Alejandro Marcelo Gonzales Vargas

Intensive larviculture of the South American ribbed mussel (Aulacomya atra) is constrained by recurrent mortality during pre-metamorphic development. This study characterized cultivable bacteria associated with an acute 79% mortality event on day 12 post-fertilization and screened autochthonous bacterial isolates for in vitro antagonistic activity. Two independently collected and homogenized samples per larval condition were examined; serial dilutions and plate observations were treated as technical observations and summarized within the sample. Cultivable heterotrophic abundance on Plate Count Agar was 5.54 ± 4.75 × 10⁷ CFU g⁻¹ in surviving larvae and 1.24 ± 0.05 × 10⁸ CFU g⁻¹ in moribund larvae. Because only two independent samples were available per condition, these counts were interpreted descriptively. Presumptive Vibrio spp. were not detected in either surviving-larvae sample but were detected in one of two moribund-larvae samples. Sequencing of the 16S rRNA gene assigned representative isolates recovered from moribund larvae to Staphylococcus saprophyticus (P2 and P4), Staphylococcus warneri (P20), and Vibrio sp. (P22). In a blocked analysis of 12 target-by-plate combinations, inhibition differed among the four candidate isolates and the negative control (Friedman χ² = 16.275, df = 4, p = 0.0027; Kendall’s W = 0.339). After Holm adjustment of four planned paired comparisons with the control, only Bacillus pumilus B3 differed significantly from the control (adjusted p = 0.025). Its mean inhibition varied by target, from 3.58 ± 0.55 mm against P2 to 0.58 ± 1.01 mm against P22. These findings identify B3 as a promising candidate with target-dependent in vitro antagonistic activity. Controlled in vivo challenge and safety studies are required before probiotic efficacy or practical biological-control value can be established.

La investigación compara la propagación vegetativa de Chondracanthus chamissoi, conocida también como “Yuyo” en Perú, en tres tipos diferentes de sustrato, bajo condiciones controladas en laboratorio. Los sustratos usados para la comparación fueron; TA; valva de almeja, TB; Malla de fruta, TC; cabo de propileno y TP; concha de Concholepas concholepas. Según el estudio, existió mejor supervivencia en TB, determinando la formación de (DFS) a partir de 20 a 23 días. Según los resultados, la estrategia de propagación vegetativa es viable para el escalamiento comercial en el litoral de Moquegua, Perú.