Factors affecting the predation of otter (Lutra lutra) on European pond turtle (Emys orbicularis)

Abstract

In this case study, the ecological background of an unusual hunting behaviour was investigated, when otters Lutra lutra preyed upon European pond turtles Emys orbicularis in a Hungarian fish pond system during an 18-month period. Predation on turtle was found only during cold periods (established by spraint analysis and also by the collection of 182 turtle carcasses in 2003). The relationship was not close between fish availability and turtle consumption (r P =À0.325, P= 0.19). The crude protein content of the turtle head and leg was higher than that of fish, frog and turtle body, whereas the energy content of the samples was similar. The mean body weight of the killed turtles (460 g) fell within the range of the optimal prey size of the otter. Turtles were used as cache foods by otters during extreme environmental conditions (as in the long winter), but occurred only rarely as buffer foods during moderate winter. In fish ponds, the conservation of the coexistent otter and turtle depends on pond management. The maintenance of a higher fish availability in ponds during winter makes it possible to avoid the need to acquire a proper hunting technique on turtle, indicated by the scarcity of primary fish food.

Post‐catastrophe patterns of abundance and survival reveal no evidence of population recovery in a long‐lived animal

“…Another instance of mass mortality of turtles ( Emys orbicularis ) resulting from otter ( Lutra lutra ) predation was attributed to reduced availability of prey fish (Lanszki et al. ). Human‐subsidized native predators have also been implicated in acute mortality events that may affect chelonians (Fincham and Lambrechts ).…”

Genetic diversity of the European pond turtle (Emys orbicularis) in the South-West region of Hungary – first results

“…Samples of 155 turtles from 4 populations were collected from muscle tissue inserted on the plastron of 36 turtle bodies (predated by otter, for details see Lanszki et al, 2006) from Dávodpuszta fish pond system (Pop D, n = 36) and from blood of live animals from the same population (Pop D, n = 20), Mike fish pond system (Pop M, n = 67), Rigóc fish pond system (Pop R, n = 22) and Gyűrűs fish pond system (Pop Gy, n = 10). Approximately 100 μl of blood were sampled from the tail vein of each specimen.…”

“…In Hungary, both natural and anthropogenic factors such as habitat destruction, fragmentation and isolation (Puky et al, 2004) or predation (Lanszki et al, 2006) endanger E. orbicularis leading to local extinctions. However, data are generally available only for the presence or absence of the species (Farkas, 2000) and population size estimation has occurred only occasionally at a regional level (Balázs and Györffy, 2006).…”

Severe mortality of a population of threatened Agassiz’s desert tortoises: the American badger as a potential predator

“…Although little is known about badger ecology in the deserts of the American Southwest, studies of badgers in other parts of their range and other Mustelid species suggest that predation on desert tortoises should not be surprising. Multiple species of otters are known to consume turtles (Brooks et al 1991, Lanszki et al 2006, Ligon & Reasor 2007, Platt & Rainwater 2011, and European badgers Meles meles have depredated Hermann's tortoises Testudo hermanni in reintroduction projects in both Spain and France (Bertolero et al 2007, Caron et al 2013.…”