ABSTRACT Mangroves support high faunal diversity and provide essential ecological services. However, biodiversity assessments in these habitats remain constrained by their structural complexity, resulting in limited accessibility, low visibility, and persistent taxonomic gaps. Rapid advances in molecular techniques use environmental DNA (eDNA) metabarcoding as an emerging, powerful alternative to conventional surveys. However, its effectiveness in tropical systems, such as Philippine mangroves, is constrained by gaps in publicly available genetic reference data, particularly for invertebrates. To address this, we systematically reviewed 48 years (1977–2025) of literature records of Philippine mangrove‐associated fauna and assessed their representation in public genetic databases to address three questions: (a) What is the current state of faunal biodiversity in Philippine mangroves? (b) How complete are public genetic reference libraries for eDNA applications? and (c) How can integrating eDNA with conventional surveys enhance ecological monitoring? We outlined a workflow for literature screening, taxonomic standardization, and programmatic retrieval and quality‐filtering of GenBank accessions. Across 999 species spanning nine phyla, the ray‐finned fishes (40.4%) dominated the records, followed by gastropods (21.7%) and bivalves (16.5%). Only 70.27% of species had at least one mitochondrial marker, dominated by COI (89.03%), followed by 16S (70.23%), 12S (60.97%), and Cytb (2.45%). Coverage was particularly low for invertebrates and some commercially important conservation‐relevant fishes, limiting species‐level detection in eDNA metabarcoding. Nevertheless, integrating eDNA with traditional methods increases the detection of cryptic, rare, juvenile, and hard‐to‐sample taxa, enabling more comprehensive biodiversity assessments. This combined approach enhances the capacity for spatial and temporal monitoring and supports more informed conservation strategies. Additionally, these data have the potential to enhance faunal assessments and strengthen biodiversity management practices. Overall, this review underscores the need to expand locally curated, voucher‐linked reference databases through targeted sequencing and highlights how national and regional partnerships can improve the accuracy and conservation relevance of eDNA‐based biodiversity monitoring.

ABSTRACT Mangroves play a vital role in supporting diverse associated fauna, yet information on the fish communities they host in the Philippines remains limited. In this study, we assessed fish diversity across four Philippine bioregions—Catanduanes, Batangas, Aklan, and Palawan—using environmental DNA (eDNA) metabarcoding. We analyzed 2,053,055 sequence reads of the 12S rRNA gene from water samples. We annotated 276 operational taxonomic units (OTUs), of which 159 (57.6%) were resolved to species level. OTU richness was highest in Batangas, followed by Aklan, Catanduanes, and Palawan (medians = 57, 46, 34, and 26, respectively), with many unique OTUs per site (40–48) and per habitat type (111 in fringe mangroves, 98 in riverine mangroves). However, alpha diversity, which accounts for species richness and evenness, did not differ significantly among sites or habitats, indicating overall similar diversity. In contrast, beta diversity varied significantly across bioregions, driven by biogeographic and environmental factors such as site, salinity, climate, habitat type, vegetation, and water flow. Most identified species were classified as ‘Least Concern’ (n = 123), but the presence of ‘Not Evaluated’ (n = 22) and ‘Data Deficient’ (n = 12) species highlights gaps in conservation knowledge. Two Vulnerable species, the brown‐marbled grouper (Epinephelus fuscoguttatus) and the spotted seahorse (Hippocampus kuda), were also detected, emphasizing the conservation value of mangroves. More than half of the species‐level OTUs (n = 96; 60.38%) have commercial value, illustrating the role of mangroves in supporting coastal livelihoods. Several OTUs could only be annotated to genus or family, and the presence of ‘Unknown species’ indicates unexplored biodiversity, underscoring the need to expand tropical genetic reference databases. Overall, our findings demonstrate that eDNA metabarcoding is a reliable tool for assessing fish diversity across spatial scales and has strong potential for long‐term monitoring and management to support mangrove resilience and sustainability.

