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The tropical catadromous eel, Anguilla bicolor pacifica, an important fishery resource in Southeast Asia, is under threat due to overexploitation (especially of its glass eel phase) and the limited information on their current genetic status which is necessary for resource management. Mitochondrial DNA (mtDNA) control region sequences, a useful marker for population genetic studies in many aquatic organisms, were used to investigate the genetic diversity, population structure and demographic history of A. bicolor pacifica in the region. A total of 151 specimens were collected from three sites in Southeast Asia, namely: Phu Yen, Vietnam (n = 48); General Santos, Philippines (n = 52); and, Palu, Indonesia (n = 51). A total of 138 haplotypes were identified using the mtDNA control region sequences. In spite of the lack of shared haplotypes, low and non-significant FST values, high haplotype diversity in concurrence with relatively low nucleotide diversity, a haplotype network with no phylogeographic structuring indicate no significant genetic population structuring among the eel samples from Vietnam, Philippines and Indonesia. Population expansion of A. bicolor pacifica was also suggested based on the results of the neutrality tests, mismatch distribution analysis and Bayesian skyline plot. Taken together, a joint management strategy for A. bicolor pacifica must involve countries in Southeast Asia particularly Vietnam, Philippines and Indonesia for its sustainable use.

Recent studies have demonstrated that interstices of coral rubble harbor rich and diverse assemblages of motile cryptic animals. Habitats of coral rubble are prone to frequent physical disturbances, so colonization is an important process to maintain the assemblages of these cryptic animals. In order to examine the pattern of colonization, field experiments were carried out using mesh traps with defaunated coral rubble: one treatment placed on the bottom and the other raised 15 cm above the bottom (throughout as “raised”) to restrict colonizers to only organisms that are able to invade via the water column. Results of nMDS and PERMANOVA showed significant differences between the assemblages of the bottom and raised treatments. Species-specific variations in the rate of colonization, which were estimated by fitting the von Bertalanffy equation, contributed to the variations in the cryptic assemblages. Generally, decapods and gastropods colonized via the benthic pathway with colonizing individuals moving on the surface of the bottom substrate, while copepods and non-shelled gammarids colonized via the planktonic pathway. Variations in cryptic assemblages in coral rubble microhabitats may be partly due to differences in contributions via the two colonization pathways.

Donkey's ear abalone (Haliotis asinina) is a gourmet seafood export of the Philippines but its wild stock is at risk due to high fishing pressure. This paper aims to show evidences that abalone seeds produced in hatcheries can be used to rehabilitate its fisheries in multi-use buffer zones of marine reserves. This study released hatchery-reared abalone juveniles in a community-based resource enhancement site located in multi-use reef surrounding Molocaboc. This island is populated by fisherfolks who participated in protecting the 4000 m2 coralline release site. Molocaboc Reef comprise the buffer zone of Sagay Marine Reserve in Negros Occidental province in central Philippines. Data obtained during monthly monitoring of the release site from 2011 to 2016 showed that hatchery-reared abalone established together with its wild counterparts. Baseline wild abalone catch per unit effort (CPUE = 3 divers 1 h fishing) is 0.005/100 m2 in 2011. Mean monthly CPUE after release increased to 53 hatchery-reared and wild individuals combined. The mean shell length, body weight and body mass index of the hatchery-reared individuals (6.4 cm, 70.9 g, 10.5 g/cm) is not significantly different from those of the recovered wild stocks (6.9 cm, 85.0 g, 12.0 g/cm). The stocks recovered in the midst of undisrupted fishing activities in areas immediately outside and beyond the release site. Thus, mass production of seeds of overfished species is advised to repopulate degraded fisheries, improve catch of fisherfolks living within buffer areas of marine reserves and contribute to production and trade of high-value species.

Most demersal fishes maintain strong relations with bottom substrates and bottom depths and/or topography during their lives. It is important to know these relations to for understand their lives. In Tokyo Bay, red stingray, Dasyatis akajei, classified as near-threatened species by IUCN, has increased since the 1980s. It is a top predator and engages in ecosystem engineer by mixing the sand bed surface through burring behavior, and greatly influences a coastal ecosystem. It is reported that this species invades in plage and tidal flats and has sometimes injured beachgoers and people gathering clams in Tokyo bay. Thus, it is necessary to know its behavior and habitat use to avoid accidents and to better conserve the biodiversity of ecosystems. However, previous studies have not examined its relationship with the bottom environment. This study aims to describe its behavior in relation to the bottom environment. We sounded three dimensional bottom topography of their habitat off Kaneda Cove in Tokyo Bay with interferometric sidescan sonar system and traced the movement of red stingrays by attaching a data logger system to survey their migration. The results revealed that red stingray repeated vertical movement between the surface and bottom, and used not only sand beds but also rocky beds.

