Marine Biodiversity Hotspot Research Articles

Application of DNA Barcoding for Monitoring Madagascar Fish Biodiversity in Coastal Areas

Madagascar is a marine biodiversity hotspot. A recent checklist recorded 1689 marine or transitional water fish species, 2.5% being endemic. To date, studies in this country were mostly focused on adult fishes using morphological-based identification. The early life stages of fishes remain largely understudied. The present work aimed to improve knowledge of fish biodiversity in Madagascar by focusing on post-larval reef fishes and settled juveniles in seagrass meadows of southwest Madagascar by using either species identification keys or DNA barcoding. Up to 119,500 individuals were collected, and 1096 individuals were successfully barcoded. We identified 387 species—85 through their morphology (with 58 unsuccessfully sequenced) and 302 by using CO1 barcoding corresponding to 302 barcode index numbers (BINs). This study added 27 new BINs for the BOLD database, 120 new for Madagascar, but only 159 were assigned a precise species name. By referring to the updated checklist of Madagascar fishes, 10 new species were detected for Madagascar. This number will probably increase when all the barcoded specimens become assigned to precise species names. These preliminary findings stress our poor knowledge of marine fish biodiversity in Madagascar and demonstrate the relevance of DNA barcoding in improving this knowledge.

Comparative phylogeography in a marine biodiversity hotspot provides novel insights into evolutionary processes across the Atlantic‐Indian Ocean transition

AbstractAimIntraspecific genetic variation is a key component of biodiversity, with higher diversity indicating greater resilience and population substructuring suggesting unique evolutionary histories. Comparative approaches, in which intraspecific genetic variation is assessed across multiple species, are powerful tools to identify evolutionary hotspots, but are still rarely applied at spatial scales relevant to conservation planning. Here, we use comparative phylogeography to understand patterns and potential drivers of genetic variation within a biodiversity and ocean warming hotspot.LocationThe South African coastline, Indian/Atlantic Oceans.MethodsA literature search was conducted to obtain mitochondrial DNA cytochrome oxidasecsubunit I and cytochromebsequence data for 17 marine fish and invertebrate species. From these data, we compared averages of haplotype and nucleotide diversity, and within‐region ΦSTbetween four biogeographic provinces in the region. Mixed linear models tested whether environmental variability, habitat preference, or geographic location significantly influence genetic variation.ResultsAverage diversity values differed between haplotype and nucleotide diversity, but both broadly displayed highest diversity levels within the South‐West bioregion, which is also a region of high levels of within‐region ΦST. Range in sea surface temperatures (SSTs) was the only significant fixed‐effect term in the haplotype diversity mixed linear models. Mean SST, stability in SSTs since the Mid‐Holocene and position within the species' geographic distribution all had no significant effect on genetic variation.Main conclusionsAlong this coastline characterized by high environmental heterogeneity, we find that variation in temperature is a prominent source of intraspecific variation. Genetic diversity differs between bioregions, but does not display higher levels within the core of each species’ range when assessed across multiple species. With elevated levels of genetic diversity, the South‐West region of the South African coast is highlighted as a conservation priority area, representing both high genetic diversity and differentiation across taxa.

Genomic insights into the historical and contemporary demographics of the grey reef shark.

Analyses of genetic diversity can shed light on both the origins of biodiversity hotspots, as well as the conservation status of species that are impacted by human activities. With these objectives, we assembled a genomic dataset of 14,935 single nucleotide polymorphisms from 513 grey reef sharks (Carcharhinus amblyrhynchos) sampled across 17 locations in the tropical Indo-Pacific. We analysed geographic variation in genetic diversity, estimated ancient and contemporary effective population size (Ne) across sampling locations (using coalescent and linkage disequilibrium methods) and modelled the history of gene flow between the Coral Triangle and the Coral Sea. Genetic diversity decreased with distance away from the Coral Triangle and north-western Australia, implying that C. amblyrhynchos may have originated in this region. Increases in Ne were detected across almost all sampling locations 40,000-90,000 generations ago (approximately 0.6-1.5 mya, given an estimated generation time of 16.4 years), suggesting a range expansion around this time. More recent, secondary increases in Ne were inferred for the Misool and North Great Barrier Reef sampling locations, but joint modelling did not clarify whether these were due to population growth, migration, or both. Despite the greater genetic diversity and ancient Ne observed at sites around Australia and the Coral Triangle, remote reefs around north-western New Caledonia had the highest contemporary Ne, demonstrating the importance of using multiple population size assessment methods. This study provides insight into both the past and present demographics of C. amblyrhynchos and contributes to our understanding of evolution in marine biodiversity hotspots.

