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Although numerous coral reef fish species utilize substrates with high structural complexities as habitats and refuge spaces, quantitative analysis of nocturnal fish substrate associations has not been sufficiently examined yet. The aims of the present study were to clarify the nocturnal substrate associations of 17 coral reef fish species (nine parrotfish, two surgeonfish, two grouper and four butterflyfish) in relation to substrate architectural characteristics. Substrate architectural characteristics were categorized into seven types: (1) eave-like space, (2) large inter-branch space, (3) overhang by protrusion of fine branching structure, (4) overhang by coarse structure, (5) uneven structure without large space or overhang, (6) flat and (7) macroalgae. Overall, fishes were primarily associated with three architectural characteristics (eave-like space, large inter-branch space and overhang by coarse structure). The main providers of these three architectural characteristics were tabular and corymbose Acropora, staghorn Acropora, and rock. Species-specific significant positive associations with particular architectural characteristics were found as follows. For the nine parrotfish species, Chlorurus microrhinos with large inter-branch space and overhang by coarse structure; Ch. spilurus with eave-like space and large inter-branch space; Hipposcarus longiceps with large inter-branch space; Scarus ghobban with overhang by coarse structure; five species (Scarus forsteni, S. niger, S. oviceps, S. rivulatus and S. schlegeli) with eave-like space. For the two surgeonfish species, Naso unicornis with overhang by coarse structure; N. lituratus with eave-like space. For the two grouper species, Plectropomus leopardus with eave-like space; Epinephelus ongus with overhang by coarse structure. For the four butterflyfish species, Chaetodon trifascialis with eave-like space and large inter-branch space; C. lunulatus and C. ephippium with large inter-branch space; C. auriga showed no significant associations with any architectural characteristics. Four species (Ch. microrhinos, H. longiceps, S. niger and N. unicornis) also showed clear variations in substrate associations among the different fish size classes. Since parrotfishes, surgeonfishes and groupers are main fisheries targets in coral reefs, conservation and restoration of coral species that provide eave-like space (tabular and corymbose Acropora) and large inter-branch space (staghorn Acropora) as well as hard substrates with coarse structure that provide overhang (rock) should be considered for effective fisheries management in coral reefs. For butterflyfishes, coral species that provide eave-like space (tabular Acropora) and large inter-branch space (staghorn Acropora) should also be conserved and restored for provision of sleeping sites. [ABSTRACT FROM AUTHOR]

Although numerous coral reef fish species utilize substrates with high structural complexities as habitats and refuge spaces, quantitative analysis of nocturnal fish substrate associations has not been sufficiently examined yet. The aims of the present study were to clarify the nocturnal substrate associations of 17 coral reef fish species (nine parrotfish, two surgeonfish, two grouper and four butterflyfish) in relation to substrate architectural characteristics. Substrate architectural characteristics were categorized into seven types: (1) eave-like space, (2) large inter-branch space, (3) overhang by protrusion of fine branching structure, (4) overhang by coarse structure, (5) uneven structure without large space or overhang, (6) flat and (7) macroalgae. Overall, fishes were primarily associated with three architectural characteristics (eave-like space, large inter-branch space and overhang by coarse structure). The main providers of these three architectural characteristics were tabular and corymbose Acropora, staghorn Acropora, and rock. Species-specific significant positive associations with particular architectural characteristics were found as follows. For the nine parrotfish species, Chlorurus microrhinos with large inter-branch space and overhang by coarse structure; Ch. spilurus with eave-like space and large inter-branch space; Hipposcarus longiceps with large inter-branch space; Scarus ghobban with overhang by coarse structure; five species (Scarus forsteni, S. niger, S. oviceps, S. rivulatus and S. schlegeli) with eave-like space. For the two surgeonfish species, Naso unicornis with overhang by coarse structure; N. lituratus with eave-like space. For the two grouper species, Plectropomus leopardus with eave-like space; Epinephelus ongus with overhang by coarse structure. For the four butterflyfish species, Chaetodon trifascialis with eave-like space and large inter-branch space; C. lunulatus and C. ephippium with large inter-branch space; C. auriga showed no significant associations with any architectural characteristics. Four species (Ch. microrhinos, H. longiceps, S. niger and N. unicornis) also showed clear variations in substrate associations among the different fish size classes. Since parrotfishes, surgeonfishes and groupers are main fisheries targets in coral reefs, conservation and restoration of coral species that provide eave-like space (tabular and corymbose Acropora) and large inter-branch space (staghorn Acropora) as well as hard substrates with coarse structure that provide overhang (rock) should be considered for effective fisheries management in coral reefs. For butterflyfishes, coral species that provide eave-like space (tabular Acropora) and large inter-branch space (staghorn Acropora) should also be conserved and restored for provision of sleeping sites.

The coral reef ecosystem is an important ecosystem; its existence has a very close relationship with the surrounding ecosystem and the reef fish community. The direct and indirect dependence of reef fish on coral reefs has become an important issue at the national and international levels. This study aimed to determine the characteristics of coral reef ecosystem conditions, the percentage of coral growth, identify the types of coral reefs, and the diversity of reef fish species on Gosong Island, Southwest Aceh. Coral reef biophysical characteristics were collected by measuring water quality, calculating the percentage of coral coverage using the Point Intercept Transect (PIT) method, and the abundance of reef fish using the Underwater Fish Visual Census (UFVC) method. The condition of average percentage of coral reefs in the waters of Gosong Island was in a good category (55%), found as many as 31 genera of hard corals included in the line transect. The percentage of base substrate that dominates other than live coral is dead coral with algae (DCA) of 28%. The average abundance of reef fish in Gosong Island waters is 11,260 ind/ha with an average reef fish biomass of 2074,095 kg/yield. The water quality results show good conditions for coral growth in location. Based on the analysis of the structure of the fish community found in the coral reef area, the results showed good results, so the research location became a good habitat for various types of fish associated with coral reef ecosystems on Gosong Island [ABSTRACT FROM AUTHOR]

The razor surgeonfish, Prionurus laticlavius, listed on the IUCN Red List of Threatened Species under the Least Concern category, plays an important ecological role as energy regulator in reef communities, but it is sought by the aquarium and aquaculture industry, and also is consumed by people. This study estimated the length-weight relationship (LWR) and relative condition factor (Krel) in P. laticlavius. The equation for length-weight relationship was TW= 0.02 TL3.01 for the Overall category, and the relative condition factor was 1.28. A total of 379 fish (3-45.6 cm total length) were collected in the southwestern coast of the Gulf of California using harpoon (for large fishes) and hand net (for small fishes), of which 181 were females (20.2-45.6 cm), 137 males (20.6-43.4 cm), and 61 juveniles (3-19.5 cm). Allometric coefficient b of LWR for the Overall category suggested isometric growth (b = 3.01), positive allometric growth for juveniles (b = 3.14), and negative allometric growth for adults (2.75). Results of Krel showed higher values for females during the warm season. The population showed a good nutritional condition, mainly in the warm season. This work is the first to estimate LWR and Krel for P. laticlavius, which will inform stock assessment and the management of this species in the Gulf of California. [ABSTRACT FROM AUTHOR]

