Persister Cell Formation and Elevated lsrA and lsrC Gene Expression upon Hydrogen Peroxide Exposure in a Periodontal Pathogen Aggregatibacter actinomycetemcomitans.

The effect of hydrogen peroxide, an antiseptic dental treatment, on Aggregatibacter actinomycetemcomitans, the main causative agent of localized invasive periodontitis, was investigated. Hydrogen peroxide treatment (0.06%, 4× minimum inhibitory concentration) resulted in the persistence and survival of approximately 0.5% of the bacterial population. The surviving bacteria did not genetically acquire hydrogen peroxide resistance but exhibited a known persister behavior. Sterilization with mitomycin C significantly reduced the number of A. actinomycetemcomitans persister survivors. RNA sequencing of hydrogen peroxide-treated A. actinomycetemcomitans showed elevated expression of Lsr family members, suggesting a strong involvement of autoinducer uptake. In this study, we found a risk of A. actinomycetemcomitans persister residual from hydrogen peroxide treatment and hypothesized associated genetic mechanisms of persister from RNA sequencing.

The value of ecosystem services in global marine kelp forests.

While marine kelp forests have provided valuable ecosystem services for millennia, the global ecological and economic value of those services is largely unresolved. Kelp forests are diminishing in many regions worldwide, and efforts to manage these ecosystems are hindered without accurate estimates of the value of the services that kelp forests provide to human societies. Here, we present a global estimate of the ecological and economic potential of three key ecosystem services - fisheries production, nutrient cycling, and carbon removal provided by six major forest forming kelp genera (Ecklonia, Laminaria, Lessonia, Macrocystis, Nereocystis, and Saccharina). Each of these genera creates a potential value of between $64,400 and $147,100/hectare each year. Collectively, they generate between $465 and $562 billion/year worldwide, with an average of $500 billion. These values are primarily driven by fisheries production (mean $29,900, 904 Kg/Ha/year) and nitrogen removal ($73,800, 657 Kg N/Ha/year), though kelp forests are also estimated to sequester 4.91 megatons of carbon from the atmosphere/year highlighting their potential as blue carbon systems for climate change mitigation. These findings highlight the ecological and economic value of kelp forests to society and will facilitate better informed marine management and conservation decisions.

Differences in fish herbivory among tropical and temperate seaweeds and annual patterns in kelp consumption influence the tropicalisation of temperate reefs.

Climate change is leading to novel species interactions and profoundly altering ecosystems. In marine systems, tropical and subtropical species are increasing in higher latitudes. This has been linked to the deforestation of temperate coastlines, as direct effects of ocean warming combine with increased herbivory from tropical and sub-tropical fishes and lead to the decline of canopy-forming kelp. Here, we tested the hypothesis that this deforestation may be facilitated by greater palatability of temperate kelp and other canopy seaweeds compared to tropical taxa. We used multiple-choice filmed feeding field experiments and chemical analyses to measure the palatability of temperate and tropical seaweeds from Tosa Bay (southeastern Japan) and we used single-species feeding assays to measure changes in consumption of the kelp Ecklonia cava throughout the year. We found no evidence that temperate seaweeds are more palatable to herbivorous fish. In the multiple-choice assays, consumption was concentrated on both tropical and temperate Sargassum species, which are ephemeral and peak in abundance in the spring/early summer. Consumption of the kelp Ecklonia cava peaked during the autumn, when Sargassum species are absent. The highest levels of kelp herbivory coincide with the reproductive season for E. cava and may contribute to the long-term decline of these kelp forests in southern Japan.

Effectiveness of blocking primers and a peptide nucleic acid (PNA) clamp for 18S metabarcoding dietary analysis of herbivorous fish.

