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Replenishment of benthic marine populations typically involves "settlement" from pelagic larval to benthic juvenile habitats. Mortality during this transition has been unknown because. of the difficulty of measuring propagule supply in open water. For three weeks, we compared the nocturnal passage of presettlement fishes across the barrier reef encircling Moorea Island (French Polynesia) with the abundance of benthic recruits in the back-reef lagoon on the following morning. During this time, >40,000 presettlement unicornfish, Naso unicornis entered our study area of ∼1 km² with half arriving on just two nights. Using coupled Beverton-Holt functions to describe the decay of each cohort, we were able to predict the daily abundance of recruits and their final age structure from the presettlement inputs. The best model estimated that ∼61% of the potential settlers were lost between their nocturnal arrival and the following morning, independent of cohort size. Postsettlement mortality was density dependent, varying between 9% and 20% per day. We attribute all mortality to predation and suggest that high risk associated with settlement has shaped colonization strategies. Because fishing targets the survivors of this population bottleneck, aquarium fisheries may be more sustainable when sourced from pelagic juveniles. [ABSTRACT FROM AUTHOR]

Mimicry is a widely documented phenomenon in coral reef fishes, but the underlying relationships between mimics and models are poorly understood. Juveniles of the surgeonfish Acanthurus pyroferus mimic the coloration of different pygmy angelfish Centropyge spp. at different locations throughout the geographic range of the surgeonfish, while adopting a common species-specific coloration as adults. This study examines the ecological and behavioural relationships between A. pyroferus and one of its models, Centropyge vroliki, in Papua New Guinea. Surgeonfish underwent a transition from the juvenile (mimetic) coloration to the adult (non-mimetic) coloration when they reached the maximum size of the angelfish. As typical of mimic–model relationships, mimic surgeonfish were always less abundant than their model. Spatial variation in the abundance of mimics was correlated with models, while the abundance of adults was not. We show that juvenile surgeonfish gain a foraging advantage by mimicking the angelfish. Mimic surgeonfish were always found within 1–2 m of a similar-sized individual of C. vroliki with which they spent c. 10% of their time in close association. When in association with angelfish, juvenile surgeonfish exhibited an increase of c. 10% in the amount of time spent feeding compared to when they were alone. This foraging benefit seems to be explained by reduced aggression by the territorial damselfish Plectroglyphidon lacrymatus, which dominates the reef crest habitat. While adult A. pyroferus and all other surgeonfish were aggressively displaced from damselfish territories, mimic surgeonfish and their models were attacked less frequently and were not always displaced. Stomach contents analysis showed that the diet of C. vroliki differed substantially from P. lacrymatus, while that of A. pyroferus was more similar to the damselfish. We hypothesize that mimics deceive damselfish as to their diet in order to gain access to food supplies in defended areas. [ABSTRACT FROM AUTHOR]