While prior research has examined age, growth, and reproduction of yellow tang (Zebrasoma flavescens), size at maturity was only preliminarily assessed and is a very important biological metric to fully understand yellow tang biology and population status. We had a unique opportunity to sample from the Oahu, Hawaiʻi, aquarium fishery and across a size range from 55- to 110-mm total length (TL). We found a smaller than expected size at maturity for females (L50 = 63.4-mm TL (CI: 62.7 – 65.5-mm TL)) and males (L50 = 67.4-mm TL (CI: 66.4 – 70.3-mm TL)). Females as small as 65-mm TL had ovaries that contained hydrated oocytes, suggesting that spawning can occur at a size that was previously considered within the juvenile size range. However, very low gonad weights (< 0.26 g) limit any significant egg production from these small, young individuals. These results provide additional insight into the biology of Z. flavescens, but further research is needed to determine if size at maturity varies spatially and under different levels of fishing pressure. [ABSTRACT FROM AUTHOR]

The jellyfish-baited trap fishery was studied at four fishing grounds off the eastern coast of Sri Lanka throughout the entire fishing season (February and March) in three consecutive years, from 2017 to 2019, due to its uniqueness of export-oriented small-scale fishery. The composition of catch and their respective stomach content analysis revealed that the highly expensive Malabar groupers, which are predominantly targeted for export markets get attracted to traps as the secondary catch because they predate on the primary catch, e.g., filefishes, rabbitfishes, surgeonfishes and triggerfishes, and the bycatch, i.e., angelfishes and butterflyfishes. The varieties of primary catch are attracted to the jellyfish-bait. Among the 24 species of fishes caught, medusivorous Siganus javus had the highest abundance (24%), followed by Acanthurus mata (21%). Family-wise, the maximum contribution to the total catch was by Siganidae (56%), followed by Acanthuridae (34%). The average CPUE (kg three-man group-1 boat-1 day-1) ± SD of primary, secondary and by-catch during the fishing season was 87.0 ± 18.4 kg (~80%), 15.1 ± 3.4 kg (~14%) and 6.3 ± 1.4 kg (~6%) respectively, while the average total catch per trap was 7.2 ± 1.4 kg. The results of this study are important for utilizing the commonly available jellyfish bait to expand this trap fishery as well as to adapt the strategies for similar fisheries. [ABSTRACT FROM AUTHOR]

Harsh environmental conditions limit how species use the landscape, strongly influencing the way assemblages are distributed. In the wake of repeated coral bleaching mortalities in Lakshadweep, we examined how wave exposure influences herbivory in exposed and sheltered reefs. We used a combination of i. field observations of fish herbivore composition, abundance and activity across 6 exposed and 6 sheltered reefs; ii. experimental manipulations in a subset of these reefs (herbivore exclosures); and iii. opportunistic observations of fish recruitment, to determine how exposure influences herbivore biomass and herbivory. Species richness, biomass, abundance, total bite rates and species-specific per capita bite rates were lower in exposed compared to sheltered reefs, linked to strong environmental filtering of species composition, abundance and behaviour. For some critical species, this environmental filtering begins with differential recruitment and post-recruitment processes between exposures. Bite rates at sheltered sites were dominated by just a few species, most being laterally compressed surgeonfish that may find it difficult accessing or surviving in wave-battered shallow reefs. Exclosure experiments confirmed that exposed reefs were less controlled by herbivores than sheltered reefs. In post-disturbed reefs like Lakshadweep, environmental gradients appear to be key mediators of critical functions like herbivory by determining species composition, abundance and behaviour. [ABSTRACT FROM AUTHOR]

Aim: To describe the global biogeography of key herbivorous coral reef fish groups since their presumed origins, using data from both fossil and extant species. Location: Global Cenozoic reefs. Taxon: Acanthuridae (surgeonfishes), Siganidae (rabbitfishes) and Scarini (parrotfishes). Methods: We applied the fossilized birth–death model to build chronograms including a comprehensive sampling of extant species and all the fossil occurrences described for each group. With the resulting chronograms, we built biogeographical models considering the geological changes in reef habitat availability since the ancient Tethys Sea. Finally, we used biogeographical stochastic mappings to trace the routes of colonization of the Atlantic Ocean by lineages in our focal taxa. Results: We found that the Palaeocene–Eocene was a period of significant lineage origination for surgeonfishes and rabbitfishes in the central Tethys Sea with the appearance of ancient genera. Most of these genera were probably extinct by the Eocene–Oligocene boundary as they do not correspond with modern taxa. Parrotfishes, however, originated in the early Oligocene, an epoch that corresponds with the geographical transition of the marine biodiversity hotspot. In all groups, extant genera had similar origin times and all expanded in the Miocene, mainly in the Indo‐Pacific. In the Atlantic, only one parrotfish lineage with Tethyan ancestry appears to have survived. It subsequently gave rise to extant endemic genera (Sparisoma and Cryptotomus). The other extant lineages in the Atlantic all have Indo‐Pacific origins and colonized more recently using different dispersal pathways. Main conclusions: The Indo‐Pacific herbivorous fish fauna is the result of ongoing lineage expansion that started in the central Tethys. The Atlantic is a composite fauna with just one endemic lineage and at least four colonization events from the Indo‐Pacific. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Dory, the animated surgeonfish created by the Pixar Animation studios, famously suffered from short-term memory loss leading to many adventures. In reality, many fishes have excellent cognitive abilities and are able to learn and retain important information such as the identity of predators. However, if and how cognition can be affected by anthropogenically altered oceanic conditions is poorly understood. Here, we examine the effect of a widely used pesticide, chlorpyrifos, on the retention of acquired predator recognition in post-larval stage of the surgeonfish Acanthurus triostegus . Through associative learning, post-larvae of A. triostegus were first observed to forage significantly less in the presence of conspecific alarm cues and alarm cues associated to a predator's odor. The retention of this anti-predator behavior was estimated to last between 2 and 5 days in the absence of pesticide. However, environmentally-relevant concentrations of chlorpyrifos (1 μg.L −1 ) induced the loss of this acquired predator recognition. This reduced ability to recognize learned predators is discussed as it may lead to more vulnerable fish communities in coastal areas subjected to organophosphate pesticide pollution. [ABSTRACT FROM AUTHOR]

Yellow Tang, Zebrasoma flavescens , are a popular species in the aquarium industry. Currently, all Yellow Tang are collected from wild stocks, with collection in Hawaii accounting for the bulk of the individuals found in the trade. Although culture of this species has recently been successful, survival remains low and mass mortality events, particularly associated with the transition from endogenous to exogenous feeding, continue to be observed. Improving survival and gaining a more thorough understanding of the drivers behind early prey selection, such as mouth gape and osteological development, are of primary importance in advancing the culture of Yellow Tang. For the present study, a supplemental size-sorted mixture of wild zooplankton was offered in conjunction with and compared to the cultured nauplii of Parvocalanus crassirostris to determine the effect on survival. Prey selection was determined via metabarcoding. Osteological development was documented and mouth gape measured from 1 to 6 days post hatch to better determine appropriate prey types and size ranges. Survival was significantly lower in larvae fed cultured nauplii supplemented with wild zooplankton, 6.9% v. 18.5%. Regardless of the presence of wild zooplankton, larvae preferentially selected for P. crassirostris based on molecular determination of prey consumption . However, it is likely that protozoans were mostly excluded from this molecular analysis possibly due to the type of primer selected. Mouth gape height increased by approximately 100 μm and mouth gape width by approximately 55 μm, during the study period. Although no significant difference in growth was calculated between treatments, larvae receiving the wild zooplankton supplement diet were observed to grow at a slightly slower rate than larvae being fed only cultured copepod nauplii. The rate at which the mouth gape increased suggests that the currently cultured and utilized copepod nauplii may not be an optimally sized prey item shortly after first feed. These findings indicate that first feeding Yellow Tang larvae are capable of consuming larger prey at an earlier age than they have been offered in previous rearing attempts, but that the larvae may continue to benefit from the presence of less elusive prey items, such as ciliates or rotifers, due to their delayed osteological development. Osteological development was slow with very little ossification occurring by 6 days post hatch and only in those larvae fed solely cultured nauplii. However, their selection of copepod nauplii suggests that some aspect of this prey item is preferential to the first feeding larvae and may elicit a hunting response essential to initiating exogenous feeding. [ABSTRACT FROM AUTHOR]