Because fish have a high dispersal ability, an understanding coral reef fish metacommunity structure is vital for effective conservation. Coral reefs provide patchy habitat of various sizes and scales. We examined the species–area relationship (SAR) of damselfish (Pomacentridae) assemblages over 81 environmentally homogenous patch reefs ranging 0.07–45.4 m2 with low coral cover. Patch reefs were located in the shallow back reef ( 1/2500) color aerial photograph used as a fine-scale seascape map. To assess the effects of three-dimensional meso-scale rugosity on species richness, we assumed that all reefs had a cylindrical shape and examined species by volume (area × height) relationships (SVR). Patch reef volume was a better determinant of species richness than area, and the regression functions of SVR provided better estimates of patch reef species richness. Neither the observed SVRs nor SARs, however, could be explained by a random placement model alone. Our results suggest that several small reefs are likely to have higher species richness than a single large reef of equivalent area in the shallow back reef where large patch reefs are flat. Thus, total patch reef volume (area × height) better reflects meso-scale rugosity and is a useful indicator of total species richness relative to the total amount of essential habitat in shallow back reefs.

Small cryptic animals utilize the interstices of coral rubble as a refuge from predators and form a significant part of the diversity and productivity of coral reef ecosystems. In the present study, we examined the composition of cryptic mobile animals along an estuarine gradient within a mangrove-seagrass-coral reef seascape off Ishigaki Island, southwest Japan. We used mesh traps with defaunated coral rubble to sample cryptic mobile animals quantitatively at four sites: upper-estuary mangrove, lower-estuary mangrove, seagrass bed, and coral lagoon. Sixty-five species of decapod crustaceans, gastropods, fishes, and other mobile animals were identified. The assemblage composition of these identified species was significantly different among the four sites. Low-resolution taxa including copepods, gammarids, and other taxa also showed significant differences in composition among the four sites. Two types of rubble (branch and lump) were used to examine the possible effects of microhabitat structure, but no significant effect on assemblage composition was detected. Results indicate that, despite the close proximity and high degree of water mass mixing among the sites, cryptic animals colonized the trays from the surrounding habitats, and that the assemblage of cryptic animals varied considerably along the estuarine gradient.

Determination of the growth pattern of a harvested species is an important step toward a proper assessment and suitable management of the stock. Although coconut crab Birgus latro populations in most regions have been severely depleted, few reliable biological data are available. We assessed the growth of B. latro using a mark-recapture method based on the use of passive integrated transponder (PIT) tags on Hatoma Island, located southwest of Okinawa, Japan. Of 781 crabs tagged (337 males, 444 females; 14.89 to 58.03 mm thoracic length (ThL)), 17 males and 20 females were recaptured. The application of PIT tags provided field data for growth of individuals for up to 2326 d and confirmed that coconut crabs molt during the winter dry season on Hatoma Island. The curves relating ThL with age, estimated from data of 29 crabs that had spent one or multiple winter dry seasons at liberty, showed that the coconut crab is an extremely slow growing species, with males showing much higher mean asymptotic ThL (69.87 mm) than females (42.79 mm). The Brody growth coefficient (K)was 0.061 yr �1 for males and 0.091 yr �1 for females. This study is the first to provide growth estimates of wild coconut crabs based on mark- recapture over multiple years. Potentially long-lived, slow growing species such as coconut crabs may be susceptible to overharvesting, and a cautious approach is recommended to the determina- tion of resource management regimes for B. latro.

In local reef fish communities, species richness increases with increasing reef area. At Ishigaki Island, Japan, species richness is much lower on large reefs in the shallow back reef than that expected from random placement model simulations (RPMS). As three aggressive territorial herbivorous damselfish, Stegastes nigricans, Stegastes lividus and Hemiglyphidodon plagiometopon, coexist only on such large reefs, we focused on these species and examined patterns of their distribution and abundance on 84 patch reefs of various sizes (area and height). We also examined their aggressive intra- and interspecific behavioural interactions and habitat use on the two large reefs (the largest complex patch reef and the large flat patch reef) among the 84 patch reefs. While the abundance of both S. lividus and H. plagiometopon was highly correlated with patch reef area, that of S. nigricans was closely correlated with patch reef height. For S. nigricans and S. lividus, interspecific interactions occurred significantly more frequently than intraspecific interactions on the large flat patch reef. However, there was no significant difference in frequencies of the two interaction types on the largest complex patch reef, where they three-dimensionally segregated conspecific territories. This study suggested that reef height as well as reef area influence the distribution and abundance of these territorial herbivorous damselfish in the shallow back reef. As large patch reefs cannot be tall allometrically in shallow back reefs, relatively flat patch reefs may not have the high species richness expected from RPMS based on reef area.