The structure of food webs and carbon flow in aquatic ecosystems can be better understood by studying contributing factors such as the diets of herbivorous fish. Metabarcoding using a high-throughput sequencer has recently been used to clarify prey organisms of various fish except herbivorous fish. Since sequences of predator fish have dominated in sequences obtained by metabarcoding, we investigated a method for suppressing the amplification of fish DNA by using a blocking primer or peptide nucleic acid (PNA) clamp to determine the prey organisms of herbivorous fish. We designed three blocking primers and one PNA clamp that anneal to fish-specific sequences and examined how efficient they were in suppressing DNA amplification in various herbivorous fish. The results showed that the PNA clamp completely suppressed fish DNA amplification, and one of the blocking primers suppressed fish DNA amplification but less efficiently than the PNA clamp. Finally, we conducted metabarcoding using mock community samples as templates to determine whether the blocking primer or the PNA clamp was effective in suppressing fish DNA amplification. The results showed that the PNA clamp suppressed 99.3%-99.9% of fish DNA amplification, whereas the blocking primer suppressed 3.3%-32.9%. Therefore, we propose the application of the PNA clamp for clarifying the prey organisms and food preferences of various herbivorous fish.

Energy expenditure and oxygen uptake kinetics in critically ill elderly patients.

BACKGROUND: Resting energy expenditure (REE) measurement of critically ill patients is essential for better nutrition management. Younger people increase their oxygen delivery ( ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ ) to meet energy demands, but few reports have investigated oxygen uptake kinetics in elderly patients, which are the main target population in today's intensive care units (ICUs). In this study, we evaluated REE, ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ , and oxygen extraction ratio (O2 Ext: oxygen consumption [ V̇O2${\dot{{\rm{V}}}}{{\rm{O}}_2}$ ]/ ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ ) to clarify appropriate energy needs and consumption in elderly ICU patients. METHODS: This retrospective observational study included ventilated ICU patients who were divided into elderly participants (age ≥ 65 years) and nonelderly participants (age ≤64 years). V̇O2${\dot{{\rm{V}}}}{{\rm{O}}_2}$ , CO2 production, and cardiac output were measured by indirect calorimetry and noninvasive hemodynamic monitoring for up to 5 days. The initial values of REE, ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ , and O2 Ext were compared between elderly and nonelderly patients. RESULTS: This study included 102 patients, of whom 52% (n = 53) were elderly. The absolute deviation of measured REE per ideal body weight (IBW) was significantly higher in elderly than in nonelderly patients (9.3 ± 6.9 vs 6.3 ± 6.6 kcal/kg; P < .01). ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ had a strong negative correlation with age (P < .01). The O2 Ext value was significantly higher in elderly than in nonelderly patients (37 ± 19% vs 29 ± 13%; P = .03). CONCLUSIONS: Elderly critically ill patients were characterized by higher deviations in REE, lower ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ , and higher O2 Ext. In elderly patients, O2 Ext rather than ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ could be increased to meet energy consumption demands.

Magnesium Hydroxide Nanoparticles Kill Exponentially Growing and Persister Escherichia coli Cells by Causing Physical Damage.

Magnesium hydroxide nanoparticles are widely used in medicinal and hygiene products because of their low toxicity, environment-friendliness, and low cost. Here, we studied the effects of three different sizes of magnesium hydroxide nanoparticles on antibacterial activity: NM80, NM300, and NM700. NM80 (D50 = 75.2 nm) showed a higher bactericidal effect against Escherichia coli than larger nanoparticles (D50 = 328 nm (NM300) or 726 nm (NM700)). Moreover, NM80 showed a high bactericidal effect against not only exponential cells but also persister cells, which are difficult to eliminate owing to their high tolerance to antibiotics. NM80 eliminated strains in which magnesium-transport genes were knocked out and exhibited a bactericidal effect similar to that observed in the wild-type strain. The bactericidal action involved physical cell damage, as confirmed using scanning electron microscopy, which showed that E. coli cells treated with NM80 were directly injured.

Homogenization and miniaturization of habitat structure in temperate marine forests.

Humans are rapidly transforming the structural configuration of the planet's ecosystems, but these changes and their ecological consequences remain poorly quantified in underwater habitats. Here, we show that the loss of forest-forming seaweeds and the rise of ground-covering 'turfs' across four continents consistently resulted in the miniaturization of underwater habitat structure, with seascapes converging towards flattened habitats with smaller habitable spaces. Globally, turf seascapes occupied a smaller architectural trait space and were structurally more similar across regions than marine forests, evidencing habitat homogenization. Surprisingly, such habitat convergence occurred despite turf seascapes consisting of vastly different species richness and with different taxa providing habitat architecture, as well as across disparate drivers of marine forest decline. Turf seascapes contained high sediment loads, with the miniaturization of habitat across 100s of km in mid-Western Australia resulting in reefs retaining an additional ~242 million tons of sediment (four orders of magnitude more than the sediments delivered fluvially annually). Together, this work demonstrates that the replacement of marine forests by turfs is a generalizable phenomenon that has profound consequences for the ecology of temperate reefs.