Abstract: The current ease of obtaining thousands of molecular markers challenges the notion that full phylogenetic concordance, as proposed by phylogenetic species concepts, is a requirement for defining species delimitations. Indeed, the presence of genomic islands of divergence, which may be the cause, or in some cases the consequence, of speciation, precludes concordance. Here, we explore this issue using thousands of RAD markers on two sister species of surgeonfishes (Teleostei: Acanthuridae), Zebrasoma flavescens and Z. scopas, and several populations within each species. Species are readily distinguished based on their colors (solid yellow and solid brown, respectively), yet populations and species are neither distinguishable using mitochondrial markers (cytochrome c oxidase 1), nor using 5193 SNPs (pairwise Φst = 0.034). In contrast, when using outlier loci, some of them presumably under selection, species delimitations, and strong population structure follow recognized taxonomic positions (pairwise Φst = 0.326). Species and population delimitation differences based on neutral and selected markers are likely due to local adaptation, thus being consistent with the idea that these genomic islands of divergence arose as a consequence of isolation. These findings, which are not unique, raise the question of a potentially important pathway of divergence based on local adaptation that is only evident when looking at thousands of loci. [ABSTRACT FROM AUTHOR]

Abstract: Fishery landings of coral reef fish from a nearshore commercial spear fishery from 2011 to 2014 were analyzed and summarized. Results showed that the fishery comprised two effort components—shore‐ and boat‐based fishing—with shore‐based fishing dominating fishery effort. These two components yielded differing fishery characteristics, including landings, CPUE, seasonality, fishing locations, and targeted species. Time series of select species’ sizes (family Acanthuridae and subfamily Scarinae) showed relatively consistent trends over the sampling period, with the sizes of most harvested species exceeding the life history milestones of length at maturity and length at sex change. Sizes of harvested species were influenced by fishing effort type. Brief comparisons with prior spear fishery analyses focusing on the Northern Mariana Islands indicated that effectively evaluating the nighttime commercial coral reef spear fishery requires an understanding of fishery dynamics and implementation of a long‐term monitoring program. [ABSTRACT FROM AUTHOR]

X‐ray micro‐computed tomography scans were used to examine the caudal‐fin structure of an unusual double‐tailed deformity in an adult brown surgeonfish Acanthurus nigrofuscus from the Great Barrier Reef. In both this case and in a similar double‐tailed deformity in a juvenile Tomini surgeonfish Ctenochaetus tominiensis from the Philippines, the caudal fin was duplicated along the dorsoventral axis. Detailed examination of the A. nigrofuscus specimen revealed that the deformity was associated with duplication and reflection of the hypural plates and the posterior vertebrae, yet the fish survived to adulthood, indicating that the effects of duplication on survival may be limited. [ABSTRACT FROM AUTHOR]

Belemnites from the lower Bathonian of the Russian Plate are revised on the basis of the study of two reference sections—Pletnyovka and Sokur quarries. The first part of the study deals with the members of the family Megateuthididae. They include eight species of the genus Barskovisella gen. nov., neoendemic to the territory of the Russian Plate and originating from high Boreal taxa—species of the genus Paramegateuthis Gustomesov, 1960, which immigrated to the Middle Russian Sea in the early Bathonian via a short-lived meridional strait. The new genus includes six new species described in the present paper—Barskovisella pseudoishmensis sp. nov., B. issae sp. nov., B. variabilis sp. nov., B. barskovi sp. nov., B. gracilis sp. nov., and B. renegata sp. nov. The beds with Barskovisella, a new belemnite-based unit, corresponding to the Oraniceras besnosovi ammonite zone and including four successive phylogenetic biohorizons well comparable in resolution with ammonite-based infrazonal subdivisions, are introduced. [ABSTRACT FROM AUTHOR]

Abstract: Zebrasoma flavescens (Bennett) aquaculture is limited by high mortality during first feeding. Photoperiod, light intensity, turbidity and prey density are culture parameters that have been shown to affect feed incidence and survival in some food fish species, offering a logical starting point to improve first feeding in Z. flavescens. This study aimed to determine the effect of photoperiod, light intensity, turbidity and prey density on feed incidence and survival in larval yellow tang age 3 DPH to 5 DPH (days post hatch). Larvae were reared in four photoperiods (24L:0D, 16L:8D, 12L:12D, 0L:24D), four light intensities (1,500, 3,000, 4,500 and 6,500 lx), three turbidity ranges (0 cells/ml, 100,000–200,000 cells/ml and 400,000–600,000 cells/ml) and four prey densities (1, 3, 6 and 9 per mL). Photoperiod at 16L:8D and 12L:12D significantly increased feed incidence; 16L:8D significantly increased survival. Light intensities at 3,000 and 4,500 lx significantly increased feed incidence. Larvae reared in 400,000–600,000 cells/ml fed and survived significantly better than those in clear water. Larvae in 1 per mL fed and survived significantly less than those fed at 6 per mL. [ABSTRACT FROM AUTHOR]

Given the current degradation of Caribbean coral reefs, considerable regional emphasis has been put into monitoring the state of key exploited reef fish herbivores, namely surgeonfishes and parrotfishes, through underwater visual fish surveys (UVFS). However, like all survey methods, UVFS suffer from sampling errors that could mask real spatio-temporal trends in fish metrics. Here, we compare trends in simple reef fish herbivore metrics, i.e. average individual fish weight, fish abundance and fish biomass, between UVFS and fish trap surveys, an alternative survey method. Because both methods fundamentally differ in the underlying nature of their sampling errors, we argue that fish metrics exhibiting high consistency between methods will more likely reflect real environmentally-induced trends and should thus be emphasized in monitoring programs. We conducted repeated surveys using both methods concurrently at six sites along a fishing pressure gradient in a Caribbean island. We then examined between-method consistency in fish metric trends across sites and precision in fish metric estimates for each method using surgeonfish and parrotfish data at different levels of aggregation, i.e. species-, family- and functional-level (both herbivorous families combined). We found high and robust between-method consistency only for parrotfish data aggregated at the family level, which also exhibited the highest overall precision in metric estimates. All other fish groups exhibited poorer between-method consistency and poorer precision in their metrics, indicating comparatively higher sensitivity to method-specific sampling errors. Overall, our study supports that family-level parrotfish metrics are particularly robust to survey method, which considerably increases their value as indicators for Caribbean reef monitoring programs. [ABSTRACT FROM AUTHOR]

