This study aims to determine the levels of mercury and histopathological alterations in selected organs of Rastrelliger spp., Selar spp., and Katsuwonus spp. from the Jasaan Municipal Fish Port. A total of 15 randomly selected fish samples were tested for Cold Vapor-Atomic Absorption Spectrophotometry (CV-AAS) for mercury detection and selected organs were examined for histopathology applying a semi-quantitative scoring on the severity of the lesions. Nine out of 15 (60%) of the fish samples tested positive for mercury. Katsuwonus spp. (0.025 mg/kg) and Selar spp. (0.0102 mg/kg) were positive for mercury while Rastrelliger spp. tested negative. Mercury concentrations remain under the maximum permissible limit (MPL) for mercury. Statistical analysis revealed a highly significant (p < 0.001) mean levels of mercury in three fish species. Non-carcinogenic Hazard Quotient (NHQ) values were less than one. Histopathologic examination of the organs’ lesions revealed mercury-related morphological alterations. Mild to moderate severity of the lesions were observed in the kidney, liver, muscle, and gills.

This study evaluates the heavy metal content in milkfish (Chanos chanos) sold in Metro Manila to assess its safety for human consumption. Milkfish samples were collected from public markets across the National Capital Region (NCR) and analyzed for lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) using Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES). The analysis revealed lower concentrations of these metals compared to previous studies, with Pb levels at 0.07 ppm, Cd at 0.03 ppm, Hg at 0.04 ppm, and As at 0.01 ppm—all within permissible limits set by both the Bureau of Fisheries and Aquatic Resources (BFAR) and the European Union.

The socio-economic contributions of women in fisheries are increasingly recognized, yet their participation remains limited by structural barriers and cultural norms. In the Sulu Archipelago, the fisheries sector is deeply male-centric, with men dominating most fishing activities. In this context, gender-focused research, particularly from the male perspective, is essential in understanding and addressing persistent inequalities. This study examines women’s roles in the small-scale commercial sardine fishery of the Sulu Archipelago using the Gendered Value Chain Framework (GVCF). Data were collected through one-on-one interviews with fishers using kulibu—an outrigger fishing vessel employing ring nets to catch sardines and other small pelagic fishes. A five-point Likert scale was employed to capture active kulibu fishers’ perceptions of gender participation across pre-production, production, and post-production activities. Additionally, focus group discussions and visits to fishing communities, including on-board surveys, were conducted to observe actual practices and validate results of the interviews.

The introduction of non-native species into inland waters poses a serious threat to aquatic ecosystems, particularly by disrupting aquatic ecosystems, displacing native fish populations, and facilitating the spread of diseases. One species of growing concern in the Philippines is Amphilophus citrinellus, a non-native cichlid that has recently been recorded in Taal Lake. This study aimed to assess the distribution, abundance, and potential ecological impact of A. citrinellus based on stock assessment data collected by the National Fisheries Research and Development Institute from 2011 to 2022. Data were gathered from 15 landing sites across nine municipalities surrounding Taal Lake. Based on this study, A. citrinellus was first detected in 2011 in the municipalities of Talisay, Laurel, and Agoncillo, with an annual catch of just 0.444 metric tons (MT). However, its population rapidly increased, with annual catches reaching 116.43 MT in 2014, 151.74 MT in 2015, 425.22 MT in 2018, and peaking at 479.99 MT by 2022. Correspondingly, its geographic spread expanded from three municipalities in 2011 to all nine municipalities by 2015. A. citrinellus is known for its high fecundity, aggressive behavior, and resilience, all of which contribute to its potential as an invasive species.

Guava leaves (Psidium guajava) have the potential to be an immunomodulator in fish. This potential must be followed by an optimal dose to influence the fish's immunity and growth rate. This research aimed to determine the optimal dose of guava leaves on common carp growth, immune response, and survival (Cyprinus carpio L). An experimental method was applied using a completely randomized design with five treatments and three replications: T0 (control), T1 (guava dose 1 g/100 g feed), T2 (1.5 g/100 g), T3 (2 g/100 g), and T4 (2.5 g/100 g). Some 300 fish (weighed 4.00 ± 0.50 g) were kept in brackish water (5 ppt) tanks for 60 days, fed with feed containing phytoimmunostimulant, and challenged with Aeromonas hydrophila.

Milkfish (Chanos chanos) is one of the most important finfish species in Philippine aquaculture. However, its processing and consumer acceptability are hindered by the presence of “spicule-like” intermuscular bones (IBs), a feature that has received limited research attention. In this study, milkfish samples of varying sizes, from larval to sub-adult stages, were examined to visualize IB development and describe their morphology. Differential bone staining and tissue clearing techniques revealed skeletal elements derived from either cartilage or tendon. Through this approach, IBs were identified and documented in detail with respect to their number, morphology, and ossification patterns, allowing classification into epineurals, epipleurals, and epicentrals. Among these, epineurals, particularly those at the anterior region of the body, exhibited the most complex morphology, while ossification was observed to proceed in a posterior-to-anterior sequence. To understand the mechanism of IB formation, a preliminary molecular analysis was carried out, which identified potential milkfish homologs of IB-associated genes runx2b and bmp6.

Degradation of coastal habitats and environmental damage, depletion of marine resources, poverty among municipal fisherfolk, and low productivity of aquaculture are the major problems that beset the Philippine fisheries sector today. Despite the implementation of Coastal Resource Management (CRM) programs, it is ironic that the richness of our fisheries and coastal resources has not increased the catch per unit effort of the fisherfolk. This study was conducted to determine the knowledge, attitudes, and practices among fisherfolk towards CRM in the Philippines. This descriptive comparative correlational research study surveyed 399 fisherfolk in the coastal barangays using a validated and reliable researcher-made instrument. This study used the mean, standard deviation, t-test, and Spearman’s Rho to analyze the findings. Results showed that awareness, behavior, and participation of fisherfolk on CRM when taken as an entire group were “high”.

