Journal of Fisheries and Environment

Seaweed Growth, Transcriptomics, and Defense Responses: Trends and Insights from Bibliometric Mapping

Thu, 20 Aug 2026 00:00:00 +0700

Seaweeds (macroalgae) play a critical ecological role and hold growing promise for aquaculture, biotechnology, and the sustainable bioeconomy. Despite substantial advances in seaweed physiology, transcriptomics, and stress biology, current knowledge remains fragmented across physiological, molecular, and applied research domains. Here, we present a comprehensive bibliometric and critical synthesis of global seaweed research, integrating co-occurrence mapping with in-depth literature analysis. A dataset of 13,657 publications from Scopus and Web of Science (1970–2026) was analyzed using the Bibliometrix R-package (Biblioshiny) to identify research trends, thematic clusters, and knowledge gaps. Three dominant themes emerged: (i) growth and physiological regulation, (ii) stress responses and molecular adaptation, and (iii) cultivation and applied systems. Trend analysis indicates a clear shift from traditional ecological studies toward stress-related and application-driven research, including biostimulants and climate resilience. However, thematic mapping reveals a persistent disconnect between physiological and molecular approaches, alongside limited mechanistic insight in cultivation research. Our critical synthesis further uncovers inconsistencies in reported growth responses under environmental stress and a weak linkage between transcriptomic insights and practical aquaculture outcomes. These findings emphasize significant gaps in connecting gene expression with phenotypic performance and in translating laboratory-based molecular knowledge into field-scale cultivation systems. Collectively, the results suggest that interdisciplinary, multi-omics frameworks are essential for advancing seaweed growth and stress tolerance research, and that bridging fundamental and applied science is key to developing resilient, sustainable seaweed production systems.

Shore Height and Low-tide Exposure as Regulators of Intertidal Distribution Thresholds of Seagrass Enhalus acoroides in the Gulf of Thailand

Thu, 20 Aug 2026 00:00:00 +0700

Understanding environmental controls on seagrass distribution is essential because inappropriate elevation selection can reduce restoration and transplantation success. This study investigated how shore height and low-tide exposure influence the distribution of Enhalus acoroides in the upper intertidal zone of the Gulf of Thailand. Shore height was measured at 261 stations across seven sites during 2022–2023 using a theodolite and a surveyors’ rod, and expressed as height above lowest low water (cm H_LLW) based on predicted tidal levels. Aboveground biomass was estimated using a modified Rapid Visual Estimation Technique. Across shore heights of 0‒120 cm H_LLW, the frequency of E. acoroides occurrence followed a normal distribution (D = 0.09, p = 0.35), with most observations between 40 and 80 cm H_LLW. Preferred shore-height ranges varied among sites, extending from 0 to 106 H_LLW. Percentage cover did not differ significantly among H_LLW intervals of 0‒40 cm, 40‒80 cm, 80‒120 cm. However, aboveground biomass differed significantly among groups, with the highest biomass at 0–20 cm H_LLW (17.77±6.75 g DW·m⁻²), where mean cover was 48.18±35.73%. The upper shore-height threshold of E. acoroides was lower in the eastern Gulf of Thailand (77 cm H_LLW) than in the southern coastal region (106 cm H_LLW) and was substantially lower than thresholds reported for the Andaman Sea. These regional and local differences were closely associated with tidal regime, low-tide level, desiccation duration, and sediment water-level drawdown. The findings provide practical guidance for restoring and transplantation intertidal E. acoroides meadows under changing coastal conditions associated with global warming.