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The present study was intended to screen the wild shrimps of Andaman and Nicobar Islands (ANI) against infectious diseases. A total of 175 shrimp samples (35 pools) consisting of Fenneropenaeus indicus, Penaeus monodon, Penaeus merguiensis and Metapenaeus monoceros were collected from different landing centres across ANI. Out of 35 pools of samples analysed by polymerase chain reaction (PCR), a total of 10 pools of Penaeus monodon collected from Betapur (1 pool), Lohabarrack (4 pools) and Campbell Bay (5 pools) were found positive for Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV). Nucleotide sequence of IHHNV isolated from ANI showed 100% identity to the sequences of IHHNV reported from Vietnam, Taiwan, Australia, China, Egypt, USA, Ecuador, 99% identity to IHHNV reported from Brazil, Venezuela, Korea, 96% identity to IHHNV reported from Thailand and 95% identity to IHHNV reported from India. Based on phylogenetic tree analysis, IHHNV of ANI is closely related to IHHNV of Vietnam. Histopathological analysis revealed typical eosinophilic intranuclear cowdry type A inclusion bodies in gill lamellae which further confirmed the IHHNV infection. The present study provides a definitive evidence for the first report of infectious IHHNV in wild P. monodon from ANI. [ABSTRACT FROM AUTHOR]

Herbivorous surgeonfishes are an ecologically successful group of reef fish that rely on marine algae as their principal food source. Here, we elucidated the significance of giant enteric symbionts colonizing these fishes regarding their roles in the digestive processes of hosts feeding predominantly on polysiphonous red algae and brown Turbinaria algae, which contain different polysaccharide constituents. Using metagenomics, single-cell genomics, and metatranscriptomic analyses, we provide evidence of metabolic diversification of enteric microbiota involved in the degradation of algal biomass in these fishes. The enteric microbiota is also phylogenetically and functionally simple relative to the complex lignocellulose-degrading microbiota of terrestrial herbivores. Over 90% of the enzymes for deconstructing algal polysaccharides emanate from members of a single bacterial lineage, "Candidatus Epulopiscium" and related giant bacteria. These symbionts lack cellulases but encode a distinctive and lineage-specific array of mostly intracellular carbohydrases concurrent with the unique and tractable dietary resources of their hosts. Importantly, enzymes initiating the breakdown of the abundant and complex algal polysaccharides also originate from these symbionts. These are also highly transcribed and peak according to the diel lifestyle of their host, further supporting their importance and host-symbiont cospeciation. Because of their distinctive genomic blueprint, we propose the classification of these giant bacteria into three candidate genera. Collectively, our findings show that the acquisition of metabolically distinct "Epulopiscium" symbionts in hosts feeding on compositionally varied algal diets is a key niche-partitioning driver in the nutritional ecology of herbivorous surgeonfishes. [ABSTRACT FROM AUTHOR]

The doctorfish Acanthurus chirurgus (Bloch, 1787) is reported for the first time from the central Mediterranean, based on a specimen caught in Maltese waters during August 2016. Since the only previous Mediterranean record of this species was based on a single individual observed in the Tyrrhenian Sea, the present record likely represents an independent introduction that may have occurred through the aquarium trade or via shipping. Two other surgeonfish species, Acanthurus coeruleus Bloch and Schneider, 1801 and Acanthurus monroviae Steindachner, 1876, were previously recorded from the central Mediterranean. While A. coeruleus may have established a population in the Levantine Sea, like A. chirurgus it has only been reported once from Malta (and from the central Mediterranean in general); both A. coeruleus and A. chirurgus are, therefore, considered to be casual species in Maltese waters. In contrast, A. monroviae was reported from several Mediterranean countries including Tunisia and Malta in the central Mediterranean. Here we present several authenticated reports of this species from Maltese waters, which strongly suggest that it has managed to establish a population in this region, although the possibility of multiple introductions cannot be excluded. [ABSTRACT FROM AUTHOR]

Increasing sediment inputs are recognised as an important factor leading to coral reef degradation. However, the role of sediments in ecological processes is poorly understood. This study used paired-choice trials to quantify the effects of sediment grain size and chemical composition on feeding by the abundant detritivorous reef fish, Ctenochaetus striatus . The size of sediments from algal turfs were also compared to those ingested by reef-dwelling C. striatus . Algal turfs containing coarser sediments were preferred by C. striatus , while sediment composition (reefal carbonates vs. riverine silicates) had little effect. On the reef, C. striatus ingested finer sediments than those present in algal turfs. C. striatus appears to prefer algal turfs with coarser sediments as this facilitates ingestion of fine detrital particles, while finer sediments prevent selective feeding on detritus. These findings suggest that fine sediments from terrestrial runoff or dredging may be detrimental to feeding by detritivorous species. [ABSTRACT FROM AUTHOR]

Herbivorous and detritivorous fishes interact closely with the epilithic algal matrix (EAM) on coral reefs. While sediment and organic detrital loads within the EAM might influence this interaction, the responses of functionally distinct fishes to changing sediment and organic loads have not been investigated. Aquarium based feeding trials were performed to assess how different sediment and organic loads affected feeding by the highly abundant surgeonfishes, Ctenochaetus striatus, a detritivore, and Acanthurus nigrofuscus, a herbivore. C. striatus were highly sensitive to even small increases in sediment loads (of just 75 g m-2), displaying a significant decline in feeding rates as sediment loads increased. Although C. striatus is a specialised detritivore, changing organic loads had no effect and suggests that selection of feeding surfaces is primarily mediated by total sediment loads rather than organic loads. By contrast, A. nigrofuscus displayed no changes to its feeding behaviour regardless of sediment or organic load. These findings highlight the complex, species-specific way that sediments may mediate key ecological processes on coral reefs. [ABSTRACT FROM AUTHOR]

Acanthurus albimento is described as a new surgeonfish from northeastern Luzon from six specimens collected during extensive fish-market surveys in the Philippines. The new species is characterized by a distinctive white band below the lower jaw; many irregular, wavy, thin, blue lines on the head; a brown-orange pectoral fin with a bluish tinge on the outer membrane of the rays and a dark band on the posterior margin; a narrow rust-orange stripe along the base of the dorsal fin; and a large blackish caudal spine and sheath with the socket broadly edged in black. An analysis using the mitochondrial cytochrome c oxidase subunit 1 (COI), supported by an independent multi-locus analysis, suggests phylogenetic affinities with an Acanthurus clade that includes A. auranticavus, A. bariene, A. blochii, A. dussumieri, A. gahhm, A. leucocheilus, A. maculiceps, A. mata, A. nigricauda, and A. xanthopterus; a clade that shares a suite of color characteristics. Based on the sampling history in the region, the new species may be a limited-range endemic in the westernmost Pacific Ocean, which is unusual for members of this genus. This raises potential questions about drivers of dispersal and long-held assumptions about zoogeographic patterns along the Kuroshio Current. [ABSTRACT FROM AUTHOR]

