Loggerhead Turtle (Caretta caretta) Nests at High Latitudes in Italy: A Call for Vigilance in the Western Mediterranean

Four new loggerhead turtle nest sites were discovered in July 2006 and July 2008 on Italian beaches in the regions of Puglia, Sardinia, and Campania. Previously, no nesting has been reported on those beaches. All nests were protected by a fence and a surveillance team and nest temperatures were monitored throughout the incubation period. The 2006 nests experienced low incubation temperatures, which lead to long incubation conditions and two of the nests had to be rescued and transferred into an artificial incubator. Both nests failed to hatch after >100 days of incubation, but for different reasons: in Puglia the entire clutch (47 eggs) contained only eggs with yolk, and hence, if the eggs were fertilized then embryonic death occurred early and could not be determined; in Sardinia all but two of the embryos (clutch size 92) developed until the pre-pipping stage but did not hatch, probably due to a lack of gas-exchange caused by a disrupted chorioallantoic membrane. The Campania nest in 2006 (93 eggs) hatched with a low success (33.3%) after a prolonged incubation period (72 days) and also contained many undeveloped eggs (60%). In 2008 instead, another nest in Campania incubated at very high temperatures (mean 33.2°C) and hatched after 46 days with a 92.2% success (clutch size was 115 eggs). The four nests reported here occurred contemporaneously with other nine unusual loggerhead turtle nesting events in the Western Mediterranean over the last decade. The possibility that turtles with relaxed philopatry explore new nest sites is discussed, but since no historical data on nesting in this region are available, organised monitoring of potential new nest sites is required to evaluate this behaviour.