Effect of Chestnut Wood Polyphenols on Growth, Survival, and Disease Resistance in Pacific White Shrimp (Litopenaeus vannamei Boone, 1931)

Thu, 20 Aug 2026 00:00:00 +0700

Chestnut wood polyphenols (CWP) represent a natural feed additive with potential antibacterial and immunostimulant properties. This study evaluated the in vitro antibacterial activity of CWP against Photobacterium damselae subsp. damselae (PDD) and its effects on the growth performance, immune responses, and disease resistance of Pacific white shrimp (Litopenaeus vannamei Boone, 1931). The minimum inhibitory concentration and minimum bactericidal concentration of CWP against PDD were 10 µg·mL⁻¹ and 20 µg·mL⁻¹, respectively. In the feeding trial, shrimp (initial weight, 5.58±0.19 g) were given diets supplemented with CWP at 0 (control), 1, 3, or 5 g·kg feed⁻¹ for 30 days. The results indicate that dietary CWP significantly improved survival rates and feed conversion ratios in a dose-dependent manner, with the highest survival (92.00±4.00%) and lowest FCR (0.99±0.04) observed in the 5 g·kg feed⁻¹ group. In addition, CWP supplementation notably reduced intestinal Vibrio spp. counts and enhanced superoxide dismutase activity, while the immune parameters, including total hemocyte count, phagocytic activity, and phenoloxidase activity, remained unaffected. Following experimental challenge with PDD, shrimp fed 5 g·kg feed⁻¹ CWP exhibited higher survival (70.00%) compared to the control group (43.33%). On day 7 post-challenge, attenuation of PDD-associated lesions in the hepatopancreas and muscle by dietary CWP was revealed by histopathological examination. These findings thus demonstrate that dietary supplementation with CWP, particularly at 5 g·kg feed⁻¹, enhances growth performance and immune responses, while reducing pathogenic bacterial loads and improving disease resistance in Pacific white shrimp.

Microplastic Distribution in Khlong Wong, Songkhla Lake, Thailand: Implications for Household and Fishing-Related Sources

Thu, 20 Aug 2026 00:00:00 +0700

Microplastic pollution has emerged as a global environmental concern affecting aquatic ecosystems. Khlong Wong, a major canal draining into Songkhla Lake in southern Thailand, may serve as an important transport pathway for land-based microplastics into the lake system. This study aimed to investigate the spatial and temporal distribution of microplastics in the water column of Khlong Wong and examine their relationships with environmental factors. Water samples were collected bimonthly for one year from seven sampling stations along the canal, together with measurements of key water quality parameters. Five types of microplastics were identified: polyester, cotton, nylon, alkyd, and polypropylene (PP). Polyester fibers were the dominant type, accounting for 53.94% of total microplastics, suggesting inputs from household activities and fishing practices. Spatial analysis showed high similarity in microplastic composition along the canal (79.52%–94.88%), with the greatest observed accumulation at the canal mouth, indicating its possible role as a convergence zone before discharge into Songkhla Lake. Temporal analysis showed descriptive seasonal variation, with the greatest observed microplastic abundance recorded during the northeast monsoon in December (36.14±7.69 items∙100 L⁻¹), dominated by polyester fibers likely transported by increased runoff. In contrast, PP and nylon were more prevalent during the hot season (February–April), possibly associated with degradation of fishing gear under prolonged sunlight exposure. Overall, the results suggest that Khlong Wong may function as an important transport pathway conveying microplastics from terrestrial sources and fishing practices into Songkhla Lake. This study provides baseline information to support water quality management and strategies to mitigate microplastic contamination.

Assessment of Coral Reef Conditions and Resilience in Eastern and Northern Bali, Indonesia

Tue, 25 Aug 2026 00:00:00 +0700

Across the Indo-Pacific, coral reef condition is increasingly affected by human pressures, land-based pollution, and climate-related stressors, including bleaching events. These challenges threaten biodiversity and the ecological services provided by coral reefs. This study aimed to assess coral health and recovery potential in East and North Bali and provide baseline data for conservation and management strategies. The research was conducted from June to November 2023 at seven reef sites, consisting of three sites in East Bali and four sites in North Bali. Benthic composition and live coral cover were assessed using the Underwater Photo Transect method, while reef fish abundance and biomass were evaluated using the Underwater Visual Census method. Site-level values were used to calculate coral cover, reef fish parameters, and Coral Health Index scores. Live coral cover ranged from 13.14% to 38.77% with regional means of 19.40% in East and 25.94% in North Bali; however, the difference was not statistically significant (p = 0.9998). A total of 380 reef fish representing 30 species and six families were recorded, comprising 85 individuals in East Bali and 295 in North Bali. Reef fish abundance also did not differ significantly between regions (p = 0.4277). Acanthuridae was the dominant family. Coral Health Index scores ranged from 3 to 6, while reef fish biomass was classified as low at all sites. These findings provide baseline information to support long-term monitoring, site-specific management, and conservation prioritization for Bali’s coral reef ecosystems.