Bluespine unicornfish ( Naso unicornis) from Hawaii were aged to >50 years using cross-sectioned sagittal otoliths. Fish length was a poor indicator of age because of rapid and variable early growth, exemplified by fish aged to be 4 years near maximum length. Growth was deterministic with adult ages decoupled from body length. Otolith mass and thickness were evaluated as proxies for age and both were encouraging; thickness explained more variance but mass was easier to measure. An age estimation protocol was validated through ontogeny using bomb radiocarbon (14C) dating. Use of the postbomb 14C decline period from a regional reference chronology enabled age validation of young fish - a novel approach for the Pacific Ocean. A probabilistic procedure for assigning bomb 14C dates (CALIBomb) was used for the first time to determine fish birth years. The age-reading protocol was generally validated, and it was possible to describe length-at-age despite difficulties in counting otolith annuli beyond 30-40 years. Growth curves differed between the sexes, and a four-parameter generalized von Bertalanffy growth function provided the best fit. [ABSTRACT FROM AUTHOR]

Closely related species can provide valuable insights into evolutionary processes through comparison of their ecology, geographic distribution and the history recorded in their genomes. In the Indo-Pacific, many reef fishes are divided into sister species that come into secondary contact at biogeographic borders, most prominently where Indian Ocean and Pacific Ocean faunas meet. It is unclear whether hybridization in this contact zone represents incomplete speciation, secondary contact, an evolutionary dead-end (for hybrids) or some combination of the above. To address these issues, we conducted comprehensive surveys of two widely-distributed surgeonfish species, Acanthurus leucosternon ( N = 141) and A. nigricans ( N = 412), with mtDNA cytochrome b sequences and ten microsatellite loci. These surgeonfishes are found primarily in the Indian and Pacific Oceans, respectively, but overlap at the Christmas and Cocos-Keeling Islands hybrid zone in the eastern Indian Ocean. We also sampled the two other Pacific members of this species complex, A. achilles ( N = 54) and A. japonicus ( N = 49), which are known to hybridize with A. nigricans where their ranges overlap. Our results indicate separation between the four species that range from the recent Pleistocene to late Pliocene (235,000–2.25 million years ago). The Pacific A. achilles is the most divergent (and possibly ancestral) species with mtDNA d corr ≈ 0.04, whereas the other two Pacific species ( A. japonicus and A. nigricans ) are distinguishable only at a population or subspecies level ( Φ ST = 0.6533, P < 0.001). Little population structure was observed within species, with evidence of recent population expansion across all four geographic ranges. We detected sharing of mtDNA haplotypes between species and extensive hybridization based on microsatellites, consistent with later generation hybrids but also the effects of allele homoplasy. Despite extensive introgression, 98% of specimens had concordance between mtDNA lineage and species identification based on external morphology, indicating that species integrity may not be eroding. The A. nigricans complex demonstrates a range of outcomes from incomplete speciation to secondary contact to decreasing hybridization with increasing evolutionary depth. [ABSTRACT FROM AUTHOR]

Middle Miocene deposits at the Dubravica locality in SW Medvednica Mt. (N Croatia) contain various marine fossils, including one tooth of the surgeonfish (Acanthuridae). This is the first such record in Croatia and the second in the wider region, besides the Vienna Basin. The appearance of surgeonfishes in the Paratethys coincides with the Miocene thermal maximum. Their distribution was probably controlled by available reef habitat and their paiaeobiogeography and migration routes are yet to be studied. [ABSTRACT FROM AUTHOR]

Morphological convergence plays a central role in the study of evolution. Often induced by shared ecological specialization, homoplasy hints at underlying selective pressures and adaptive constraints that deterministically shape the diversification of life. Although midwater zooplanktivory has arisen in adult surgeonfishes (family Acanthuridae) at least four independent times, it represents a clearly specialized state, requiring the capacity to swiftly swim in midwater locating and sucking small prey items. Whereas this diet has commonly been associated with specific functional adaptations in fishes, acanthurids present an interesting case study as all nonplanktivorous species feed by grazing on benthic algae and detritus, requiring a vastly different functional morphology that emphasizes biting behaviours. We examined the feeding morphology in 30 acanthurid species and, combined with a pre-existing phylogenetic tree, compared the fit of evolutionary models across two diet regimes: zooplanktivores and nonzooplanktivorous grazers. Accounting for phylogenetic relationships, the best-fitting model indicates that zooplanktivorous species are converging on a separate adaptive peak from their grazing relatives. Driving this bimodal landscape, zooplanktivorous acanthurids tend to develop a slender body, reduced facial features, smaller teeth and weakened jaw adductor muscles. However, despite these phenotypic changes, model fitting suggests that lineages have not yet reached the adaptive peak associated with plankton feeding even though some transitions appear to be over 10 million years old. These findings demonstrate that the selective demands of pelagic feeding promote repeated - albeit very gradual - ecomorphological convergence within surgeonfishes, while allowing local divergences between closely related species, contributing to the overall diversity of the clade. [ABSTRACT FROM AUTHOR]

The reconstituted stone used in the Orval Abbey is highly susceptible to salt weathering. It was produced from debris of natural stones (which were at that time in short supply) by craftsmen working in the Abbey and its composition is highly variable. The major salt involved in weathering is sodium sulfate (NaSO). This study focused on the thermal behavior of a reconstituted stone with various degrees of weathering observed on-site and it was studied by passive and active infrared thermography (IRT), and on the evolution of reconstituted-stone samples in a salt uptake experiment in the laboratory. On-site, the thermal responses of salt-weathered and unweathered zones were different. IRT allowed to detect unweathered though highly salt-laden zones, although correlations between thermal response and salt concentration are difficult to establish due to the influence of surface properties (color and roughness). In the laboratory, samples of the reconstituted stone were submitted to successive immersion-drying cycles in solutions of NaSO with 7, 14 and 26 % concentration and characterized by weighing, surface colorimetry and active IRT. Results showed that the thermal response (increase in surface temperature due to flash excitation: T) increased with salt concentration and with the number of cycles, as long as sample disintegration had not started. Then, it decreased and stabilized, whatever the salt concentration. Those results indicated that an increase in the thermal response of building materials (in active IRT) can be interpreted as an indicator of salt accumulation, possibly leading to damage. IRT proved to be an interesting non-destructive technique in this respect. [ABSTRACT FROM AUTHOR]

Epulopiscium is a group of giant bacteria found in high abundance in intestinal tracts of herbivorous surgeonfish. Despite their peculiarly large cell size (can be up to 600 μm), extreme polyploidy (some with over 100,000 genome copies per cell) and viviparity (whereby mother cells produce live offspring), details about their diversity, distribution or their role in the host gut are lacking. Previous studies have highlighted the existence of morphologically distinct Epulopiscium cell types (defined as morphotypes A to J) in some surgeonfish genera, but the corresponding genetic diversity and distribution among other surgeonfishes remain mostly unknown. Therefore, we investigated the phylogenetic diversity of Epulopiscium, distribution and co-occurrence in multiple hosts. Here, we identified eleven new phylogenetic clades, six of which were also morphologically characterized. Three of these novel clades were phylogenetically and morphologically similar to cigar-shaped type A1 cells, found in a wide range of surgeonfishes including Acanthurus nigrofuscus, while three were similar to smaller, rodshaped type E that has not been phylogenetically classified thus far. Our results also confirmed that biogeography appears to have relatively little influence on Epulopiscium diversity, as clades found in the Great Barrier Reef and Hawaii were also recovered from the Red Sea. Although multiple symbiont clades inhabited a given species of host surgeonfish and multiple host species possessed a given symbiont clade, statistical analysis of host and symbiont phylogenies indicated significant cophylogeny, which in turn suggests co-evolutionary relationships. A cluster analysis of Epulopiscium sequences from previously published amplicon sequencing dataset revealed a similar pattern, where specific clades were consistently found in high abundance amongst closely related surgeonfishes. Differences in abundance may indicate specialization of clades to certain gut environments reflected by inferred differences in the host diets. Overall, our analysis identified a large phylogenetic diversity of Epulopiscium (up to 10% sequence divergence of 16S rRNA genes), which lets us hypothesize that there are multiple species that are spread across guts of different host species. [ABSTRACT FROM AUTHOR]