Genetic Connectivity and Diversity of a Protected, Habitat-Forming Species: Evidence Demonstrating the Need for Wider Environmental Protection and Integration of the Marine Protected Area Network

Modiolus modiolus (horse mussel) reefs are an example of marine biodiversity hotspots of high conservation importance. Due to historical destruction and slow rates of recovery, the habitat is considered threatened and/or declining under the OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic 1992, and therefore incorporated into the conservation legislation of several countries. An analysis of genetic connectivity and diversity of nine M. modiolus reefs across Scotland, both within and outside of Marine Protected Areas (MPAs), was undertaken using 12 newly developed microsatellite markers. Analyses indicated moderate to high levels of genetic connectivity between all populations and significantly low genetic variance among populations. Generally, a lack of spatial genetic structure was determined though several populations were highlighted as potentially genetically separated. Structure and connectivity results were largely corroborated by network visualization which additionally identified several potentially key populations. All populations showed departure from Hardy–Weinberg Equilibrium (HWE) and positive inbreeding coefficients, suggesting reduced genetic diversity and/or reflecting the high frequency of null alleles observed across populations. However, allelic richness was uniformly high across all reefs compared to previously reported results for the habitat. Results broadly suggest that an open system of M. modiolus populations exists in Scottish waters and align with conclusions from prior larval dispersal modeling. Findings highlight that neither M. modiolus populations nor the MPAs where they are found should be considered discrete, independent entities and support the protection of features within MPAs in concert with non-designated areas and across varying spatial scales. It is proposed that potential for greater protection exists if all relevant Scottish MPAs, i.e., both those where M. modiolus reefs are a designated feature and those that host M. modiolus reefs, had statutory restrictions on all activities that cause damage to the sea bed. Such protection may facilitate the support of vulnerable populations by more resilient populations, particularly under climate change. Furthermore, given that a large number of unprotected M. modiolus populations may be important components in the interdependent system of reef populations, supplementary genetics studies informed by larval dispersal modeling are recommended to identify further key populations for safeguarding.

Stable isotopes reveal overlooked incorporation of diffuse land-based sources of nutrients and organic matter by intertidal communities at Rapa Nui (Easter Island)

Rapa Nui is an important hotspot of endemic marine biodiversity, where diffuse land-based sources (e.g., nutrients and organic matter) entering into coastal waters could develop eutrophication in coastal environments, with deleterious impacts on the marine ecosystem. Stable isotopes (δ13C and δ15N) of intertidal communities (macroalgae and invertebrates) were studied from sites with contrasting human influence (populated and unpopulated), to evaluate the incorporation and transfer of diffuse land-based sources through food webs. Macroalgae showed differences between some sites, and invertebrates showed a 15N-enrichment pattern at populated areas relative to unpopulated, being these differences significant in gastropods, barnacles and sea urchins. Moreover, trophic structure metrics suggest a higher trophic diversity in populated areas relative to unpopulated and support the isotopic partitioning between sites, associated with the incorporation of sources with 15N-enriched values. The above suggests that diffuse land-based sources could be incorporated by macroalgae, transferred into benthic consumers, and altering the trophic structure.

The health status of coral reef ecosystem in Taka Bonerate, Kepulauan Selayar Biosphere Reserve, Indonesia

Abstract. Wulandari P, Sainal, Cholifatullah F, Janwar Z, Nasruddin, Setia TM, Soedharma D, Praptiwi RA, Sugardjito J. 2021. The health status of coral reef ecosystem in Taka Bonerate, Kepulauan Selayar Biosphere Reserve, Indonesia. Biodiversitas 23: 721-732. This study assessed the coral reef conditions in a tropical marine biodiversity hotspot, Tambolongan and Polassi islands, located within the transition zone of UNESCO's Taka Bonerate Kepulauan Selayar Biosphere Reserve in Indonesia. The islands' coral reefs receive a multitude of pressures from anthropogenic activities, risking the livelihood of local communities which rely on resources, such as fish stocks, from this ecosystem. This study measured the coral and reef fish characteristics and current biodiversity status in the coastal waters surrounding the two islands. The evaluation of the coral reefs condition used the Coral Health Index (CHI), which was determined from the two main components of benthic coverage (using underwater photo transect) and reef fish assemblages. The results showed that, overall, coral reef health status in both islands could be classified as very poor (with scores ranging from 1 to 3, out of 10 for CHI), with medium to nearly low diversity for coral (H' index of 1.5 to 2.24), and medium to high diversity for reef fish (H' index of 2.90 to 3.37). This study observed the ecological responses of both habitat and fish within each environment towards the existing damages, which indicated a degree of habitat resiliency. The results obtained contribute to further understanding the extent of pressures towards the quality of marine habitats in the area. They can also be used as baseline data to devise management measures, such as rehabilitation, restoration, or monitoring programs, to ensure that sustainable development can be pursued without neglecting the necessity for conservation.

