ABSTRACT
This study is the first to report ciliate infection on soft corals in the Northern Coral Triangle. Infected Briareum violacea will undergo tissue ulceration and death within a short period of time. This ciliate was identified as Scuticociliatia sp. through 18S rRNA gene identification. In this study, the body length of the ciliate was approximately 80-85⯵m before parasitizing the B. violacea. After being parasitizing, the body length was approximately 200-250⯵m, and the body width was 50⯵m. Body size increased three times after parasitism. According to observations, ciliates will first parasitize the coral endoderm in the early stage of infection, and no ciliates were found in the ectoderm. Preliminary judgment suggests that it may invade the coral endoderm through the mouth for parasitism. After parasitism, the ciliate eats the coral tissue and zooxanthellae. The antioxidant enzymes SOD, CAT, and MDA of infected corals were significantly increased, which also means that the corals are in a stress response. Ciliates will eat the zooxanthellae in the coral body, resulting in a significant reduction in the number of zooxanthellae and chlorophyll a. To effectively prevent and treat this disease, Combretum indicum extract was used in this study. It is a tropical plant commonly used medicinally to treat roundworms, pinworms and parasitic diseases. The results showed that at a concentration of 1500-2500â¯ppm, Combretum indicum extract can be used to treat ciliates and can applied via medicinal bath therapy for long periods without causing coral stress reactions. The results of this study regarding coral disease prevention are in line with SDG 14 and promote the practical application of coral reef ecological sustainability and large-scale coral aquaculture.
ABSTRACT
Symbiotic dinoflagellates in the genus Symbiodiniaceae play vital roles in promoting resilience and increasing stress tolerance in their coral hosts. While much of the world's coral succumb to the stresses associated with increasingly severe and frequent thermal bleaching events, live coral cover in Papua New Guinea (PNG) remains some of the highest reported globally despite the historically warm waters surrounding the country. Yet, in spite of the high coral cover in PNG and the acknowledged roles Symbiodiniaceae play within their hosts, these communities have not been characterized in this global biodiversity hotspot. Using high-throughput sequencing of the ITS2 rDNA gene, we profiled the endosymbionts of four coral species, Diploastrea heliopora, Pachyseris speciosa, Pocillopora acuta, and Porites lutea, across six sites in PNG. Our findings reveal patterns of Cladocopium and Durusdinium dominance similar to other reefs in the Coral Triangle, albeit with much greater intra- and intergenomic variation. Host- and site-specific variations in Symbiodiniaceae type profiles were observed across collection sites, appearing to be driven by environmental conditions. Notably, the extensive intra- and intergenomic variation, coupled with many previously unreported sequences, highlight PNG as a potential hotspot of symbiont diversity. This work represents the first characterization of the coral-symbiont community structure in the PNG marine biodiversity hotspot, serving as a baseline for future studies.
Subject(s)
Anthozoa , Biodiversity , Coral Reefs , Dinoflagellida , Symbiosis , Anthozoa/microbiology , Animals , Dinoflagellida/genetics , Dinoflagellida/classification , Dinoflagellida/physiology , Papua New Guinea , Phylogeny , High-Throughput Nucleotide SequencingABSTRACT
This article contains the data on the Length-weight relationship (LWR) parameters play a crucial role in fisheries management, particularly in fish stock monitoring methods like fish visual census, where biomass estimation relies on the measurement of individual fish lengths in situ. Localized LWR parameters provide more accurate assessments of local fish stocks due to the influence of environmental conditions, which vary across different locations. In this study, we present the LWR parameters for 161 species belonging to 60 genera and 21 families of commercially important coral reef-associated fishes found in the waters surrounding the Tawi-Tawi islands in Southern Philippines. Among the families with at least 10 species recorded were the Serranidae or groupers (24 species), Lutjanidae or snappers (17 species), Nemipteridae or coral breams (14 species), Acanthuridae or surgeonfishes (12 species), Carangidae or jacks (12 species), Scaridae or parrotfishes (12 species), and Siganidae or rabbitfishes (10 species). Approximately 30% or 48 species exhibited a negative allometric growth pattern (b < 3), indicating that these species tend to become more slender as they increase in length. Conversely, around 14% or 23 species displayed a positive growth type (b > 3), where the fish becomes heavier as they increase in length. The majority of the species, accounting for 56% or 90 species, demonstrated an isometric growth pattern (b = 3), where the growth rate for weight and length is proportional. The LWR analysis yielded a coefficient of determination (r2) with an average value of 0.9553, indicating highly significant relationships between length and weight for all species studied (P < 0.001). Furthermore, this study unveiled new total length records for 27 species. Additionally, 73 species represent the first LWR records for marine fishes in the Philippines.