Halodule uninervis plays a critical role in the seagrass ecosystem because its opportunistic traits facilitate expansion and persistence under changing environmental conditions. Yet the population genetic structure and connectivity of this species in the Philippines remain poorly understood. Using genome-wide single-nucleotide polymorphisms (6952 SNPs) generated from MIG-seq data, we assessed clonal reproduction, genetic diversity, population structure, isolation by distance, and recent migration across 10 populations in the Bohol Sea and adjacent waters. Clone detection revealed pronounced spatial variation ranging from predominantly sexual populations with high genotypic richness to populations with strongly clonal populations dominated by relatively few multilocus genotypes. Genetic diversity was generally low to moderate across populations. A geographically separated population from the Visayan Sea exhibited comparatively higher nucleotide diversity and distinct ancestry patterns relative to most Bohol Sea populations. Population structure analyzes showed weak but detectable genetic structuring, with the first two principal components explaining 6.3% and 5.1% of the total variance. ADMIXTURE analyzes showed partially shared ancestry profiles among several populations. Genetic differentiation was low to moderate, with no significant association between geographic distances. These results suggest that geographic distance alone may not fully explain connectivity patterns within the study area. Recent migration analyzes revealed generally high self-recruitment together with asymmetric migration estimates among several populations, including comparatively higher incoming migration into Mambajao. These overall findings suggest a partially connected population dynamics influenced by clonal reproduction, localized recruitment, and regional dispersal processes. This study provides baseline genetic information that may support future conservation, monitoring, and restoration planning for tropical seagrass ecosystems in the Philippines.

As it expands rapidly across Asia, the invasive black mussel Mytella strigata readily establishes dense populations in estuarine and coastal systems. Panguil Bay in the Philippines represents a critically invaded region, providing a compelling case for examining the biological traits that facilitate its establishment. Despite its accelerating spread, the species' reproductive biology remains undescribed, limiting insight into the mechanisms underpinning its invasion success. Here, we examined sex ratio, condition index (CI), gonadal index (GI), gonadal development, size at sexual maturity, and fecundity. Histological analyses revealed five gonadal stages in both sexes with substantial overlap among phases, indicating continuous or near-continuous reproductive activity. The sex ratio was balanced (1:1), and CI showed seasonal patterns consistent with reproductive investment. Females and males reached maturity at 33.6 mm and 32.2 mm, respectively, with fecundity ranging from 3904 to 791,857 eggs per female. Relative reproductive potential analysis showed that individuals within the 35-50 mm size class accounted for 68.5% of total reproductive output, identifying the principal reproductive cohort. Generalized linear models explained over half of GI variability and demonstrated associations with elevated dissolved oxygen and reduced salinity, reflecting reproductive tolerance to fluctuating estuarine conditions. The observed early maturation, high fecundity, and year-round spawning are consistent with traits of successful invasive species and provide a crucial baseline for management in invaded coastal systems.

Background/Objectives: The aim of this study was to determine the plasma and muscle pharmacokinetics of ceftriaxone (25 mg/kg) in tilapia after different administration routes. Methods: Two hundred and sixteen fish maintained at 30 ± 1.5 °C were divided equally into three treatment groups: intravascular (IV), intraperitoneal (IP), and intramuscular (IM). Ceftriaxone concentrations were quantified using high-performance liquid chromatography, and pharmacokinetic parameters were calculated by non-compartmental analysis. Results: The plasma total body clearance, volume of distribution at steady state, and elimination half-life (t1/2λz) were 0.22 L/h/kg, 0.85 L/kg, and 5.27 h, respectively. The t1/2λz values were comparable among the IV, IP, and IM injection groups. The peak plasma concentration was 37.71 ± 3.12 µg/mL and 40.51 ± 2.77 µg/mL following IP and IM injection, respectively. The bioavailability was 67.04% for IP and 101.48% for IM. The peak muscle concentration was 9.49 ± 0.75 µg/g for IV, 5.71 ± 0.85 µg/g for IP, and 12.24 ± 2.41 µg/g for IM injection. The AUC0–∞muscle/AUC0–∞plasma ratio was 0.23, 0.18, and 0.30 for the IV, IP, and IM groups, respectively. The AUCmuscle/AUCplasma indicates the ratio of drug penetration into the muscle, and a value less than 1 indicates that ceftriaxone penetrates into muscle tissue at a low ratio. Conclusions: These results indicate that ceftriaxone is well absorbed after IP and IM injections and passes into muscle tissue at a low tissue penetration. Ceftriaxone can be administered via IP and IM injection in Nile tilapia; nevertheless, its therapeutic efficacy requires evaluation.