Estimates of feeding rates, alimentary tract structure and temporal patterns of food processing obtained from twelve species of nominally herbivorous fishes on the northern Great Barrier Reef were compared. These included members of the families Acanthuridae, Scaridae and Kyphosidae. Based on an analysis of diet and short-chain fatty acid (SCFA) profiles from a previous study we initially partitioned the twelve species into four dietary categories, as follows: (a) Category 1: herbivores with a diet of macroscopic brown algae and high SCFA profiles in the hindgut region (Naso unicornis,Kyphosus vaigiensis); (b) Category 2: herbivores feeding on turfing and filamentous red and green algae with moderate SCFA profiles in the hindgut region (N. tonganus,K. cinerascens,Zebrasoma scopas,Acanthurus lineatus); (c) Category 3: zooplankton feeders with moderate SCFA profiles (N. vlamingii,N. brevirostris); (d) Category 4: species feeding on detrital and sedimentary materials with low levels of SCFA(Chlorurus microrhinos,Scarus schlegeli,Ctenochaetus striatus,A. olivaceus). The purpose of this comparison was to determine whether measures of feeding activity, alimentary tract structure, and food processing were concordant with diet. A dichotomy in feeding rates was observed. Species with a diet of algae and zooplankton (categories 1-3) had slower feeding rates than those feeding on detrital aggregates and sediment (category 4). The pattern of food processing also followed the same dichotomy with species of categories 1-3 retaining food in the alimentary tract overnight and commencing the feeding day with substantial amounts of food in the intestine and hindgut. Category-4 species commenced the feeding day with empty alimentary tracts suggesting a rapid turnover of gut contents. Within the herbivorous and zooplankton-feeding species neither alimentary tract structure nor food processing mode were predicted by diet or SCFA profiles. A hindgut fermentation chamber was present inK. vaigiensisbut not inN. unicornis, a species with high levels of SCFA in the hindgut region and a diet of brown macroscopic algae. In contrastN. vlamingii, with a diet dominated by animal matter, retained large amounts of food material in a hindgut chamber over the entire feeding cycle. In tropical perciform fishes, herbivory and fermentation are not associated with the alimentary tract structures that characterise herbivorous terrestrial vertebrates. Estimates of the abundance of the different groupings of nominally herbivorous fishes indicated that the dominant elements in the reef grazing and browsing fauna were consumers of detrital and sedimentary materials. These could not be classified as herbivores. Members of this group were dominant in all habitats investigated. Explicitly herbivorous taxa were a minority component in all habitats investigated. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the feasibility of enhancing fish populations as a means of controlling macroalgal populations in Kāne'ohe Bay, O'ahu, Hawai'i. Fleshy macroalgae have overgrown corals on reef slopes of Kāne'ohe Bay. Such shifts to fleshy macroalgal domination are often thought to be due to a decrease in abundance of herbivorous fishes. This experiment added 650 herbivorous fishes (acanthurids and scarids) to two reefs, constituting a potential addition of approximately 70% to the total populations of the two reefs. Fish censuses and grazing assays were used to assess the effectiveness of these additions in increasing grazing on these reefs and thereby diminishing the abundance of macroalgae. Fish censuses showed a smaller than expected increase in acanthurid abundance across all reefs, including the control reef, and no increase in scarid abundance. Grazing assays did not show any significant differences between pre- and postaddition. The fishes did not appear to remain on the small isolated reefs to which they were added. It is possible that habitat degradation and lack of shelter on the experimental reefs made them unsuitable for enhanced herbivore populations, because initial and postaddition biomass/ unit area was smaller than the published values for many sites. Increasing the abundance of shelter may be necessary to increase the number of fishes on these reefs. [ABSTRACT FROM AUTHOR]

Reports the serendipitous findings of a pilot study designed to evaluate whether implantation of visible, colored subcutaneous tags in juvenile surgeonfishes (Acanthurus bahianus and A. chirugus) influenced predation rates. Vulnerability to attacks by benthic invertebrates; Lagoon habitat; Unforeseen artifacts of tethering that caused termination of the experiment.

Abstract Although many reef fishes of the tropical Atlantic are widely distributed, there are large discontinuities that may strongly influence phylogeographical patterns. The freshwater outflow of the Amazon basin is recognized as a major barrier that produces a break between Brazilian and Caribbean faunas. The vast oceanic distances between Brazil and the mid-Atlantic ridge islands represent another formidable barrier. To assess the relative importance of these barriers, we compared a fragment of the mitochondrial DNA (mtDNA) cytochrome b gene among populations of three species of Atlantic surgeonfishes: Acanthurus bahianus , A. chirurgus and A. coeruleus . These species have similar life histories but different adult habitat preferences. The mtDNA data show no population structure between Brazil and the mid-Atlantic islands, indicating that this oceanic barrier is readily traversed by the pelagic larval stage of all three surgeonfishes, which spend ~45–70 days in the pelagic environment. The Amazon is a strong barrier to dispersal of A. bahianus (d = 0.024, ΦST = 0.724), a modest barrier for A. coeruleus (ΦST = 0.356), and has no discernible effect as a barrier for A. chirurgus . The later species has been collected on soft bottoms with sponge habitats under the Amazon outflow, indicating that relaxed adult habitat requirements enable it to readily cross that barrier. A limited ability to use soft bottom habitats may also explain the low (but significant) population structure in A. coeruleus . In contrast, A. bahianus has not been collected over deep sponge bottoms, and rarely settles outside shallow reefs. Overall, adult habitat preferences seem to be the factor that differentiates phylogeographical patterns in these reef-associated species. [ABSTRACT FROM AUTHOR]

Presents a study that examined the genetic diversity of the coral reef fish surgeonfish from the different regions of the Pacific Ocean to investigate the origin of the differentiation. Discussion on the genetic structure of the samples; Genetic diversity distribution; Isolation by distance in the tropical Pacific.

