Preliminary analysis of the biological response of sub-adult scylla serrata (mangrove crabs) on phosphate & on phosphate-containing shampoo

• Main Author: Bacolod, Kobee D.
• Format: text
• Language: English
• Published: Animo Repository 2022
• Subjects: Scylla serrata > Analysis; Biology
• Online Access: https://animorepository.dlsu.edu.ph/etdb_bio/21; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=1023&context=etdb_bio
• Institution: De La Salle University

The Philippines is rich in marine and aquaculture resources such as mangrove crabs being a local commodity and having high commercial value contributing to the country’s economy. However, the prevalent deterioration of marine and coastal ecosystems has affected various marine organisms triggering abnormalities or aberrations leading to population and productivity decrease. In the Philippines, eutrophication caused by excessive nutrient loading such as phosphate is prevalent indicating its high levels may cause possible abnormalities in their activity, growth, and development. This study aims to analyze the possible biological response of Scylla serrata mangrove crabs toward phosphate pollution by observing their growth parameters, protein content and manifested abnormalities. Three treatment groups: shampoo, phosphate and control were prepared each having six randomly selected mangrove crabs that have undergone a 24-hour depuration with their weight and carapace sizes initially measured. After four weeks of exposure, their final weight, carapace sizes, protein content, and observed abnormalities were standardized and recorded. Statistical analysis using single-factor ANOVA was done indicating no significant difference in weight, carapace size, and protein content across the treatment groups. Identified abnormalities were observed in the crabs that were exposed to pollutant treatments such as accumulation of algal growth on their underside, rust lesions, and algal encrustation providing evidence for the detrimental effects of phosphate on the early developmental stages of mangrove crabs. Principal Component Analysis (PCA) was obtained for multivariate analysis of the measured growth parameters and exhibited an isolated cluster of control organisms while a spread-out distribution of the pollutant treatments indicated varied biological responses. The researcher recommends: 1) considering mangrove crabs’ sex as reproductive maturity may influence observed abnormalities, 2) Adding subsamples and replicates to distinguish groupings of their biological responses, and 3) having longer observation periods to analyze the long-term accumulation effects of these pollutants. These results can be then utilized in providing the basis for formulating a method for immediate assessment of marine health & water quality for farmers and local growers as well as supportive evidence for policy recommendations addressing the reduction or abolishment of pollutant chemicals promoting eutrophication. This would help in the mitigation of the degradation of their natural habitats and prevent long-term harmful effects on mangrove crabs and their population.