An aerobic, polarly flagellated marine bacterium that produces a prodigiosinlike pigment was isolated from the red-spotted culture beds of Laminaria japonica. Five isolates had unique bacteriolytic activity for both Gram-positive and -negative bacteria, which had never been observed among Alteromonas or related species. The isolates were identified as the causative agent of red spot disease of L. japonica seeds. The phenotypic features of the isolates were similar to these of Pseudoalteromonas rubra ATCC 29570T, but they could be differentiated using 10 traits (growth at 37 "C, requirement for organic growth factors, bacteriolytic activity, utilization of sucrose, N-acetylglucosamine, fumarate, succinate, D-galactose, L-proline and acetate). The G+C content of DNAs from the isolates was 4 4 4 6 mol0/o. The isolates constitute a new species, distinct from the other A/teromonas and Pseudoalteromonas species, as shown by DNA-DNA hybridization experiments and phylogenetic clustering of 165 rRNA gene sequences, for which the name Pseudoalteromonas bacteriolytica sp. nov. (type strain = IAM 145953 is proposed. A set o f phenotypic features which differentiate this new species from closely related Pseudoalteromonas and Akeromonas species is provided.

The phenotypic properties and genotypic characteristics of 44 aeromonads isolated from fish affected by epizootic ulcerative syndrome (EUS) in Southeast Asia were investigated. Among the 13 A. hydrophila phenospecies 9 were genotypically identical to A. hydrophila (HG 1) and 4 were A. veronii biotype sobria (HG8Y) or A. veronii biotype sobria-related genospecies. All the 6 A. veronii biotype sobria phenospecies were placed in the same genospecies, A. veronii biotype sobria. Of the 12 A. jandaei phenospecies, 5 were A. veronii biotype sobria or A. veronii biotype sobria-related genospecies and 7 were A. jandaei genospecies. Of 13 Aeromonas isolates unspeciated by phenotyping 9 were genotypically identical to A. hydrophila or very similar to A. hydrophila and 2 isolates were A. veronii biotype sobria or very similar to A. veronii biotype sobria; 2 isolates could not be identified to genospecies level. These results strongly suggest that Aeromonas species from fish affected by EUS could not correctly be identified to the species level using various published biochemical schemes; it needs genetic identification like DNA-DNA hybridization.

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Different reproductive aspects such as sexual maturity, spawning, gonadosomatic index, fecundity, and histological changes in gonads of captive reared Sperata aor were investigated for a period of one year. Male and female fish were identified by based on morphological characteristics. The spawning season was found to be extended from May-August. Gonadosomatic index reaches maximum in August and lowest in September. Absolute fecundity varied from 59255 to 70586 with an average value of 64920. Absolute fecundity had been reported to be increased with total length, body weight. Histological study of ovary of S. aor indicated the presence of four developmental stages viz, early perinucleolar s oocytes, late perinucleolar oocytes, yolk vesicle stage and yolk granular stage. Findings reveal that, S. aor has group asynchronous manner of ovarian growth and used to spawn numerous times in a year under favorable environmental conditions. The testes histology represents the presence of spermatocyte, spermatid, and spermatozoa. This species builds nests during breeding season and fries are found within the nests.

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