ABSTRACT
Global warming threatens the viability of tropical coral reefs and associated marine calcifiers, including symbiont-bearing larger benthic foraminifera (LBF). The impacts of current climate change on LBF are debated because they were particularly diverse and abundant during past warm periods. Studies on the responses of selected LBF species to changing environmental conditions reveal varying results. Based on a comprehensive review of the scientific literature on LBF species occurrences, we applied species distribution modeling using Maxent to estimate present-day and future species richness patterns on a global scale for the time periods 2040-2050 and 2090-2100. For our future projections, we focus on Representative Concentration Pathway 6.0 from the Intergovernmental Panel on Climate Change, which projects mean surface temperature changes of +2.2°C by the year 2100. Our results suggest that species richness in the Central Indo-Pacific is two to three times higher than in the Bahamian ecoregion, which we have identified as the present-day center of LBF diversity in the Atlantic. Our future predictions project a dramatic temperature-driven decline in low-latitude species richness and an increasing widening bimodal latitudinal pattern of species diversity. While the central Indo-Pacific, now the stronghold of LBF diversity, is expected to be most pushed outside of the currently realized niches of most species, refugia may be largely preserved in the Atlantic. LBF species will face large-scale non-analogous climatic conditions compared to currently realized climate space in the near future, as reflected in the extensive areas of extrapolation, particularly in the Indo-Pacific. Our study supports hypotheses that species richness and biogeographic patterns of LBF will fundamentally change under future climate conditions, possibly initiating a faunal turnover by the late 21st century.
Subject(s)
Climate Change , Foraminifera , Foraminifera/physiology , Coral Reefs , Global Warming , Temperature , Biodiversity , EcosystemABSTRACT
Background: Dinoflagellates of family Symbiodiniaceae are important to coral reef ecosystems because of their contribution to coral health and growth; however, only a few studies have investigated the function and distribution of Symbiodiniaceae in Indonesia. Understanding the distribution of different kinds of Symbiodiniaceae can improve forecasting of future responses of various coral reef systems to climate change. This study aimed to determine the diversity of Symbiodiniaceae around Lombok using environmental DNA (eDNA). Methods: Seawater and sediment samples were collected from 18 locations and filtered to obtain fractions of 0.4-12 and >12 µm. After extraction, molecular barcoding polymerase chain reaction was conducted to amplify the primary V9-SSU 18S rRNA gene, followed by sequencing (Illumina MiSeq). BLAST, Naïve-fit-Bayes, and maximum likelihood routines were used for classification and phylogenetic reconstruction. We compared results across sampling sites, sample types (seawater/sediment), and filter pore sizes (fraction). Results: Phylogenetic analyses resolved the amplicon sequence variants into 16 subclades comprising six Symbiodiniaceae genera (or genera-equivalent clades) as follows: Symbiodinium, Breviolum, Cladocopium, Durusdinium, Foraminifera Clade G, and Halluxium. Comparative analyses showed that the three distinct lineages within Cladocopium, Durusdinium, and Foraminifera Clade G were the most common. Most of the recovered sequences appeared to be distinctive of different sampling locations, supporting the possibility that eDNA may resolve regional and local differences among Symbiodiniaceae genera and species. Conclusions: eDNA surveys offer a rapid proxy for evaluating Symbiodiniaceae species on coral reefs and are a potentially useful approach to revealing diversity and relative ecological dominance of certain Symbiodiniaceae organisms. Moreover, Symbiodiniaceae eDNA analysis shows potential in monitoring the local and regional stability of coral-algal mutualisms.