Effects of Dietary Cucumber Tree Leaf Extract (Averrhoa bilimbi) Supplementation on Survival and Growth Performance of Bilih Fish (Rasbora maninjau)

Tue, 25 Aug 2026 00:00:00 +0700

This study investigated the effect of dietary supplementation with cucumber tree leaf extract (Averrhoa bilimbi) as a natural feed additive on the survival and growth performance of bilih fish (Rasbora maninjau). Leaves of A. bilimbi were dried, ground, and macerated in 96% ethanol (1:10 w/v) for 72 h. The solvent was evaporated, and the viscous extract was stored at 4°C prior to feed incorporation. A completely randomized design (CRD) was applied, comprising four dietary treatments with three replicates each: P0 (control, no extract), P1 (1% extract), P2 (3% extract), and P3 (5% extract) per kilogram of feed. Juvenile bilih fish measuring 2–3 cm in length were stocked at a density of one fish per liter and reared for 40 days. Feed was administered at 3% of biomass daily in two equal meals. Key response variables included survival rate and growth performance. Analysis of variance (ANOVA) revealed that dietary supplementation with cucumber tree leaf extract had a significant effect on growth performance (p<0.05) but exerted no significant influence on survival rate (p≥0.05). The optimal supplementation dose was approximately 3% (P2), with lower or higher doses resulting in reduced growth performance. A. bilimbi may be effective as a natural feed supplement for improving the growth of R. maninjau, possibly because of its bioactive compound content and the slight increase in the dietary protein level.

Phytoplankton Composition Indicators for the Assessment of Eutrophication at Patong Beach, Phuket

Audomlak Khongsang, Raymond James Ritchie, Suhailar Sma-Air — Mon, 31 Aug 2026 00:00:00 +0700

Recurrent phytoplankton blooms at Patong Beach, Phuket, Thailand, a major international tourist destination, pose a potential threat to coastal ecosystems, public health, and the local tourism economy. This study monitored phytoplankton community structure, cell abundance, diversity indices, and chlorophyll a (Chl a) at five stations spanning a drainage canal and adjacent beach waters from December 2022 to September 2023. Bloom events were observed at the southern end of the beach in February and April. In February, the estuarine station was dominated by the colonial diatom Chaetoceros socialis (up to 99% of total abundance; 695,750 cells·L⁻¹), while the beach stations showed a strong contribution from the dinoflagellate Peridinium quinquecorne. In April, C. socialis dominated all marine stations, coinciding with sharp reductions in species diversity and Chl a concentrations approaching 100 µg·L⁻¹. Blooms were not observed in the drainage canal during the study period, despite its strong land-based influence, suggesting that physical retention conditions in the bay, together with nutrient inputs, may be important in promoting bloom formation near the beach. Shannon–Wiener diversity (H′) and Margalef richness (d) were the most sensitive indices for detecting bloom-related community change and are recommended for routine monitoring. These findings provide a useful framework for bloom detection and risk assessment at Patong Beach and comparable tropical tourist destinations, while also highlighting the need for future studies integrating nutrient dynamics, sediment cyst surveys, and hydrodynamic observations.

Beyond Seagrass Density: Holothuroid Occurrence across Fine-scale Habitat Mosaics in Reef Flats of Tomini Bay, Indonesia

Femy Mahmud Sahami, Faizal Kasim, Sitty Nursinar, Delvinawati Malawo — Mon, 31 Aug 2026 00:00:00 +0700