Diel vertical movements and feeding behaviour of blue humphead parrotfish Scarus ovifrons in a temperate reef of Japan.

The feeding ecology of scarinine parrotfishes on tropical coral reefs has received considerable attention in the past few decades; nonetheless, relatively few studies have been conducted in high-latitude reefs. Among the Indo-Pacific Scarus species, Scarus ovifrons is unique, being largely restricted to the warm temperate waters of Japan. Nonetheless, there is very little information available on the feeding ecology of this species. In this study, the authors used acoustic telemetry to detect the diel vertical movement patterns of S. ovifrons, video survey to detect its feeding depths and substrata and focal follow survey and genetic analysis to identify algae composition on the feeding scars at Kashiwajima Island, southwestern Japan (32° 46' N, 132° 38' E). Acoustic telemetry revealed that S. ovifrons spent most of its time in shallow water (<10 m) during the day and slept in deeper water (10-15 m) at night. Video and focal follow surveys revealed that most fishes of various sizes regularly took bites on epilithic algae and detrital materials on rocky substrata at depths of <10 m, but large fishes (>40 cm total length) sometimes took bites directly on live corals (Acropora solitaryensis) at the 5 m depth zone where live tabular corals dominated the benthos. Molecular phylogenetic analyses revealed that epilithic algae collected from feeding scars were mainly composed of Rhodophyta, and coralline algae were less often targeted. Overall, this study revealed that S. ovifrons feeds mostly at depths <10 m, and the feeding algae substrata of the species are similar to those of tropical coral reef parrotfishes.

A case of mixed neuroendocrine non-neuroendocrine neoplasm of the distal bile duct with biliary intraepithelial neoplasia.

A 72-year-old man with obstructive jaundice, diagnosed with distal biliary carcinoma, underwent pylorus-preserving pancreaticoduodenectomy. The patient was histopathologically and immunohistochemically diagnosed with mixed neuroendocrine non-neuroendocrine neoplasm. Pathological examination revealed that the well-differentiated adenocarcinoma components occupied the superficial portion of the bile duct and the neuroendocrine carcinoma components were located in the deeper portion of the bile duct. Pathological examination showed that a portion of the biliary intraepithelial neoplasia arose from the proximal bile duct and then extended to the gallbladder. The patient was administered tegafur/gimeracil/oteracil as adjuvant chemotherapy, and the lesion did not recur for 6 months postoperatively.

Random PCR-based genotyping by sequencing technology GRAS-Di (genotyping by random amplicon sequencing, direct) reveals genetic structure of mangrove fishes.

While various technologies for high-throughput genotyping have been developed for ecological studies, simple methods tolerant to low-quality DNA samples are still limited. In this study, we tested the availability of a random PCR-based genotyping-by-sequencing technology, genotyping by random amplicon sequencing, direct (GRAS-Di). We focused on population genetic analysis of estuarine mangrove fishes, including two resident species, the Amboina cardinalfish (Fibramia amboinensis, Bleeker, 1853) and the Duncker's river garfish (Zenarchopterus dunckeri, Mohr, 1926), and a marine migrant, the blacktail snapper (Lutjanus fulvus, Forster, 1801). Collections were from the Ryukyu Islands, southern Japan. PCR amplicons derived from ~130 individuals were pooled and sequenced in a single lane on a HiSeq2500 platform, and an average of three million reads was obtained per individual. Consensus contigs were assembled for each species and used for genotyping of single nucleotide polymorphisms by mapping trimmed reads onto the contigs. After quality filtering steps, 4,000-9,000 putative single nucleotide polymorphisms were detected for each species. Although DNA fragmentation can diminish genotyping performance when analysed on next-generation sequencing technology, the effect was small. Genetic differentiation and a clear pattern of isolation-by-distance was observed in F. amboinensis and Z. dunckeri by means of principal component analysis, FST and the admixture analysis. By contrast, L. fulvus comprised a genetically homogeneous population with directional recent gene flow. These genetic differentiation patterns reflect patterns of estuary use through life history. These results showed the power of GRAS-Di for fine-grained genetic analysis using field samples, including mangrove fishes.