Subject(s)
Anthozoa , DNA, Environmental , Dinoflagellida , Animals , Coral Reefs , Ecosystem , Phylogeny , Indonesia , Bayes Theorem , DNA Barcoding, Taxonomic , Anthozoa/geneticsABSTRACT
Background: The reef manta ray (Mobula alfredi) is a globally threatened species and an iconic tourist attraction for visitors to Indonesia's Komodo National Park (NP). In 2013, manta ray fishing was banned in Komodo NP and its surroundings, preceding the nationwide manta ray protection in 2014. Over a decade ago, a previous acoustic telemetry study demonstrated that reef manta rays had high fidelity to sites within the park, while more recent photo-identification data indicated that some individuals move up to 450 km elsewhere. Characterization of manta ray demographics, behavior, and a focused assessment on site use of popular tourism locations within the park is vital to assist the Komodo NP Management Authority formulate appropriate manta ray conservation and management policies. Methods: This study uses a long-term library (MantaMatcher.org) of photo-identification data collected by researchers and citizen scientists to investigate manta ray demographics and habitat use within the park at four sites frequented by tour operators: Cauldron, Karang Makassar, Mawan, and Manta Alley. Residency and movements of manta rays were investigated with maximum likelihood analyses and Markov movement models. Results: A total of 1,085 individual manta rays were identified from photographs dating from 2013 to 2018. In general, individual manta rays displayed a higher affinity to specific sites than others. The highest re-sighting probabilities came from the remote southern site, Manta Alley. Karang Makassar and Mawan are only ~5 km apart; however, manta rays displayed distinct site affinities. Exchange of individuals between Manta Alley and the two central sites (~35.5 km apart) occurred, particularly seasonally. More manta rays were recorded traveling from the south to the central area than vice versa. Female manta rays were more mobile than males. Similar demographic groups used Karang Makassar, Mawan, and Manta Alley for foraging, cleaning, cruising, or courtship activities. Conversely, a higher proportion of immature manta rays used the northern site, Cauldron, where foraging was commonly observed. Fishing gear-related injuries were noted on 56 individuals (~5%), and predatory injuries were present on 32 individuals (~3%). Tourism within the park increased from 2014 to 2017, with 34% more dive boats per survey at Karang Makassar and Mawan. Discussion: The Komodo NP contains several distinct critical habitats for manta rays that encompass all demographics and accommodate seasonal manta ray movements. While the present study has not examined population trends, it does provide foundational data for such work. Continued research into manta ray abundance, long-range movements, and identifying and protecting other critical aggregation areas within the region is integral to securing the species' recovery. We provide management recommendations to limit undue pressure on manta rays and their critical habitats from tourism.
Subject(s)
Elasmobranchii , Internship and Residency , Skates, Fish , Humans , Male , Animals , Female , Parks, Recreational , DemographyABSTRACT
Species with limited dispersal abilities are often composed of highly genetically structured populations across small geographic ranges. This study aimed to investigate the haplotype diversity and genetic connectivity of the coastal horseshoe crab (Tachypleus gigas) in Indonesia. To achieve this, we collected a total of 91 samples from six main T. gigas habitats: Bintan, Balikpapan, Demak, Madura, Subang, and Ujung Kulon. The samples were amplified using primers for mitochondrial (mt) AT-rich region DNA sequences. The results showed 34 haplotypes, including seven shared and 22 unique haplotypes, across all localities. The pairwise genetic differentiation (F ST) values were low (0 to 0.13) and not significantly different (p > 0.05), except among samples from Ujung Kulon-Madura and Kulon-Subang (p < 0.05). Additionally, the 34 analysis of molecular variance (AMOVA) showed the most variation within populations (95.23%) compared to less among populations (4.77%). The haplotype network showed evidence of shared haplotypes between populations. Tajima's D and Fu's F S test values indicated a population expansion. Our results showed a low level of differentiation, suggesting a single stock and high connectivity. Therefore, a regionally-based conservation strategy is recommended for the coastal horseshoe crab in Indonesia.