Review of Potential Effects of Oil Spills on Coastal and Marine Resources on Western Libyan Coastal

An oil spill can significantly affect coastal resources and the economy through economic activities that depend on clean seawater, coastal areas, and tourist sites, which may cause substantial economic losses after oil spills. However, this effect usually depends on the volume and type of oil spill and how sensitive it is to coastal and marine resources. Libya has one of the important Mediterranean marine biodiversity hotspots, which is the western Libyan coast that extends from western Tripoli city to the Gulf of Gabes with Tunisia. This work considers some of the effects of oil spills on a variety of coastal industries and social activities. In addition, this work provides a systematic literature review of biological, economic, and cultural resources and their sensitivity to oil spill scenarios on this coast. The findings of this work help provide a basis for the definition of priorities for protection to develop the capacity to respond to oil spills on the Libyan coast.

Citizen science highlights litter associated with COVID-19 as a potential threat on the island of Mindanao, Philippines: a marine biodiversity hotspot

The on-going COVID-19 pandemic is expected to exacerbate the marine litter problem. The use of disposable personal protective equipment (e.g., facemasks) will result to increase in marine plastics pollution. Here we explored the potential of citizen science to determine the distribution of marine litter associated with COVID-19 in Mindanao, Philippines. Volunteers were invited through social media, contributing geotagged photographs of marine litter associated with COVID-19. Although the information is limited, results showed the possible pervasiveness of marine litter associated with COVID-19. Since the waters surrounding the Southern Philippines is known to host high marine biodiversity, the potential negative interaction of marine litter associated with COVID-19 and marine species is inevitable. The contribution of citizen science to address some of the limitations on marine litter research is highlighted and is recommended to be explored further.

Are well-studied marine biodiversity hotspots still blackspots for animal barcoding?

Marine biodiversity underpins ecosystem health and societal well-being. Preservation of biodiversity hotspots is a global challenge. Molecular tools, like DNA barcoding and metabarcoding, hold great potential for biodiversity monitoring, possibly outperforming more traditional taxonomic methods. However, metabarcoding-based biodiversity assessments are limited by the availability of sequences in barcoding reference databases; a lack thereof results in high percentages of unassigned sequences. In this study, we (i) present the current status of known vs. barcoded marine animal species at a global scale based on online taxonomic and genetic databases (NCBI and BOLD) and (ii) compare the current status with data from ten years ago. Then, we focused our attention on occurrence data of marine animal species from five Large Marine Ecosystems (LMEs) representing the most well studied biodiversity hotspots, to identify disparities in COI barcoding coverage between geographic regions and at phylum level. Barcoding coverage varied among LMEs (from 36.8% to 62.4% COI-barcoded species) and phyla (from 4.8% to 74.7% COI-barcoded species), with Porifera, Bryozoa and Platyhelminthes being highly underrepresented, compared to Chordata, Arthropoda and Mollusca. We demonstrate that barcoded marine species increased from 9.5% to 14.2% since the last assessment in 2011, due to new barcodes both on already described species and on newly described ones (about 15,000 new species were described from 2011 to 2021). The next ten years will thus be crucial to enroll concrete collaborative measures and long term initiatives (e.g., Horizon 2030, Ocean Decade) to boost animal barcoding libraries for the marine realm.

