Lanszki József - Ábrahám Levente (szerk.): Vadon élő vidrák Magyarországon - Natura Somogyiensis 14. (Kaposvár, 2009)

WILD LIVING OTTERS IN HUNGARY (SUMMARY)

Biological data from post mortem analysis of otters in Hungary We examined the characteristics of reproduction parameters, stomach content and inner organ weights of the otter (male, n=67, female n=57, unknown n=3). These otter carcases were collected in Hungary between 1999 and 2006 and most (90.6%) were collected as road casualties. In breeding females (n=28), the mean (±SE) number of placental scars was 2.22±0.17. One female was pregnant with embryos. Suckling was detected in four females, and the number of active teats (2-4) was equivalent to the number of placental scars. Reproduction period, calculated from the age of juveniles, was long (from winter to summer). No seasonal difference was found in the gonado-somatic index values of adult males, and births were estimated to have occurred from winter to summer. The stomach was empty in 31% of the cases, while mean weight of the stomach content was 49 g. The main food eaten by the otters was small-sized, non-commercial fish. In the adult age group, the organ weight index of the kidneys (P<0.01) and adrenal glands (P<0.()5) was greater in females, while in the case of the other organs: heart, liver, spleen, thyroid glands and lungs, no significant difference was found. Morphologic parameters and causes of death in otters in Hungary, as shown by post mortem analysis Morphologic parameters and causes of death of the strictly protected otter was examined in carcasses collected between 1999 and 2006 (male n=67, female n=57, unknown n=3). The mean weight of adult males was 8.68 kg, and that of females was 6.02 kg (PO.0001). The body lengths of males and females were 694 mm and 629 mm (PO.0001), and tail lengths were 430 mm and 392 mm, respectively (PO.0001). Values of the condition index (Kl) of adult males and females were 1.31 and 0.95 (PO.0001). Kl did not change significantly according to season (P>0.05). Occurrence of wounds on food pads and claws (n=19 and 16 cases) were accidental, and there were no relationships between wounds and sex, body weight or condition. The percentage of traffic mortalities was 90.6% of causes of death. In addition, poaching, bite wounds by dogs, presumed poisoning and drowning in fish-trap (totalling 7.9%), and rarely attack by otters and disease (1,6%) also occurred. The condition of road-killed otters were significantly better, in comparison with others (PO.05). Metal levels in tissues of Eurasian otters from Hungary: variation with sex, age, condition and location Liver samples of otters from various parts of Hungary were analyzed for mercury, copper, zinc, lead and cadmium. Only zinc concentration was significantly higher in females. Higher mercury and cadmium concentrations in adults and higher zinc values in immature otters were measured. Accumulation of mercury, copper and zinc in tissues increased with the declining condition of animals. Mercury and copper were detected with higher values in samples from large rivers. Comparison of the feeding habits of Eurasian otters on a fast flowing river and its backwater habitats The diet and feeding habits of otters were studied by spraint analysis over a two year period, on three sections of the Drava River and three backwaters, in south-west Hungary. The primary food was fish (mean: 89.8% and 87.5% for riverine and backwater habitats, respectively); otters living in riverine habitats compared to backwaters consumed more birds (3.9% and 0.7%, respectively), less mammals (0.5% and 0.9%, respectively), less reptiles and amphibians (5.6% and 10.2%, respectively) and less invertebrates (0.1% and 0.6%», respectively). In riverine habitats otters preyed more