Seagrass beds are often considered to be important nurseries for coral reef fish, yet the effectiveness of these nursery functions (refuge and food availability) at different juvenile stages is poorly understood. To understand how the demands of juvenile fish on seagrass nursery functions determines the timing of ontogenetic habitat shifts from seagrass beds to coral reefs, we conducted visual transect survey and field tethering and caging experiments on three different sizes of the coral reef fish Pacific yellowtail emperor (Lethrinus atkinsoni) during its juvenile tenure in seagrass beds at Ishigaki Island, southern Japan. The study showed that although the number of individual L. atkinsoni juveniles decreased by >90 % during their stay in the seagrass nursery, the shelter and/or food availability functions of the nursery, at least for a juvenile size of approximately 5 cm total length (TL), provided the best survival and growth option. The timing of ontogenetic migration to coral reefs of larger fish (>8 cm TL) was attributed to foraging efficiency for larger food items in different habitats. Overall, the function of the seagrass bed nursery changed with juvenile body size, with marginally higher survival and significantly greater growth rates during early juvenile stages in seagrass beds compared to coral reefs. This would contribute to the enhancement in the number of individuals eventually recruited to adult populations.

The interstices of coral rubble provide a good refuge for cryptic small crustaceans and molluscs, which are important prey items for reef fishes. In this study, we focused on the assemblage composition of cryptic mobile species along the depth gradient at an outer reef slope. Traps with coral rubble (22 × 18 × 6 cm) were set at three sites at different depths, and mobile animals that colonized the traps were sorted. In total, 117 species of larger animals (mainly Decapoda and Gastropoda) were recorded: 71 species at the 3 m point, 53 species at the 11 m point, and 37 species at the 22 m point. On average, 260.3 individuals were captured in the traps at 3 m, while 95.3 and 57.8 individuals were captured at 11 and 22 m, respectively. MDS ordination showed that assemblage composition differed among the three sites. The most abundant species at the 3 m was the galathean crab Galathea mauritiana, followed by the gastropod Diala albugo. At 11 and 22 m, the galathean crab Sadayoshia edwardsii was most abundant. Thus, at the reef slope, the benthic assemblage was most diverse at the shallow site, and specific communities occurred at the three sites.

Molecular and otolith analyses were conducted for 173 settlement-stage larvae of emperor fishes (family Lethrinidae) collected by light traps at Ishigaki Island, southern Japan, in July and August (summer season), to (1) present diagnostic DNA markers for identification of lethrinid species and (2) compare the size and age at settlement of each species. PCR–RFLP and direct nucleotide sequencing analyses identified 8 species. Size (standard length, SL) at settlement differed significantly between species; Lethrinus ornatus (mean SL ± SD, 12.8 ± 1.5 mm), L. obsoletus (14.2 ± 0.8 mm) and L. harak (15.8 ± 1.6 mm) settled at a smaller size than L. atkinsoni (17.0 ± 1.3 mm), L. genivittatus (17.3 ± 1.0 mm), L. olivaceus (18.1 ± 0.6 mm), L. nebulosus (18.6 ± 4.2 mm), and L. sp.2 reported by Lo Galbo et al. (J Mol Evol 54:754–762, 2002) (21.7 ± 1.4 mm). Age at settlement tends to increase with settlement size; L. obsoletus (mean age ± SD, 25.6 ± 1.2 days), L. atkinsoni (26.1 ± 2.1 days) and L. ornatus (26.3 ± 2.9 days) were younger at settlement than L. nebulosus (28.4 ± 2.1 days), L. harak (29.2 ± 1.7 days), L. olivaceus (29.5 ± 1.0 days), L. genivittatus (30.5 ± 1.7 days) and L. sp.2 (31.0 ± 2.0 days). Although our study showed interspecific variation in body size and age at settlement among 8 lethrinid species, further seasonal replication is necessary to clarify the general patterns.

