Post-mortem examination of eurasian otters (Lutra lutra) in Southern Italy. Obtaining relevant data to inform conservation (IX Congresso Italiano di Teriologia)

After a sharp and large decline of otter (Lutra lutra) populations, a general recovery has been noted in recent years in several European countries. This positive trend has occurred also in Italy, although otter distribution is still limited to the southern regions. Increasing numbers of dead otters were reported during the last decade in Italy, likely due to increasing population size. Recording locations of death and performing post-mortem (PM) examination of otters found dead provide valuable data that can contribute to assess the status of populations and to identify threats. However, until recent years the collection and PM examination of dead otters were still inadequate in Italy and a relevant amount of information was lost. In 2009 the RECAL project was started in the National Park of Cilento, Vallo di Diano and Alburni aimed at: 1. collecting mortality data and monitoring health and reproductive status and contaminant body burdens of otter populations; 2. improving the scheme “reporting-recovery-necropsy” of otters in Italy. Later, other protected areas and wildlife rehabilitation centers joined the project and submitted dead otters for necropsy. PM examinations were carried out by a multi-disciplinary team including otter ecologists and animal pathologists, to a standard protocol developed for Lutra lutra. At present 15 otters were examined. Nine otters were collected in the Salerno province, and 6 in the Matera and Potenza provinces. Otters received were sexed and aged based on teeth cementum analysis, body and organs were measured and weighed; tissue and organ samples were taken for genetic, chemical and histological analyses; the nutritional condition and reproductive status were evaluated; parasites were identified and diseases and the cause of death were determined. Most (67%) of otters received were males and 60% was less than 4 years old. The majority of otters died in road traffic accident. One female found dead in June showed 2 placental scars, indication of a recent pregnancy. Three males showed lesions compatible with intraspecific aggressions, that represent a significant cause of death for otters in other countries. In at least three cases the investigation of the scene of death revealed what forced otters to travel out of the water and move over the road, suggesting mitigation measures. Contaminants (PCBs, PAHs, pesticides, dioxins and heavy metals) concentrations in liver or muscle samples of otters revealed relatively high levels of PCBs and Hg and Pb in some otters. However, the sample is still small and results require further confirmation. Nevertheless, for the first time in Italy, contaminant body burdens were measured in otters and tissue/organ samples were stored for future analyses and comparisons. Sample collection is ongoing in order to provide mid-long term data.