Determination of Aqueous Formic and Acetic Acids by Purge-and-Trap Analysis with a Needle-Type Extraction Device and Gas Chromatography Barrier Discharge Ionization Detector.

A purge-and-trap method using a needle-type extraction device and a gas chromatography-barrier discharge ionization detector for the analysis of formic (FA) and acetic acids (AA) in aqueous samples is presented. An activated carbon-based adsorbent, Carboxen 1000, was employed as the extraction medium for the needle-type extraction device. The sampling time was 5 min for collecting headspace gas in a glass vial, including 10 mL of an aqueous sample. The detection limits for FA and AA with a headspace sampling volume of 100 mL were 3.3 and 2.0 mg L-1, respectively. Since the proposed method was based on purge-and-trap collection, it was suitable for the determination of aqueous FA and AA in complex matrices with simple and rapid sample preparation steps. The proposed method was applied to the determination of FA and AA in fruit juice samples and FA generated by the electrochemical reduction of carbon dioxide.

Is modified brief assertiveness training for nurses effective? A single-group study with long-term follow-up.

AIM: To evaluate the long-term effectiveness of modified brief assertiveness training (with cognitive techniques) for nurses. BACKGROUND: Most assertiveness training takes a long time to conduct; thus, briefer training is required for universal on-the-job training in the workplace. METHODS: In this single-group study, nurses received two 90-min training sessions with a 1-month interval between sessions. The degree of assertiveness was assessed by using the Rathus Assertiveness Schedule as the primary outcome, at four time points: pre- and post-training, 3-month follow-up and 6-month follow-up. RESULTS: A total of 33 nurses received the training, and the mean Rathus Assertiveness Schedule score improved from -14.2 (SD = 16.5) pre-training to -10.5 (SD = 18.0) post-training (p < .05). These improvements were maintained until the 6-month follow-up. The pre-post effect size of 0.22 (indicating small effect) was larger than the effect sizes ranging from -0.56 to 0.17 (no effect) reported in previous studies that used brief training. CONCLUSIONS: Modified brief assertiveness training seems feasible and may achieve long-term favourable outcomes in improving assertiveness among nurses. IMPLICATIONS FOR NURSING MANAGEMENT: The ease of implementation of assertiveness training is important because creating an open environment for communication leads to improved job satisfaction, improved nursing care and increased patient safety.

Marine protected area restricts demographic connectivity: Dissimilarity in a marine environment can function as a biological barrier.

The establishment of marine protected areas (MPAs) can often lead to environmental differences between MPAs and fishing zones. To determine the effects on marine dispersal of environmental dissimilarity between an MPA and fishing zone, we examined the abundance and recruitment patterns of two anemonefishes (Amphiprion frenatus and A. perideraion) that inhabit sea anemones in different management zones (i.e., an MPA and two fishing zones) by performing a field survey and a genetic parentage analysis. We found lower levels of abundance per anemone in the MPA compared to the fishing zones for both species (n = 1,525 anemones, p = .032). The parentage analysis also showed that lower numbers of fishes were recruited from the fishing zones and outside of the study area into each anemone in the MPA than into each anemone in the fishing zones (n = 1,525 anemones, p < .017). However, the number of self-recruit production per female did not differ between the MPA and fishing zones (n = 384 females, p = .516). Because the ocean currents around the study site were unlikely to cause a lower settlement intensity of larvae in the MPA, the ocean circulation was not considered crucial to the observed abundance and recruitment patterns. Instead, stronger top-down control and/or a lower density of host anemones in the MPA were potential factors for such patterns. Our results highlight the importance of dissimilarity in a marine environment as a factor that affects connectivity.

Development and evaluation of a modified brief assertiveness training for nurses in the workplace: a single-group feasibility study.