Introduction: Early management of severe acute pancreatitis (SAP) includes intravenous fluid resuscitation. Aim: To confirm feasibility of naso-jejunal (NJ) fluid resuscitation using oral hydration solution (ORS) and compare its efficacy with intravenous (IV) fluid resuscitation using Ringer Lactate (RL) in predicted SAP. Patients and Methods: All patients of predicted SAP (presence of SIRS or BISAP > 2) without significant co morbidities were randomized to NJ group (ORS: 20 ml/kg bolus and then 3 mL/kg/h) or IV group (RL infusion at same rate). The groups were compared vis-à-vis persistent organ failure (POF), pancreatic necrosis, and mortality. Results: Seventy-seven patients were assessed and after exclusion, 49 patients were randomized to either NJ (24 patients) or IV group (25). The demographic and baseline clinical profile of both groups including BISAP score (2.25 ± 0.73 and 2.32 ± 0.56), hematocrit (40.2 ± 6.8 and 38.3 ± 6.6), blood urea nitrogen (16.88 ± 6.69 and 21.44 ± 17.56 mg/dL), and intra-abdominal pressure (14.55 ± 4.8 and 14.76 ± 5.5 cm of water) were similar. NJ resuscitation had to be stopped in two patients because of abdominal discomfort and distension. The change in intra abdominal pressure after 48 h of hydration was comparable in both groups. The occurrence of POF (66.67% and 68%), pancreatic necrosis (69.5% and 76%), intervention (5 each), surgery (1 each), and mortality (16.5% and 8%) were comparable ( P > 0.05). Conclusion: In select group of patients with SAP, NJ fluid resuscitation with ORS is feasible and is equally efficacious as IV fluid resuscitation with RL. [ABSTRACT FROM AUTHOR]

Length-weight relationships (LWRs) were developed for 85 reef and bottom-fish species from Guam. These are the first published LWRs for Guam, and include new LWRs for nine species lacking these relationships in Fish-Base. [ABSTRACT FROM AUTHOR]

Coral reefs are one of the most highly productive marine ecosystems, with a strong connection between herbivores and the production of benthic algae. The epilithic algal matrix (EAM) is a major source of primary production on coral reefs, and it is one of the dominant benthic microhabitats, covering up to 80% of reef flats and back reefs and up to 70% of reef slopes on outer-shelf sites of the Great Barrier Reef, Australia. Although herbivorous surgeonfish (Acanthuridae) are dominant members of most reef fish assemblages, there is a lack of quantitative information on their grazing impact, particularly those that feed upon the EAM in the Indo-Pacific. Therefore, the aim of this study was to investigate the role of surgeonfish in maintaining algal turf biomass on coral reefs. Spatial patterns of EAM productivity, and herbivorous fish biomass and grazing intensity were quantified at different depths (deep vs. shallow) and exposures (windward vs. leeward) of reef slope environments of Heron Island, southern Great Barrier Reef. Surgeonfish were the numerically-dominant EAM grazing fish family, and to identify the daily impact of surgeonfish species on the EAM, data on their biomass (g m − 2 ) and grazing intensity (total bites m − 2 day − 1 ) were combined with EAM productivity estimates (g C m − 2 day − 1 ). EAM productivity was greatest in windward and shallow sites, and herbivorous fish biomass mirrored this pattern. Yet, there was no difference in the EAM standing crop or grazing intensity among habitats. In the most productive habitat (windward-shallow), grazer/detritivore surgeonfish species accounted for 74% of the total herbivore biomass (g m − 2 ), took 51% of the total bites (m − 2 day − 1 ), and removed an estimated 73% of daily EAM productivity (g C m − 2 day − 1 ). This study quantifies the role of surgeonfish in maintaining EAM biomass, and highlights their possible contribution to preventing shifts from coral- to algal-dominance following disturbance. [ABSTRACT FROM AUTHOR]

Surgeonfish and parrotfish play an important role in structuring the benthic communities of coral reefs. However, despite their importance, little is known about their distribution patterns in the north sector of the Mesoamerican Reef System. This study evaluated the distribution of these fish in 34 sites in four habitats (lagoon, front, slopes and terrace) along a depth gradient ( c 0.5-20 m). These herbivorous fish were assessed by visual censuses. Species dominance was evaluated for each habitat using SIMPER analysis. Habitat characteristics data were collected to determine the relationship between habitat conditions and spatial variations in herbivorous fish (using abundance and biomass as a proxy) via redundancy analysis. The herbivorous fish assemblage had a low density (fish per 100 m2) and biomass (g·100 m−2) in comparison with assemblages in similar studies. In contrast, species richness was high compared with other studies in the Caribbean. Spatial variation of the abundance, biomass and size of herbivorous fish was strongly related to coral and seagrass cover, as well as to depth and rugosity. These four variables were critical in controlling the distribution patterns of the herbivorous fish assemblages. No associations were found between fish and macroalgae or any other benthic group. The present study indicates that the species richness of surgeonfish and parrotfish was not regionally affected by the dominance of macroalgae in the habitats studied. Seagrass beds and the coral reef matrix need to be preserved for the herbivorous fish assemblages to remain healthy and capable of controlling excess macroalgae growth. [ABSTRACT FROM AUTHOR]

We report the collection of specimens of Paranthias furcifer (Serranidae), Abudefduf hoefleri (Pomacentridae), Acanthurus bahianus, A. chirurgus, A. coeruleus (Acanthuridae), and Cantherhines pullus (Monacanthidae) as first records for these tropical and subtropical species from the Canary Islands (north-eastern Atlantic). Most of these records coincide with the presence of oil platforms towards and within the Port of Las Palmas. Regarding the management of the arrival of warm-affinity fish species, it would be necessary to implement control and monitoring measures to avoid they become invaders, displacing indigenous species and changing the ecosystems. [ABSTRACT FROM AUTHOR]

Fishes described as “anti-equatorial” have disjunct distributions, inhabiting temperate habitat patches on both sides of the tropics. Several alternative hypotheses suggest how and when species with disjunct distributions crossed uninhabitable areas, including: ancient vicariant events, competitive exclusion from the tropics, and more recent dispersal during Pliocene and Pleistocene glacial periods. Surgeonfishes in the genus Prionurus can provide novel insight into this pattern as its member species have disjunct distributions inhabiting either temperate latitudes, cold-water upwellings in the tropics, or low diversity tropical reef ecosystems. Here the evolutionary history and historical biogeography of Prionurus is examined using a dataset containing both mitochondrial and nuclear data for all seven extant species. Our results indicate that Prionurus is monophyletic and Miocene in origin. Several relationships remain problematic, including the placement of the Australian P. microlepidotus , and the relationship between P. laticlavius and P. punctatus . Equatorial divergence events between temperate western Pacific habitats occurred at least twice in Prionurus : once in the Miocene and again in the late Pliocene/early Pleistocene. Three species with tropical affinities, P. laticlavius, P. punctatus, and P. biafraensis, form a clade that originated in the Pliocene. These results suggest that a variety of mechanisms may regulate the disjunct distribution of temperate fishes, and provide support for both older and younger equatorial crossing events. They also suggest that interspecific competitive exclusion may be influential in fishes with “anti-equatorial” distributions. [ABSTRACT FROM AUTHOR]

