• Culture of Caulerpa lentillifera on screen mats 

  Luhan, Maria Rovilla ; Sollesta-Pitogo, Hananiah; Samson, Edcel Jed D. (Polytechnic University of the Philippines, 2024)

  Caulerpa lentillifera is one of the species of seaweeds cultivated commercially in the Philippines. C. lentillifera is either cultured in ponds or gathered from the wild. In this study, the use of screen mats as substrate for C. lentillifera was tested for small scale production in ponds or in shallow areas offshore. Seaweeds were fertilized once a day, twice a day, once a week, and after 15 days. The growth was determined after 30 days. The growth of C. lentillifera fertilized once a week was significantly higher at 5.65% a day than unfertilized C. lentillifera at 2.55% a day. The use of screen mats in ponds and shallow foreshore area for the culture of C. lentillifera could be recommended for small scale cultivation.
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  Growth, survival, and economics of milkfish (Chanos chanos) and giant freshwater prawn (Macrobrachium rosenbergii) in monoculture and polyculture systems in brackishwater earthen ponds 

  Dela Cruz, Marwin (Springer, 2026-05-28)

  Sustainable and effective production practices are needed to meet the growing global demand for food. Here, polyculture of milkfish and freshwater prawn with modified feeding scheme (POLY) was tested against monoculture of milkfish (MONO-Fish) and monoculture of freshwater prawn (MONO-Prawn) based on growth, survival, and economic parameters for 150 days. Each group was compared in triplicates. Milkfish juvenile at 1 indiv m^-2 and freshwater prawn at 10 indiv m^-2 were randomly distributed in brackishwater ponds each with an area of 20 m × 15 m and salinity at 5–10 ppt. Significantly higher FBW and DGR were observed in milkfish grown in POLY compared with MONO-Fish (P < 0.05) while growth rates of freshwater prawn did not vary between POLY and MONO-Prawn despite the absence of feeding for prawn in POLY group (P > 0.05). Survival rates and condition factors of both species in POLY were comparable with those in MONO-Fish and MONO-Prawn (P > 0.05). Higher feed intake was observed in POLY compared to MONO-Fish but FCRs were not significantly different (P > 0.05). In addition, higher yield for milkfish were recorded in POLY than MONO-Fish (P < 0.05), whereas yield for freshwater prawn was similar with MONO-Prawn (P > 0.05). Furthermore, there was no competition between the two species instead, a facilitative relationship was observed, with freshwater prawns positively influencing milkfish growth. The polyculture system incurred the highest production cost but also generated the highest net income, ROI, NPV, and DBCR (P < 0.05), making it more profitable than monoculture.
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  Documentation, tagging, release, and recapture of sea turtles caught in municipal fisheries around Panay and Guimaras 

  Bagarinao, Teodora (Science and Technology Information Institute, Department of Science and Technology, 2026-02)

  SEAFDEC FishWorld worked with fishers and various government agencies and officers to document 335 sea turtles (local name pawikan first given) captured, stranded, or otherwise reported along the coasts of Panay and Guimaras Islands, the Philippines from 2000 to 2016: 187 green turtles Chelonia mydas (40–111 cm curved carapace length), 64 olive ridleys Lepidochelys olivacea (34–73 cm), 79 hawksbills Eretmochelys imbricata (28–89 cm), four leatherbacks Dermochelys coriacea (128–150 cm), and one loggerhead Caretta caretta (77 cm). In addition, 150 hawksbill hatchlings were recorded from Lawi, Guimaras, and 84 green turtle hatchlings from Miagao, Iloilo, and San Jose, Antique. This paper includes a database on 335 sea turtles but focuses on the sea turtle bycatch in municipal fishing gears: 178 green turtles (89% caught in nearshore fish corrals), 50 olive ridleys (62% in gillnets, 18% in longlines), 17 hawksbills in various fishing gears, and the leatherbacks and loggerhead in gillnets. Many turtles suffered and survived capture injuries on the head, beak, flippers, carapace, and plastron, but several dead turtles were found near fishing gears. Most turtles were clean and healthy and released at the sites of capture. Officers of the Department of Environment and Natural Resources, local government units, and the police brought many turtles to FishWorld for medication, medical care or surgery, and feeding; 62 turtles were later released in Panaw Pawikan (Go, Turtles!) events witnessed by various stakeholders. In total, 291 turtles were released, 195 of them tagged (67%)—104 green turtles, 43 olive ridleys, 47 hawksbills, and one loggerhead—with inconel flipper tags from the Pawikan Conservation Project, to which tag recaptures are to be reported. Several turtles were recaptured near FishWorld, including a green turtle from the Malaysian Turtle Islands.
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  Predator-induced behavioral adaptation by hatchery-bred sandfish Holothuria scabra juveniles 