BACKGROUND: Effective communication has a great impact on nurses' job satisfaction, team relationships, as well as patient care/safety. Previous studies have highlighted the various beneficial effects of enhancing communication through assertiveness training programs for nurses. However, most programs take a long time to implement; thus, briefer programs are urgently required for universal on-the-job-training in the workplace. The purpose of this feasibility study was to develop and evaluate a modified brief assertiveness training program (with cognitive techniques) for nurses in the workplace. METHODS: This study was carried out as a single-group, open trial (pre-post comparison without a control group). Registered nurses and assistant nurses, working at two private psychiatric hospitals in Miyazaki Prefecture in Japan, were recruited. After enrolling in the study, participants received a program of two 90-min sessions with a 1-month interval between sessions. The primary outcome was the Rathus Assertiveness Schedule (RAS), with secondary measurements using the Brief Version of the Fear of Negative Evaluation Scale (BFNE) and the Brief Job Stress Questionnaire (BJSQ). Assessments were conducted at baseline and after a 1-month interval (pre- and post-intervention). RESULTS: A total of 22 participants enrolled in the study and completed the program. The mean total score on the primary outcome (RAS) significantly improved from -12.9 (SD = 17.2) to -8.6 (SD = 18.6) (p = 0.01). The within-group effect size at the post-intervention was Cohen's d = 0.24; this corresponds to the small effect of the program. Regarding secondary outcomes, there were no statistically significant effects on the BFNE or any of the BJSQ subscales (job-stressors, psychological distress, physical distress, worksite support, and satisfaction). CONCLUSIONS: This single-group feasibility study demonstrated that our modified brief assertiveness training for nurses seems feasible and may achieve a favorable outcome in improving their assertiveness. Further controlled trials with longer follow-up periods are required in order to address the limitations of this study.

Image quality of a novel light-emitting diode (LED)-illuminated colonoscope.

BACKGROUND AND STUDY AIMS: Light-emitting diodes (LEDs) are used widely for their high luminous efficiency and durability. We developed a novel prototype high definition endoscope with white LEDs and evaluated the image quality it produced against a commercial endoscope with conventional light source. PATIENTS AND METHODS: The specifications of both colonoscopes were identical, except for the LED light source at the tip of the prototype. We examined 20 patients with rectal or sigmoid colon lesions and the image quality was evaluated in 40 images (one image from the LED colonoscope and one from the conventional colonoscope for each lesion) by three endoscopists. We additionally evaluated the 17 videos recorded with the LED colonoscope that were available. Image quality, mucosal and vascular color, and luminous distribution and intensity were scored on a 5-point scale. RESULTS: The mean score for vascular color given by one evaluator was significantly higher using the LED colonoscope than using the conventional colonoscope. The mean scores for mucosal color and luminous intensity from another evaluator were significantly lower with the LED colonoscope than with the conventional colonoscope. There were no significant differences in the luminous distribution scores for any of the evaluators. The image quality of the videos was evaluated as being similar with both colonoscopes. CONCLUSIONS: Image quality from the LED and conventional colonoscopes were similar, although the luminous intensity of the LEDs is inferior to that of the conventional light source at the present time.

Sediment pollution impacts sensory ability and performance of settling coral-reef fish.

Marine organisms are under threat globally from a suite of anthropogenic sources, but the current emphasis on global climate change has deflected the focus from local impacts. While the effect of increased sedimentation on the settlement of coral species is well studied, little is known about the impact on larval fish. Here, the effect of a laterite "red soil" sediment pollutant on settlement behaviour and post-settlement performance of reef fish was tested. In aquarium tests that isolated sensory cues, we found significant olfaction-based avoidance behaviour and disruption of visual cue use in settlement-stage larval fish at 50 mg L(-1), a concentration regularly exceeded in situ during rain events. In situ light trap catches showed lower abundance and species richness in the presence of red soil, but were not significantly different due to high variance in the data. Prolonged exposure to red soil produced altered olfactory cue responses, whereby fish in red soil made a likely maladaptive choice for dead coral compared to controls where fish chose live coral. Other significant effects of prolonged exposure included decreased feeding rates and body condition. These effects on fish larvae reared over 5 days occurred in the presence of a minor drop in pH and may be due to the chemical influence of the sediment. Our results show that sediment pollution of coral reefs may have more complex effects on the ability of larval fish to successfully locate suitable habitat than previously thought, as well as impacting on their post-settlement performance and, ultimately, recruitment success.