Addressing Marine Wildlife Entanglement in Derelict Fishing Nets Using Community-Based Social Marketing: Case Study and Lessons Learnt

Background Entanglement of marine species, particularly endangered sea turtles and cetaceans, in abandoned, lost or otherwise discarded fishing gear is a major conservation concern. Focus of the Article This case study applies Community-Based Social Marketing (CBSM) to reduce marine wildlife net entanglement in the waters surrounding Masirah Island, a marine biodiversity hotspot in Oman. Importance to the Social Marketing Field The study demonstrates the use of social marketing tools in biodiversity conservation, bringing new knowledge to the cross-application of these two fields. Methods The CBSM methodology was applied to select behaviours, identify barriers and benefits, develop strategies and design a pilot study. The responsible disposal of derelict nets in skip bins was selected as the target behaviour, and a mix of behavioural change tools was applied to achieve change: convenience (installation of three skip bins), education (installation of informative signs, distribution of awareness posters, one-to-one engagement with fishers on the beaches), prompts (installation of signs and posters on vessels) and social norms (one-to-one engagement with key influencers and decision makers). The monitoring of behaviour change took place through structured observations over 23 weeks, focussing on the number of nets disposed of in the allocated skip bins. Results Results showed a low level of behaviour adoption rate by skiff and launch vessel fisheries, respectively, 5.36% and 2.58%. Positive results were observed for a short time but did not reach the estimated target value throughout the study period. Recommendations for Research Our pilot study did not lead to broad-scale implementation and we recommend further awareness and engagement with the target audience, trials of various behaviour change tools and increase field monitoring time. We further recommend the application and funding of behaviour change methods applied to fishers with the incorporation of conventional financial, conservation and regulatory tools to support resource management. Limitations Our results show that focussing on specific behaviours with appropriate measurement is both resource and time demanding to solve pressing conservation problems, particularly ones generated by complex industries such as fishing. Various lessons, useful for other social marketers, have been drawn from our evaluation of the overall study.

Global shifts in species richness have shaped carpet shark evolution

BackgroundThe evolutionary processes that shape patterns of species richness in marine ecosystems are complex and may differ between organismal groups. There has been considerable interest in understanding the evolutionary processes that led to marine species richness being concentrated in specific geographical locations. In this study we focus on the evolutionary history of a group of small-to-medium sized sharks known as carpet sharks. While a few carpet shark species are widespread, the majority of carpet shark species richness is contained within a biodiversity hotspot at the boundary of the Indian and Pacific oceans. We address the significance of this biodiversity hotspot in carpet shark evolution and speciation by leveraging a rich fossil record and molecular phylogenetics to examine the prehistoric distribution of carpet sharks.ResultsWe find that carpet sharks species richness was greatest in shallow seas connected to the Atlantic Ocean during the Late Cretaceous, but that there was a subsequent loss of biodiversity in Atlantic waters. Fossil evidence from sites in close geographic proximity to the current center of carpet shark diversity are generally restricted to younger geologic strata.ConclusionsFrom this data we conclude that (1) center of carpet shark biodiversity has shifted during the last 100 million years, (2) carpet sharks have repeatedly dispersed to nascent habitat (including to their current center of diversity), and (3) the current center of carpet shark biodiversity conserves lineages that have been extirpated from this prehistoric range and is a source of new carpet shark species. Our findings provide insights into the roles of marine biodiversity hotspots for higher-tropic level predators and the methods applied here can be used for additional studies of shark evolution.

Observations of sharks (Elasmobranchii) at Europa Island, a remote marine protected area important for shark conservation in the southern Mozambique Channel

Sharks have declined worldwide and remote sanctuaries are becoming crucial for shark conservation. The southwest Indian Ocean is a hotspot of both terrestrial and marine biodiversity mostly impacted by anthropogenic damage. Sharks were observed during surveys performed from April to June 2013 in the virtually pristine coral reefs around Europa Island, a remote Marine Protected Area located in the southern Mozambique Channel. Observation events comprised 67 1-hour scientific dives between 5 – 35m depth and 7 snorkeling inspections, as well as 4 dinghy-based observations in the shallow lagoon. In a period of 24 days, 475 sharks were tallied. Carcharhinus galapagensis was most encountered and contributed 20% of the abundance during diving, followed by C. albimarginatus (10%). Both species were more abundant between 11-14h, and on the exposed sides of the island. Numbers of Sphyrna lewini were highest with 370 individuals windward and leeward, mostly schooling. S. lewini aggregations in the area are hypothesized to be attracted to the seamount archipelago offering favorable conditions for deep incursions and of which Europa Island forms part. C. amblyrhynchos, Galeocerdo cuvier and S. mokarran were uncommon, while there was an additional observation of Rhincodon typus. The lagoon of Europa was a nursery ground for C. melanopterus where it was the only species present. A total of 8 species was recorded, contributing to the shark diversity of 15 species reported from Europa since 1952 in the scientific and gray literature. Overall, with the occurrence of several species of apex predators in addition to that of R. typus, large schools of S. lewini, fair numbers of reef sharks and a nursery of C. melanopterus, Europa’s sharks constitute a significant reservoir of biodiversity, which contributes to preserve the functioning of the ecosystem. Our observations highlight the relevance of Europa Island for shark conservation and the need for shark-targeted management in the EEZ of both Europa and Bassas da India.

