Bacterial flora of healthy and abnormal chaetognaths.

Abstract

Freshly captured chaetognath Sagitta samples were grouped into apparently healthy and abnormal specimens and the viable heterotrophic bacterial population of both groups were ex-amined. The bacterial population ranged from 1.3×102 to 1.0×104 per animal, and was one order higher in opaque specimens regardless of whether they were still moving or moribund at the time of capture. Although Pseudomonas-Alteromonas was the predominant bacteria in both groups, Vibrio comprised 36.3%, of the bacterial population in the abnormal Sagitta. By the method of numerical taxonomy the total 143 strains were grouped into 14 main phena, of which 4 were exclusively composed of strains from healthy Sagitta and 1 from abnormal Sagitta. The rest of the strains were unevenly distributed into 9 phena, 4 of which were mostly comprised of strains from abnormal Sagitta and 1 of which mostly included strains from healthy Sagitta. In general, the isolates of abnormal Sagitta grew under a wide range of physiological conditions and showed greater hydrolytic activities of organic compounds.