  Baylon, Roselyn ; Altamirano, Jon ; Santander - de Leon, Sheila Mae ; Monteclaro, Harold (National Shellfisheries Association, 2026-05-12)

  Wild populations of sea cucumbers are under threat from overexploitation driven by the increasing global demand for their dried products called trepang or beche-de-mer. Fortunately, hatchery techniques have been developed especially for the tropical sandfish Holothuria scabra. Farming and restocking programs, however, often overlook critical behavioral factors that can affect the survival of hatchery-bred sea cucumbers, particularly predation risk. This study investigated the predator-induced behavioral adaptations of hatchery-bred sandfish juveniles under tank conditions. The Conditioned sandfish (CS) group was exposed to a predator cue (i.e., caged crab) and a conspecific distress cue (i.e., injured sandfish) for 20 h daily (1200H to 0800H) over 5 days. In contrast, the naïve sandfish (NS) group was not exposed to such cues but presented only with empty cages. The findings suggest that the daily burying behavior of sandfish is not affected by short-term exposure (≤2 days) to predator and distress cues. But, extended exposure (≥3 days) elicited a significant antipredatory response in CS, prolonging their buried state from 8 h on Day 1 to 16 h by Day 5. Meanwhile, NS showed consistent burying periods throughout. Consequently, exposures to predator and distress cues resulted in significantly fewer sandfish juveniles emerging among CS. Following the release of predator crabs on Day 6, the CS group exhibited a significantly higher proportion of unharmed sandfish (63.00%) compared with NS group (45.83%). The NS had experienced higher mortality (20.83%) and injury rates (33.33%), whereas CS demonstrated lower mortality (8.33%) and injury rates (29.00%) after 24 h. These findings confirmed that sandfish are capable of associative learning and defensive behavioral adaptations in response to a potential predation threat, including extending their burying state. Regardless of treatment, sandfish preferred to bury beneath the cages, suggesting an innate tendency to shelter even in the absence of predation cues. For practical application, it is recommended that hatchery-bred sandfish juveniles (3–5 g) should be conditioned for 3–5 days prior to release at sites that offer natural refuge or, if necessary, provided with artificial shelter to increase their survival during restocking or farm-site releases.
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  Bacterial microbiota of African catfish Clarias gariepinus during the hatchery and nursery phases of culture in the Philippines 

  Pakingking, Rolando ; Solis, Faye Danielle; Palma, Peter ; de la Peña, Leobert D. (Bowling Green State University, 2025-04)

  The bacterial microbiota of African catfish (Clarias gariepinus) during hatchery and nursery phases were examined across eight production cycles in two commercial farms in the Philippines. Bacterial identification was performed using conventional methods and the API 20E test, with further confirmation of selected isolates via 16S rRNA gene sequencing. Heterotrophic plate count (HPC), presumptive Aeromonas count (PAC), and presumptive Vibrio count (PVC) varied in hatchery rearing water (10³–10⁵ CFU/mL for HPC; 10²–10⁴ CFU/mL for PAC and PVC) and fry samples (10⁴–10⁷ CFU/g for HPC; undetectable–10⁶ CFU/g for PAC; 10²–10⁴ CFU/g for PVC). In the nursery phase, similar fluctuations were observed in rearing water, fingerlings, and sediment. Microbial diversity analysis revealed 21 species (15 genera) in hatchery rearing water and 14 species (8 genera) in fry, with Aeromonas hydrophila, A. sobria, and Vibrio cholerae as predominant species (>15%). In the nursery phase, 29 species (16 genera), 28 species (15 genera), and 21 species (14 genera) were identified from rearing water, sediment, and fingerlings, respectively, with A. hydrophila, A. sobria, and Bacillus subtilis dominating (>14%). This study highlights the dynamic composition of bacterial communities in catfish culture systems, with rearing environments shaping the microbiota of juvenile fish. The presence of opportunistic and zoonotic pathogens underscores the risk of disease outbreaks, particularly under suboptimal conditions. These findings emphasize the need for stringent biosecurity measures and improved hatchery and nursery management practices to enhance fish health, prevent economic losses, and ensure the sustainability of aquaculture production. Educating hatchery and nursery workers on safe aquaculture practices and hygiene protocols is crucial to minimizing health risks to both fish and humans while ensuring efficient and responsible catfish production.
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  Genome sequencing and genome-wide analysis uncover candidate genes and loci linked to key production traits in the Philippine black tiger shrimp (Penaeus monodon) 

