The invention relates to the protocol for harvesting of microalgae, Chaetoceros calcitrans by manipulation of electrolytic flocculator settings. The harvesting system comprised of a holding tank for the microalgae, a DC power supply with variable voltage selector, ammeter and voltmeter. The best settings of 6/6 units Al/Pb probes with voltage selector set at point 1 to supply 3 volts to complete the electrolytic cell. The Pb in the paste was reduced by 97% with values of 34.27 ± 0.39 ppm with 0 - 0.24 ppm Pb in the effluent discharge. The Pb content in secondary live food, Artemia salina was further reduced by 78% based on feeding trials with 7.8 ± 5.1 ppm Pb content. This system will be beneficial to hatcheries for use onsite due to its simplicity and affordability.

The study investigated the growth, survival rates, and limb loss occurrence of blue swimming crabs (BSC), Portunus pelagicus from crab instar to the early juvenile stage at different culture systems (outdoor tanks, net cages in ponds, and net cages in pens), and varying stocking densities (30, 50, and 100 individuals/m²). These variables were assessed during the wet and dry seasons for 21 days following a 2 × 3 × 3 factorial design. Survival showed a significant interaction between culture systems and seasons (p < 0.001). However, no significant differences were found between culture systems and stocking densities, or between stocking densities and seasons (p > 0.05). Results showed that pond and pen systems, particularly at moderate densities (30–50 individuals/m²), yielded significantly higher growth, survival, and biomass production compared to tank systems (p < 0.05). Survival rates were significantly higher in ponds (76.69% ± 2.58) than in pens (54.97% ± 2.10), and tanks (38.32% ± 4.61). Moreover, BSC juveniles exhibited limb loss (%) ranging from 11.43% to 35.17%, with loss of a single limb being the most common, occurring in 49–70% of the crabs. Overall, the study recommends the use of pond and pen systems with moderate stocking densities for optimal nursery production of P. pelagicus, contributing valuable insights for improving aquaculture protocols and supporting stock enhancement initiatives toward sustainable fisheries.

Data on the landing value for each of the eight fisheries commodities in small-scale coastal fisheries in Nemuro City was collected and analyzed to understand the importance of kelp fishery in local communities along the Pacific coast of eastern Hokkaido. Over the past 25 years from 1991 to 2015, a trend in small-scale coastal fisheries in the region has significantly varied. However, in all year groups, the landing value of the kelps accounted for about 40% of its total value, indicating no significant change in its importance. The kelp fishery always has a profit center within the small- scale fisheries operations in the region. The influences of seawater temperature and the physical environmental factors of the seafloor on kelp production were investigated using GIS. Mean seawater temperatures in July, September, and October of the year before the harvest negatively correlated with the kelp harvest in Nemuro City from 2006 to 2014. The kelp length was mainly explained by the water temperatures in September and July of the year before the harvest, bottom current velocity, and water depth. These results indicate that the water temperature during summer and the seafloor physical environment have significant effect on kelp growth. Recent increases in seawater temperature along the Pacific coast of eastern Hokkaido during summer would significantly impact the local socio-economy through reduced kelp production.

This study compared tubes and drums as containers for the grow-out culture of abalone Haliotis asinina using mixed seaweeds and formulated diet as feed. The recycled drums were newly tested containers for abalone culture as the cheaper and larger alternative. However, on the 10th month of culture, serpulids (Pomatoceros sp. and Spirorbis sp.) were observed on the abalone shells; hence, the 12-month culture was extended to 16 months to observe further the effects of these ectoparasites on the growth and survival of abalone. Throughout the culture period, abalone reared in tubes had significantly higher mean shell length and body weight than those reared in drums, measuring 45.42 ± 0.36 mm, 23.40 ± 0.99 g, and 41.45 ± 0.23 mm, 18.26 ± 0.40 g at harvest, respectively. Mean growth rates of those in tubes were significantly higher than those in drums before serpulid infestation but did not differ during months of infestation. Survival was consistently higher in tubes than drums, except during May–September 2023. At harvest, survival in tubes was 46.7 ± 11.0%, 37.8 ± 5.9% in drums. Daily water temperature ranged 28.00–32.33 °C, salinity 16.00–34.37 ppt. Monthly readings (ppm) of dissolved oxygen ranged 3.1–7.4, sulfide 0.00–0.73, phosphate 0.01–0.87, nitrate 0.00–0.99, nitrite 0.00–0.22, and total suspended solids 0.22–4.83. In April–October 2023, serpulids became prevalent (tubes = 31.5 ± 3.4%; drums = 38.3 ± 3.4%) when mean DO was significantly lower and sulfide higher than in June 2022-March 2023. These fluctuations in water parameters may have triggered the infestation, resulting in lower growth rates and abalone survival. But, despite these fluctuations and infestations, tubes remained a better culture container for the abalone.