Invasive bivalves are important agents of ecological change in estuarine food webs, with the potential to influence nutrient cycling and community dynamics. The black mussel Mytella strigata, native to Central and South America, has recently spread to Southeast Asia, a range expansion likely facilitated by its broad salinity tolerance. However, its feeding performance under variable salinity and food conditions remains poorly understood, particularly in newly colonized regions. In this exploratory study, we quantified the clearance rates of M. strigata across a salinity gradient (low: 8 PSU; intermediate: 16 PSU; high: 29 PSU) under two feeding regimes: natural seston and monocultures of the diatom Thalassiosira weissflogii. Under seston conditions, clearance rates declined by 1.14

Mangrove forests are vital ecosystems at the intersection of land and sea that provide food resources, supporting the food security and livelihoods of coastal communities in tropical and subtropical areas. This systematic review investigated the food and medicinal potential of mangrove species in Indonesia, with relevant global insights incorporated to enrich the context. The review also examines how environmental degradation affects the productivity of these resources and identifies the key knowledge gaps related to sustainable use and management practices. A comprehensive search revealed 31 articles that met the screening criteria. The findings highlight Nypa fruticans and Bruguiera gymnorrhiza as the most frequently utilized mangrove species for food, with their leaves, fruits, and plant sap being consumed directly or processed into products such as syrup, flour, and fermented beverages. These mangrove-derived foods hold not only nutritional importance but also cultural and traditional value for local communities. In addition to their role as food sources, several mangrove species possess notable medicinal properties, including antioxidant, anticancer, antidiabetic, and antimicrobial activities, indicating their dual potential in nutrition and healthcare. Despite their ecological and socioeconomic value, mangrove resources face productivity threats from environmental degradation and unsustainable practices. This review identifies key knowledge gaps, particularly the limited research on underutilized mangrove species with food or medicinal value. This review underscores the role of mangrove-derived foods and medicines in advancing sustainable development by supporting coastal food security, promoting health, and contributing to the achievement of global sustainability goals, particularly SDG 2 (Zero Hunger) and SDG 15 (Life on Land). Future research and policy interventions that integrate food security objectives into mangrove conservation and rehabilitation efforts are needed. Strengthening sustainable mangrove management and increasing awareness of their benefits will be key to guaranteeing the long-term resilience of coastal communities in the face of climate and environmental change.

The invasion of Mytella strigata in Panguil Bay, Philippines, presents both challenges and opportunities for local fisheries and coastal communities. Understanding gendered perspectives on this invasive mussel is crucial for leveraging diverse knowledge and practices in its sustainable management. This study investigates gender differences in knowledge, attitudes, and practices (KAP) towards M. strigata, aiming to form strategies that integrate both men’s and women’s roles in addressing the impacts of its management and use. A KAP survey was conducted in Lala, Lanao del Norte, and Tangub City, Misamis Occidental, with 62 respondents, including fish pond operators, fish cage operators, artisanal fishers, and gleaners. The findings reveal gendered differences in how stakeholders perceive and engage with M. strigata. Women tend to focus on the mussel’s potential economic benefits, while men emphasize its environmental and economic risks. These differing perspectives highlight the need for integrative management approaches that balance both challenges and opportunities. Knowledge gaps exist between male and female respondents, particularly regarding the timing of the initial invasion and the spatial scope of infestations, shaped by different occupational roles and levels of engagement with coastal resources. Additionally, gendered differences in attitudes are influenced by economic priorities, perceived utility, and access to information, while practices related to managing and utilizing M. strigata are shaped by sociocultural roles. By identifying these gendered dynamics, the study highlights the need for inclusive and gender-sensitive management approaches that harness both men’s and women’s perspectives, ensuring more effective and sustainable strategies for addressing biological invasions in coastal ecosystems.