  Cadorna, Kreighton ; Aguinaldo, Zae-Zae ; de la Cruz, Miguel Paolo E.; Pasaquian, Hannah Mae E.; Corre, Valeriano L.; Estepa, Fe Dolores ; Amar, Edgar ; Maningas, Mary Beth B.; Lluisma, Arturo O. (Wiley, 2026-03-16)

  Penaeus monodon (black tiger shrimp) is a key species in aquaculture globally and in the Philippines. The selection and development of stocks with desirable production traits, such as enhanced growth and disease resistance, are critical for improving production. In this study, we leveraged a newly assembled, high-quality genome sequence from a Philippine population to perform genome-wide scans for SNPs associated with key production traits. Using cohort-based extreme phenotype GWAS (XP-GWAS), we identified variants linked to resistance against white spot syndrome virus (WSSV), body weight, and carapace length-to-abdomen length (CL/AL) ratio. Candidate genes previously implicated in immune defense and growth regulation were located within 1-Mb regions surrounding these variants, reinforcing their likely functional involvement and providing biological support for the associations. These findings highlight genomic loci and gene candidates of direct relevance to selective breeding, offering molecular markers with potential utility in stock improvement programs for P. monodon. These genomic data, alongside the identified polymorphisms, constitute a valuable resource for enhancement of production and selective breeding strategies in the Penaeid species, contributing to the improvement of shrimp aquaculture.
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  Dietary supplementation of Durvillaea potatorum fucoidan enhances the immune responses and improves survival of juvenile black tiger shrimp Penaeus monodon against white spot syndrome virus and acute hepatopancreatic necrosis disease 

  Faisan, Joseph P., Jr. ; Traifalgar, Rex Ferdinand ; de la Peña, Leobert D.; Corre, Valeriano L.; Pagapulan, Mary Jessa Bell B.; Gayosa, Vyenge Erre (Springer, 2026-03-09)

  The use of natural immunostimulants as alternatives to antibiotics has gained attention in aquaculture to mitigate disease impacts. In this study, we evaluated fucoidan extracted from giant bull kelp (Durvillaea potatorum) as a dietary additive in black tiger shrimp (Penaeus monodon). Four experimental diets containing increasing levels of fucoidan (0, 1.0, 2.5, and 5.0 g kg⁻¹ diet) were tested for their effects on growth, non-specific immune parameters, and survival against white spot syndrome virus (WSSV) and acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio parahaemolyticus. After 30 days of feeding, fucoidan supplementation did not adversely affect shrimp growth or culture survival, even at the highest inclusion level (5 g kg⁻¹). Non-specific immunological indices, including total hemocyte count (THC), differential hemocyte count (DHC), phenoloxidase (PO) activity, plasma total protein (PTP), and plasma agglutination titer (PAT), were enhanced by fucoidan supplementation, with improvements observed even at 1 g kg⁻¹ relative to the control group. Activation of non-specific immunity translated into increased resistance against WSSV and AHPND, with the highest survival recorded in shrimp fed 5 g kg⁻¹ fucoidan, followed by 2.5 g kg⁻¹. In comparison, similar survival rates against WSSV and AHPND were observed in the unsupplemented control and 1 g kg⁻¹ fucoidan. Overall, this study demonstrates that dietary inclusion of D. potatorum fucoidan at 5 g kg⁻¹ effectively enhances immune responses and disease resistance in P. monodon without negatively impacting growth performance, highlighting its potential as a functional feed additive in shrimp aquaculture.
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  Growth performance and feed utilization of snubnose pompano (Trachinotus blochii) fed with Pirenella sp. as a dietary supplement 

  Somblingo, Edgar ; Baliao, Dan D.; Mamauag, Roger Edward ; Ciacico, Albert ; Villanueva, Roy (Prensip Publishing, 2026-03-06)

  Sustainable aquaculture requires the exploration of alternative, eco-friendly feed sources that can reduce production costs and dependence on commercial feeds. Pirenella sp., a common brackish water snail often considered a pest in aquaculture ponds, has potential as a natural feed ingredient for carnivorous fish species such as the snubnose pompano (Trachinotus blochii). This study assessed the growth performance, survival rate, and feed conversion ratio (FCR) of snubnose pompano fed with Pirenella sp. as a dietary supplement. Nine hapa nets (5 × 5 × 1.5 m) were installed in a brackish water pond and assigned to three treatments with three replicates each: 100% commercial feed (T1), 50% commercial feed + 50% snails (T2), and 100% snails (T3). Results showed that Treatment I achieved the highest growth performance, while Treatment II exhibited comparable outcomes, indicating that partial replacement of commercial feeds with Pirenella sp. did not significantly affect growth. Treatment III, which used only snails, produced markedly lower growth metrics (p<0.05). Survival rate remained at 100% across all treatments (P > 0.05). The lowest FCR (0.34) was recorded in Treatment II, suggesting optimal feed utilization. Although Treatment III had lower growth performance, it was the most cost-efficient due to the natural availability of snails. Overall, the incorporation of Pirenella sp. as a supplemental feed demonstrates potential for enhancing sustainability and reducing feed costs in pompano aquaculture while contributing to the biological control of pest snails in brackish water ponds.
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  Evaluation of cultivation potential and carrageenan properties of Hypnea sp. from Panay Island, Philippines 

