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SITES
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Greatham, Teesside, United Kingdom Wildlife in Adjacent Areas of the Tees Estuary Invertebrates of the Teesmouth Mudflats Nematodes are a major component of the benthic meiofauna in Seaton Channel with over 170 species recorded in since the surveys began. Historically, a few tolerant nematode species have dominated the communities present in the Channel sediments. The population densities of these species however, have declined as environmental conditions have improved over the years and species-richness has increased with the appearance of more sensitive estuarine organisms. The macro-faunal surveys of the Seaton Channel have identified more than 50 species. The most commonly observed group being oligochaete worms. These, as with the dominant, resistant nematode species, are non-selective deposit feeders and appear to flourish in the comparatively poorly oxygenated sediments that are usually associated with decaying organic materials. The most abundant invertebrates on Seal Sands are Oligochaetae worms and reach densities of 64,000 individuals per m2. Although macro invertebrate fauna biodiversity has increased the Tessmouth mudflats dominated by the six species listed in Table 12.
As shown in Table
13 the site has been designated on account
of its national and in some cases international importance for
waterbirds. The birds of Teesmouth have been the subjects of intensive research for many years and the results of this work are well documented. Systematic wildfowl counts have been carried out under the national census programme since the late 1940s and expanded these counts to include wading birds in the 1970s when the BTO launched its “Birds of Estuary Enquiry”. These monthly counts still continue as the Wetland Bird Survey (WeBS) programme. Tioxide and other companies operating around the estuary co-operate with this important monitoring programme by allowing access to their properties. Whilst the main conservation value of the Tees Estuary rests with the large populations of migrant waterbirds, the site also attracts rare, and even very rare birds, with often surprising frequency. In October 1996 only the second Great Knot (Calidris tenuirostris) ever to be recorded in Britain was seen on the Tioxide site. This is a vagrant that breeds in northern Asia and winters in the Far East and Australia, remained in the estuary for several weeks and was seen by over 1000 birders (Ward 1996). On 29 October 1999 another extremely rare wading bird, a Short-billed Dowitcher (Limnodromus griseus), from North America visited the marshes around the Tioxide site. This was the same bird that had been recorded in Scotland a few days previously and was the first occurrence of this species in Britain (Beck 1999). These in turn are of enormous interest to recreational birders, with enthusiasts travelling from all over Europe to see a particular rare species. Tioxide is always keen to co-operate and allow as many people as possible to look at these rare birds. Seals of the Tees Estuary
Harbour Seal These animals had been known and exploited in the Tees Estuary for hundreds of years and seal meat from the Tees was eaten in the monastery of Durham in the 16th century. In fact “seals, purposes (sic), sturgeons and other like fish” caught in the Tees were the property of the Bishop of Durham (Howes 1985). Until about the 1830s the Harbour Seal population of the estuary was evidently quite substantial with an estimated thousand animals present. By the late 1860’s, however, numbers had fallen to 20-30 individuals and breeding no longer took place (Howes 1985). At one period in 1862 it was reported that only three individuals remained (Lofthouse 1899-1900).
From the late 1860s few seals were reported from the Tees, and none
was reported in the estuary during the extensive government sponsored
River Tees survey (Alexander 1932). In the late 1950s and early 1960s
another species, the Grey Seal, began to appear more or less regularly
in the estuary and Tees Bay and Harbour Seal was again recorded, but
were still “rather scarce” (Howes 1985). Corbet (1971) reported
that Harbour Seal had bred again in the estuary between 1960-1970, but
details are lacking and the record must be regarded as doubtful. By
the early 1980s there were counts of up to 20 animals (R. T. McAndrew
pers. comm.) but no confirmed record of breeding although a young animal
was seen in Greatham Creek in 1984.
In 1988 the Tees Seal Research programme was launched. Originally sponsored by the Tees Development Corporation (TDC) the programme is now supported by local industry including Tioxide. Studies over the past 13 years have shown that the Harbour Seal population has steadily increased to at least 71 animals in 2001 and the Grey Seal population to 29 (Figure 10). The national significance of Teesmouth’s seal population is shown in Table 14. The first confirmed breeding of Harbour Seal at Teesmouth since the 19th century was in 1989. A further two pups were born up to 1993 but all died within 1-5 days of birth (Turner 2001). The first viable pup was recorded in 1994. Table 15 summarises the breeding of Harbour Seals at Teesmouth since systematic monitoring started in 1988.
Grey Seal |
Birds
of the Tees Estuary
A
number of factors have been cited for the animal’s demise: (i)
increased shipping through the estuary caused increased disturbance,
(ii) river dredging removed the large sandbanks that the animals needed
for hauling-out and pupping, (iii) increased industrialisation of the
estuary lead to increased disturbance and pollution, (iv) salmon fishermen
blamed seals for lower catches and tried to eliminate them, and (v)
animals were shot for sport.