Cefuroxime is a broad-spectrum antibiotic extensively utilized in humans and animals. Although it has been reported as beneficial against certain fish infections, pharmacokinetic studies are lacking. The purpose of this study was to evaluate the pharmacokinetics of cefuroxime following intravascular (IV, n = 72), intraperitoneal (IP, n = 72), intramuscular (IM, n = 72), and oral (n = 72) administration of 20 mg/kg in Nile tilapia (Oreochromis niloticus) maintained at 29 ± 1.5 °C. Two hundred and eighty-eight fish were equally distributed among four treatment groups: IV, IP, IM, and oral. Blood samples were obtained from 6 fish per group at 12 distinct time intervals over a duration of 96 h. Cefuroxime plasma concentrations were quantified with high-performance liquid chromatography and subsequently evaluated through non-compartmental analysis. Following IV injection, the t1/2ʎz was 8.04 h, the Vdss was 1.03 L/kg, and the ClT was 0.14 L/h/kg. The Cmax of cefuroxime was 53.38±4.28 µg/mL at 0.25 h for IP injection, 28.70±3.41 µg/mL at 0.5 h for IM injection, and 6.77±0.81 µg/mL at 1 h for oral administration. Bioavailability was 80.26

The effective management of a nonindigenous species with invasive potential hinges on a thorough understanding of its population dynamics. In Panguil Bay, Philippines, the black mussel Mytella strigata, an emerging invasive species in Asia, has recently established populations. Investigating the population dynamics of M. strigata in this estuarine mangrove ecosystem provides critical insights into its environmental adaptability and invasive potential. Thus, the present study investigated the spatial variability in physicochemical parameters and their influence on the growth, mortality, and recruitment patterns of the nonindigenous black mussel M. strigata across the inner, middle, and outer locations of the bay. Significant differences were observed in temperature, salinity, total dissolved solids, and pH across the bay, with the middle location exhibiting the highest temperature, whereas salinity and total dissolved solids increased from the inner to the outer locations. The growth parameters varied accordingly, with the middle location showing the highest asymptotic length but the lowest growth rate, resulting in a longer lifespan for mussels in this area. Conversely, the inner location had the highest growth rate but the shortest lifespan. The mortality rates were lowest in the inner location and highest in the outer location. Recruitment patterns also showed spatial variability, with peaks occurring in different months depending on the location. A linear model incorporating pH, dissolved oxygen, salinity, and temperature explained 59.32% of the variance in recruitment, highlighting the complex environmental influences on recruitment. The yield-per-recruit analysis indicated that the middle and outer locations could sustain greater biomass production than the inner location, suggesting areas for targeted management for population collapse. These findings offer valuable insights for developing effective management strategies to mitigate the impact of M. strigata in Panguil Bay.

As an emerging invasive species, the black mussel Mytella strigata has been recognized for its adverse ecological impacts, such as biofouling and negative effects on shellfish aquaculture. This study examined perceptions and responses from eight key stakeholder groups directly affected by M. strigata in Panguil Bay, Philippines. We also quantified its effects on human well-being (safety, material goods, social practices, health) and ecosystem services (biodiversity, aesthetics, water quality, livelihood, and food sources). Affected stakeholders were primarily young to middle-aged married adults with at least a high school education, living in households of 4 to 6 members. They identified various impacts of M. strigata, including biofouling and financial setbacks, as well as benefits like additional food sources and increased income. Responses ranged from manual removal to exploring alternative livelihoods. Stakeholders acknowledged significant negative effects on human well-being and ecosystem services, reflecting shifts in priorities based on direct interactions with bay resources. The limited use of M. strigata as food, aquaculture feed, and bait was noted, with varying local preferences regarding consumption and sale. Stakeholders recommended livelihood training, removal/control initiatives, market development, awareness campaigns, and policy support to address M. strigata challenges. These findings highlight the need for management strategies that balance ecological sustainability with economic stability. The community's adaptive resource use, proactive strategies, and participatory governance provide a robust framework for addressing the challenges posed by M. strigata.

