specific reproductive metrics investigated were the sex ratio, the proportion of vitellogenic females and the spawning fraction of local populations. Sex ratios became increasingly male biased with length and age, as expected for a protogyne, but were more male biased in southern regions of the GBR (Mackay and Storm Cay) than in northern regions (Lizard Island and Townsville) across all lengths and ages. The proportion of vitellogenic females also increased with length and age. Female P. leopardus were capable of daily spawning during the spawning season, but on average spawned every 4·3 days. Mature females spawned most frequently on Townsville reserve reefs (every 2·3 days) and Lizard Island fished reefs (every 3·2 days). Females on Mackay reefs open to fishing showed no evidence of spawning over 4 years of sampling, while females on reserve reefs spawned only once every 2–3 months. No effect of length on spawning frequency was detected. Spawning frequency increased with age on Lizard Island fished reefs, declined with age on Storm Cay fished reefs, and declined with age on reserve reefs in all regions. It is hypothesized that the variation in P. leopardus sex ratios and spawning frequency among GBR regions is primarily driven by water temperature, while no-take management zones influence spawning frequency depending on the region in which the reserve is located. Male bias and lack of spawning activity on southern GBR, where densities of adult P. leopardus are highest, suggest that recruits may be supplied from central or northern GBR. Significant regional variation in reproductive traits suggests that a regional approach to management of P. leopardus is appropriate and highlights the need for considering spatial variation in reproduction where reserves are used as fishery or conservation management tools.

Severe climatic disturbance events often have major impacts on coral reef communities, generating cycles of decline and recovery, and in some extreme cases, community-level phase shifts from coral- to algal-dominated states. Benthic habitat changes directly affect reef fish communities, with low coral cover usually associated with low fish diversity and abundance. No-take marine reserves (NTRs) are widely advocated for conserving biodiversity and enhancing the sustainability of exploited fish populations. Numerous studies have documented positive ecological and socio-economic benefits of NTRs; however, the ability of NTRs to ameliorate the effects of acute disturbances on coral reefs has seldom been investigated. Here, we test these factors by tracking the dynamics of benthic and fish communities, including the important fishery species, coral trout (Plectropomus spp.), over 8 years in both NTRs and fished areas in the Keppel Island group, Great Barrier Reef, Australia. Two major disturbances impacted the reefs during the monitoring period, a coral bleaching event in 2006 and a freshwater flood plume in 2011. Both disturbances generated significant declines in coral cover and habitat complexity, with subsequent declines in fish abundance and diversity, and pronounced shifts in fish assemblage structure. Coral trout density also declined in response to the loss of live coral, however, the approximately 2:1 density ratio between NTRs and fished zones was maintained over time. The only post-disturbance refuges for coral trout spawning stocks were within the NTRs that escaped the worst effects of the disturbances. Although NTRs had little discernible effect on the temporal dynamics of benthic or fish communities, it was evident that the post-disturbance refuges for coral trout spawning stocks within some NTRs may be critically important to regional-scale population persistence and recovery.

No-take marine reserves are increasingly popular tools for conservation and fisheries management. While much attention has been paid to evaluating the effects of design aspects (size, location, etc.) in achieving reserve objectives, less emphasis has been placed on the role of stakeholder compliance. Therefore, the first aim of this study was to evaluate the state of compliance literature and examine the methods used to measure compliance in reserves. The state of compliance literature is limited, although publications with compliance information have increased sixfold in the last decade. However, most studies containing compliance information (63%) fail to provide quantitative estimates. Furthermore, most (95%) quantitative estimates of compliance were reported using a single method, which is problematic because each method has biases and limited applicability. Methods used to indicate compliance include (i) direct observation; (ii) indirect observation; (iii) law enforcement records; (iv) direct questioning; (v) expert opinion; and (vi) modelling. Our second aim was to empirically demonstrate the critical role of compliance in reserve outcomes by comparing a mixed-effects model on compliance data synthesized from 63 marine reserves to that of a null model. The model of best fit demonstrated a negative relationship between non-compliance and target species biomass response ratios. Thus, without incorporating any aspects of reserve design, compliance data predicted reserve response ratios of fish biomass. Accordingly, researchers should explore ways to better understand and measure non-compliance. Therefore, future research should triangulate multiple sources of quantitative compliance data collected using standardized techniques and conduct baseline surveys before reserve implementation.