  Matsuda, Ryuya ; Faisan, Jr., Joseph ; Sollesta-Pitogo, Hananiah; de la Peña, Leobert D. (Springer, 2026-02-10)

  Hypnea is a cosmopolitan genus of red seaweeds and an important source of carrageenan worldwide. However, Hypnea species remain largely unutilized in seaweed aquaculture in the Philippines. This study aimed to evaluate the growth performance and carrageenan properties of an indigenous, unexploited Hypnea sp. collected from Panay Island and to compare them with those of the commercially cultivated Kappaphycus striatus. In a field cultivation experiment, Hypnea sp. showed significantly higher biomass (145.1 ± 53.7 g) than K. striatus (92.9 ± 10.3 g) up to day 28 (p < 0.001), while no significant difference was observed at days 36 and 43. The final yields were 181.0 ± 68.4 g for Hypnea sp. and 191.1 ± 33.0 g for K. striatus (p > 0.05). Semi-refined carrageenan extracted from the cultured Hypnea sp. exhibited gel-forming capacity, suggesting the presence of κ-carrageenan. However, both the viscosity and gel strength of Hypnea sp. (9.52 ± 3.53 cP; 148 ± 41.6 g cm⁻²) were significantly lower in K. striatus (70.9 ± 49.4 cP; 456 ± 201 g cm⁻²) (p < 0.001), indicating that Hypnea sp. possesses distinct carrageenan properties from conventional commercial seaweed. Although further development of carrageenan-based products tailored to its unique properties will be required for commercial utilization, these findings highlight the potential of Hypnea sp. as a candidate seaweed for aquaculture in the Philippines.
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  Application of predatory bacteria (Bacteriovorax sp.) as a biocontrol agent against the pathogenic Vibrios in Pacific whiteleg shrimp (Penaeus vannamei) 

  Nievales-Naluaran, Lovelyn Marie; Corre, Valeriano L., Jr.; Dequito, Angel Queenee D.; Gomez, Dennis K.; Traifalgar, Rex Ferdinand (Taylor and Francis, 2026-01-21)

  Vibriosis, a bacterial disease, is considered a significant threat to the sustainability and economic viability of shrimp production. The present study evaluated the application of a predatory bacterium to control the population growth of pathogenic Vibrios in Pacific whiteleg shrimp (Penaeus vannamei). The predatory bacterium was identified as Bacteriovorax sp. OP175948.1 based on the 16S rRNA sequence. The Vibrio-inhibitory activity of Bacteriovorax sp. was evaluated using two independent trials with P. vannamei, exposed to two pathogenic Vibrios, including Vibrio parahaemolyticus and Vibrio harveyi. Each trial was conducted in five treatments, including a negative control, a positive control, and a treatment with Bacteriovorax sp. applied at 10², 10⁴, and 10⁶ plaque-forming units mL⁻¹ (PFU mL⁻¹). Results indicated that shrimp infected with V. parahaemolyticus and V. harveyi, and then treated with Bacteriovorax, showed a 6-fold increase in survival for V. parahaemolyticus and a 3-fold increase for V. harveyi, relative to the control. The shrimp treated with 10⁴ to 10⁶ Bacteriovorax sp. improved survival associated with a significant decline in Vibrio spp. counts in the shrimp tissues and rearing water. The Bacteriovorax sp. should be used as a practical strategy to prevent Vibrio-associated mortalities in P. vannamei aquaculture.
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  Species composition of seaweed biofoulers in fish cage aquaculture in Bongao Channel, Tawi-Tawi, Philippines 

  Bara, Aldimar ; Jeva, Marcelita ; Adjad, Rosalina ; Arik, Mudzrina ; Somblingo, Edgar ; Tahiluddin, Albaris B. (Prensip Publishing, 2025-12-29)

