The Herpetological Journal

pp.163-168

Authors: Ulrich Sinsch

Abstract: The metamorphic success oflarval cohorts and the post-metamorphic growth of toad lets were studied in a large metapopulation of natterjack toads (Bufo calamita) in the Rhinelands, Germany. Larval density was greater in the cohorts studied in 1 99 1 than in those studied in 1992 and metamorphs were smaller in 1991 than in 1992, indicating short-term carry-over effects. Metamorphic success and average snout-vent length were larger in the cohort originating from the early breeding period than in those from the main breeding period in the previous year. The further terrestrial development of three metamorph cohorts was followed until adulthood using commercial fish marks (microtags) for batch-tagging. Microtags are small pieces of wire which are injected below the skin. Their presence is determined using a hand-wand metal detector. The short- and long-term effects of this new marking technique on growth and survival of almost 2000 free-ranging toadlets are reported. The results obtained indicate that microtagging is a useful and harmless technique for the study of metamorphs.