In Southern Philippines where coastal research is scarce and hindered by safety and security concerns, the present study on seagrass assessment and its associated macroinvertebrates is imperative for resource conservation and management. The study was conducted in 19 seagrass sites across 18 coastal municipalities spanning the seagrass beds in the Southern Philippines. The results identified eight seagrasses with Thalassia hemprichii, Enhalus acoroides, and Cymodocea rotundata as the most frequent species. Seagrass cover ranged from 26.50 (fair) to 91.30

The studied fifteen populations of Cymodocea rotundata and Enhalus acoroides in Mindanao, southern Philippines revealed a remarkable strategy for reproduction and dispersal. E. acoroides populations exhibits high rates of sexual recruitment with high clonal richness ranged from 0.9 to 1.0, while C. rotundata exhibited monoclonal to high clonal richness ranged from 0 to 1.0. Overall, clonal richness was high indicating sexual reproduction is prevalent, but varied for C. rotundata. The largest genet found in the study was at Rizal (RIZ), northern Mindanao wherein throughout the sampling area only one genet was identified, maybe influenced by environmental condition and hydrodynamic of the water currents and tidal fluctuation in this range-edge population. Significant pairwise population genetic differentiation was found among many sites. Isolation by distance (IBD) was detected in C. rotundata (P < 0.05) but not in E. acoroides (P = 0.253). IBD manifested among populations maybe influenced by the ocean currents in Mindanao, but it has to be confirmed yet in the future study. The results have implications for understanding on how the environmental conditions can influenced the dispersal strategy of these species in natural settings. These species manifested high plasticity most likely to adopt to environmental conditions favoring natural selection for long term demographic stability and fitness. The genetic diversity, structure, reproduction and dispersal strategies observed in this study may prove useful for eventual genetic conservation plans of these two foundational seagrass species.

Asia is widely recognized for its grouper aquaculture. China (65%), Taiwan (17%), and Indonesia (11%) together account for 93% of global grouper production. This study recorded 48 species, and 16 hybrids were used in Asian aquaculture. The conservation status of cultured grouper species is 67% least concern, 17% data deficient, 10% vulnerable, and 2% critically endangered, endangered, and near threatened. Most Asian countries face issues such as (1) lack of hatcheries, (2) poor seed stock, (3) poor broodstock quality, (4) lack of financial and technical support, (5) trash fish and accessibility to fish pellets, (6) poor water quality, (7) diseases, and (8) capture-based aquaculture. These issues, combined with overfishing, contribute to a decline in grouper productivity and their wild population. The decline has alarmed experts and conservationists looking into the causes and potential remedies to this problem. Some management strategies mentioned in this paper include: (1) closed season during spawning aggregation, (2) establishing more marine protected areas (MPAs), particularly the no-take marine reserve, (3) non-consumptive utilization of groupers (eco-tourism) and (4) establishing more full-cycle grouper aquaculture. The results of this study suggest that implementing these strategies could be an effective means of addressing the issue of grouper production and that additional research is required to determine the most effective method of addressing this problem. The findings of this study have significant implications for the development and sustainability of grouper aquaculture and highlight the need for further research in this area.

Abstract Large-scale genetic population study of the two dominant tropical species of seagrass is conducted in Mindanao, southern Philippines. The goal of the study was to understand population genetic status of the dominant tropical seagrass species, Cymodocea rotundata and Enhalus acoroides for appropriate management. Population genetics structure for the 15 sites was performed by using polymorphic microsatellite markers. The results showed that the clonal richness was high in E. acoroides than C. rotundata. The largest genet found in the study was at Rizal, northern Mindanao wherein throughout the sampling area (i.e. 300 x 40 m) only one genet was identified for C. rotundata. The mean FIS (coefficient of local inbreeding) values was positive (heterozygous deficit) with some sites deviated from Hardy-Weinberg Equilibrium. Isolation by distance (IBD) was detected in C. rotundata (P < 0.05) but not in E. acoroides (P = 0.253), with the Mindanao ocean currents influenced genetic connectivity and structure. Genetic differentiation did not show any relationship between the geographical location and distance exhibiting high FST values for E. acoroides (0.183) and C. rotundata (0.205). The floating, buoyant fruits of E. acoroides may play a role in their long-distance dispersal; however, such dispersal is not frequent. Almost all of the seeds and fruits of C. rotundata are derived from self-recruitment in the natal meadow. This study suggests that C. rotundata and E. acoroides populations possess a weak genetic connectivity, and that the persistence of the meadow is threatened due to the low genetic diversity and high degree of population isolation.