Biological dynamics and ecological capacity, important environmental concepts, demonstrate the potential of an ecosystem to support a biological community and uphold resilience, given the varying environmental conditions. Phytoplankton are important components of lakes, serving as primary producers, bioindicators, and responding dynamically to environmental factors. However, studies of phytoplankton dynamics and ecological capacity of the Seven Crater Lakes in San Pablo City, Laguna, remain limited. In this study, phytoplankton composition, richness, and diversity were examined to determine phytoplankton dynamics and ecological capacity. Also, the influences of physical factors on phytoplankton were investigated to determine the main drivers of variation. We conducted monthly collections of phytoplankton samples and physical factors, including water temperature, pH, conductivity, transparency, and dissolved oxygen, in the Seven Crater Lakes from July to December 2015.

KEY POINTS

• Populations of all giant clam species in the Philippines have declined significantly over the past four decades, with a collective decline of 98%.
• Despite massive culture and restocking efforts for the true giant clam (Tridacna gigas) since the 1980s, recruitment rates for the species are still very low, mainly because of persistent threats from anthropogenic activities, habitat degradation, and extreme weather events.
• The harvest and trade of giant clams and their derivatives have been completely banned in the Philippines since the 1990s; however, live giant clams, meat, and shells are still sold illegally around the country up to the present.
• Based on the best available information gathered, the assessment showed that the harvest and trade of giant clam shells pose a high risk to all species and are detrimental to the survival of wild giant clam populations in the Philippines.
• The Scientific Authority is, therefore, unable to issue a positive non-detriment finding (NDF) for giant clam shells at this time, and trade must be confined to certified captive-bred specimens and their derivatives.

The high buying price for spiny lobster (Panulirus spp.) pueruli (SLP), commonly known as "seed lobsters", has driven increasing collection efforts, particularly along the eastern coast of Palawan, Philippines. These pueruli represent a transitional stage between the phyllosoma larva and juvenile, and despite their growing commercial importance, little is known about the specific species being harvested in the region. This study aimed to document the daily morphological changes in SLP until they could be reliably identified at the species level. A total of 27 SLP were collected from various sites along Palawan’s eastern coast and individually reared for 15 to 25 days in improvised aquaria made from the bottom halves of 1.5-liter soda bottles. Each container was supplied with continuous aeration and regular water changes. Boiled mussel meat was introduced as feed once the pueruli began to show signs of pigmentation. By the end of the rearing period, the pueruli developed distinct morphological features resembling miniature adults and were identified as Panulirus ornatus, P. versicolor, and P. longipes longipes. A daily photographic record of each specimen revealed that even during the early, unpigmented stages, each species exhibited unique and distinguishable traits.

Fishes endemic to freshwater habitat are strongly influenced by water hardness, initiating physiological changes. The present study aimed to understand the effects of a four-fold sequential increase from soft to hard waters on selected tissues of Koi carp, a commercially valued ornamental freshwater fish. Secondary stress markers, Glucose, Oxidative Stress (Malondialdehyde (MDA)/Lipid Peroxidation (LPO) and Antioxidants (Catalase (CAT)), Glutathione-S-Transferase (GST), and Glutathione (GSH) were quantified in gill and white muscle (hereafter referred as muscle) after 14 days of exposure to soft waters of 75 mg CaCO₃/L (TS), moderately hard waters of 150 mg CaCO₃/L (TM), hard waters of 225 mg CaCO₃/L (TH), and very hard waters of 225 mg CaCO₃/L (TV). Both the examined tissues were distinctly affected by soft and moderate waters. Glucose in gills (p < 0.05) was proportional to the rise in hardness levels. Soft, moderate, and very hard waters (75, 150, and 300 mg CaCO₃/L) affected gills and muscle due to elevated MDA (p < 0.05). CAT and GST provided considerable antioxidant protection to the tissues. Conclusively, results revealed tissue-specific differential responses and suitability of holding water hardness approximating 225 mg CaCO3/L.

This study presents a gut content analysis of nine freshwater fish species representing six families from Lake Wood, Zamboanga del Sur, Philippines. A total of 144 stomach samples were examined to assess dietary composition and feeding strategies using frequency of occurrence (%O_i), volumetric composition (%V_i), Index of Preponderance (IP_i), and Index of Relative Importance (IRI_i, %IRI_i). Algae emerged as the dominant food item, indicating its foundational role in the lake’s food web. Oreochromis niloticus and O. aureus were primarily herbivorous, while Oreochromis sp. exhibited an omnivorous diet dominated by mollusks. Cyprinus carpio showed generalist feeding, consuming algae, mollusks, fish, and sand. Barbodes binotatus fed mainly on algae but also ingested mollusks and sand, indicating benthic foraging. Rasbora sp. was strictly herbivorous, feeding on algae. Air-breathing species such as Anabas testudineus and Clarias batrachus consumed algae and sand equally, suggesting substrate feeding. Channa striata displayed omnivory with notable insect consumption. The diversity of food items and trophic roles highlights a multi-guild but algae-driven ecosystem. Comparisons with regional studies affirm the prevalence of algae as a key dietary component in Philippine inland waters. This baseline information enhances our understanding of trophic interactions and resource use in Lake Wood and can inform future ecological monitoring and sustainable fisheries management efforts in the region.