Seasonal changes in carbohydrate metabolism and its relationship with summer mortality of Pacific oyster Crassostrea gigas (Thunberg) in Marennes-Ole'ron bay (France)
This paper investigates the biological responses of Crassostrea gigas under traditional culture conditions on a mudflat in Marennes-Oleron bay. Summer mortality has been regularly observed in recent years in oysters reared using "on bottom" culture conditions. The present study attempts to...
Published in: | Aquaculture |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier
2006
|
Subjects: | |
Online Access: | https://archimer.ifremer.fr/doc/2006/publication-1116.pdf https://doi.org/10.1016/j.aquaculture.2005.07.008 https://archimer.ifremer.fr/doc/00000/1116/ |
Summary: | This paper investigates the biological responses of Crassostrea gigas under traditional culture conditions on a mudflat in Marennes-Oleron bay. Summer mortality has been regularly observed in recent years in oysters reared using "on bottom" culture conditions. The present study attempts to provide a better understanding of the mortality phenomenon through biological parameters. Classical 'field parameters' such as mortality and growth rates, and quality index (dry meat weight/ dry shell weight x 1000) were monitored. Additional parameters, as biochemical composition of oyster meat and glucose incorporation capacity, were included as potential new bioindicators. The work highlighted a critical timing (May-June) preceding the summer mortality and characterised by an arrest in lipid synthesis and a decrease in carbohydrate content. During this period, growth (especially gonad maturation) either slowed down significantly or even stopped. The first mortality event occurred during a growth renewal period at the end of June. Short-term analysis (15 days) provided information to identify such responses which may indicate a physiological stress and demonstrating the need for further investigation. The seasonal food availability (estimated from chlorophyll a levels) did not facilitate the mortality understanding which occurred after water temperature went above 18-19 T. Nevertheless, this study shows carbohydrate anabolism contributed in the physiological stress leading to mortality events. |
---|