The combined effects of restricted feeding rates [50–75% apparent satiation (AS) and 100% AS] and culture systems [biofloc (BFT) and traditional pond system (TP)] on the growth, production, and economics of Nile tilapia-freshwater prawn polyculture were examined in a 2 × 2 factorial feeding trial for 120 days. Each treatment was carried out in triplicate following complete randomized design. Nile tilapia fingerlings (2.09 g) and freshwater prawn post larvae (PL₂₀; 0.05 g) were stocked at an initial density ratio of 6:6 individuals/m². Lower dissolved oxygen (DO) and higher Total Ammonia Nitrogen (TAN) and nitrite concentrations were observed in BFT system. Similarly, higher levels of DO were recorded in 50–75% AS-fed group, while TAN, nitrite, nitrate, and total suspended solids (TSS) were significantly higher at 100% AS-fed group. Culture system, feeding rate, and their interactions had significant effect on final body weight (FBW) and daily growth rate (DGR) of Nile tilapia. Lower FCR in Nile tilapia was noted in both BFT system and 50–75% AS-fed group. For freshwater prawn, the highest FBW and DGR were obtained in BFT system and fed 100% AS. However, survival rates and condition factor did not differ across all treatments for both species. Higher yield for both species and more large-size tilapia were obtained when fed at 100% AS. An increase in yield and significant improvement on the size distribution of prawns were also achieved in BFT system. Although both BFT and 100% AS have led to better performance, cost and return analysis have instead revealed better profitability using TP system and feeding rate of 50–75% AS. The lower cost of production in these treatments has economically compensated for the unfavorable growth, yield, and size distribution.

This study highlights the value of grey literature in climate change research in the Philippines, emphasizing its essential role in understanding the issue within the country’s unique socioeconomic and natural environment. A bibliometric analysis of publications in local journals reveals that various types and formats of grey literature are not merely supplementary but essential for communicating climate change, its effects, and adaptation strategies. Despite the prevalence of major publishers, a substantial amount of research in the country continues to be disseminated through local journals. However, these journals face significant challenges, including limited coverage in major databases and concerns about quality, which hinder their global recognition and impact. The findings recommend that the Commission on Higher Education (CHED) enhance the capacity of higher education institutions (HEIs) to improve the quality and credibility of local journals. This improvement would increase their visibility and reach, ensuring that the comprehensive body of Filipino research is preserved, recognized, and utilized in the global discourse on climate change. Consequently, this will foster a more inclusive and informed approach to understanding and addressing this global challenge.

Farming of groupers (members of the Serranidae, subfamily Epinephelinae) is widely practiced in Asia. Groupers are carnivorous and consequently prefer feeds high in fish protein. Most farms in Asia still rely on what is commonly termed "trash fish". Despite the apparent abundance and availability of "trash" fish in many areas, there are some issues and problems related to its use in fish farming. To provide farmers with a viable alternative to feeding trash fish to grouper, the Australian Centre for International Agricultural Research (ACIAR) supported project FIS/97/73 Improved hatchery and grow-out technology for grouper aquaculture in the Asia-Pacific region from 1999 to 2002, with one component to develop formulated feed for grouper aquaculture. The experiences of the project have been synthesized into this Practical Guide to Feeds and Feed Management for Cultured Groupers to promote the use of formulated feeds; promote reduction in the use of trash fish in grouper aquaculture; and to assist farmers in making more efficient use of feeds and feed resources. This guide explores new and better farming practices making use of formulated feeds, as well as technical aspects of feed storage and quality control, management of feeding including weaning of groupers onto formulated feeds and economic considerations.

