MEPS 393:55-67 (2009)  -  DOI: https://doi.org/10.3354/meps08239

ABSTRACT: We compared behavioural (burrowing speed), biochemical (acetylcholinesterase [AChE] inhibition, activities of digestive enzymes) and physiological (feeding and egestion rates, condition) responses in Nereis diversicolor originating from a multipolluted estuary (Loire estuary) and a relatively clean site (Bay of Bourgneuf) on 3 occasions during spring 2008. Significant inhibition of AChE and digestive enzymes (amylase and carboxymethylcellulase) activities were recorded in individuals from the Loire estuary compared to the reference site. At the individual level no significant intersite differences in burrowing speed were observed when ragworms were exposed to their sediment of origin. No link between AChE activity and burrowing behaviour was found in worms from either site. Cross-tests revealed that behavioural disturbances in locomotion were not due to neurological dysfunction but to avoidance of contaminated sediments. Feeding and egestion rates were depressed significantly in worms originating from the Loire estuary compared to the reference site. These behavioural impairments were accompanied by changes in digestive enzyme activities, which can explain the generally poorer condition of ragworms from the Loire estuary. Temporal changes in responses reported in the present study underline the importance of the fluctuation of environmental factors and thus the need for more than one sampling series to assess the health status of a given site. Disturbances at the different levels of biological organisation are likely explained by environmental contamination either chronic in the Loire estuary or the result of a small oil spill.

KEY WORDS: Nereis diversicolor · Estuarine sediment · Biomonitoring · Behavioural impairments · Biochemical biomarkers