Biogeography of acoustic biodiversity of NW Mediterranean coralligenous reefs

Monitoring the biodiversity of key habitats and understanding the drivers across spatial scales is essential for preserving ecosystem functions and associated services. Coralligenous reefs are threatened marine biodiversity hotspots that are challenging to monitor. As fish sounds reflect biodiversity in other habitats, we unveiled the biogeography of coralligenous reef sounds across the north-western Mediterranean using data from 27 sites covering 2000 km and 3 regions over a 3-year period. We assessed how acoustic biodiversity is related to habitat parameters and environmental status. We identified 28 putative fish sound types, which is up to four times as many as recorded in other Mediterranean habitats. 40% of these sounds are not found in other coastal habitats, thus strongly related to coralligenous reefs. Acoustic diversity differed between geographical regions. Ubiquitous sound types were identified, including sounds from top-predator species and others that were more specifically related to the presence of ecosystem engineers (red coral, gorgonians), which are key players in maintaining habitat function. The main determinants of acoustic community composition were depth and percentage coverage of coralligenous outcrops, suggesting that fish-related acoustic communities exhibit bathymetric stratification and are related to benthic reef assemblages. Multivariate analysis also revealed that acoustic communities can reflect different environmental states. This study presents the first large-scale map of acoustic fish biodiversity providing insights into the ichthyofauna that is otherwise difficult to assess because of reduced diving times. It also highlights the potential of passive acoustics in providing new aspects of the correlates of biogeographical patterns of this emblematic habitat relevant for monitoring and conservation.

Observations of marine species from whale watching vessels suggest that anthropogenic disturbance decreases biodiversity in the Pelagos Sanctuary

The Pelagos Sanctuary is a marine biodiversity hotspot, as well as a busy zone for vessel traffic. Long term research on cetaceans has been important in guiding management of this protected area; however, non-cetacean species have received less attention. For this study, we included cetacean and non-cetacean species in an assessment of biodiversity and the potential for anthropogenic disturbance to cause ecosystem stress, indicated by a decline in species richness or evenness. We analyzed sightings of marine wildlife collected on whale watching vessels operating from Imperia and Genova, Italy, using 95% minimum convex polygons to quantify survey area in each region. Our analysis indicated similar levels of species richness in both areas, however Genova had lower Simpson and Shannon-Wiener diversity indices than Imperia. This suggests that Genova has lower species evenness, with the community being more dominated by common species, while rare species are more elusive. Disturbance was quantified based on vessel traffic and fishermen long lines. Genova exhibited significantly higher levels of vessel traffic, but there was no evidence of a difference in disturbance from long lines. These results suggest that anthropogenic disturbance in Genova may result in more ecosystem stress than Imperia. Consequently, management programs should prioritize reducing the impact of vessel traffic on marine life in the northwest Mediterranean Sea.

Distribution of Cetaceans in the Canary Islands (Northeast Atlantic Ocean): Implications for the Natura 2000 Network and Future Conservation Measures

