Oyster condition index in Crassostrea rhizophorae (Guilding, 1828) from a heavy-metal polluted coastal lagoon

Abstract

The condition index (CI) of oysters represents an ecophysiological approach to estimate meat quality and yield in cultured bivalve mollusks. In the present study, the CI of oysters from a heavy-metal polluted bay was analyzed with respect to Zn and Cd contamination in soft tissues, spawning, and polychaete infestation. The CI was calculated through a new technique based on molds made to measure the volume of oyster-shell internal cavities. The higher CI values (over 9 in the dry season) were probably related availability of suspended particles rich in organic matter in the bay, while the rapid reduction in the CI from one season to the next at some stations suggests the effect of spawning. Polychaete infestation was considered low (18.7%) and produced no clear CI effects. The Cd in the oyster tissue collected during the rainy season was weak, although still significantly correlated with the CI (r = -0.36; p < 0.05). All other comparisons of CI and metal concentrations demonstrated a non-significant correlation. The CI variations observed on the temporal and spatial scale were likely to have been caused by availability of organic matter and spawning, rather than spionid infestation or metal body burdens.

Growth, mortality and susceptibility of oyster Crassostrea spp. to Perkinsus spp. infection during on growing in northeast Brazil

“…A decrease of the mean whole weight observed in December and February compared with October could be related to spawning events, which caused an important decrease in body weight, as already described in C. rhizophorae from Brazil (NASCIMENTO & PEREIRA, 1980;REBELO et al, 2005). Cultured C. gasar oysters became mature and present several spawning peaks during most parts of the year (PAIXÃO et al, 2013;RAMOS et al, 2014).…”

Growth and economic performance of diploid and triploid Pacific oysters Crassostrea gigas cultivated in three lagoons of the Gulf of California

“…The condition index of oysters represents an important tool to estimate meat quality and yield in cultured bivalve mollusks, and can be affected by multiple abiotic and biotic factors (Rebelo et al, 2005). Despite of the advantages (improved meat quality and superior growth) pointed out by Guo et al (1996) for triploid oysters, no differences in the CI were detected among the C. gigas populations cultivated at the three sites.…”

Seasonal variation in the condition index, meat yield and biochemical composition of the flat oysterOstrea edulis(Linnaeus, 1758) from the Dardanelles, Turkey

“…Water temperature in Aegean Sea rises over 15°C generally in March (Acarlı, 2005;Lök et al, 2007;Serdar et al, 2007), whereas these values are observed in Dardanelles only after April. Other environmental parameters, which are as important as the water temperature for oyster culturing, are the amount and quality of food in the region (Andersen and Nass, 1993;Rodriguez et al, 1997;Lodeiros et al, 1998;Laing, 2000;Tomaru et al, 2002;Baghurst and Mitchell, 2002;Mercado-Silva, 2005;Rebelo et al, 2005). Numerous studies display a strong relationship specifically between chlorophyll-a and CI.…”