Natural factors to consider when using acetylcholinesterase activity as neurotoxicity biomarker in Young-Of-Year striped bass (Morone saxatilis)

Abstract

Acetylcholinesterase (AChE) activity is one of the most common biomarkers of neurotoxicity used in aquatic organisms. However, compared to its extensive use as biomarker, the effects of natural factors on AChE activity remain unclear especially in estuarine fishes. The aim of this study was to evaluate the effects of natural factors on AChE activity of striped bass (Morone saxatilis) juveniles. Brain AChE activity was measured in YOY (Young-Of-Year) individuals collected monthly from August 2007 to January 2008 at 12 different sites in the San Francisco Estuary system. The spatio-temporal variability of AChE was analyzed relative to water temperature and salinity as well as fish size. AChE activity was highly positively correlated with water temperature and to a lesser extent negatively with fish size while no relationship was detected with salinity. Taking into account these natural factors when using AChE as a biomarker will help to determine and understand the effects of neurotoxic contaminants on fish in estuarine systems.

Fig. 1

Location of the 12 sampling sites for Young-Of-Year juveniles striped bass (Morone saxatilis) in the San Francisco Estuary (Northern California, USA)

Fig. 2

Monthly mean (±SE) AChE activity (nmol min⁻¹ mg prot⁻¹) of Young-Of-Year juveniles striped bass (Morone saxatilis) collected from August 2007 to January 2008 in 12 sampling sites from the San Francisco Estuary (Northern California, USA). The three different regions sampled in the Estuary (SR Sacramento River, SJR San Joaquin River, SB Suisun Bay) are represented

Fig. 3

Relationship between log AChE activity and water temperature in Young-Of-Year striped bass (Morone saxatilis) collected monthly from August 2007 to January 2008 in the San Francisco Estuary (Northern California, USA)

Fig. 4

Relationship between log AChE activity and fish size (fork length) in Young-Of-Year striped bass (Morone saxatilis) collected monthly from August 2007 to January 2008 in the San Francisco Estuary (Northern California, USA)