Sticky-Shark: glueing multisensory tags to sharks to monitor behaviour around the magnetic field from offshore power cables

Hermans, A.; Derksen, H.N.S.; Winter, Hendrik V.


Behavioural research is needed to implement and optimize conservation efforts and ensure adequate mitigation for anthropogenic influences. Currently the standard in in-situ behavioural research of elasmobranchs is through placing an invasive tag under the skin, in muscle tissue or cartilage of the fish. Current non-invasive methods include harnesses and suction cups. Due to the size of multi-sensor tags and stress associated with placement, both methods are not suitable for smaller elasmobranchs and/or for short duration. In a controlled ex-situ setting behavioural research is often carried out by analysing video data. Video data alone is however not suitable to detect all parameters that might be of interest, as for example in research on the behavioural response to a gradient electromagnetic fields. Attaching tags using adhesives is, to our knowledge, a relatively understudied methodology in rough skinned fish and so far only applied in-situ to other taxa as for example marine mammals with furs {seals) or fish with smooth skin or scales.
Adhesive tagging could be a promising technique for short term non-invasive behavioural research of small benthic elasmobranchs. This study investigated different adhesive methods suitable for the marine environment and the application on small benthic elasmobranchs for behavioural research. An inventory was made of the available marine adhesives for both short- and long-term application. The adhesives were tested on three deceased ray {Raya c/avafa) and shark {Scyliorhinus canicula) individuals. The adhesives that performed to specifications were tested on live individuals in a controlled environment. The results were then applied in short term behavioural research in a laboratory setting focusing on benthic elasmobranch behavioural response to anthropogenic magnetic fields. This proof of concept will show if using adhesives of multiparameter sensors is a suitable method to monitor behaviour of small benthic elasmobranchs in relation to environmental stressors as magnetic fields. If successful this research will further the field of non-invasive tagging, reducing handling and placement stress and broadening the parameters to be monitored ex-situ.