The waters of the Canary Islands are considered a hotspot for marine biodiversity, especially regarding cetacean species. Based on this fact, this study pays attention to the spatial distribution pattern of cetacean species and the conservation role of the Natura 2000 Network, a set of Special Areas of Conservation (SACs), which were defined mainly based on data compiled in 1996, under the framework of the European Habitats Directive. In recent years, the declaration of conservation areas for cetaceans between the Tenerife—La Gomera Islands by two global conservation programs, Mission Blue (“Hope Spots”) and Whale Heritage Site (“Whale Sanctuary”) sent clear signals of scientific and social interest to promote better protection of the cetacean species in the Canary Islands. The main aim of the designated SACs is the conservation of its biological and ecological diversity, ensuring the long-term survival of the target species in the waters around islands. In this case, the enactment of the SACs was based only on the sparse data available for the common bottlenose dolphin,Tursiops truncatus. This study shows that the spatial distribution of cetaceans in the Canary archipelago generated from a large database of cetacean sightings, from 2007 to 2018. The results obtained show the main marine areas where the different cetacean species are distributed around the different islands of the archipelago. The spatial distribution maps of the cetacean species, when compared with the existing SACs of the Natura 2000, show the need to extend these SACs into the open sea to include more cetacean species and a larger number of individuals for better conservation of the endangered marine mammals. As a consequence, some suggestions were proposed to improve and update the role of SACs in European Northeast Atlantic waters as a key environmental tool for cetacean conservation. The data supporting the recent declarations of these two new milestones the “Hope Spot” and the “Whale Sanctuary” enhance more keystone information to promote a large marine protected area in the Eastern Atlantic Ocean, such as the “Macaronesian Biodiversity and Ecological Migration Corridor for Cetaceans,” a conservation figure that has been already proposed in the scientific literature as a deserving candidate of governmental regulations and policies by Portugal and Spain; it would also require joint cross-border cooperation efforts for marine spatial planning.

Integrating eDNA metabarcoding and simultaneous underwater visual surveys to describe complex fish communities in a marine biodiversity hotspot.

Marine biodiversity can be surveyed using underwater visual censuses and recently with eDNA metabarcoding. Although a promising tool, eDNA studies have shown contrasting results related to its detection scale and the number of species identified compared to other survey methods. Also, its accuracy relies on complete reference databases used for taxonomic assignment and, as other survey methods, species detection may show false-negative and false-positive errors. Here, we compared results from underwater visual censuses and simultaneous eDNA metabarcoding fish surveys in terms of observed species and community composition. We also assess the effect of a custom reference database in the taxonomic assignment, and evaluate occupancy, capture and detection probabilities, as well as error rates of eDNA survey data. We amplified a 12S rRNA fish barcode from 24 sampling sites in the gulf of California. More species were detected with eDNA metabarcoding than with UVC. Because each survey method largely detected different sets of species, the combined approach doubled the number of species registered. Both survey methods recovered a known biodiversity gradient and a biogeographic break, but eDNA captured diversity over a broader geographic and bathymetric scale. Furthermore, the use of a modest-sized custom reference database significantly increased taxonomic assignment. In a subset of species, occupancy models revealed eDNA surveys provided similar or higher detection probabilities compared to UVC. The occupancy value of each species had a large influence on eDNA detectability, and in the false positive and negative error. Overall, these results highlight the potential of eDNA metabarcoding in complementing other established ecological methods for studies of marine fishes.

Life-history traits, geographical range, and conservation aspects of reef fishes from the Atlantic and Eastern Pacific.

Reef fish represent one of the most diverse vertebrate groups on Earth, with over 7,000 species distributed around the globe. This richness is not evenly distributed geographically. The Atlantic (AT) and the Eastern Pacific (EP) encompass 30% of the global fish fauna. These areas have been considered the most isolated from the marine biodiversity hotspot in the Indo-Pacific due to distinct physical barriers, such as the Tethyan closure and the distance between the EP and the western Pacific. Despite their comparatively lower species richness, these realms host unique fish assemblages characterized by a remarkable proportion of regional endemics and species with large body size. Here, we present the largest database of life-history traits and biogeographical and conservation aspects presently available for the reef fish fauna of the AT and the EP realms. The database includes 21 traits distributed into behavioral (home range, diel activity, group size, level in the water column, three measures of preferred temperature), morphological (maximum body size, size class, body shape, aspect ratio, caudal fin, mouth position), and ecological (trophic level, diet, spawning strategy, depth of occurrence, two allometric constants, pelagic larval duration, and life span), as well as biogeographical (geographic range index, range extension, species distribution in 20 marine provinces, latitude north and south of occurrence, total number of provinces where species occur, occurrence in the AT and EP), and conservation aspects (IUCN status, vulnerability and global market price). We compiled these data through a careful review of 104 local checklists published between 1982 and 2020, online repositories, local reports, books, and monographs on specific families or genera. We limited our database to localities situated between latitudes 51°N and 45°S that including shallow and upper mesophotic biogenic and/or rocky reefs habitats. Our database covers 2,198 species belonging to 146 families and 655 reef fish genera distributed in two marine realms (1,458 in the AT, 829 in the EP, and 89 in both realms) and 20 marine provinces. This database of reef fish offers the opportunity to explore novel ecological and evolutionary questions at different scales and provides tools for species conservation based on these traits. There are no copyright or proprietary restrictions for research or teaching purposes.

