SignificanceMarine reserves that prohibit fishing are a critical tool for sustaining coral reef ecosystems, yet it remains unclear how human impacts in surrounding areas affect the capacity of marine reserves to deliver key conservation benefits. Our global study found that only marine reserves in areas of low human impact consistently sustained top predators. Fish biomass inside marine reserves declined along a gradient of human impacts in surrounding areas; however, reserves located where human impacts are moderate had the greatest difference in fish biomass compared with openly fished areas. Reserves in low human-impact areas are required for sustaining ecological functions like high-order predation, but reserves in high-impact areas can provide substantial conservation gains in fish biomass.

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Ecological habitats with greater structural complexity contain more species due to increased niche diversity. This is especially apparent on coral reefs where individual coral colonies aggregate to give a reef its morphology, species zonation, and three dimensionality. Structural complexity is classically measured with a reef rugosity index, which is the ratio of a straight line transect to the distance a flexible chain of equal length travels when draped over the reef substrate; yet, other techniques from visual categories to remote sensing have been used to characterize structural complexity at scales from microhabitats to reefscapes. Reef-scale methods either lack quantitative precision or are too time consuming to be routinely practical, while remotely sensed indices are mismatched to the finer scale morphology of coral colonies and reef habitats. In this communication a new digital technique, Digital Reef Rugosity (DRR) is described which utilizes a self-contained water level gauge enabling a diver to quickly and accurately characterize rugosity with non-invasive millimeter scale measurements of coral reef surface height at decimeter intervals along meter scale transects. The precise measurements require very little post-processing and are easily imported into a spreadsheet for statistical analyses and modeling. To assess its applicability we investigated the relationship between DRR and fish community structure at four coral reef sites on Menjangan Island off the northwest corner of Bali, Indonesia and one on mainland Bali to the west of Menjangan Island; our findings show a positive relationship between DRR and fish diversity. Since structural complexity drives key ecological processes on coral reefs, we consider that DRR may become a useful quantitative community-level descriptor to characterize reef complexity.

Coral reef fisheries depend on reef fish biomass to support ecosystem functioning and sustainable fisheries. Here, we evaluated coral reefs across 4,000 km of the Indonesian archipelago to reveal a large gradient of biomass, from <100 kg/ha to >17,000 kg/ha. Trophic pyramids characterized by planktivore dominance emerged at high biomass,suggesting the importance of pelagic pathways for reef productivity. Total biomass and the biomass of most trophic groups were higher within gear restricted and no-take management, but the greatest biomass was found on unmanaged remote reefs. Within marine protected areas (MPAs), 41.6% and 43.6% of gear restricted and no-take zones, respectively, met a global biomass target of 500 kg/ha, compared with 71.8% of remote sites. To improve conservation outcomes for Indonesia's biodiverse and economically important coral reef fisheries, our results suggest to: (1) strengthen management within Indonesia's existing MPAs and (2) precautionarily manage remote reefs with high biomass. K E Y W O R D Sdata-poor fisheries, food webs, gear restrictions, marine protected areas, small-scale fisheries, South East Asia Conservation Letters. 2020;13:e12698.wileyonlinelibrary.com/journal/conl

The Sumatra-Andanaman tsunami was one of the greatest natural disasters in recorded human history. Here, we show that on the northwest coast of Aceh, Indonesia, where the tsunami was most ferocious, the damage to corals, although occasionally spectacular, was surprisingly limited. We detected no change in shallow coral assemblages between March 2003 and March 2005, with the exception of one site smothered by sediment. Direct tsunami damage was dependent on habitat and largely restricted to corals growing in unconsolidated substrata, a feature unique to tsunami disturbance. Reef condition, however, varied widely within the region and was clearly correlated with human impacts prior to the tsunami. Where fishing has been controlled, coral cover was high. In contrast, reefs exposed to destructive fishing had low coral cover and high algal cover, a phase shift the tsunami may exacerbate with an influx of sediments and nutrients. Healthy reefs did not mitigate the damage on land. Inundation distance was largely determined by wave height and coastal topography. We conclude that although chronic human misuse has been much more destructive to reefs in Aceh than this rare natural disturbance, human modification of the reef did not contribute to the magnitude of damage on land.

