ALBERT

Description: Attaching objects to bivalve shells is an increasing requirement for conservation projects, mark-recapture studies and behavioural analysis. We investigated the suitability of eight different glues to attach a metallic object to a mussel shell and confirmed the utility of the best glue in a filtration behaviour experiment using Anodonta anatina . We used removal forces up to 1.35 kg cm –2 7 d after submerging in water and found an epoxy resin and a cyanoacrylate adhesive to perform best. Not all epoxy resins or cyanoacrylate adhesives performed equally. The best performing cyanoacrylate adhesive was used to glue magnets and rubber-coated Hall sensors to 26 mussels for a filtration-behaviour experiment. Nine months after attachment, all magnets and rubber-coated Hall sensors remained attached and withstood 1.35 kg cm –2 . The epoxy resin was not chosen, because it contained Bisphenol A and required a more complex application procedure. Mussel filtration behaviours were monitored for 96 h in the presence of algae. The results showed that the presence of algae stimulated the filtration rate of A. anatina in the first 24 h. Over the experimental period, the mussels' mean filtration duration was 20 ± 12 h, while the resting duration was 16 ± 7 h. We identified a pronounced circadian rhythm, despite the long filtration duration and variation in behaviour patterns. However, at any one time some mussels were observed to be filtering. The mussels were more likely to open their shells and become active at around 20:00. Thus the majority of mussels were active at midnight and a minority at noon. We interpret the strong response to increased algal concentration and the pronounced circadian rhythm as evidence that neither the glue nor the attached sensors disturbed the mussels even in a short-term experiment. Hence, we recommend the selected cyanoacrylate adhesive for use in tagging projects and behavioural studies of freshwater mussels.