Small patch reefs can harbor many reef fishes because most fishes have a drifting larval phase to randomly disperse over patchy habitats. We examined the species–area relationship (SAR) of damselfish (Pomacentridae) assemblages over 84 small patch reefs (0.05–45.4 m2) using an enlarged section of a high-resolution color aerial photograph as a field map (1/2500) in a shallow coral reef shore zone (

Whilst the importance of seagrass beds as nurseries for coral reef fishes has been clearly recognized, the vast majority of early studies on fish nursery habitats emphasized the close proximity of the latter to coral reefs. To determine the potential nursery role of isolated seagrass beds, we investigated the degree to which juvenile emperor fishes (Lethrinidae) utilized seagrass beds in the presence/absence of adjacent coral habitats at Ishigaki Island (southern Japan), such fishes being known to use seagrass beds as nurseries. Seagrass beds in close proximity to coral habitats (distance between the two habitats of 50–200 m) had greater densities of lethrinid juveniles than those without adjacent coral habitats (2.5–4 km) for 3 different sites investigated, although a significant difference was obtained only for 1 site. Juveniles of Lethrinus atkinsoni, L. obsoletus, L. harak, and L. nebulosus were observed in seagrass beds with and without adjacent coral habitats, whereas L. ornatus occurred only in the former. Overall, most lethrinid juveniles utilize seagrass beds irrespective of the presence of adjacent adult coral habitat, suggesting that both types of seagrass beds would contribute to lethrinid adult populations. Therefore, management efforts for lethrinid populations should be applied not only to contiguous coral-seagrass habitat systems but also to isolated habitats.

Successful settlement of pelagic fish larvae into benthic juvenile habitats may be enhanced by a shortened settlement period, since it limits larval exposure to predation in the new habitat. Because the spatial distribution of marine fish larvae immediately prior to settlement versus during settlement was unknown, field experiments were conducted at Ishigaki Island (Japan) using light trap sampling and underwater visual belt transect surveys to investigate the spatial distribution patterns of selected pre- and post-settlement fishes (Acanthuridae, Pomacentridae, Chaetodonidae and Lethrinidae) among four habitats (seagrass bed, coral rubble, branching coral and tabular coral). The results highlighted two patterns: patterns 1, pre- and post-settlement individuals showing a ubiquitous distribution among the four habitats (Acanthuridae) and pattern 2, pre-settlement individuals distributed in all habitats, but post-settlement individuals restricted to coral (most species of Pomacentridae and Chaetodontidae) or seagrass habitats (Lethrinidae). The first pattern minimizes the transition time between the larval pelagic stage and acquisition of a benthic reef habitat, the latter leading immediately to a juvenile lifestyle. In contrast, the second pattern is characterized by high settlement habitat selectivity by larvae and/or differential mortality immediately after settlement.

The assemblage composition of cryptic mobile animals inhabiting coral rubble was sampled using mesh traps containing clean coral rubble, and used as indicators of land-based pollution at 14 sites in three coral lagoons at Ishigaki Island, southern Japan. Cluster analyses identified three groups of large mobile animal assemblages (molluscs, echinoderms, fishes, decapod and stomatopod crustaceans). Using a distance-based redundancy analysis (db-RDA) there was a significant relationship between the assemblage composition and environmental variables. The 1st axis of the db-RDA ordination was regarded as the land-based pollution gradient because of the strong relationship with silicate sediment, turbidity, and salinity, indicating effects of terrestrial-sediment runoff. Species response curves were derived from a plot of the number of individuals against the 1st axis of the db-RDA sites sample score. The response curves of Galathea mauritiana, an indicator species for the intermediate sites, were unimodal along the land-based pollution gradient. This study demonstrates the use of traps containing clean coral rubble for nondestructive quantitative sampling and environmental monitoring in coral lagoons, and their potential for monitoring changes in the reef environment.

