Phytoplankton production systems in a shellfish hatchery: variations of the bacterial load and diversity of vibrios.
OBJECTIVE
Outbreaks of disease caused by some Vibrio species represent the main production bottleneck in shellfish hatcheries. Although the phytoplankton used as food is one of the main sources of bacteria, studies of the associated bacterial populations, specifically vibrios, are scarce. The aim of the study was the microbiological monitoring of the microalgae as the first step in assessing the risk disease for bivalve cultures.


RESULTS
Two phytoplankton production systems were sampled weekly throughout 1-year period in a bivalve hatchery. Quantitative analysis revealed high levels of marine heterotrophic bacteria in both systems throughout the study. Presumptive vibrios were detected occasionally and at low concentrations. In most of the cases, they belonged to the Splendidus and Harveyi clades.


CONCLUSIONS
The early detection of vibrios in the microalgae may be the key for a successful bivalve culture. Their abundance and diversity were affected by factors related to the hatchery environment.


CONCLUSIONS
This work represents the first long study where the presence of vibrios was evaluated rigorously in phytoplankton production systems and provides a suitable microbiological protocol to control and guarantee the quality of the algal cultures to avoid the risk of transferring potential pathogens to shellfish larvae and/or broodstock.
Departamento de Microbiología y Parasitología, CIBUS-Facultad de Biología, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
J
J
Dubert
Centro de Cultivos Mariños, Consellería do Mar, Xunta de Galicia, Ribadeo, Lugo, Spain.
A
A
Fernández-Pardo
Centro de Cultivos Mariños, Consellería do Mar, Xunta de Galicia, Ribadeo, Lugo, Spain.
S
S
Nóvoa
Departamento de Microbiología y Parasitología, CIBUS-Facultad de Biología, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
J L
JL
Barja
Departamento de Microbiología y Parasitología, CIBUS-Facultad de Biología, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
S
S
Prado
D000818:Animals; D058491:Bacterial Load; D044822:Biodiversity; D049872:Bivalvia / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis; D008969:Molecular Sequence Data; D010839:Phytoplankton / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D012758:Shellfish / Q000382:microbiology*; D014733:Vibrio / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification
Vibrio; bacteria; continuous culture system; intermediate scale culture; microbiota; phytoplankton production systems; shellfish hatchery