ABSTRACT
Corals are experiencing unprecedented decline from climate change-induced mass bleaching events. Dispersal not only contributes to coral reef persistence through demographic rescue but can also hinder or facilitate evolutionary adaptation. Locations of reefs that are likely to survive future warming therefore remain largely unknown, particularly within the context of both ecological and evolutionary processes across complex seascapes that differ in temperature range, strength of connectivity, network size, and other characteristics. Here, we used eco-evolutionary simulations to examine coral adaptation to warming across reef networks in the Caribbean, the Southwest Pacific, and the Coral Triangle. We assessed the factors associated with coral persistence in multiple reef systems to understand which results are general and which are sensitive to particular geographic contexts. We found that evolution can be critical in preventing extinction and facilitating the long-term recovery of coral communities in all regions. Furthermore, the strength of immigration to a reef (destination strength) and current sea surface temperature robustly predicted reef persistence across all reef networks and across temperature projections. However, we found higher initial coral cover, slower recovery, and more evolutionary lag in the Coral Triangle, which has a greater number of reefs and more larval settlement than the other regions. We also found the lowest projected future coral cover in the Caribbean. These findings suggest that coral reef persistence depends on ecology, evolution, and habitat network characteristics, and that, under an emissions stabilization scenario (RCP 4.5), recovery may be possible over multiple centuries.
Subject(s)
Anthozoa , Coral Reefs , Animals , Climate Change , Ecosystem , TemperatureABSTRACT
The genus Peronia Fleming, 1822 includes all the onchidiid slugs with dorsal gills. Its taxonomy is revised for the first time based on a large collection of fresh material from the entire Indo-West Pacific, from South Africa to Hawaii. Nine species are supported by mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) sequences as well as comparative anatomy. All types available were examined and the nomenclatural status of each existing name in the genus is addressed. Of 31 Peronia species-group names available, 27 are regarded as invalid (twenty-one synonyms, sixteen of which are new, five nomina dubia, and one homonym), and four as valid: Peronia peronii (Cuvier, 1804), Peronia verruculata (Cuvier, 1830), Peronia platei (Hoffmann, 1928), and Peronia madagascariensis (Labbé, 1934a). Five new species names are created: P. griffithsi Dayrat & Goulding, sp. nov., P. okinawensis Dayrat & Goulding, sp. nov., P. setoensis Dayrat & Goulding, sp. nov., P. sydneyensis Dayrat & Goulding, sp. nov., and P. willani Dayrat & Goulding, sp. nov. Peronia species are cryptic externally but can be distinguished using internal characters, with the exception of P. platei and P. setoensis. The anatomy of most species is described in detail here for the first time. All the secondary literature is commented on and historical specimens from museum collections were also examined to better establish species distributions. The genus Peronia includes two species that are widespread across the Indo-West Pacific (P. verruculata and P. peronii) as well as endemic species: P. okinawensis and P. setoensis are endemic to Japan, and P. willani is endemic to Northern Territory, Australia. Many new geographical records are provided, as well as a key to the species using morphological traits.
ABSTRACT
East Timor is an island located to the south of the Indonesian Archipelago and to the north of Australia, between the Indian and Pacific Oceans. It is included in the Coral Triangle and houses an amazing quantity of marine biodiversity. However, only two species of Syllidae (Annelida) have been reported up to now: Trypanosyllis migueli and T. devae. Based on a small collection from the Australian Museum, we have identified nine genera and 17 species: Brevicirrosyllis mariae, Opisthodonta morena, Sphaerosyllis densopapillata, Branchiosyllis australis, B. exilis, B. maculata, B. verruculosa, Haplosyllis djiboutiensis, Opisthosyllis brunnea, Syllis alternata, S. broomensis, S. corallicola, S. erikae, S. gerlachi, S. hyalina, S. setoensis and Trypanosyllis luzonensis. This is the first record of S. gerlachi outside the Indian Ocean, and B. mariae, O. morena, S. densopapillata, H. djiboutiensis, S. corallicola and S. erikae have not been previously reported in tropical Asia. A specimen of Parahaplosyllis sp. could not be identified due to its poor condition. Three species belonging to Syllis are herein described as new: S. cambuk n. sp. has a large size body, with anterior segments much wider and shorter than posterior ones, long whip-shaped dorsal cirri and bidentate midbody and posterior chaetae, with both teeth equal in size and shape; Syllis hampirmenyatu n. sp. has three chaetae per posterior parapodium, with short and wide blades appearing to be fused with shafts, but still clearly distinguishable from each other, bidentate, with proximal tooth clearly smaller and thinner than distal one; and S. maganda n. sp. is easily recognizable because of its spectacular orange and blue colouration, only observable in living specimens, with broad transverse red stripes on the dorsum forming a distinctive pattern and red spots on the cirri and prostomium observable in both living and fixed specimens. Additionally, Philippine samples from the Museo Nacional de Ciencias Naturales of Madrid have been examined corresponding to S. maganda n. sp. A Philippine specimen of S. maganda n. sp. had a small unidentified specimen of Haplosyllis attached to a posterior dorsal cirrus, which is the first documented case of such an interaction between two species of Syllidae. This provisionally called Haplosyllis sp. is characterized by its simple chaetae with short spur and two very long, distinct curved teeth, very close to each other. A regenerated prostomium and a stolon were also found in other Philippine specimens of S. maganda n. sp.