Examines the genetic relatedness among selected surgeonfishes in the genus Naso (Nasinae). Data used for examination; Characters that separate the genus Naso into two subgenera; Determination of allozyme mobility; Results of the cladistic analysis.

Examines the contribution of ciliates as a food source to survival of first-feeding surgeonfish larvae, Paracanthurus hepatus. Exposure of the larvae to eight treatments; Observation of highest survival of the larvae in the highest densities of Amphorellopsis acuta; Role of tintinnid and ciliates as alternative food sources to copepod nauplii.

A single specimen of a sub-adult specimen of the Atlantic species, Acanthurus coeruleus Bloch et Schneider, 1801, was collected in the Mediterranean coast of Israel. This collection was the first confirmed record of this species in the Mediterranean since hitherto it was known from this region only by a single underwater photograph from Cyprus. We postulate that this species may be considered as having established a population in this region. [ABSTRACT FROM AUTHOR]

Studies the morphology and partial cytology of a group of bacteria-related organisms from the guts of surgeonfish. Information on the organism; Materials and methods used on the study; Results and discussion.

Explores several aspects of the biogeographic and microevolutionary events during the evolution of acanthuroid fishes. Use of a highly corroborated cladogram of acanthuroid fishes; Documentation of five events in acanthuroid evolution; Occurrence of the basal cladogenesis of the acanthuroids; Origin of the ancestors of the Acanthurinae.

Presents information on a study which examined the composition of lipids from different parts of three species of surgeonfish from Ishigaki Island, Japan. Collection of fish samples; Lipid extraction and analysis; Results.

Surgeonfish (Acanthuridae) are prominent, herbivorous members of coral reef communities that occur as dispersed individuals and small, loose groups (`non-schooling fish') or as members of large, highly aggregated, mixed-species schools (`schooling' fish). We examined the relationships among fish size, habitat use and schooling in two species of surgeonfish on a fringing reef in Barbados, West Indies. Both ocean surgeonfish, Acanthurus bahianus, and blue tangs, A. coeruleus, appeared to show ontogenetic habitat shifts. The density of juvenile ocean surgeonfish was highest in the back reef (inshore), lower on the reef crest (intermediate) and lowest in the spurs and grooves (offshore) zone, but schooling adults were most abundant in the spurs and grooves zone. In a multiple regression considering the effects of depth, algal cover, rugosity and distance from shore, the density of non-schooling ocean surgeonfish was positively associated with percent algal cover on the substratum and negatively with distance from shore. Newly settled blue tangs occurred only in the reef crest and spurs and grooves zones, but larger juveniles were more common in the back reef, while adults were more evenly distributed across zones. The density of non-schooling blue tang was positively associated with rugosity, distance from shore, and percent algal cover. In both species, schooling occurred primarily in adults; small juveniles never participated in the large, dense schools. The proportion of adults that were schooling increased from the back reef to the reef crest to the spurs and grooves zone, These results are consistent with the hypothesis that schooling permits adult surgeonfish access to higher quality food in the territories of damselfish (Pomacentridae) that predominate on the reef crest and spurs. [ABSTRACT FROM AUTHOR]