  The excessive growth of seaweeds (macroalgal biofouling) on submerged cage structures is a severe operational constraint for fish cage aquaculture in tropical environments. This study investigated the species composition of macroalgal biofouling growing on the submerged structures of the fish cage aquaculture in Bongao Channel, Tawi-Tawi, Philippines, via a qualitative survey (e.g., snorkeling around the cage systems). The primary objective was to provide a taxonomic inventory of the colonizing seaweed species to understand the biological makeup of the fouling community. Through morphological examination of the collected samples, a total of 26 species belonging to 16 distinct genera were identified, representing the three major algal divisions: Chlorophyta (green algae) exhibited the highest generic richness, including Boergesenia, Caulerpa, Chaetomorpha, Cladophora, Halimeda, Boodlea, and Ulva. Rhodophyta (red algae) were represented by Acanthophora, Actinotrichia, Chondrophycus, Yonagunia, Gracilaria, Hypnea, and Endosiphonia, while Ochrophyta (brown algae) included Padina and Sargassum. The presence of various taxa, particularly filamentous Chaetomorpha and stoloniferous Caulerpa, identifies these groups as the key structural components of the biofouling community on the cage nets. Additionally, the inventory recorded the occurrence of economically valuable red algae (e.g., Gracilaria and Hypnea) and ecologically significant brown algae (e.g., Sargassum) within the assemblage. These findings establish a critical taxonomic baseline, providing the essential species-level data required to develop targeted mitigation strategies and sustainable management practices for the floating cage aquaculture in Tawi-Tawi.
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  Stocking density effects on growth performance of glass eels (Anguilla bicolor pacifica) in outdoor tank conditions 

  Aya, Frolan (College of Agriculture and Food Science, University of the Philippines Los Baños, 2025-12)

  Optimizing stocking density is necessary to maximize the production efficiency of farmed fish. This study examined the effect of stocking density on the growth performance of the Pacific shortfin eel Anguilla bicolor pacifica reared in outdoor tank conditions. Glass eels (0.72 ± 0.03 g mean body weight [BW]) were stocked at 50 and 100 individuals m⁻² in 6 4-m² outdoor tanks with a flow-through system set up in triplicate. Eels were individually measured for total length and BW, followed by blood sampling at the end of the 286-d trial. Glass eels stocked at a density of 50 m⁻² exhibited significantly higher specific growth rate, feed efficiency, and protein efficiency ratio. However, survival, final BW, percent weight gain, biomass, biometric indices, and Fulton’s condition factor were not significantly different between density groups. Although size class distribution was not significantly affected by stocking density, a higher proportion of larger eels (> 50 g) was evident at low stocking density. The coefficients of variation in both length and weight and in skewness were likewise slightly reduced at low stocking density. In contrast, high stocking density resulted in significantly elevated levels of serum total protein. Partial costs-and-returns analysis showed that 50 m⁻² density resulted in higher net profit and profit index. These results suggest that under outdoor tank conditions, a stocking density of 50 m−2 will result in higher growth rate and feed utilization, less size variation, better physiological condition, and higher net returns for the culture of A. bicolor pacifica.
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  First report on the use of various fishing gears and transport schemes for the captive breeding of shortfin scad (Decapterus macrosoma) as a potential species for aquaculture 

  Legaspi, Ma. Irene ; Ito, Sayaka ; de la Peña, Leobert D.; Silorio, Jernet Zyca (Elsevier, 2026-01)

  This study establishes the first protocols for the live capture and transport of shortfin scad (Decapterus macrosoma), a potential new species for aquaculture. Wild fish were collected in the central Philippines using different fishing gears (ring net, otoshi-ami, hook-and-line), held for conditioning in a temporary cage, and transported using polyethylene bags or a customized chilled tank. While 3-day post-transport survival varied widely (1.5–100 %), a key finding was that a prolonged conditioning period prior to transport was essential for achieving high (100 %) survival rates, regardless of the capture method or transport system used. This research provides a critical foundation for supplying healthy broodstock to initiate captive breeding programs for shortfin scad.
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  Storm-induced stress and mortality of juvenile black tiger shrimp Penaeus monodon during intermediate culture for stock enhancement 

  Altamirano, Jon ; Kurokura, Hisashi; Recente, Charlemagne ; Fushimi, Hiroshi ; Ishikawa, Satoshi (Springer, 2025-12-08)