Subject(s)
Annelida , Animals , Australia , Pacific Ocean , Philippines , Timor-LesteABSTRACT
DNA barcoding opens new perspectives on the way we document biodiversity. Initially proposed to circumvent the limits of morphological characters to assign unknown individuals to known species, DNA barcoding has been used in a wide array of studies where collecting species identity constitutes a crucial step. The assignment of unknowns to knowns assumes that species are already well identified and delineated, making the assignment performed reliable. Here, we used DNA-based species delimitation and specimen assignment methods iteratively to tackle the inventory of the Indo-Australian Archipelago grey mullets, a notorious case of taxonomic complexity that requires DNA-based identification methods considering that traditional morphological identifications are usually not repeatable and sequence mislabeling is common in international sequence repositories. We first revisited a DNA barcode reference library available at the global scale for Mugilidae through different DNA-based species delimitation methods to produce a robust consensus scheme of species delineation. We then used this curated library to assign unknown specimens collected throughout the Indo-Australian Archipelago to known species. A second iteration of OTU delimitation and specimen assignment was then performed. We show the benefits of using species delimitation and specimen assignment methods iteratively to improve the accuracy of specimen identification and propose a workflow to do so.
ABSTRACT
To contribute to the taxonomic knowledge of barnacles in this understudied area, the first checklist of barnacles from the Moluccas is presented, including additional information on morphology, distribution, and substrate as well as molecular data. The species of barnacles from the Moluccas have been determined using morphological analysis and DNA sequences. During 19 field trips conducted between January 2016 and September 2017, 1,513 specimens of 24 species of intertidal and one species of deep-sea barnacles were collected from 51 localities from the islands. Morphological and molecular analysis of the collected material detected members of three families of stalked barnacles and four families of acorn barnacles. In addition to sampling in the field, we also surveyed the literature on barnacles from the Moluccas. In total, our checklist comprises 97 species from the Moluccas including 23 new records, two of them yet to be described species. Results suggest that the Moluccas have a much higher diversity of barnacles than previously known, for example, from the reports of Challenger and Siboga expeditions. For further work, routine application of molecular systematics could aid the detection of cryptic species, while increased sampling of more islands and a taxonomic revision of several groups would likely lead to an even higher number of species than currently known.
ABSTRACT
Coral reef fisheries support the livelihoods of millions of people in tropical countries, despite large-scale depletion of fish biomass. While human adaptability can help to explain the resistance of fisheries to biomass depletion, compensatory ecological mechanisms may also be involved. If this is the case, high productivity should coexist with low biomass under relatively high exploitation. Here we integrate large spatial scale empirical data analysis and a theory-driven modelling approach to unveil the effects of human exploitation on reef fish productivity-biomass relationships. We show that differences in how productivity and biomass respond to overexploitation can decouple their relationship. As size-selective exploitation depletes fish biomass, it triggers increased production per unit biomass, averting immediate productivity collapse in both the modelling and the empirical systems. This 'buffering productivity' exposes the danger of assuming resource production-biomass equivalence, but may help to explain why some biomass-depleted fish assemblages still provide ecosystem goods under continued global fishing exploitation.