Recruitment limitation models of coral reef fishes assume that interactions between demersal individuals and settling larvae are of little consequence to local population dynamics, as are interactions among reef residents. To test this premise, I examined the effects of interactions on the settlement and persistence of the ocean surgeonfish,A canthurus bahianus. I also looked at behavioural exchanges among ocean surgeonfish of different sizes and between ocean surgeonfish and other reef residents to determine whether the nature of these exchanges changes ontogenetically. Settlement of ocean surgeonfish to Tague Bay Reef, St. Croix, U.S.V.I. was increased in the presence of conspecifies and decreased in the presence of a common Caribbean damsel- fish, the beaugregory Stegastes leucostictus. Additionally, post-settlement persistence was negatively related to the level of aggression received from beaugregories. Interactions among ocean surgeonfish and between ocean surgeonfish and damselfish were size-dependent; the largest and smallest size classes had higher levels of association with conspecifics than did the middle size classes, and larger size classes received more aggression from damselfish than did the smaller size classes. These results suggest that behavioural interactions may significantly affect the distribution, abundance and early post-settlement persistence of ocean surgeonfish settlers, and that the nature of these interactions changes over the lifetime of individuals. [ABSTRACT FROM AUTHOR]

The article presents a study of the role of herbivorous fishes in the families Acanthuridae or surgeonfishes and Scaridae or parrotfishes in the determination of the distributions and abundances of benthic species in tropical reef habitats in the Caribbean sea. Results demonstrate the significant influence of herbivorous fish on benthic species distributions and abundances within a number of tropical reef habitats.

In a field experiment, two juvenile size classes of striped parrotfish (Scarus iserti), stoplight parrotfish (Sparisoma viride), and ocean surgeonfish (Acanthurus bahianus) were threatened by a model of a common predator (the trumpetfish, Aulostomus maculatus) while alone and in mixed-species groups of 3-100 members. Striped parrotfish, which usually constitute the majority of a group, used the groups for protection. Stoplight parrotfish, present in very low numbers, hid in the coral. Individuals of both species left a group sooner if it had fewer conspecifics. Small surgeonfish sought protection in groups, while larger individuals, too big to be consumed by the trumpetfish, swam away alone. These results may be explained by differences in the protection derived from mixed-species groups, and particularly, by the high predation risk suffered by odd individuals. [ABSTRACT FROM AUTHOR]

The article provides information on an application to the International Commission on Zoological Nomenclature (ICZN) to conserve the generic name Acanthurus Forsskål, 1775 in its accustomed usage the designation of Chaetodon sohal Forsskål, 1775 as the type species. Topics discussed include the nominal species Chaetodon unicornis Forsskål, 1775, the first designation of a type species, and the use of the genus Acanthurus for species of surgeonfishes.

The purpose of this application, under Article 81 of the Code, is to conserve the widely used generic name Acanthurus Forsskål, 1775 in its accustomed usage by the designation of Chaetodon sohal Forsskål, 1775 as the type species. The nominal species Chaetodon unicornis Forsskål, 1775 is currently the type species of Acanthurus by the subsequent designation of Jordan & Everman (1898), but this species currently belongs in the unicornfish genus Naso Lacepède, 1801, effectively rendering Acanthurus a senior synonym of Naso. It is proposed that all previous type fixations for Acanthurus including the one by Jordan & Evermann (1898) be set aside and that C. sohal be designated the type species of Acanthurus in accordance with the current usage of Acanthurus. [ABSTRACT FROM AUTHOR]

We report the first confirmed record of Rhynchonycteris naso in southwestern Ecuador. We observed a colony of about 10 individuals roosting under a bridge of a water reservoir that was surrounded by sugar cane crops and located in Naranjito in the Province of Guayas. This is a heavily disturbed area with small remnants of humid evergreen forest in the lowlands of the Ecuadorian coast. This record constitutes a new locality of Rhychonycteris naso for the Guayas province in a different type of vegetation and habitat from previous records for this species in Ecuador and it represents the southwesternmost record for Ecuador and South America. [ABSTRACT FROM AUTHOR]

Twenty-three microsatellites were isolated from the yellow tang ( Zebrasoma flavescens), an ecologically and commercially important reef fish. Genetic diversity was assessed in 90 adults collected from Honokohau, Hawaii. The number of alleles per locus varied from four to 29 (mean = 13.8) and observed and expected heterozygosities ranged from 0.15 to 0.94 (mean = 0.70) and from 0.29 to 0.93 (mean = 0.81), respectively. Eight loci exhibited significant departure from Hardy–Weinberg equilibrium due to the presence of null alleles. Exact tests showed no evidence of genotypic disequilibrium between loci. Overall, loci were well resolved, easy to score and highly polymorphic. [ABSTRACT FROM AUTHOR]

