Problems, progress and prospects in marking sympatric newt species with passive integrated transponders

In this essay I evaluate the use of passive integrated transponders (PIT-tags) for individual recognition in five sympatric populations of the large-bodied newts Triturus cristatus and T. marmoratus . Advice is given on how (not) to insert PIT-tags. With pattern mapping applied in parallel, tag loss was shown to be absent or rare from live animals. Tags on the loose (i.e., without its carrier that presumably died and decomposed) were located in two ponds when these fell dry. Results suggest that aquatic T. marmoratus and juvenile T. cristatus experience higher natural mortality than adult T. cristatus . The long-term research on both species in the département Mayenne, France may be paralleled by research on sympatric Lissotriton helveticus and L. vulgaris , provided that miniature PIT-tags can justifiably be applied to these small-bodied species.