Subject(s)
Anthozoa , Coral Reefs , Animals , Biomass , Conservation of Natural Resources , Ecosystem , Fisheries , Fishes , HumansABSTRACT
Sabah, Malaysia, is well known for its extensive and diverse coral reefs. It is located on the northwestern edge of the Coral Triangle, the region with the highest marine biodiversity. Much of the marine fauna here is still unknown, especially inconspicuous animals, such as small stoloniferous octocorals, which are common on coral reefs. Here, we describe two new monospecific genera of the family Arulidae found off the coast of Kota Kinabalu, Sabah, East Malaysia; Bunga payung gen. nov. et sp. nov. and Laeta waheedae gen. nov. et sp. nov. As well, the stoloniferan genus Phenganax Alderslade & McFadden, 2011 belonging to the family Clavulariidae is expanded with three new species, P. marumi sp. nov., P. subtilis sp. nov., and P. stokvisi sp. nov., which are all sclerite-free. Additionally, we report a possibly undescribed species, closely related to the clavulariid genera Azoriella Lopez-Gonzalez & Gili, 2001 and Cervera Lopez-Gonzalez et al., 1995. As this and other recent studies have shown, discoveries of small stoloniferous octocorals are helping to fill gaps in our knowledge of the overall systematics of Octocorallia.
ABSTRACT
This article contains the data on fish biomass inside and outside 57 locally managed marine protected areas (MPAs) and within the nationally protected Tubbataha Reef National Marine Park (TRNMP) from 57 coastal municipalities and 20 provinces in the Philippines. It includes the seven major commercially important coral reef fishes, namely, the surgeonfish (family Acanthuridae), parrotfish (subfamily Scarinae, family Labridae), snappers (family Lutjanidae), groupers (subfamily Epinephelinae, family Serranidae), goatfish (family Mullidae), sweetlips (family Haemulidae) and emperor (family Lethrinidae). Fish visual census (FVC) surveys were done by scuba diving along 10 m × 50 m belt transects established on upper reef slope, mostly with depths ranging from 5 to 10 m. Four to twelve transects were surveyed for the locally managed MPAs, half of which were established inside MPAs and the other half outside MPAs. Thirty-three transects were surveyed for the TRNMP. FVC was performed by swimming slowly and stopping every 5 m to record all the fish within a 10 m - wide belt. All FVC surveys were conducted from 2006 to 2014 between 9:00-16:00 hours. Each fish was identified to the species level and total length (TL) was estimated to the nearest centimeter. Fish biomass was estimated using the relationship between length (L) and weight (W) with the equation W = aLb. The data we provide can be used for coral reef fisheries management and for monitoring and evaluation of coral reef fishes in the Philippines particularly for the MPAs included in this dataset. These data support the information presented in the article Muallil et al., 2019.
ABSTRACT
Three new species of Chromis (Perciformes, Pomacentridae) from the Philippines, collected between 75-150 m depth, are described by a combination of morphological features and their coloration. Chromisgunting sp. n. was found in Batangas and Oriental Mindoro, and differs from its congeners in body depth (2.1-2.2 in SL), and color of adults, light brown, with a silver area on the anterior end and a bilateral black margin along the exterior side of the tail. It is most similar to C.scotochiloptera, with a 5.3% genetic divergence in COI. Chromishangganan sp. n. was found around Lubang Island. Body depth (1.9-2.0 in SL) and adult coloration (yellowish with dark black outer margins on dorsal and anal fins) also separate this species from its congeners. It is most similar to C.pembae, with a 2.5% genetic divergence. Chromisbowesi sp. n. was found in Batangas, and also differs from its congeners by the combination of body depth (1.5-1.6 in SL), and color of adults (brownish grey in the dorsal side to whitish on the ventral side, with alternating dark and light stripes in the sides of body). It is most similar to C.earina, with a 3.6% genetic divergence in COI.
ABSTRACT
The variability in reef-fish species assemblages was examined at three geographic locations in the Philippines (Apo, Abra and Patn), each showing varying levels of disturbances (low to high) at two depths, shallow-water reef (SWR; 8-20 m) and the upper mesophotic coral ecosystem (MCE; 30-35 m). Fish species assemblages varied among locations and between depths. Differences in fish assemblages among locations corresponded to the variability in benthic assemblages and levels of disturbances, wherein locations with higher coral cover and less disturbances had the highest fish species richness, abundance and biomass. Variation in fish assemblages between depths was also associated with changes in benthic assemblages and possibly inaccessibility to local fishing techniques. Fish species richness decreased with depth in all locations, but biomass increased only in the MCEs of Apo and Abra, which is a similar pattern exhibited in many MCEs. Our results suggest that despite location differences, depth had a relatively consistent influence on fish species assemblages, particularly in locations exposed to low and intermediate disturbance. Under high disturbance, MCEs exhibit similar vulnerability to SWRs.