The tropicalization of temperate marine ecosystems: climate-mediated changes in herbivory and community phase shifts.

Climate-driven changes in biotic interactions can profoundly alter ecological communities, particularly when they impact foundation species. In marine systems, changes in herbivory and the consequent loss of dominant habitat forming species can result in dramatic community phase shifts, such as from coral to macroalgal dominance when tropical fish herbivory decreases, and from algal forests to 'barrens' when temperate urchin grazing increases. Here, we propose a novel phase-shift away from macroalgal dominance caused by tropical herbivores extending their range into temperate regions. We argue that this phase shift is facilitated by poleward-flowing boundary currents that are creating ocean warming hotspots around the globe, enabling the range expansion of tropical species and increasing their grazing rates in temperate areas. Overgrazing of temperate macroalgae by tropical herbivorous fishes has already occurred in Japan and the Mediterranean. Emerging evidence suggests similar phenomena are occurring in other temperate regions, with increasing occurrence of tropical fishes on temperate reefs.

Tropical fishes dominate temperate reef fish communities within western Japan.

Climate change is resulting in rapid poleward shifts in the geographical distribution of tropical and subtropical fish species. We can expect that such range shifts are likely to be limited by species-specific resource requirements, with temperate rocky reefs potentially lacking a range of settlement substrates or specific dietary components important in structuring the settlement and success of tropical and subtropical fish species. We examined the importance of resource use in structuring the distribution patterns of range shifting tropical and subtropical fishes, comparing this with resident temperate fish species within western Japan (Tosa Bay); the abundance, diversity, size class, functional structure and latitudinal range of reef fishes utilizing both coral reef and adjacent rocky reef habitat were quantified over a 2 year period (2008-2010). This region has undergone rapid poleward expansion of reef-building corals in response to increasing coastal water temperatures, and forms one of the global hotspots for rapid coastal changes. Despite the temperate latitude surveyed (33°N, 133°E) the fish assemblage was both numerically, and in terms of richness, dominated by tropical fishes. Such tropical faunal dominance was apparent within both coral, and rocky reef habitats. The size structure of the assemblage suggested that a relatively large number of tropical species are overwintering within both coral and rocky habitats, with a subset of these species being potentially reproductively active. The relatively high abundance and richness of tropical species with obligate associations with live coral resources (i.e., obligate corallivores) shows that this region holds the most well developed temperate-located tropical fish fauna globally. We argue that future tropicalisation of the fish fauna in western Japan, associated with increasing coral habitat development and reported increasing shifts in coastal water temperatures, may have considerable positive economic impacts to the local tourism industry and bring qualitative changes to both local and regional fisheries resources.

Habitat use by fishes in coral reefs, seagrass beds and mangrove habitats in the Philippines.

Understanding the interconnectivity of organisms among different habitats is a key requirement for generating effective management plans in coastal ecosystems, particularly when determining component habitat structures in marine protected areas. To elucidate the patterns of habitat use by fishes among coral, seagrass, and mangrove habitats, and between natural and transplanted mangroves, visual censuses were conducted semiannually at two sites in the Philippines during September and March 2010-2012. In total, 265 species and 15,930 individuals were recorded. Species richness and abundance of fishes were significantly higher in coral reefs (234 species, 12,306 individuals) than in seagrass (38 species, 1,198 individuals) and mangrove (47 species, 2,426 individuals) habitats. Similarity tests revealed a highly significant difference among the three habitats. Fishes exhibited two different strategies for habitat use, inhabiting either a single (85.6% of recorded species) or several habitats (14.4%). Some fish that utilized multiple habitats, such as Lutjanus monostigma and Parupeneus barberinus, showed possible ontogenetic habitat shifts from mangroves and/or seagrass habitats to coral reefs. Moreover, over 20% of commercial fish species used multiple habitats, highlighting the importance of including different habitat types within marine protected areas to achieve efficient and effective resource management. Neither species richness nor abundance of fishes significantly differed between natural and transplanted mangroves. In addition, 14 fish species were recorded in a 20-year-old transplanted mangrove area, and over 90% of these species used multiple habitats, further demonstrating the key role of transplanted mangroves as a reef fish habitat in this region.