A Comparative Assessment of Morphometrics and Bacterial Assemblages of Crassostrea gasar (Oyster) from Riparian Swampy Areas of the Lagos Lagoon, Nigeria

Abstract

The Crassostrea gasar (C. gasar) are economically important bivalves. The study investigated the physico-chemistry, the  morphometrics and microbial profiles of C. gasar, water, and sediment from the Lagos Lagoon. The physico-chemistry  and morphometry of C. gasar were determined using standard methods while the microbial were identified by Vitek 2  automated system. The mean Total Heterotrophic Bacterial Counts (Log CFU/mL) of C. gasar flesh and shells ranged from 5.28 ± 0.3 to 5.41 ± 0.3 and 5.49 ± 0.1 to 5.62 ± 0.3 respectively. The mean total coliform counts of sediment ranged  from 4.34 ± 0.2 to 4.39 ± 0.2 Log CFU/mL, while the highest mean faecal coliform counts and total fungal counts of water  samples were 2.41 ± 0.3 and 2.41 ± 0.1 Log CFU/mL, respectively. Vibrio spp, Pseudomonas aeruginosa, Staphylococcus  aureus, Bacillus spp, Streptococcus faecalis, Escherichia coli and Aspergillus niger were the species found in all samples  in varying percentages. The median-sized C. gasar had the highest values of 7.5 – 12.4 cm (TL); 4.5 – 7.4 cm (MW); and  80.5 – 160.4 g (TW). The highest mean values for surface water temperature, pH, salinity, Chemical Oxygen Demand and  Phosphate were 27.3 ±1.51^oC, 29.8 ± 1.94, 16.5 ± 0.39 ‰. 7.26 ±0.01 mg/L and 0.39 ± 0.01 mg/L respectively. This study  revealed that C. gasar from the riparian swampy areas harboured some potential pathogenic organisms of significant  public health concern and can contribute to the spread of illnesses when consumed.