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Submitted on 2016, 10th October; revised on 2016, 31th October; accepted on 2016, 5th December
Editor: Marco Sannolo
Abstract. Individual marking has become essential for studying population dynamics and ecological requirements. However, marking small-bodied species such as amphibians is becoming a challenge in the last decades. Amphibian surveys may require to mark manually individuals, using toe clipping, polymers and pigments, or passive integrated transponders (PIT-tags). Even if ethics committees have recently recommend avoiding toe clipping in amphibians, the use of PIT-tags led to controversial results because low tag retention reported in some studies. Here, we describe a protocol of potentially life-long PIT-tag marking in a protected species, the marbled newt Triturus marmoratus. In addition, we also detailed a second procedure of surgery for the implantation of transmitters needed in radio-tracking surveys. During both procedures, we found that the newt phase (either aquatic or terrestrial) strongly affected the anesthesia duration. Indeed, newts in aquatic phase were more quickly anesthetized than newts under terrestrial phase. We then recommend to pay attention of this physiological particularity when performing this kind of procedure. Improving our knowledge on ecological requirements and population dynamics of this species is crucial for management and conservation plans, and could be extended to other large newts.
Keywords. Anesthesia, transmitter implantation, Triturus marmoratus, PIT-tagging, newts, skin permeability
INTRODUCTION
Individual marking has become an essential method for studying ecological requirements, population dynamics or colonization rates (McCarthy and Parris, 2004). Two different methods are widely used for monitoring species: capture-marking-recapture (CMR) and radiotracking surveys. The CMR method is a powerful method for estimating population parameters such as abundance (Thompson et al., 1998), survival, recruitment, and population growth rate (Lettink and Armstrong, 2003). For CMR studies, marking of individuals can be performed using several techniques (Ferner, 2007), such as color pattern (non-invasive method often used in some salamanders and anurans species; see Delarze et al., 2000; Lama et al., 2011; Ribeiro and Rebelo, 2011; Waye, 2013; Elgue et al., 2014), the use of passive integrated transponders (PIT-tags; Jehle and Hödl, 1998), toe clipping, or the use of polymers and pigments (Brannelly et al., 2014). Toe clipping is a technique commonly applied to amphibians, but may be useful for a limited time due to their regeneration ability (Andreone, 1986)....