Nutritional Composition, Fatty Acid Profile, Mineral Content, and Preliminary Spine Extract Toxicity of the Estuarine Sea Catfish Arius maculatus (Thunberg, 1792) from Panguil Bay, Southern Philippines

Estuarine fishes significantly contribute to food security, fisheries production, and coastal livelihoods throughout Southeast Asia. Despite its ecological and commercial importance, limited information exists regarding the nutritional composition and toxicity-associated characteristics of Arius maculatus (Thunberg, 1792) inhabiting Panguil Bay, Southern Philippines. This study evaluates the proximate composition, fatty acid profile, mineral content, and preliminary toxicity of crude spine extracts obtained from A. maculatus. Muscle tissues were subjected to standard biochemical analyses for moisture, protein, lipid, carbohydrate, and ash content. Fatty acids were quantified using gas chromatography, while mineral concentrations were determined using atomic absorption spectrophotometry and flame photometry. The toxicity of crude spine extracts was assessed using a brine shrimp (Artemia sp.) lethality bioassay and probit regression analysis. The results show that A. maculatus contained high moisture (81.37 ± 2.20%) and moderate protein content (14.53 ± 1.33%), with relatively low fat (1.09 ± 0.34%), carbohydrate (3.63 ± 0.97%), and ash (0.95 ± 0.12%) levels. The fatty acid profile was dominated by palmitic acid (29.74%), stearic acid (14.76%), and oleic acid (20.87%), while nutritionally important polyunsaturated fatty acids included docosahexaenoic acid (3.23%) and eicosapentaenoic acid (1.76%). Mineral analysis revealed considerable concentrations of sodium (511.67 mg/kg), magnesium (76.50 mg/kg), iron (12.33 mg/kg), and zinc (5.83 mg/kg). Toxicity evaluation demonstrated a clear dose-dependent response, with complete mortality observed at concentrations ≥0.800 mg/mL and an LC50 value of 0.362 mg/mL. These findings indicate that A. maculatus is a nutritionally valuable estuarine fish resource and that its spine extracts contain biologically active compounds that warrant further biochemical characterization. This study provides baseline information that supports the sustainable utilization of underexplored fishery resources from Panguil Bay.