Marine Bacteria Community in a 150-m Depth Tachai Island, the Southeast Andaman Sea of Thailand

The southeast Andaman Sea 52-m off the west coast of Phang Nga province, Thailand, is located in the Indian Ocean, representing a hotspot for marine biodiversity of the world. This study utilized metagenomics combined 16S rRNA gene (V3–V4) sequencing, and firstly revealed the microbiota and their metabolism potentials of this site at an epipelagic depth (150-m depth, TC150M), including comparison with its pelagic depth (30-m depth, TC30M) as well as other nearby Thailand and global ocean sites. Between TC150M and TC30M, the TC150M microbial metagenomics was an eight-fold higher, and the microbiota comprised, for examples more abundant Bacteroidetes while fewer Proteobacteria, than the TC30M. The microbial metabolic potentials of the TC150M were statistically higher in replication repair and metabolisms of amino acids, lipids, nucleotides, and xenobiotics biodegradation, etc. Following comparative microbiota analyses between three Andaman Sea sites and two Gulf of Thailand sites, the relatively great proportions of Bacteroidetes, Nitrospirae, Gemmatimonadetes, and Chlorobi characterized the southeast Andaman Sea. Nevertheless, the microbiota representing Thailand marine sites remained distinguished from the global ocean sites where beta diversities were close. Thai maritime sites showed proportionally higher Proteobacteria, Bacteroides, Nitrospirae, Gemmatimonadetes, and Chlorobi. Thus, the Thai marine microbiota database helps better understand our global ocean microbiota and microbial metabolic potentials. Here, the microbial metabolism potentials between Thailand and the global ocean sites of relatively close microbiota databases encompose the similar functions yet in statistically different frequencies. Our research provided the first preliminary marine microbiome comparison between the epipelagic and pelagic sea levels of the southeast Andaman Sea, Thailand.

Planktivores as trophic drivers of global coral reef fish diversity patterns

One of the most prominent features of life on Earth is the uneven number of species across large spatial scales. Despite being inherently linked to energetic constraints, these gradients in species richness distribution have rarely been examined from a trophic perspective. Here we dissect the global diversity of over 3,600 coral reef fishes to reveal patterns across major trophic groups. By analyzing multiple nested spatial scales, we show that planktivores contribute disproportionally to the formation of the Indo-Australian Archipelago (IAA) marine biodiversity hotspot. Besides being "hotter" at the hotspot, planktivorous fishes display the steepest decline in species numbers with distance from the IAA when compared to other trophic groups. Surprisingly, we did not detect differences in diversification, transition, and dispersal rates in extant species phylogenies that would explain this remarkable gradient in planktivorous fish richness. Thus, we identify two potential complementary drivers for this pattern. First, exceptional levels of partitioning among planktivorous coral reef fishes were driven by temporally stable oceanographic conditions and abundant planktonic resources in the IAA. Second, extinctions of planktivores outside the IAA have been particularly pronounced during Quaternary climate fluctuations. Overall, our results highlight trophic ecology as an important component of global species richness gradients.

In situ observations of coral spawning and spawn slick at Lankayan Island, Sabah, Malaysia

Sexual reproduction of corals is one of the most important processes for the persistence of coral populations. The Coral Triangle is recognised as a global hotspot of marine biodiversity, harbouring 75% of the world coral species. However, coral reproductive studies remain underrepresented in many reefs in the Coral Triangle. This study reports the coral spawning and spawn slicks occurrences from 2012 to 2019 at Lankayan Island, Malaysia, a small island located in the Sulu Sea at the westernmost boundary of the Coral Triangle. A total of 14 species belonging to three genera and two families were recorded to spawn on the reefs between March and May in 2012–2015 and 2019. Between one and eight species spawned on each observed spawning night. Acropora corals appear to dominate the spawning events based on direct observations on the reefs. Coral-spawn slicks were observed during March to May every year and in October 2019. We observed coral spawning between March and May in Lankayan Island, similar to other localities within the Coral Triangle.