Mortality of Otters (Lutra lutra) in Shetland

Abstract

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Semi Aquatic Top-Predators as Sentinels of Diversity and Dynamics of Pesticides in Aquatic Food Webs: The Case of Eurasian Otter (Lutra lutra) and Osprey (Pandion haliaetus) in Loire River Catchment, France

“…59%) were adults, 11 were subadults, 9 were juvenile and only one was an old individual. This mortality picture is different from those observed in previous studies, where most of discovered otters were juvenile or subadults, with an linear increasing in probability of death with age, considering the rareness of very old individuals in nature (Kruuk and Conroy, 1991;Kruuk, 2006;Lemarchand, 2007). With the exception of only two individuals found in the wild during the study, all otters died after a vehicular collision.…”

“…Age was defined as "juvenile" (milk teeth, little size and weight), "subadult" (adult size and weight, teeth without wear and tartar) and "adult" or "old" (worn teeth with tartar). Body condition index K was determined according to Kruuk and Conroy (1991). Osprey sex and weight were determined; animals were measured (wing, body, foot and tail lengths).…”

Reproduction in otters in Belarus and north-western Russia

“…The results of studies by other authors (Fairley 1967, Stubbe 1969, Vshivtsev 1972, Heptner and Naumov 1974, Danilov and Tumanov 1976, Wayre 1979, Jenkins 1980, Kruuk et al 1987, Heggberget 1988 further reinforce the suggestion that there is no strict reproductive conformity in otter populations. On inland rivers that are seasonally covered with ice, the more severe the winter (e.g.…”

“…Reproduction in the wild is one of the least understood aspects of otter Lutra lutra (Linnaeus, 1758) biology (Erlinge 1967, Vshivtsev 1972, Heptner and Naumov 1974, Danilov and Tumanov 1976, Stubbe 1977, Wayre 1979, Jenkins 1980, Jenkins and Harper 1982, Trowbridge 1983, Mason and Macdonald 1986, Kruuk et al 1987, Sidorovich 1991. Although the reproduction of captive otters has been studied in some detail, many aspects of reproduction in the wild are still poorly known, including the timing of the cycles of female oestrus and male spermatogenesis, the timing of mating and its relation to age, and duration of pregnancy and anoestrus.…”

Otter Surveys of the North West Scottish Islands

“…Studies of the diet of coastal otters have been undertaken in Shetland [22,23], in Norway [24], on Loch Broom [25], the Isle of Mull [26], and on the Isle of Eigg [27]. These all show the importance of the same five key prey species (viviparous blenny, five-bearded rockling, butterfish, sea scorpion, and saithe) to the diet of the otter population.…”