  In aquaculture-based stock enhancement, releasing juveniles at larger sizes can increase their chances of survival. Moreover, on-site (or within the release area) nursery rearing or intermediate culture of hatchery-bred stocks is important for acclimatization prior to release. In the Philippines, the prospect for tiger shrimp (Penaeus monodon Fabricius 1798) intermediate culture was evaluated in the New Washington Estuary (NWE), Aklan, Philippines. Locally sourced postlarval (PL₁₃) tiger shrimp P. monodon were reared in a temporary netted pen within a disused pond with mangroves. Serendipitously, storm events occurred during a couple of our rearing trials (Runs 1 and 2). This provided us with the unique opportunity to assess the effects of rainstorms on the cultured PL using morphological and environmental data, measured before, during, and after storm events. Notably for Run 1, four distinct phases were identified: Acclimatization phase (ACCL), Stable phase (STBL), Storm phase (STRM), and Recovery phase (RCVR). Culture performance indicators like growth, survival/mortality rate, and condition factor (CF) revealed significant differences among phases. Mortality rate of − 6.4% d⁻¹, growth rate of 9.9% d⁻¹, and low CF (0.24) of shrimp in the initial first week (D1–D9 of ACCL before the storm) were associated with stress and density stabilization (from 325 m⁻² to 178 m⁻²). During STBL (D10–D18), stock conditions improved (growth: 20% d⁻¹, mortality: − 0.17% d⁻¹, CF: 0.49). However, this abruptly degraded during STRM (D20–D28) with negative growth rate (− 9.7% d⁻¹), high mortality (− 4.3% d⁻¹), and low CF (0.28), indicating very high stress levels of stocks induced by acute heavy rainstorms, leading to steeply fluctuated water temperatures. Subsequently, recuperation of stocks after the storm (D30 onwards) was significant during RCVR (Growth: 19% d⁻¹; Mortality: − 0.34% d⁻¹; CF: 0.41). Remarkably, the surviving shrimp (now > 0.5 g) became adapted and resilient, showing stable growth and survival despite another abrupt rainstorm with fluctuating water conditions at D45–46. On the other hand, Run 2 with a lower initial stocking density (56 m⁻²) showed better performance during ACCL (D1–10) and STBL (D11–30) with respective low mortality rates (− .2% d⁻¹ and − 0.75% d⁻¹) and high growth rates (24.4% d⁻¹ and 14.6% d⁻¹). However, two subsequent storms caused prolonged (> 10 d) rainfall during STRM, leaving only 4% survival at D38 with no RCVR phase. We showed that acute (~ 2 d) intense rainstorms can be detrimental to young (< 0.2 g) PL, but the stable environmental conditions after storms can allow the surviving stocks to recuperate, grow fast (> 0.5 g), then become quite resilient even to a subsequent acute (2 d) rainfall. However, extended rainstorms (> 10 d) cause continuous decline in salinity and temperature, leading to high mortality of shrimp. Therefore, careful programming of future on-site intermediate culture activities is important, considering the space and duration required for culture, initial densities and target sizes of PL, and cautious account of rainstorm seasonality.
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  Gleaning of fishery of conch (Gastropoda: Strombidae) in seagrass beds of Guimaras Island, the Philippines 

  Diamante, Rose Ann; Monteclaro, Harold ; Altamirano, Jon ; Santander - de Leon, Sheila Mae (Department of Science and Technology, 2025-12)

  Gleaning is a subsistence fishery vital to the lives of coastal communities. The gastropod conch is among those found abundant in gleaners’ catch, particularly observed in Nueva Valencia, Guimaras, the Philippines. Three adjacent barangays with a wide expanse of seagrass intertidal area were studied for aspects of conch gleaning fishery through a structured questionnaire and the conduct of an actual catch survey. Results showed that conch gleaning is a secondary source of income (80%), mainly conducted by women (85%) during low tide. It contributes to their food consumption and additional income, where a kilo of conch is sold fresh and unprocessed at PHP 50–60, contributing to their monthly income at PHP 500–1000 maximum and PHP 100–200 minimum. Six species of conch were identified from the actual catch survey. Gleaning time ranges 2–4 h/d at 0.2–0.6 kg/h CPUE. An estimated 1,728–5,184 kg of conch, or around 180,000–550,000 individuals, may be exploited annually based on actual catch calculations. These levels of exploitation may pose a risk to the sustainability of the resource. An observed decline in the abundance of conch for the past 20 years, where management measures such as limitations on conch size and collection volume were indicated by the respondents. As an undocumented fishery in the Philippines, this study presented the importance of conch gleaning in the livelihood of coastal residents and may serve as vital information for fishery policy recommendations. This study also showed that the use of an actual catch survey, aside from a questionnaire, enhanced the data and earned better interpretation of results.
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  Single initial inoculation of bioflocs maintains water quality in the long-term culture collection of Brachionus plicatilis 

  Mandario, Mary Anne ; Kozue, Noa; Wassel, Mai A.; Makabe-Kobayashi, Yoko; Han, Chengyan ; Hamasaki, Koji ; Sakakura, Yoshitaka (Springer, 2025-11-13)

