Cadmium bioaccumulates after acute exposure but has no effect on locomotion or shelter-seeking behaviour in the invasive green shore crab (Carcinus maenas)

Cadmium (Cd(2+)) is a non-essential metal ubiquitous in the environment due to industrial processes. However, little is known regarding the ability of Cd(2+) to impact the behaviour of aquatic animals in receiving environments. Green shore crabs (Carcinus maenas) were exposed to waterborne Cd(2+) [control (no Cd(2+)), low (0.30 μmol/L), medium (3.3 μmol/L) and high (63 μmol/L)], for 24 h, then, crabs were placed in an open field and shelter test to determine potential changes in locomotion and preference for shelter. Tissues (gill, haemolymph, stomatogastric ganglion) were taken for bioaccumulation analysis of Cd(2+) and ion content. Behavioural testing was recorded with a motion-tracking software system and showed no impact of Cd(2+) on any variable in either of the tests used. All three tissues accumulated Cd(2+) in a concentration-dependent manner. Crabs exposed to low Cd(2+) showed a small but significant decrease in haemolymph Ca(2+), however, this effect was not present at higher Cd(2+) exposures. Overall, the results indicate that short-term Cd(2+) exposure, and the resulting Cd(2+) accumulation, had no effect on locomotor and anxiety-related behaviour of green shore crabs.