Abstract The aim of the study was to investigate the plasma and muscle pharmacokinetic of enrofloxacin (ENR) and its active metabolite ciprofloxacin (CIP) in Nile tilapia (Oreochromis niloticus) following single intravascular (IV), intraperitoneal (IP), or oral (PO) administration at 30 ± 1 °C. In this study, 234 healthy Nile tilapia (120–150 g) were used. The fish received a single IV, IP, or PO treatment of ENR at a dose of 10 mg/kg. The plasma and muscle tissue concentrations of ENR and CIP were measured using high–performance liquid chromatography with fluorescence detection and were evaluated using non–compartmental analysis. The elimination half–life, volume of distribution at steady state, and total body clearance of ENR were 21.7 h, 2.69 L/kg, and 0.09 L/h/kg, respectively. The peak plasma concentrations of ENR after IP or PO administration were 6.11 and 4.21 µg/mL at 0.25 and 2 h, respectively. The bioavailability of ENR for IP or PO routes was 78% and 86%, respectively. AUC(0–120)muscle/AUC(0–120)plasma ratios following the IV, IP, or PO administrations were 1.43, 1.49, and 1.07, respectively. CIP was detected after all routes, but the AUC0–last ratios of CIP to ENR were <1.0% for plasma and muscle. ENR was detected up to 120 h following the IV, IP, or PO administrations. The long residence time of ENR after single IV, IP, or PO administration ensured the plasma concentration was ≥1 × MIC for bacteria with threshold MIC values of 0.92, 0.72, and 0.80 μg/mL over the whole 120 h observed. However, further studies are necessary to determine the optimum pharmacokinetic/pharmacodynamics data of ENR for the treatment of infections caused by susceptible bacteria in tilapia.

This study is the first large‐scale genetic population study of the three dominant tropical species of seagrass in the southern Philippines. The aim was to understand the genetic diversity, population structure, and clonality of Enhalus acoroides, Thalassia hemprichii, and Cymodocea rotundata for appropriate ecosystem management and conservation. Population genetics analysis for the 15 sites was performed by using polymorphic microsatellite markers within the regional geographical scale. The results showed that the population genetic parameters across the Mindanao region are low to high. Overall, Clonal richness was highest in E. acoroides, followed by T. hemprichii and C. rotundata, indicating sexual reproduction is prevalent. The largest genet found in the study was at Rizal, Northern Mindanao, wherein throughout the sampling area only one genet was identified. The mean FIS (coefficient of local inbreeding) values were positive (heterozygous deficit) with some sites deviating from Hardy-Weinberg equilibrium. Significant pairwise population genetic differentiation was found among many sites. Isolation by distance (IBD) was detected in T. hemprichii and C. rotundata (P < 0.05) but not in E. acoroides (P = 0.253). IBD is present among populations, maybe influenced by the ocean current system in the southern Philippines, but it has to be confirmed yet in the future study. If the goal is to maintain the genetic connectivity of these ecologically important seagrass species, conservation planning and implementation of marine protection should be considered at the regional scale – following the Mindanao Ocean currents.

Bioaccumulation of Trace Metals in Golden Rabbit fish Siganus guttatus, Collected in Selected Seagrass Meadows of Northern Mindanao, Philippines The high-value Golden Rabbit fish (Siganus guttatus) was used to assess the current levels of trace metals zinc (Zn), copper (Cu), aluminium (Al) and cadmium (Cd) in 3 different seagrass meadows. The level of trace metals detected in the flesh of S. guttatus was at in the order of Al (18.360 mg/kg) >Zn (15.783 mg/kg) >Cu (1.0046 mg/kg) >Cd (0.100 mg/kg). Highest Al concentration was found in S. guttatus samples from Rizal, Zamboanga del Norte, as well as the toxic Cd. Human risk assessment based on the average Filipino consumption, showed that it is still safe to consume the fish S. guttatus on a daily basis. In general, Al was the most interactive element while Cd was the least. Regular monitoring of trace metals in these important seagrass meadows is recommended to avoid human health risk and ecological toxicity that may arise.