  While rotifers are important first live feed in marine fish hatcheries, maintaining the rotifer culture collection by feeding live microalgae and water exchange is laborious and costly. It is therefore necessary to streamline the culture collection protocol and reduce operating costs. The use of microalgal paste in rotifer production is well documented, but there is limited information on its use in rotifer culture collection because of its ability to deteriorate water quality, such as increasing unionized ammonia (NH₃). This study aimed to determine the effectiveness of bioflocs (BF) in regulating NH₃ in rotifer culture collection fed microalgal paste Fresh Chlorella V12 (CV12) under zero-water exchange (ZWE) conditions for 42 days. The marine rotifers Brachionus plicatilis were subjected to six treatments, namely: (1) Nannochloropsis oculata (Nanno) × weekly water exchange (WWE), Nanno × WWE as the control, (2) CV12 × WWE, (3) Nanno × ZWE, (4) CV12 × ZWE, (5) Nanno + BF × ZWE, and (6) CV12 + BF × ZWE. Rotifer density was estimated every 3 days, while NH₃ was measured weekly. Bacterial compositions were determined. On day 42, the lowest NH₃ was observed in CV12 + BF × ZWE, which was significantly different from CV12 × WWE and CV12 × ZWE. Rotifer density was higher in Nanno + BF × ZWE and CV12 + BF × ZWE than in CV12 × ZWE, but egg-bearing rotifers were similar in all treatments on day 42. Single initial inoculation of BF maintains water quality by regulating NH₃ concentration via the activity of ammonia oxidizer Nitrosomonas nitrosa and the bacterial groups under phylum Chloroflexota in the long-term B. plicatilis culture collection and that microalgal paste combined with BF can be a cost-effective alternative to live microalgae.
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  Bioflocs-assisted mass culture of Brachionus plicatilis under prolonged zero-water exchange and its application to Pagrus major larviculture 

  Mandario, Mary Anne ; Aoyagi, Rinko; Wassel, Mai A.; Makabe-Kobayashi, Yoko; Han, Chengyan ; Hamasaki, Koji ; Sakakura, Yoshitaka (Elsevier, 2026-02)

  The sustainable mass production of rotifers is crucial to sufficiently supply marine fish hatcheries. However, maintaining a stable rotifer culture is still a challenge mainly due to unionized ammonia (NH₃) toxicity and biological contaminants. This study investigated the effectiveness of single initial inoculation of bioflocs (BF) in addressing the abovementioned problems on rotifer mass culture using Brachionus plicatilis subjected to three treatments for 29 days, namely: 1) water exchange (WE), 2) zero water exchange (ZE), and 3) bioflocs × zero water exchange (BF × ZE). The effects of feeding BF-cultured B. plicatilis and supplementing BF in the rearing water on the survival and growth of red sea bream Pagrus major larvae for 14 days were evaluated. Bacterial composition of BF was determined. BF inoculation resulted in significantly higher rotifer densities from day 14 to day 29 (BF × ZE with 226–434 individuals/mL vs WE and ZE with 69–131 individuals/mL). BF inoculation significantly controlled ciliate contamination (BF × ZE with 7–25 ciliates/mL vs ZE with 421–531 ciliates/mL) from day 21 to day 25. TAN and NH₃ concentrations were significantly reduced in the BF × ZE than in ZE and WE treatments on day 29. P. major larvae fed BF-cultured rotifers and reared in BF-supplemented water did not show reduced survival and growth. BF inoculation significantly improves B. plicatilis productivity through the effective removal of NH₃ via the ammonia-oxidizing activity of Nitrosomonas nitrosa and bacteria within the phylum Chloroflexota under prolonged zero-water exchange conditions. Furthermore, the study demonstrates the viability of BF in P. major larviculture.
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  Dietary crude ulvan from Ulva intestinalis enhances growth, salinity stress tolerance, and immunity against Vibrio harveyi in early juvenile milkfish Chanos chanos 

  Gayosa, Vyenge Erre ; Traifalgar, Rex Ferdinand ; Nievales-Naluaran, Lovelyn Marie; De Leon, Mark Henry (Elsevier, 2025-10)