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Parrotfishes and surgeonfishes perform important functional roles in the dynamics of coral reef systems. This is a consequence of their varied feeding behaviors ranging from targeted consumption of living plant material (primarily surgeonfishes) to feeding on detrital aggregates that are either scraped from the reef surface or excavated from the deeper reef substratum (primarily parrotfishes). Increased fishing pressure and widespread habitat destruction have led to population declines for several species of these two groups. Species-specific data on global distribution, population status, life history characteristics, and major threats were compiled for each of the 179 known species of parrotfishes and surgeonfishes to determine the likelihood of extinction of each species under the Categories and Criteria of the IUCN Red List of Threatened Species. Due in part to the extensive distributions of most species and the life history traits exhibited in these two families, only three (1.7%) of the species are listed at an elevated risk of global extinction. The majority of the parrotfishes and surgeonfishes (86%) are listed as Least Concern, 10% are listed as Data Deficient and 1% are listed as Near Threatened. The risk of localized extinction, however, is higher in some areas, particularly in the Coral Triangle region. The relatively low proportion of species globally listed in threatened Categories is highly encouraging, and some conservation successes are attributed to concentrated conservation efforts. However, with the growing realization of man's profound impact on the planet, conservation actions such as improved marine reserve networks, more stringent fishing regulations, and continued monitoring of the population status at the species and community levels are imperative for the prevention of species loss in these groups of important and iconic coral reef fishes.

The redbelly yellowtail fusilier, Caesio cuning, has a tropical Indo-West Pacific range 21 that straddles the Coral Triangle, a region of dynamic geological history and the highest 22 marine biodiversity on the planet. Previous genetic studies in the Coral Triangle indicate 23 the presence of regional limits to connectivity across this region. However, these have 24 focused almost exclusively on benthic reef dwelling species. Schooling, reef-associated 25 fusiliers (Perciformes: Caesionidae) account for a sizable portion of the annual reef catch 26 in the Coral Triangle, yet to date, there have been no in depth studies on the population 27 structure of fusiliers or other mid-water, reef-associated planktivores across this region. 28 We evaluated the genetic population structure of C. cuning using a 382bp segment of the 29 mitochondrial control region amplified from over 620 fish sampled from 33 localities 30 across the Philippines and Indonesia. Phylogeographic analysis showed that individuals 31 sampled from sites in western Sumatra belong to a distinct Indian-Ocean lineage, 32 resulting in pronounced regional structure between western Sumatra and the rest of the 33 Coral Triangle (Φ CT = 0.4796, p < 0.0043). We measured additional significant 34 population structure between central Southeast Asia and eastern Indonesia (Φ CT = 0.0450, 35 p < 0.0002). These data in conjunction with spatial analyses indicate that there are two 36 major lineages of C. cuning and at least three distinct management units across the 37 region. The location of genetic breaks as well as the distribution of divergent haplotypes 38 across our sampling range suggests that current oceanographic patterns could be 39 contributing to observed patterns of structure. 40 41 42 Keywords: connectivity, gene flow, isolation by distance, coral reef fish, artisanal 43 fisheries, Coral Triangle 44 Johannes 2002; Sale 2006). Because dispersive larvae are the primary means of 92 demographic and genetic connectivity among most populations, understanding patterns of 93 larval dispersal has been identified as one of the most critical gaps in developing effective 94 reserve networks (Sale et al. 2005). Although genetic connectivity is not equivalent to 95 demographic connectivity, genetic methods can be of use in guiding conservation 96 planning in marine ecosystems (Palumbi 2003). By identifying regions that are 97 genetically and demographically independent, conservation planners can partition large 98 marine ecosystems into smaller, more tractable management areas for which networks of 99 marine reserves can be designed (Green and Mous 2004). This approach has been 100 specifically proposed as a management mechanism in the Coral Triangle (Carpenter et al. 101 2011). 102 Schooling, reef-associated fusiliers (Perciformes: Caesionidae) are planktivores 103 found feeding at the reef face and account for a sizable portion of harvested reef species 104 in the Coral Triangle. They are caught via a variety of methods including hand-line, fish 105 traps, trawls, d...