Seagrass-associated reef flats are spatially heterogeneous, yet holothuroid occurrence is often interpreted primarily in relation to seagrass density. We examined fine-scale seagrass–holothuroid co-occurrence in Tomini Bay, Indonesia, using three stations, three 1×1 m quadrats per station, and 25 microplots per quadrat. The reconstructed sampling frame comprised 225 microplots and 450 plot-time records. Holothuroids were recorded in 37 co-presence microplots, while 33 microplots contained seagrass only and no holothuroid-only microplots were recorded. Among seagrass-present microplots, seagrass shoot-density distributions provided no evidence of a difference between seagrass-only and co-presence classes (Mann–Whitney U = 664, p = 0.533; rank-biserial effect size = 0.088). Pooled holothuroid observations were numerically greatest at ST1, whereas seagrass shoot density, seagrass richness, and holothuroid richness were numerically greatest at ST3. Field-observed substrate-class frequencies showed descriptive variation among stations. Exploratory Spearman correlations and PCA across nine quadrats summarized combined biological, environmental, and substrate-class gradients; PC1 and PC2 accounted for 35.13% and 20.50% of variation, respectively (55.63% cumulative). These patterns are consistent with a fine-scale habitat-mosaic interpretation rather than a shoot-density-only interpretation, but they do not isolate causal habitat effects. The study provides baseline ecological information for habitat assessment in Tomini Bay.

Effects of Dietary Fish Oil Levels on Growth Performance and Nutrient Utilization in Larval Glass Catfish, Kryptopterus lais (Bleeker, 1851)

Mon, 31 Aug 2026 00:00:00 +0700

The glass catfish, Kryptopterus lais (Bleeker, 1851), is economically important; however, its larval nutritional requirements remain poorly understood. This study evaluated the effects of dietary lipid levels on growth, feed utilization, survival, and whole-body composition of K. lais larvae. Eleven-day-old post-hatchlings with an initial body weight of 0.01±0.00 g and total length of 0.47±0.01 cm were reared for 60 days in net cages at 50 fish per cage, with three replicates per treatment. Four isoproteic diets containing 42.86% crude protein and 5%, 10%, 15%, or 20% lipid were compared with a commercial diet. Larvae were fed to apparent satiation four times daily. Growth performance and feed utilization improved as dietary lipid increased to 15%, whereas the 20% lipid diet provided no additional benefit. Survival exceeded 96% in all treatments and was not significantly affected by treatment. Second-order polynomial regression estimated optimal dietary lipid levels of 14.40 based on specific growth rate and 15.36% based on feed conversion ratio. Whole-body crude protein was highest in fish fed the 15% lipid diet and was comparable to that of fish fed the commercial diet. Whole-body lipid content was higher in fish fed 15%, 20%, and commercial diets than in those fed the 5% and 10% lipid diets, whereas moisture and ash were unaffected. In conclusion, these findings indicate that approximately 15% dietary supports favorable growth performance and feed utilization in K. lais larvae. Further studies using isoenergetic diets are needed to confirm the dietary lipid requirement of this species.

Decision Tree-based Prediction of Hatching Efficiency in Mud Spiny Lobster (Panulirus polyphagus): Relative Importance of Body Weight, Carapace Length, and Water Quality

Mon, 31 Aug 2026 00:00:00 +0700

Machine learning (ML) has been applied increasingly in aquaculture; however, its practical use in hatchery management remains limited due to challenges in model interpretability. This study developed an interpretable decision tree (DT) model to predict the hatching efficiency (HE) of mud spiny lobster (Panulirus polyphagus) in a hatchery system (n = 72), considering broodstock size indicators—carapace length (CL) and body weight (BW)—and key water quality parameters—temperature, salinity, dissolved oxygen (DO), pH, total ammonia nitrogen (TAN), nitrite (NO₂^-), and alkalinity). The objectives were to compare BW and CL performance, identify key factors affecting hatching success, and establish threshold-based decision rules for hatchery management. Preliminary regression analysis showed that simple linear models could not adequately capture the relationship between broodstock size and HE. However, BW performed relatively better than CL and was therefore selected for subsequent DT modeling. HE was classified into two groups using K-means clustering: low (<40.5%) and high (≥40.5%). The DT model achieved an overall classification accuracy of 62.50% based on 10-fold cross-validation of the complete dataset (n = 72), with variable classification performance between HE groups. In particular, the model showed limited ability to identify the high-HE group, with a recall of 0.11 and F1-score of 0.18. TAN, DO, and BW were identified as the most influential variables, with nitrite also contributing to the decision rules for hatchery management. Maintaining TAN below 0.14 mg-N·L^-1 was associated with higher HE, particularly in broodstock weighing 819.5–895.6 g, while a higher TAN value was associated with reduced performance. In addition, DO levels above 4.95 mg·L^-1 improved HE in larger broodstock (>904 g). Based on these findings, the DT model may serve as an exploratory and interpretable decision-support tool for understanding HE patterns and informing broodstock and water quality management in sustainable lobster hatchery systems, while further model development and validation are needed before its use as a reliable predictive system.