Mangroves are often considered to be important nurseries for coral reef fishes, yet this assumption has rarely been tested. At Ishigaki Island, southern Japan, black-tail snapper Lutjanus fulvus juveniles often occur in mangroves, whereas subadults and adults are usually found on coral reefs. To test the hypothesis that L. fulvus uses mangroves as a nursery, we conducted stomach content and stable isotope analyses of L. fulvus collected from mangroves and an adjacent coral reef. Stomach content analysis showed that specimens from mangroves fed on mangrove-associated prey, whereas those from the coral reef took coral reef-associated prey, indicating that the species undergoes ontogenetic changes in resource use from the mangroves to the coral reef, i.e. coral reef individuals did not migrate to the mangroves to feed. Stable isotope analysis showed that potential prey and mangrove red snapper L. argentimaculatus (control fish for mangroves) collected from the mangroves had 13 C-depleted values of -23 to -17‰, distinct from the -16 to -8‰ values of potential prey and humpback red snapper L. gibbus (control fish for coral reef) collected from the coral reef. δ 13 C values of L. fulvus in the mangroves had a mangrove signature, whereas individuals on the coral reef gradually shifted from a mangrove signature to a coral reef signature with growth, indicating that small individuals on the coral reef were recent migrants from the mangroves. Based on the δ 13 C values of the subadult population of L. fulvus on the coral reef, 36 of 41 individuals were estimated to have inhabited the mangroves during their juvenile stage, demonstrating that L. fulvus used the mangroves as a nursery.

To consider effective resource management strategies for the coconut crab, Birgus latro, we determined the size of males at sexual maturity by histological methods and investigated an optimal method to estimate the number of sperm in spermatophores. The size of 50% sexual maturity in male coconut crabs was estimated at 22.2 mm thoracic length (TL) on the Hatoma Island, Japan. We established a procedure to soak spermatophores for more than 120 min in a 20% NaOH solution before mixing, and to count the sperm within 24 h after mixing, thereby enabling us to assess the number of sperm per individual and estimate male reproductive potential. Using this method, we investigated the relationship between male size and number of sperm retained by males. Larger male coconut crabs have a higher number of sperm in both the vasa deferentia and testis. The relationships between male size and spermatophore volume also increased with increasing male size, and the sperm quantity packed in a spermatophore increased with increasing spermatophore volume. Thus, male coconut crabs display a size-dependent reproductive output, as is reported for other species of anomurans.

Coral rubble is one of the characteristic bottom habitats in tropical and subtropical coral reefs. Many mobile organisms inhabit the interstices among coral rubble. Because coral rubble habi- tats are frequently subjected to physical disturbances, the process of assemblage recolonization is important for maintaining the diversity and productivity in coral reefs. The present study examined the colonization patterns of these mobile organisms by using experimental traps with defaunated coral rubble at 3 areas (Back reef, Seagrass bed, and Nearshore) in a fringing coral reef on Ishigaki Island, Japan. Sixteen mesh trays filled with coral rubble were set at each of the 3 areas; 4 trays were collected after 1, 2, 4, and 8 wk. The experiment was repeated in winter and spring. The number of species that occurred in the trays generally increased with the time period, but detailed examination was difficult because of significant interaction factors. Higher order interactions (season, area, and time period) were also significant for variations in assemblage composition. Temporal and spatial variations in abundances of 15 numerically dominant species (gastropods and decapods) were analyzed by a general linear model with an Akaike's information criterion model selection. Although the patterns of colonization were species specific, initial (

In order to monitor sea surface current and transportation of heat and material in and around of coral reefs, we conducted field monitoring of wide-ranging (-70km) sea surface current using High-Frequency (HF) ocean radar, and vertical microstructure in the sea surface layer to estimate magnitude of turbulent vertical mixing. We here report time variation of wind-induced mixing in the sea surface layer which was the upper side of a strong near shore current. In our field measurement off Yaeyama Islands on September 15, 2005, the HF ocean radar could captured the presence of strong near-shore current over 50 cms-1, and the vertical microstructure measurement revealed that both elevated water temperature and uniformalization in the sea surface layer corresponding to increase of turbulent energy dissipation (e). Results suggested that energy led to this uniformalization seemed to derive from not the nearshore current but the ocean surface wind.

A manipulative experiment using small-scale artificial reefs was conducted to quantify the relationship between habitat physical complexity and recruitment of the coral reef damselfish, Pomacentrus amboinensis, at Urasoko Bay, Ishigaki Island (Ryukyu Islands, Japan), from January to July 2000. Four types of small-scale, structurally different artificial reefs, including (1) vertical bars with three layers of horizontal bars (type A), (2) vertical bars with a single layer of horizontal bars (type B), (3) vertical bars only (type C), and (4) no bars (type D), were employed for the experiment. Although the peak numbers of P. amboinensis recruits on most of the artificial reefs were recorded on 9 June, the mean number of recruits per replicate varied depending on the reef types. The mean number of recruits on type A was significantly greater than those on the other types, whereas no difference between types B and C were found, and only a few juveniles were observed on type D at one observation time. The experiment demonstrated that the degree of habitat structural complexity had a significant impact on the number of P. amboinensis recruits.