No-take marine reserves (NTMRs) are being implemented for various conservation and fishery management objectives. Well-designed ecological monitoring programs should accompany the implementation of NTMRs to assess their performance against stated objectives. However, monitoring programs often have limited funding and limited access to experienced (“expert”) underwater visual census (UVC) observers. Consequently, use of non-expert, volunteer observers to collect marine ecological data has increased. The need to assess the quality and utility of non-expert data has been acknowledged. Few studies have directly compared expert and non-expert assessments, and these are generally one-point-in-time comparisons. Here we assess the magnitude of NTMR:Non-reserve density ratios for target and non-target reef fish collected in five separate years over a decade (2000–2009) by expert and non-expert observers in the Palm Islands, Great Barrier Reef, Australia. Despite variations in methods and resultant differences in a...

Summary In many tropical nations, fisheries management requires a community-based approach because small customary marine tenure areas define the spatial scale of management [1]. However, the fate of larvae originating from a community's tenure is unknown, and thus the degree to which a community can expect their management actions to replenish the fisheries within their tenure is unclear [2, 3]. Furthermore, whether and how much larval dispersal links tenure areas can provide a strong basis for cooperative management [4, 5]. Using genetic parentage analysis, we measured larval dispersal from a single, managed spawning aggregation of squaretail coral grouper ( Plectropomus areolatus ) and determined its contribution to fisheries replenishment within five community tenure areas up to 33 km from the aggregation at Manus Island, Papua New Guinea. Within the community tenure area containing the aggregation, 17%–25% of juveniles were produced by the aggregation. In four adjacent tenure areas, 6%–17% of juveniles were from the aggregation. Larval dispersal kernels predict that 50% of larvae settled within 14 km of the aggregation. These results strongly suggest that both local and cooperative management actions can provide fisheries benefits to communities over small spatial scales.

Environmental disturbances to benthic habitat on coral reefs can affect fish assemblages, with dietary specialists like corallivorous Chaetodon butterflyfishes particularly sensitive to declines in hard coral cover. However, declines in density of corallivorous Chaetodon due to declines in hard coral cover are usually documented for individual environmental disturbances, often with limited quantification of post-disturbance recovery. Here, we documented effects of hard coral loss and recovery on the Chaetodon assemblage for 31 years at four sites in the Philippines. In this long-term “natural experiment”, we documented five environmental disturbance events (two typhoons, two mass coral bleaching events, and one period of destructive fishing) that reduced live branching hard coral cover on average by 61% and density of corallivorous butterflyfish by 47%, with an average duration of decline of 2 years. On average, these disturbance events resulted in an 8% annual decrease in absolute coral cover. We also monitored five periods of hard coral and butterflyfish recovery, with an average 202% increase in branching hard coral cover over 11 years, and a 196% increase in density of corallivorous butterflyfish over 12 years. On average, these recovery periods had a 2.4% annual rate of increase in absolute coral cover. The density of butterflyfish was not significantly affected by marine reserve protection, and thus, changes in butterflyfish density were most likely driven by change in benthic habitat. Assemblage structure of Chaetodon at each site was distinct and remained remarkably consistent for 31 years, despite substantial declines and recovery of coral cover. The difference in the rates of decline and recovery of butterflyfish raises concerns for the persistence of this iconic taxon in the face of increasing frequency and intensity of environmental disturbances to coral reefs.

No-take marine reserves (NTMRs) are increasingly implemented for fisheries management and biodiversity conservation. Yet, assessing NTMR effectiveness depends on partitioning the effects of NTMR protection and benthic habitat on protected species. Such partitioning is often difficult, since most studies lack well-designed sampling programs (i.e. Before-After-Control-Impact-Pair designs) spanning long-term time scales. Spanning 31 years, this study quantifies the effects of NTMR protection and changes to benthic habitat on the density of tropical wrasses (F. Labridae) at Sumilon and Apo Islands, Philippines. Five species of wrasse were studied: two species of large-bodied (40–50 cm TL) Hemigymnus that were vulnerable to fishing, and three species of small-bodied (10–25 cm TL) Thalassoma and Cirrhilabrus that were not targeted by fishing. NTMR protection had no measurable effect on wrasse density, irrespective of species or body size, over 20 (Sumilon) and 31 (Apo) years of protection. However, the density of wrasses was often affected strongly by benthic cover. Hemigymnus spp. had a positive association with hard coral cover, while Thalassoma spp. and Cirrhilabrus spp. had strong positive associations with cover of rubble and dead substratum. These associations were most apparent after environmental disturbances (typhoons, coral bleaching, crown of thorns starfish (COTS) outbreaks, use of explosives and drive nets) reduced live hard coral cover and increased cover of rubble, dead substratum and sand. Disturbances that reduced hard coral cover often reduced the density of Hemigymnus spp. and increased the density of Thalassoma spp. and Cirrhilabrus spp. rapidly (1–2 years). As hard coral recovered, density of Hemigymnus spp. often increased while density of Thalassoma spp. and Cirrhilabrus spp. often decreased, often on scales of 5–10 years. This study demonstrates that wrasse population density was influenced more by changes to benthic cover than by protection from fishing.