The factors that promote invasive behavior in introduced plant species occur across many scales of biological and ecological organization. Factors that act at relatively small scales, for example, the evolution of biological traits associated with invasiveness, scale up to shape species distributions among different climates and habitats, as well as other characteristics linked to invasion, such as attractiveness for cultivation (and by extension propagule pressure). To identify drivers of invasion it is therefore necessary to disentangle the contribution of multiple factors that are interdependent. To this end, we formulated a conceptual model describing the process of invasion of central European species into North America based on a sequence of ''drivers.'' We then used confirmatory path analysis to test whether the conceptual model is supported by a statistical model inferred from a comprehensive database containing 466 species. The path analysis revealed that naturalization of central European plants in North America, in terms of the number of North American regions invaded, most strongly depends on residence time in the invaded range and the number of habitats occupied by species in their native range. In addition to the confirmatory path analysis, we identified the effects of various biological traits on several important drivers of the conceptualized invasion process. The data supported a model that included indirect effects of biological traits on invasion via their effect on the number of native range habitats occupied and cultivation in the native range. For example, persistent seed banks and longer flowering periods are positively correlated with number of native habitats, while a stress-tolerant life strategy is negatively correlated with native range cultivation. However, the importance of the biological traits is nearly an order of magnitude less than that of the larger scale drivers and highly dependent on the invasion stage (traits were associated only with native range drivers). This suggests that future research should explicitly link biological traits to the different stages of invasion, and that a failure to consider residence time or characteristics of the native range may seriously overestimate the role of biological traits, which, in turn, may result in spurious predictions of plant invasiveness. [ABSTRACT FROM AUTHOR]

Limitations in our understanding of aquaculture strategies necessary for cultivating many desirable species of marine ornamental fishes have impeded examining their commercial production. Currently, only a small fraction of species have been captive bred. Recent research efforts have focused on evaluating the rearing potential of marine fish eggs and larvae collected at public aquariums. However, as exhibits contain multiple species, accurate identification is crucial for determining species-specific larval rearing protocols. In this study, marine fish eggs and larvae were collected at four public display aquariums and were preserved for genetic identification prior to and during larviculture trials. During the project, numerous marine fish species were identified ( n = 14) and three desirable species displayed traits conducive to captive breeding. Pomacanthus semicirculatus was identified using molecular techniques prior to metamorphosis and verified morphologically once grown. This species was also reared through the larval phase and into the juvenile (or nursery) phase. However, two species ( Paracanthurus hepatus and Heniochus sp.) did not reach metamorphosis and observations made during larviculture would not have been attributed to those particular species without the use of molecular identification techniques. [ABSTRACT FROM AUTHOR]

Intestinal tracts are among the most densely populated microbial ecosystems. Gut microbiota and their influence on the host have been well characterized in terrestrial vertebrates but much less so in fish. This is especially true for coral reef fishes, which are among the most abundant groups of vertebrates on earth. Surgeonfishes (family: Acanthuridae) are part of a large and diverse family of reef fish that display a wide range of feeding behaviours, which in turn has a strong impact on the reef ecology. Here, we studied the composition of the gut microbiota of nine surgeonfish and three nonsurgeonfish species from the Red Sea. High-throughput pyrosequencing results showed that members of the phylum Firmicutes, especially of the genus Epulopiscium, were dominant in the gut microbiota of seven surgeonfishes. Even so, there were large inter- and intraspecies differences in the diversity of surgeonfish microbiota. Replicates of the same host species shared only a small number of operational taxonomic units ( OTUs), although these accounted for most of the sequences. There was a statistically significant correlation between the phylogeny of the host and their gut microbiota, but the two were not completely congruent. Notably, the gut microbiota of three nonsurgeonfish species clustered with some surgeonfish species. The microbiota of the macro- and microalgavores was distinct, while the microbiota of the others (carnivores, omnivores and detritivores) seemed to be transient and dynamic. Despite some anomalies, both host phylogeny and diet were important drivers for the intestinal microbial community structure of surgeonfishes from the Red Sea. [ABSTRACT FROM AUTHOR]

Newly recruited Ctenochaetus striatus were monitored over a 16-month period in American Samoa, 2002-2003. During this period, a mass recruitment of age-0 C. striatus occurred in March 2002 with numbers reaching 22.9 recruits m. This program provided an invaluable opportunity to (1) analyze the dynamics of a mass recruitment episode and to assess its significance with respect to more typical patterns of recruitment and (2) establish the pattern of recruit growth during their first year of life. Age-based analysis indicated that the mass recruitment generated about 90 % of annual recruitment, but recruit mortality was high; thus, most recruitment was provided by continuous settlement throughout the year. The mass event appeared to be a short-lived pulse with recruits residing on the reef an average of 14.1 d compared with 161.1 d for other recruits. Recruits grew rapidly, achieving 90 % of their adult size during their first year, and they formed their first otolith annulus after 1 yr, thereby providing a firm basis for otolith interpretation of fish ages during the early life history phase of this species. The extensive age-based documentation of their first year growth in this study validates the distinctive 'square' growth pattern exhibited by acanthurids as described in the literature (i.e., long life span with rapid initial growth that quickly reaches an asymptotic size), and it demonstrates the impact that the presence of age-0 fish has when generating growth parameters for populations exhibiting square growth. We found that the parameters from the re-parameterized von Bertalanffy growth function have preferred characteristics when modeling square growth in fish and that fixing age-at-length zero to pelagic larval duration is a preferable method to constrain growth models when lacking age-0 fish. [ABSTRACT FROM AUTHOR]

1. Periodically harvested fisheries closures are widely implemented across the South Pacific as a conservation and fisheries management tool. There is a lack of information on the mechanisms and effectiveness of this management system in meeting fisheries and ecosystem sustainability goals. 2. A before-after-control-impact (BACI) pair design, was used to quantify flight initiation distance (FID), and biomass of two fishery-target (Acanthuridae and Scaridae) and one non-target (Chaetodontidae) families in two periodically harvested closures, two no-take marine reserves, and two open fished areas, prior to and after harvest of the periodically harvested closures. Creel surveys were used to quantify catch per unit effort (CPUE) in open fishing grounds, and during the periodic harvests. 3. Before harvest, FID of targeted families was higher in fished areas than periodically harvested areas. After harvest, Acanthuridae FID in periodically harvested closures increased significantly to beyond the maximum effective range of spearguns. Total biomass of fishes was lower in fished areas than areas under either type of management. Acanthuridae biomass in the periodically harvested closures was similar to fished areas, and lower than in the no-take reserves. There was no difference post-harvest for either total or Acanthuridae biomass. 4. CPUE was higher for fishing trips inside the periodically harvested closures than regular fishing activities. Fishes were generally larger in catches from periodically harvested closures, but this was not sufficient to account for the increase in CPUE, particularly of the Acanthuridae, which were significantly more abundant in the harvest catch. 5. When fishes are protected temporarily from fishing, their wariness decreases, which makes them more easily catchable when fishing is reinstated. This study shows that fish behavioural change is an important and overlooked benefit of periodically harvested closures. However, differences in the magnitude of behavioural changes between fishery-target families may result in contrasting outcomes of periodically harvested management regimes. [ABSTRACT FROM AUTHOR]