Reports on genetic diversity within/among milkfish populations using DNA markers are sparse. Earlier work dealt with evolutionary relationships among wild populations to define management units in the Indo-Pacific region where milkfish naturally abound. However, application of milkfish genetic markers in broodstock development and management remains to be investigated. Here, nine novel microsatellites developed by NGS were utilized to (a) describe the genetic structure of Philippine wild and hatchery-bred milkfish; (b) monitor the impact of domestication selection and inbreeding; and (c) formulate marker-aided broodstock management methods, a prerequisite to genetic improvement. Milkfish samples from three wild populations: Claveria (CLA), Currimao (CUR), Camiguin (CAM); eleven local hatchery stocks: SEAFDEC Integrated Hatchery (SIH), SEAFDEC Big Hatchery-Igang batches 1 and 2 (SBH-I1 and SBH-I2), SEAFDEC Big Hatchery-Dumangas (SBH-D), Hautea Hatchery (HH), Sual Pangasinan Hatchery (SPH), BFAR Dagupan Hatchery (BDH), BFAR Bohol Hatchery (BoH), BFAR Palawan Hatchery (PAL), Zambales Hatchery-P0 (ZH-P0), Zambales Hatchery-F1 (ZH-F1); and a hatchery stock from West Java in Indonesia (WJH), were examined. An Indonesian stock was included since in the Philippines, Indonesian milkfish fingerlings are imported and farmed for having purportedly better production traits. Genetic diversity indices such as expected heterozygosity (He) and allele frequency (A) ranged from 0.655 to 0.697 and 9.2 to 11.1, respectively. AMOVA showed significant but low genetic differentiation among the milkfish populations (FST = 0.013; P=0.000,) since much of the variation is attributed to intrapopulation differences (98.6%). The oldest hatchery stock SIH (30-35 years) had relatively moderate genetic variability (He = 0.66, A = 10.6), which is lower than that of 5-year old SBH-I1 (He= 0.687, A= 11.5) considering that both stocks originally came from the same source in the wild. A reduction in genetic diversity was seen when a local hatchery stock (ZH-P0;He = 0.66 and A= 10.8) was monitored after one generation (ZH-F1; He = 0.65, A=9.3). Finally, the Indonesian stock WJH had genetic variability levels (He= 0.66; A= 10.5) comparable with local stocks. Results of genetic analyses are herein discussed in the context of promoting effective milkfish broodstock management practices for the production of good quality seed stock.

Southeast Asia has the highest concentration of mangroves and brackish water aquaculture ponds. This paper describes studies that integrate mangroves as biofilters, and as pen culture sites for mud crab farming. In one study, passing shrimp pond effluents through a natural mangrove stand reduced levels of TSS, sulfide, NH₃-N and NO₃-N by 18.7%–64.2%. Estimates show that 1.4–6.5 ha of mangroves are needed to assimilate nitrogen wastes from one hectare of shrimp pond. Mangrove biomass increase was 2.5 times greater with effluents compared to a control mangrove, although plant numbers remained similar. Present mud crab Scylla spp. farming still depends on raw (“trash”) fish and wild seed. To lessen such dependence, another study compared the stocking of hatchery vs wild juveniles, and feeding of pellet + raw fish (“trash fish”) vs fish alone. Preliminary results show that low-cost pellets can reduce raw fish requirement, and that hatchery crab juveniles need immediate feeding whereas wild crabs can subsist on natural mangrove productivity for one month. Mud crab pen culture is commercially viable but technological refinements and land tenure issues remain.

The petrochemicals produced from refining oil have become a large part of human life, making oil a valuable and expensive commodity. As a non-renewable resource, extraction and transport efforts have intensified to keep up with the demand, increasing the occurrences of oil spills. Such accidents have devastating impacts on the environment, the health of organisms, and a country's economy like the Philippines, and thus, need to be resolved immediately. One way to deal with oil spills is through bioremediation but the process is still facing several challenges. For one, the toolbox for bioremediation is limited. About 79 genera of bacteria were observed to degrade oil but there are only a small number of bacterial species and/or strains that have been recognized as useful for bioremediation. Second is that most oil-degrading bacteria found have low oil degradation efficiencies. Another challenge is keeping the bacteria alive to carry out the process. Fortunately, progress has been made in solving these challenges. Researchers are now testing different consortia, including bacteria–bacteria, bacteria–fungi, bacteria–microalgae, that can complement each other such as biosurfactant-producing bacteria with different oil-degrading microorganisms or microalgae or fungi that enhance the growth of oil-degrading bacteria. A consortium like this improves the survivability of each microorganism and enhances the oil-degrading efficiency. Moreover, the search for additional oil-degrading and biosurfactant-producing bacteria and other microorganisms to add to the bioremediation toolbox has been improved with the emergence of high-throughput sequencing. Aside from microorganisms, seaweeds have shown potential for bioremediation. The seaweed Caulerpa prolifera has been demonstrated to degrade diesel up to a certain concentration with the help of the bacteria growing on its surface. Bioremediation has a long way to go, but recent developments have shown promise and it remains to be the cheapest, most environment-friendly, and most effective way of dealing with oil spills.