Abundance of Culturable Marine Heterotrophic Bacteria in Ulva lactuca Associated with Farmed Seaweeds Kappaphycus spp. and Eucheuma denticulatum

Abstract

Ulva lactuca is one of the macro-epiphytes of farmed seaweeds Kappaphycus spp. and Eucheuma denticulatum in Tawi-Tawi, southern Philippines, especially during the summer season, which affects the growth and health of farmed seaweeds. In this study, the abundance of culturable heterotrophic marine bacteria from U. lactuca associated with farmed seaweeds Kappaphycus spp. and E. denticulatum was investigated in the seaweed farms of Tongsibalo, Sibutu, Tawi-Tawi, southern Philippines, using serial dilution procedure. Results revealed that the average bacterial counts obtained from U. lactuca associated with Kappaphycus alvarezii, K. striatus, and E. denticulatum were 2.48 x 1010 CFU g-1, 1.14 x 1012 CFU g-1, and 1.32 x 1011 CFU g-1, respectively. In addition, agar-digesting bacteria were observed from U. lactuca samples associated with K. alvarezii and K. striatus manifested by the depression and liquefaction of the marine agar after 2-3 days which were suspected as pathogenic bacteria causing ice-ice disease. Therefore, U. lactuca may serve as a vector for these potential pathogens to farmed seaweeds.