The article discusses the first observations of the establishment of razor surgeonfish Prionurus punctatus population in the southern Gulf of California. Several schools of various razor surgeonfish were sighted at nearby region of Baja California, Mexico. There were nine specimens captured that represent the first documented records of several species in Mexican mainland waters. Chart is also presented that explains the morphometrics and meristics of the nine individuals of Prionurus laticlavius.

In this study, the complete mitogenome sequence of the palette surgeonfish,Paracanthurus hepatus(Perciformes: Acanthuridae), has been sequenced by next-generation sequencing method. The assembled mitogenome was 16 498 bp in length, consisted of 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNAs genes. The overall base composition of palette surgeonfish was 28.6% for A, 28.6% for C, 16.3% for G, 26.4% for T and showed 87% identities to somber surgeonfishZebrasoma flavescens.The complete mitogenome of the palette surgeonfish provides essential and important DNA molecular data for further phylogeography and evolutionary analysis for surgeonfish’s phylogeny. [ABSTRACT FROM PUBLISHER]

The article presents a routine survey of a multi-species larval settlement event in a dive site of Kadmat Island, India. The observations suggest that the larvae located at Masjid Point might have traversed the reef for over one kilometer from the nearest entry site before settling. The relative abundance of the three primary species, including Thompson's surgeonfish, lavender tang and orange-striped bristletooth tang, differed between the western and eastern aspect of Kadmat Island.

In this study, the complete mitochondrial genome ofAcanthurus leucosternonwas determined. The genome is circular, double-stranded DNA molecule with 16,434 bp in length (EU 136032). The structure, gene organization, and gene order is similar as in other vertebrates. The overall base composition is A (29.29%), C (28.53%), T (26.37%), G (15.81%), and with 44.33% G + C content. Overlapping observed between contiguous genes is encoded in the opposite strands. The two 12S and 16S rRNA genes consist of 949 and 1690 nucleotides, respectively. Non-coding control region is 754 bp long and origin of replication is located in the WANCY cluster. Conserved domains in the control regions and secondary structures for the OL regions are also predicted. Molecular phylogenetic analysis using Maximum-Likelihood method ofA. leucosternonbased on the protein-coding gene sequence was also studied. [ABSTRACT FROM PUBLISHER]

Acanthurid fishes are highly ornamental coral reef fishes, commonly called as surgeon fishes. In this study, the complete mitochondrial genome ofAcanthurus lineatuswas determined (GenBank accession no EU273284). The genome was circular, double-stranded molecules of 16,532 bp length encoded with 37 mitochondrial genes. It contained 13 protein-coding genes, 22tRNA genes, 2 rRNA genes and 852 bp long control region. The entire nucleotide composition was 29.84% A, 28.07% C, 26.60% T and 15.49% G with an A + T content of 56.44%. Phylogenetic relationship ofA. lineatusamong the closely related species of Perciformes was studied based on H-strand protein-coding genes using the maximum parsimony method. [ABSTRACT FROM PUBLISHER]

Background: Acanthurus guttatus is distributed from the Maldives to the Hawaiian Archipelago and the Pitcairn Islands, and as north as Ryukyu Islands and as south as New Caledonia. The only known locality in the Eastern Tropical Pacific is Clipperton Atoll where three vagrant specimens have been observed. Methods: On June 2016 and April 2017 small groups of A. guttatus were observed and photographed during SCUBA diving and snorkeling surveys for touristic suitability at Isla del Coco National Park, Costa Rica. Results: Six specimens of A. guttatus were observed swimming over shallow rocky reefs at Isla del Coco, a volcanic island located in the Eastern Tropical Pacific. Conclusions: This study represents the first record of A. guttatus at Isla del Coco, the second known location of occurrence in the Eastern Tropical Pacific, and the easternmost known range for the Whitespotted surgeonfish. [ABSTRACT FROM AUTHOR]

The article discusess the observations of the morphological measurements performed on surgeonfish Zebrasoma scopas, and includes intraspecific variability in caudal spine morphology; use of scanning electron microscopy for examining the same; and behaviour of surgeonfish.