Beyond Names: Phylogeographic Insights into the Mahseer (Teleostei: Cyprinidae: Tor) of Sarawak, Malaysia Using the Mitochondrial COI Gene

Stephanie Arleen Apoi, Fazimah Aziz — Mon, 31 Aug 2026 00:00:00 +0700

The mahseer (Teleostei: Cyprinidae: Tor) are highly valued freshwater fishes in Southeast Asia, with ecological, fisheries, and cultural importance. However, their taxonomy and biogeography remain unresolved, especially in Sarawak, Malaysia. This study assessed genetic divergence and phylogeographic structure of Sarawak Tor using the mitochondrial cytochrome oxidase subunit I (COI) gene. Ninety-four (94) COI sequences were analysed, comprising 19 newly determined sequences from specimens referable to T. tambroides and T. douronensis from North and South Sarawak and 75 GenBank sequences. Mean interspecific divergence between the nominal taxa was 3.62%, compared with intraspecific divergence of 2.24% for T. douronensis and 1.16% for T. tambroides, yielding a narrow difference of 1.38% between interspecific and the higher intraspecific divergence. Geographic differentiation was clearer, with 1.93% divergence between North and South Sarawak populations, compared with 0.04% and 0.62% within regions. Phylogenetic analyses recovered two major regional lineages, with the Sarawak specimens forming a distinct lineage subdivided into northern and southern subclades. The nominal taxa were not reciprocally monophyletic, and T. tambroides from Baram was nested within the North Sarawak T. douronensis lineage. These results indicate that mitochondrial variation is structured more strongly by geography than by nominal species designation and support interpreting Sarawak T. tambroides and T. douronensis as an unresolved, geographically structured species complex. Historical isolation with incomplete lineage sorting provides the most parsimonious explanation, although introgression and reference misidentification cannot be excluded. Broader sampling, nuclear or genomic data, and integrated morphological analyses are required to resolve their taxonomy and support provenance-based conservation.

Effect of Acid Type and Buffer-assisted Stimulation on Pepsin Recovery from Skipjack Tuna (Katsuwonus pelamis) Stomach

Mon, 31 Aug 2026 00:00:00 +0700

The global tuna processing industry generates substantial by-products, including stomach tissues that remain underutilized despite their potential as a source of industrial enzymes. This study evaluated the effects of acid type, acid concentration, and buffer-assisted acid stimulation on crude pepsin recovery from skipjack tuna (Katsuwonus pelamis) stomach. Acetic acid (CH₃COOH) provided better enzymatic performance than hydrochloric and sulfuric acids. Among the concentrations tested, 1 M CH₃COOH produced the highest pepsin activity (1.03±0.05 U·mL⁻¹) and specific activity (0.115±0.005 U·mg⁻¹). Buffer-assisted acid stimulation yielded higher pepsin activities than direct acid extraction. Direct extraction produced substantially higher total protein concentration, suggesting greater co-extraction of non-pepsin proteins. The recovered crude pepsin exhibited both optimal activity and stability at pH 2, while the highest pepsin activity was observed at 50 °C, with stability maintained at 30 °C or below. More than 80% of the activity was retained within moderately acidic and mid-temperature ranges. These findings demonstrate that acid selection, concentration, and extraction strategy strongly influence functional pepsin recovery. Buffer-assisted acid stimulation with acetic acid provides a simple yet promising approach for obtaining catalytically active crude pepsin from tuna stomach by-products, supporting their valorization as a sustainable source of acid proteases for potential food and biotechnological applications.