TY - JOUR
T1 - Seasonal variation in the condition index of Pacific oyster postlarvae (Crassostrea gigas) in a land-based nursery in Sonora, Mexico
AU - Barraza-Guardado, Ramón H.
AU - Chávez-Villalba, Jorge
AU - Atilano-Silva, Héctor
AU - Hoyos-Chairez, Francisco
PY - 2008/12
Y1 - 2008/12
N2 - This study examined the seasonal variation in the condition index (CI) of Crassostrea gigas postlarvae (<5 mm) that were cultivated at a commercial hatchery. Oysters were sampled weekly at the nursery using seawater from a lagoon for the grow-out that precedes commercialization. Temperature, salinity, seston, chlorophyll a, oxygen and pH were recorded at each sampling and water samples were taken to identify phytoplankton groups and their abundance. High levels of primary productivity, chlorophyll a and seston were detected during summer, but the highest CI occurred in winter. During winter, elevated phytoplankton biomass was composed by diatoms and phytoflagellates, which served as the main food source and promoted weight gain in this season. Variations in salinity, oxygen and pH were not related to differences in the CI. However, it appears that the wide temperature variation affected functions, such as feeding activity, apparently enhancing ingestion during winter (mean 16.5±1.4 °C) and reducing ingestion during summer (mean 31±1.5 °C). Winter production resulted in postlarvae with a homogeneous size range and a high CI, indicating that winter is more favourable to start cultivation. The CI represents a practical means to determine the physiological state of postlarvae before transfer to cultivation sites.
AB - This study examined the seasonal variation in the condition index (CI) of Crassostrea gigas postlarvae (<5 mm) that were cultivated at a commercial hatchery. Oysters were sampled weekly at the nursery using seawater from a lagoon for the grow-out that precedes commercialization. Temperature, salinity, seston, chlorophyll a, oxygen and pH were recorded at each sampling and water samples were taken to identify phytoplankton groups and their abundance. High levels of primary productivity, chlorophyll a and seston were detected during summer, but the highest CI occurred in winter. During winter, elevated phytoplankton biomass was composed by diatoms and phytoflagellates, which served as the main food source and promoted weight gain in this season. Variations in salinity, oxygen and pH were not related to differences in the CI. However, it appears that the wide temperature variation affected functions, such as feeding activity, apparently enhancing ingestion during winter (mean 16.5±1.4 °C) and reducing ingestion during summer (mean 31±1.5 °C). Winter production resulted in postlarvae with a homogeneous size range and a high CI, indicating that winter is more favourable to start cultivation. The CI represents a practical means to determine the physiological state of postlarvae before transfer to cultivation sites.
KW - Chlorophyll
KW - Condition index
KW - Crassostrea gigas
KW - Oyster
KW - Postlarvae
KW - Seston
UR - http://www.scopus.com/inward/record.url?scp=58149151356&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2109.2008.02076.x
DO - 10.1111/j.1365-2109.2008.02076.x
M3 - Artículo
SN - 1355-557X
VL - 40
SP - 118
EP - 128
JO - Aquaculture Research
JF - Aquaculture Research
IS - 1
ER -