Catch levels and fishing practices for the traditional subsistence reef fishery in Torres Strait, Australia, have likely changed since the 1980s. Islanders now have greater access to motorised boats and modern fishing gears. This allows them to travel further, access more fishing grounds and improve catch rates. The aim of this study was to quantify changes in the fishery over a period of 15 years (1991/1992-2005/2006). Catch information collected in 2005/2006 allowed a comparison of subsistence fish catch and yields with estimates of these variables made from data collected in the 1990s. In 2005/2006, mean annual subsistence catch from Darnley, Yorke and Murray Islands were 71 mt (SE = 21), 55 mt (SE = 18) and 43 mt (SE = 15), respectively. This represents annual reef fish yields of 1.97, 2.96 and 3.49 mt km⁻² y⁻¹, respectively, or per capita yields of 248, 206 and 92 kg person⁻¹ y⁻¹, respectively. These levels of subsistence catch were up to 6 times higher than those estimated from data collected at the same islands in 1991/1992 and 1995/1996. Estimated yields were comparable with those considered sustainable for other reef fisheries in the Pacific region. In contrast to other studied subsistence fisheries, higher levels of modernisation of fishing activities corresponded to higher fish yields. These increases are likely a consequence of the shift in the nature of the traditional subsistence activities to include the relatively recent practice of sending fish from the islands to family members in other locations. If catch levels continue to increase in the future, it will be important to estimate more reliably sustainable yields for the fishery, which would allow more informed management decisions.

There is a paucity of information on subsistence reef fisheries of indigenous communities in Torres Strait, Australia, and its role within their hybrid economy. Bus route surveys and semi-structured interviews were conducted in 2005 and 2006 on three islands in Torres Strait to understand whether subsistence fishing remains important for the livelihoods of Torres Strait communities and whether patterns of fishing effort are driven by changes in their socio-economic structure. Strong interactions among private (commercial fishing and other wage-employment), public (social security payments from the State) and subsistence sectors were observed. When social security payments were spent, Islanders were more reliant on subsistence fishing. Also, higher levels of involvement in the private sector corresponded with a shift from shore to boat-based subsistence activities. Socio-economic factors, such as involvement in commercial fishing and social security payments, were identified as the main driving factors of subsistence fishing activities. Findings of the present study stress the importance of considering socio-economic factors explicitly in future fisheries assessments and management decisions concerning the sustainability of resources in Torres Strait.

[Extract] To the Editor: Establishing Marine Protected Areas (MPAs), often including zones that are closed to fishing, is an effective approach to maintaining biodiversity and rebuilding ecosystem function (e.g. McCook et al. 2010). However, MPAs are frequently opposed by fishers and by some fisheries managers, because of the potential for displacing fishing activity and reducing catches (Caveen et al. 2015). How much catch is lost due to spatial closures in both the short and long term is a critical question, even where the objective of establishing MPAs is to conserve biodiversity rather than to regulate fisheries.

Marine reserves, areas closed to all forms of fishing, continue to be advocated and implemented to supplement fisheries and conserve populations [ [1], [2], [3] and [4]]. However, although the reproductive potential of important fishery species can dramatically increase inside reserves [ [5], [6], [7] and [8]], the extent to which larval offspring are exported and the relative contribution of reserves to recruitment in fished and protected populations are unknown [ [4], [9], [10] and [11]]. Using genetic parentage analyses, we resolve patterns of larval dispersal for two species of exploited coral reef fish within a network of marine reserves on the Great Barrier Reef. In a 1,000 km2 study area, populations resident in three reserves exported 83% (coral trout, Plectropomus maculatus) and 55% (stripey snapper, Lutjanus carponotatus) of assigned offspring to fished reefs, with the remainder having recruited to natal reserves or other reserves in the region. We estimate that reserves, which account for just 28% of the local reef area, produced approximately half of all juvenile recruitment to both reserve and fished reefs within 30 km. Our results provide compelling evidence that adequately protected reserve networks can make a significant contribution to the replenishment of populations on both reserve and fished reefs at a scale that benefits local stakeholders.