The Otter Lutra lutra in Essex 1996-2002
Recent history of Otters in Essex
In 1957 the first nation-wide account of Otter distribution in Britain was published by the Universi-
ties Federation for Animal Welfare (Stephens 1957) and was based largely on hunt data and on
anecdotal evidence. It included a small number of field observations but none of these was from
Essex. Stephens concluded that, in the Essex River Board Area, Otters were numerous with animals
even living close to London. The species was reported as plentiful on the Rivers Stour and Colne
and they had been seen on the Chelmer within Chelmsford. In the Lea catchment Stephens reported
a fairly small population but animals had been seen at Enfield and Waltham Abbey.
In regions adjacent to Essex, Stephens judged the species to be very numerous in the East Suffolk
and Norfolk River Board Areas while the Great Ouse RBA was well stocked apart from some deple-
tion in Bedfordshire, thought to be due in part to over-hunting. To the south of Essex. Kent was said
to have a small population. Thus, in the mid-1950s, the Otter seemed to be widespread throughout
south-east England and, in much of the region, was considered to be numerous. During the 1960s
and 1970s, however, hunt and survey reports suggested that the situation had changed. While no
survey was carried out in Essex at this time, reports of field studies from neighbouring Suffolk and
Norfolk indicated a marked decline (West 1975; Macdonald & Mason 1976). Conservationists fi-
nally began to show concern about Otter status and a series of national field surveys was initiated.
The surveys involved systematic and standardized searches of waterways for signs of Otters; the
animals themselves are rarely seen. The methodology has been followed in the present work and
will be described later. The field surveys of England were designed to cover alternate 50 km squares
rather than the entire country because of the time involved. Despite this, in the first survey of
England, carried out in 1977-79 (Lenton et al. 1980), the square which would have included a large
part of Essex was omitted due to lack of time. The survey sites closest to Essex were the Suffolk
rivers Gipping, Deben and Alde and the upper Cam but none of these was found to support Otters
(Lenton et al. 1980).
The second survey of England was carried out in 1984-86 (Strachan et al. 1990) and Essex rivers
were included in the study. In the autumn of 1986 sites on the Rivers Stour (middle and upper
reaches), Colne, Blackwater and Chelmer were searched but no signs of Otters were found. The
upper River Roding and a single site surveyed on the Stort also proved negative as did the upper
reaches of the Cam. However an Otter was killed by traffic on the upper Cam in 1985 and spraints
(faeces) were found at several sites in 1990-91 (Mason & Macdonald 1993a).
The survey was repeated for a third time in England between 1991 and 1994 (Strachan & Jefferies
1996). On the Stour two of 22 sites produced signs of Otters and the authors suggested that there
might have been some movement from Suffolk where captive-bred Otters had been released into the
wild. On the Colne one site out of 20 was positive and the authors considered this to represent a
transient animal although there had been odd reports of Otters on the Colne since 1992. Fifty sites
were surveyed on the Blackwater/Chelmer but all were negative. On the upper reaches of the Cam
ten of 23 sites were positive. None often sites on the Stort and Roding produced signs of the species
although captive-bred Otters were released on the Stort in 1991.
A field survey of neighbouring Suffolk carried out in 1996-1997 found 22% of sites positive, though
this did not include the Essex and Norfolk boundary rivers of the Stour or the Waveney (Bullion
1997). All river catchments had some signs of Otters but they appeared to be absent from mid-
Suffolk and there were few records from the west of the county. It seemed that the population
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Essex Naturalist (New Series) 20 (2003)