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M A R I N E F A U N A OFF T H E C O A S T OF EAST ANGLIA J. R. ELLIS AND S. I. ROGERS The marine fauna of East Anglia has been relatively well documentcd over thc last Century, and faunal lists exist for many groups (Collings, 1933; Anon, 1934, 1937, 1938; Hamond, 1971; Hughes & Quinn, 1983). The marine ecology of several estuarine and inshore sites has also been studied (Mistakidis, 1951, 1957; Hamond, 1963; Millner et al„ 1977; George et al„ 1995), although the sub-tidal fauna has reeeived little attention (Covey, 1998). Hamond (1969) reported on the sublidal fauna off thc north coast of Norfolk and some studies of the North Sea have included a few stations off thc Suffolk coast (e.g. Davis, 1925; Dyer et al„ 1983). This lack of suitablc information is despite the fact that the coastal zone of Suffolk is used extcnsively for thc extraction of sand and gravel (Rogers, 1997), and supports locally important fisheries for demersal species, including flatfish, edible crab, Cancer pagurus, brown shrimp, Crangon crangon, and other organisms on the sea floor (Pawson & Robson, 1998a,b) (see Plate 3 & Cover). A Community is broadly defined as a group of organisms living in a defincd habitat. In the present study we use the term assemblage in prefercnce to Community as marine habitats are often patchy, a trawl of 30 minutes my pass over several habitat types and the catches themselves are affected by the gear used (Basford et al„ 1990). The aim of the current study was to describc and quantify the invertebrate and fish assemblages present off the coast of East Anglia. The Centre for Environment, Fisheries and Aquaculture Science (CEFAS) undertakes regulär fish surveys in order to provide abundancc indices of commercial fish stocks. Such surveys will also catch a ränge of invertebrates and, during 1998, this invertebrate by-catch has been quantified and the data for 20 stations along the coast of East Anglia recorded. Sampling Methods Data were collected on R.V. Corystes during a research cruise in August 1998 and a total of 20 stations (A-T, Fig. 1) off the coast of East Anglia were sampled. Station details are given in Table 1. All catches were made using a 4-m beam trawl, with 40 mm mesh, as described by Kaiser and Spencer (1994) and tows were of 30 minutes duration, resulting in an approximate sampling area of 15,000 m 2 . All fish were identified, counted and weighed and the total weight of the by-catch recorded. The invertebrate by-catch was completely sorted at nine stations, and randomly sub-sampled on thc remaining 11, duc to either a large catch or time constraints. Invertebrates were identified to the lowest taxon possible, and the biomass (wet weight) of all macro-epibcnthic species recorded. Macro-epibenthic invertebrates being thosc species which are large enough to be sampled by the gear and occur on thc sca floor and not within sediments. Non-colonial species were also enumerated. Catch data for both fish and invertebrates were subsequently raised to catches per hour. These data were used in the analysis of Community stmeture, which was performed using the PRIMER analytical package (Clarke & Warwick, 1994). © British Crown Copyright reserved
Trans. Suffolk Nat. Soc. 35
(1999)