Herbivory by fishes has been identified as a key ecological process shaping coral reefs through time. Although taxonomically limited, herbivorous reef fishes display a wide range of traits, which results in varied ecosystem functions on reefs around the world. Yet, we understand little about how these trait combinations and functions in ecosystems changed through time and across biogeographic realms. Here, we used fossils and phylogenies in a functional ecological framework to reveal temporal changes in nominally herbivorous fish assemblages among oceanic basins in both trait space and lineage richness among functions. We show that the trait space occupied by extant herbivorous fishes in the Indo-Pacific resulted from an expansion of traits from the ancestral Tethyan assemblages. By contrast, trait space in the Atlantic is the result of lineage turnover, with relatively recent colonization by lineages that arose in the east Tethys/Indo-Pacific. From an ecosystem function perspective, the Atlantic supports a depauperate fauna, with few extant herbivorous reef fish lineages performing each function. Indo-Pacific fishes support both more functions and more lineages within each function, with a marked Miocene to Pleistocene expansion. These disparities highlight the importance of history in explaining global variation in fish functional composition on coral reefs.

The cover picture shows the molecular structure of maitotoxin, its producer organism (dinoflagellate Gambierdiscustoxicus), and its carrier (surgeonfish Ctenochaetusstriatus). With a molecular weight of 3422 Daltons, 32 rings, and 99 elements of isomerism, maitotoxin is the largest and most complex secondary metabolite known to date. (Image credits. Dinoflagellate: Dr. Steve Morton, NOAA; Surgeonfish: iStockphoto.com/©Shaun Lombard). The cover was contributed by K. C. Nicolaou (see Maitotoxin: An Inspiration for Synthesis, Nicolaou et al., p. 359 in this issue). [ABSTRACT FROM AUTHOR]

The article discusses research conducted on what niche two herbivorous fish species, parrotfish and surgeonfish, fill in coral reef ecology. As reefs, and Caribbean reefs in particular, are degraded through climate change, overfishing, and excessive seaweed growth known as macroalgae, this study sought to isolate factors that improve their health. It was discovered that these fish species control algal growth and allow coral cover to increase in reefs off the Florida keys.

Patterns of ecological specialization offer invaluable information about ecosystems. Yet, specialization is rarely quantified across several ecological niche axes and variables beyond the link between morphological and dietary specialization have received little attention. Here, we provide a quantitative evaluation of ecological specialization in a coral reef fish assemblage (f. Acanthuridae) along one fundamental and two realized niche axes. Specifically, we examined ecological specialization in 10 surgeonfish species with regards to morphology and two realized niche axes associated with diet and foraging microhabitat utilization using a recently developed multidimensional framework. We then investigated the potential relationships between morphological and behavioural specialization. These relationships differed markedly from the traditional ecomorphological paradigm. While morphological specialization showed no relationship with dietary specialization, it exhibited a strong relationship with foraging microhabitat specialization. However, this relationship was inverted: species with specialized morphologies were microhabitat generalists, whereas generalized morphotypes were microhabitat specialists. Interestingly, this mirrors relationships found in plant-pollinator communities and may also be applicable to other ecosystems, highlighting the potential importance of including niche axes beyond dietary specialization into ecomorphological frameworks. On coral reefs, it appears that morphotypes commonly perceived as most generalized may, in fact, be specialized in exploiting flat and easily accessible microhabitats. [ABSTRACT FROM AUTHOR]

The article presents research on the opportunity of surgeonfish aggregation to reef sharks in Moorea island. Topics discussed include the massive surgeonfish aggregation, its spawning period or events, its reproduction, its flight behavior, reef shark behavior, reproduction, and predation vulnerability.

The article lists the family names of several fishes including Acanthuridae, Albulidae, and Chaunacidae.