Colonies of the seagrass Halophila ovali s are found growing adjacent to coral Acropora sp. and Seriatopora hystrix in a submarine hot spring (at 15.7 m depth, 28.6°C) at the north coast of Taketomi Island, near the southern tip of Japan. Halophila plants grow in sea water containing sulphide 930 μg S ml −1 and on the substratum with fine precipitates of the submarine hot spring which have sulphide content up to 5400 μg S g −1 DW. The accumulated sulphide concentration reaches as high as 8400 μg S g −1 DW in under ground tissues and 5700 μg S g −1 DW in above-ground tissues, respectively. It is suggested that, not the sulphide concentration but light and possibly water temperature are the limiting factors for the Halophila colonization in the submarine hot spring.

Sessile organisms on PVC panels suspended inside and outside coral reef at Ishigaki Island, Yaeyama Islands, Japan, was monitored for 20 days just after the wide-spread incident of coral bleaching in September, 1998. The settlement of a total of 16 species of algae and invertebrates was recorded. Generally, Enteromorpha sp. (Chlorophyceae) dominated the panels. The percentage area cover, number of species, biomass and algal growth were significantly greater in waters outside the reef.

The influence of pelagic larval duration (PLD) and egg type dispersal capabilities of 35 demersal and pelagic-spawning tropical fish species is examined in relation to their abundance on the temperate coasts of Japan. The PLDs of pelagic spawners were significantly longer than those of demersal spawners, and a high occurrence of pelagic spawners on the temperate coasts suggests that these fishes are more easily transported to temperate coasts than demersal spawners. For demersal spawners, the common species on the temperate coasts had significantly longer PLDs than the rare species; this suggests that PLD is a major factor influencing the distribution patterns of tropical demersal spawners on temperate coasts. Moreover, a negative correlation between PLD and the abundance of some species of pelagic and demersal spawners suggests the presence of reproductively active fishes in northern subtropical and even in temperate waters.

Spawning sites and spawning migration paths of tagged females of the protogynous wrasse,Halichoeres marginatus, were studied on the shallow reefs at Kuchierabu-jima Island, Japan. Males set up mating territories above prominent rocks on the offshore reef slope in the late afternoon, and pair-spawned with females, which had migrated there from their home ranges located in inshore areas. Small females migrated to the spawning sites near their home ranges, whereas large females migrated to various spawning sites located within a wide area, including downcurrent sites. Spawning at the downcurrent sites favors transport of eggs offshore, thereby increasing the female’s fitness. The spawning sites where an individual had spawned as a female were subsequently used for mating after it had changed sex. It is suggested that the wide migration of females to various spawning sites, enables the storing up of information on those sites, which later helps in the acquisition of mating territories after changing sex.

One of the great puzzles of coral reef fish ecology is how pelagic larvae locate the habi- tat in which they settle. The present study explored whether offshore emperor fish (Lethrinidae) lar- vae selected a specific reef and/or habitat at settlement. Although older juveniles are known to use back-reef seagrass beds as a potential nursery habitat, information is scarce regarding pre-settle- ment larvae. Using light traps anchored on the reef slopes at seagrass-replete and seagrass-free reefs (Ishigaki Island, Japan), lethrinid larvae were sampled weekly from April to June 2008. Larval abun- dance in light traps was similar on the 2 reef types. This result implies that lethrinid larvae did not or could not differentiate between the presence or absence of seagrass before settlement. However, in the laboratory, larvae collected from both reef types selected seagrass substrate rather than bare sub- strate or coral. In underwater visual censuses, newly settled juveniles were not observed on the sea- grass-free reef, whereas they were abundant on the seagrass-replete reef. Together, these findings suggest that lethrinid larvae did not settle near the seagrass-free reef but rather preferentially settled near the seagrass-replete reef.

In order to identify the expression of coral genes induced by stressors such as suspended red soil, mRNA differential display was examined for the coral Pocillopora damicornis. Apparent differences were observed in the gene expression profiles between control colonies and those treated with local red soil, indicating that red soil affects gene expression in P. damicornis. We cloned nine candidate PCR fragments derived from the differentially expressed genes. One of the clones, pPd9-1, showed a high similarity to a member of the heat-shock protein (HSP) 70 family, suggesting that red soil may cause protein denaturation in the coral. Reverse transcription-mediated PCR showed that the expression of pPd9-1 was also increased by elevated temperature, but not by reduced salinity.