Aim To produce a statistical stratification of the European environment, suitable for stratified random sampling of ecological resources, the selection of sites for representative studies across the continent, and to provide strata for modelling exercises and reporting.

Listeria monocytogenes in sewage, sewage sludge and river water was isolated by enrichment at 4°C with subculture and enrichment in thiocyanate, naladixic acid broth and plating on to Tryptose Agar. The results indicated that L. monocytogenes is present in sewage and sewage sludge in considerable numbers and that this organism survives longer than Salmonella spp. on land sprayed with sewage sludge.

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ABSTRACT. Seasonal vanation in harbour seal diet in the south-western North Sea was investigated from faeces collected monthly, over a 2 yr period, from a high-water haulout site in the Wash on the east coast of England. A total of 12444 fish otoliths from 31 species was recovered from 708 faeces; otolith measurements were corrected for partial digestion and used to estimate the proportion, by weight, of each species in the diet. Overall, the diet was dominated by whiting (24 " L ) , sole (15%), drayonct (13''~) and sand goby (11 '16). Other flatfish (dab, flounder, plaice: l'.?%), other gadoids (blb, cod: 11 % ) , bullrout (7 % and sandeels (3 'h) were also consumed. A strong seasonality in diet was apparent which can be summarised as: whiting, bib and bullrout dominated from late autumn through early spnng; sand goby peaked during winter and early spnng; dragonet, sandeels and flatfish (except sole) dominated from late spring to early autumn; and sole peaked In spring. Harbour seal diet composition in general, and seasonal changes in diet in particular, appeared mainly to be llnked to availablllty (in terms of prcy distribution and abundance, feeding or spawning activity and, perhaps, prey si:,~) but this was not always the case. In a few species (whiting, dab and plaice), seasonal changes in consumption appeared to be related to the availability of other species. Differences in harbour seal and grey seal diets In the same area were consistent with the 2 species feeding in different areas, but there was also evldence of a maximum preferred prey size for harbour seals.

Parallel policy developments driven in the USA by the Clean Water Act and in Europe by the Water Framework Directive have focused attention on the need for quantitative information on the fluxes of faecal indicator bacteria in catchment systems. Data are required on point and diffuse source loadings, fate and transport of these non-conservative parameters, on the land surface, within soil systems, in groundwater, streams, impoundments and nearshore waters. This new information is needed by regulators to inform Total Maximum Daily Load estimates in the USA and Programmes of Measures in Europe both designed to prevent impairment of water quality at locations where compliance is assessed against health-based standards for drinking, bathing or shellfish harvesting. In the UK, the majority of catchment-scale activity in this field has been undertaken by physical geographers although microbial flux analysis and modelling has received much less attention from the research and policy communities than, for example, the nutrient parameters. This paper charts the policy drivers now operative and assesses the evidence base to support current policy questions. Finally, gaps and priority research questions are identified.