Population Structure and Morphometrics of the European Pond Turtle ( Emys orbicularis (Linnaeus, 1758)) at Lake Tonga, Algeria

A total of 100 specimens of Emys orbicularis were collected and marked at Lake Tonga (northeastern of Algeria) during 3 consecutive years (2013, 2014, 2015). Most of the turtles inhabit a canal where they remain throughout the whole activity season (March to October) and where they overwinter as well. Carapace Length (CL) and body weight (BW) were measured for each individual of E. orbicularis . The size of the turtles of our population was more similar to those of northern European populations than to the Mediterranean populations; females were significantly larger than the Spanish and Italian populations. The population size was calculated as 108.50 and the density as 8.63 turtles/ha. From 6.52 to 12.77% of the population were juveniles. The adult sex ratio was slightly in favor of males (males:females = 1.12, P < 0.005).