Before harvest, 0.25-mL water samples were collected from each
tank for microbiological analysis. Samples were homogenized
and serially diluted (1/10) in sterile saline solution (3%) and seeded
in duplicate on marine agar culture medium (Difco) to count viable
and total heterotrophic bacteria. Diluted samples were also seeded
in duplicate on thiosulfate–bile–sucrose–agar medium (TCBS, Difco) to count Vibrionaceae bacteria. Seeded media were incubated in a microbiological oven at 30 ◦ C. After 24 h, the colony
forming units (CFU) were counted.