Subject(s)
Biodiversity , Coral Reefs , Fishes/physiology , Animals , Biomass , Philippines , Phylogeography , WaterABSTRACT
The Indo-Malay Archipelago is regarded as a barrier that separates organisms of the Indian and Pacific Oceans. Previous studies of marine biota from this region have found a variety of biogeographic barriers, seemingly dependent on taxon and methodology. Several hypotheses, such as emergence of the Sunda Shelf and recent physical oceanography, have been proposed to account for the genetic structuring of marine organisms in this region. Here, we used six microsatellite loci to infer genetic diversity, population differentiation and phylogeographic patterns of Enhalus acoroides across the Indo-Malay Archipelago. Heterozygosities were consistently high, and significant isolation-by-distance, consistent with restricted gene flow, was observed. Both a neighbour joining tree based on DA distance and Bayesian clustering revealed three major clusters of E. acoroides. Our results indicate that phylogeographic patterns of E. acoroides have possibly been influenced by glaciation and deglaciation during the Pleistocene. Recent physical oceanography such as the South Java Current and the Seasonally Reversing Current may also play a role in shaping the genetic patterns of E. acoroides.
ABSTRACT
As ecosystems come under increasing anthropogenic pressure, rare species face the highest risk of extinction. Paradoxically, data necessary to evaluate the conservation status of rare species are often lacking because of the challenges of detecting species with low abundance. One group of fishes subject to this undersampling bias are those with cryptic body patterns. Twenty-one percent of cryptic fish species assessed for their extinction risk (International Union for Conservation of Nature [IUCN]) are data deficient. We developed a nondestructive method for surveying cryptically patterned marine fishes based on the presence of biofluorescence (underwater biofluorescence census, UBC). Blue LED torches were used to investigate how widespread biofluorescence was in cryptic reef fishes in the Coral Triangle region. The effectiveness of UBC to generate abundance data was tested on a data-deficient pygmy seahorse species (Hippocampus bargibanti) and compared with data obtained from standard underwater visual census (UVC) surveys. We recorded 95 reef fish species displaying biofluorescence, 73 of which had not been previously described as biofluorescent. Of those fish with cryptic patterns, 87% were biofluorescent compared with 9% for noncryptic fishes. The probability of species displaying biofluorescence was 70.9 times greater for cryptic species than for noncryptic species. Almost twice the number of H. bargibanti was counted using the UBC compared with UVC. For 2 triplefin species (Ucla xenogrammus, Enneapterygius tutuilae), the abundance detected with UBC was triple that detected with UVC. The UBC method was effective at finding cryptic species that would otherwise be difficult to detect and thus will reduce interobserver variability inherent to UVC surveys. Biofluorescence is ubiquitous in cryptic fishes, making this method applicable across a wide range of species. Data collected using UBC could be used with multiple IUCN criteria to assess the extinction risk of cryptic species. Adopting this technique will enhance researchers' ability to survey cryptic species and facilitate management and conservation of cryptic marine species.
Subject(s)
Coral Reefs , Ecosystem , Animals , Conservation of Natural Resources , Fishes , Surveys and QuestionnairesABSTRACT
A new species of the butterflyfish genus Roa is herein described from the Verde Island Passage in the Philippines, West Pacific Ocean. Roa rumsfeldisp. n. was found on mesophotic coral ecosystems at Puerto Galera and Batangas, and sampled through technical mixed-gas rebreather diving at 100-130 m depth. This represents the fifth known species of Roa. The main differences between Roa rumsfeldisp. n. and its congeners are the lower number of pored scales in the lateral line, longer snout, longer caudal peduncle, shorter caudal fin, pelvic fin color (dark first spine vs. white in all other Roa), and genetics (8.4% divergence from its closest relative Roa modesta in the mitochondrial COI gene). Roa spp. are usually seen in pairs, but the two specimens we collected were solitary individuals. We have kept one of the specimens alive in the California Academy of Sciences' Twilight Zone exhibit for more than one year, where it thrives and is feeding on a variety of dried and fresh food.