  Ulva green seaweeds are known for their rapid growth and limited commercial value, and hold significant potential as sources of bioactive compounds for aquaculture. Among these, the sulfated polysaccharide ulvan has shown promising growth-promoting and immunostimulatory properties. These properties may offer a natural solution to vibriosis caused by Vibrio harveyi that hinders the sustainability of milkfish (Chanos chanos) nursery production. To evaluate this potential, a 30-day feeding trial was conducted in a completely randomized design. Five dietary treatments in triplicate, including a control diet without ulvan and four diets supplemented with graded levels of ulvan (10, 50, 100, and 500 mg kg⁻¹) were evaluated on early juvenile C. chanos (14.62 mg mean weight). Diets with 10 and 50 mg kg⁻¹ ulvan significantly increased weight gain, specific growth rate, and protein efficiency ratio, while lowering the feed conversion ratio compared to the control group and higher ulvan doses (100 and 500 mg kg⁻¹). Fish fed as little as 10 mg kg⁻¹ ulvan also demonstrated enhanced salinity stress tolerance as evidenced by their higher cumulative stress index values. Further analysis of immune gene expression revealed that supplementation of 10 mg kg⁻¹ ulvan significantly improved immune response by upregulating TLR5, IL6, and LEAP2 mRNA expression levels, resulting in higher survival rates following a V. harveyi bacterial challenge. Overall, these results indicate that adding 10 mg kg⁻¹ ulvan to the nursery C. chanos diet is practical and efficient to boost growth and immunity, offering a promising solution to enhance nursery resilience to V. harveyi.
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  Advances in reproduction and broodstock management of mangrove crabs (Scylla spp.): A review 

  Pates, Gaudioso S.; Maceren-Pates, Mercedes ; Quinitio, Emilia ; Parado-Estepa, Fe Dolores; Caballero, Pedrita (Springer, 2025-09-25)

  The mangrove or mud crab (Scylla spp.) is among the most commercially important aquaculture species owing to its high demand in both local and international markets. However, the rapid expansion of farming activities has resulted in the intensive collection of wild stocks, posing a significant threat to natural populations. To address this, the Southeast Asian Fisheries Development Center Aquaculture Department (SEAFDEC/AQD) has developed basic larval rearing and nursery protocols for the farming of mangrove crabs. Despite these advancements, the hatchery production of seedstock remains insufficient to meet the growing demand for farming. One major challenge is the inconsistent larval quality in hatcheries, which is largely attributed to inconsistent broodstock performance. While numerous studies have explored both internal and external factors influencing the reproductive performance of mangrove crab broodstock in captivity, the findings remain fragmented. This review compiles existing research on mangrove crab maturation, providing a comprehensive overview of advancements in broodstock conditioning. It aims to identify research gaps and encourage further studies to develop improved protocols for managing captive broodstock effectively.
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  Viral load differences associated with infection outcomes and resistance to white spot syndrome virus (WSSV) infection in mud crab, Scylla serrata 

  Aguila-Toral, Angela Camille ; Silvederio, Gardel Xyza L.; Logronio, Dan Joseph ; Bateman, Kelly ; Stentiford, Grant ; Amar, Edgar ; Ravago-Gotanco, Rachel June (Elsevier, 2026-02)

  White spot syndrome virus (WSSV), the causative agent of white spot disease, remains a serious threat to crustacean aquaculture. Infecting a wide range of crustaceans, host species exhibit varying susceptibility and mortality rates. Mud crabs, Scylla serrata, a high-value aquaculture commodity across the Indo-Pacific region, are known to be relatively resistant to WSSV. However, there is limited information on the progression of WSSV infection in the species which can provide insight into mechanisms of resistance. Employing a time course experimental challenge of S. serrata with WSSV, this study characterized viral load dynamics in juveniles over a period of 144 h post infection (hpi) in relation to (1) disease outcomes (survival or mortality); (2) distribution among tissue types (gills, gut, hepatopancreas, and hemolymph); and (3) variability between two different juvenile cohorts. Viral load progression suggests that WSSV resistance in mud crabs may be due to two distinct mechanisms. One mechanism involves the capability of S. serrata for viral clearance following active viral replication. Viral growth in S. serrata demonstrates three phases: early stage or onset characterized by minimal change in viral load (0 to 24-hpi), logarithmic stage of active replication with rapid increase in viral copy number (24 to 72-hpi), with the third phase (96–144 hpi), exhibiting differential patterns with infection outcome. Dead crabs exhibited a plateau phase where viral loads remained similar to peak levels, while crabs that were still alive beyond 96 hpi exhibited a resolution phase, characterized by reduction in viral load, returning to non-infected levels. Another apparent mechanism for WSSV resistance involved overall inhibition of replication, with recalcitrant individuals exhibiting markedly low viral loads at expected logarithmic infection phase timepoints (48–72 hpi). This study also revealed tissue tropism of WSSV in S. serrata. Gills appear to be the primary site of WSSV replication, exhibiting the highest viral load from the early to peak stages of infection compared to other tissue types such as the gut, hepatopancreas, and hemolymph. The establishment of viral load curves to track the progression of WSSV infection, and characterization of viral abundance across different tissues through the course of infection, represents novel information that has key implications on the role of S. serrata as carriers/vectors of WSSV. This may have practical implications for disease mitigation measures for aquaculture facilities, and development of new strategies to prevent and reduce pathogen infection in mud crab to support sustainable aquaculture production.

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