Bluespine unicornfish Naso unicornis and orangespine unicornfish Naso lituratus were sampled in Pohnpei and Guam, Micronesia, over 13 months to identify reproductive and age-based demographic features necessary for informed management. Age and reproductive information were derived from analysis of sagittal otoliths and gonads. Both species had moderate life spans [maximum ages of 23 ( N. unicornis) and 14 years ( N. lituratus)] compared with published estimates of conspecifics from other locations (>30 years) and of other Naso species. Length at maturation for N. unicornis was similar between Pohnpei and Guam while females consistently matured at a larger size [ c. 30 cm fork length ( LF)] than males ( c. 27 cm LF). This sex-specific pattern was reversed in N. lituratus for which estimates of maturation length (females: 15 cm LF; males: 18 cm LF) were only obtained from Guam. Developmental patterns in female gonads of both species suggested that initiation of maturation occurs very early. Growth patterns of N. lituratus displayed rapid asymptotic growth compared with N. unicornis and other congeners as well as slight sex-specific patterns of length-at-age. Results highlight the considerable spatial variation that may occur in the population biology of these species across various scales. Additionally, proper management remains complicated without improved knowledge of fishery trends and reproductive behaviour in unicornfishes, species that are prime fishery targets in Micronesia and elsewhere. [ABSTRACT FROM AUTHOR]

We herein evaluate several reproductive metrics of Hawaiian Archipelagic populations of the bluespine unicornfish ( Naso unicornis), an economically and ecologically important, broadly distributed tropical Pacific reef fish, based on multi-year, fishery-dependent and fishery-independent collections. Sex-specific spawning seasonality was characterized for fish collected mostly from Oahu (Main Hawaiian Islands, MHI) using a gonadosomatic index. Histological slides preparations were used to score gonad developmental phase and to classify individuals of either sex as immature or mature. Sex-specific median body lengths at maturity (L) were estimated by logistic fits of proportion mature versus length class. Spawning was highly seasonal in Hawaii, with a single brief (May-June) peak spawning period. Proportionate gonad-to-body weight values were relatively low, averaging only about 0.1 % and 0.6 % across all months of year and 0.16 % and 1.03 % during May-June for males and females, respectively. Median lengths at sexual maturity differed between the sexes. L values for fish collected throughout all months of year were 30.1 ± 0.5 (standard error) cm Fork Length (FL) for males and 35.5 ± 0.7 cm FL for females. Spawning seasonality and L estimates for bluespine unicornfish in Hawaii suggest that the species spawns several months earlier in the calendar year and matures at larger body lengths in Hawaii versus Guam, the Northern Mariana Islands, and Pohnpei in the Federated States of Micronesia. Estimated lengths at sexual maturity are compared to the minimum length (14 inches or 35.6 cm FL) mandated for this species in Hawaii: median size at maturity occurs at a length appreciably less than (males) or approximately equal to (females) minimum legal size. A likely disproportionately large contribution of old females to population replenishment is discussed relative to the minimum size limit. [ABSTRACT FROM AUTHOR]

Twenty-eight goldring surgeonfish, Ctenochaetus strigosus ( Bennett), manifesting skin lesions and originating from the north-western and main Hawaiian Islands were examined. Skin lesions were amorphous and ranged from simple dark or light discolouration to multicoloured tan to white sessile masses with an undulant surface. Skin lesions covered 2-66% of the fish surface, and there was no predilection for lesions affecting a particular part of the fish. Males appeared over-represented. Microscopy revealed the skin lesions to be hyperplasia, melanophoromas or iridophoromas. The presence of skin tumours in a relatively unspoiled area of Hawaii is intriguing. Explaining their distribution, cause and impact on survivorship of fish all merit further study because C. strigosus is an economically important fish in the region. [ABSTRACT FROM AUTHOR]

The present study summarizes observations on the skin plates ('retention plates') and taste buds (TBs) in the oropharyngeal cavity (OC) of 15 species of surgeonfishes (Acanthuridae), all of which are predominantly herbivorous. Two phenomena mark the OC of these fishes: the presence of skin-plates rich in collagen bundles at the apex of the jaws, and cornified papillae on the surface. It is suggested that these plates help in retaining the sections of algae perforated at their base by the fishe's denticulate teeth. The TBs, especially type I, are distributed across the buccal valves, palate and floor of the OC, forming species-specific groupings along ridges established by the network of sensory nerves. The number of TBs in the OC increases with growth of the fish up to a certain standard length, especially at the posterior part of the OC, and differs among the various species: e.g., Zebrasoma veliferum possesses 1420 TBs and Parcanthurus hepatus 3410. Species of Naso show a higher number of TBs than most species of Acanthurus, possibly connected with their more diversified diet. The pharyngeal region of these fishes is expanded through lowering the base of the gill-arches, and together with the occurrence of high numbers of TBs in this region, indicates the importance of the posterior region of the OC in herbivorous fishes for identification of the engulfed food particles prior to swallowing. The discussed observations shed light on the micro-evolutionary developments of the OC within the family Acanthuridae and contribute to the taxonomic characterization of the various species. [ABSTRACT FROM AUTHOR]

Surgeonfishes are a species-rich group and a major biomass on coral reefs. Three species are commonly found throughout South Atlantic, Acanthurus bahianus, A. chirurgus, and A. coeruleus. In this paper, we present the first cytogenetic data of these species, revealing a sequential chromosomal diversification. A. coeruleus was characterized by a relatively conserved karyotype evolved by pericentric inversions of some pairs (2n = 48, 2sm + 4st + 42a). In contrast, the karyotypes of A. bahianus (2n = 36) and A. chirurgus (2n = 34) were highly differentiated by the presence of six large metacentric pairs in A. bahianus (12m + 2sm + 4st + 18a) and A. chirurgus (12m + 2sm + 4st +1 6a) probably derived by chromosomal fusions that corroborate their closer relationship. A discernible in tandem fusion represents an autapomorphic character to A. chirurgus. In spite of macrostructure variation, single nucleolar organizer regions (NORs) on short arms of a subtelocentric pair and similar distribution of C-bands were observed in the three species. Overlapping of chromosomal data with molecular phylogeny indicated pericentric inversions which took place nearly at 19Ma while centric fusions are as recent as 5Ma. A physical mapping of coding and noncoding sequences in Acanthurus could clarify the role of additional rearrangements during their chromosomal evolution. [ABSTRACT FROM AUTHOR]

Marine organisms occasionally settle at exceptional densities, whereby thousands of individuals arrive concurrently. High levels of mortality, which has historically been attributed to predation or competition, often follow this episodic settlement of reef fishes. Here, however, we observed large numbers of newly settled surgeonfish (Ctenochaetus striatus) with white lesions lying dead on the sand amongst patch reefs following separate episodic settlement events in 2006 and 2009 in Moorea, French Polynesia. Pathogens have been identified as an important driver of population dynamics in other marine organisms but less so for reef fishes. Our observations suggest that disease outbreaks may play an underappreciated role as a mechanism of mortality following episodic settlement events in reef fishes. [ABSTRACT FROM AUTHOR]