Estuarine Flora and Fauna of Smiths Lake, New South Wales K. I. M. ROBINSON, P.J. GIBBS, J. B. BARCLAY and J. L. MAY (Communicated by L. W. C. FILEWOOD) Robinson, K. I. M., Gibbs, P. J., Barclay, J. B., & May, J. L. Estuarine flora and fauna of Smiths Lake, New South Wales. Proc. Linn. Soc. N.S.W. 107 (1), (1982) 1983: 19-34. Data on the distribution of benthic invertebrates and aquatic macrophytes in Smiths Lake were collected during the summer of 1979/1980. These data are discussed in relation to information on past distributions and hydrological conditions. Qualitative data on the lagoon's fish community are presented. The distribution of aquatic macrophytes has varied over recent years, probably as a result of salinity changes associated with opening or closure of the lagoon entrance. Under the present salinity regime, seagrass distribution is probably limited by the degree of light penetration and wave action. Benthic invertebrate communities are related to substrate type and vegetation. Seagrass and sand habitats support more diverse and abundant communities than mud sediments. Both the benthic and fish communities recorded in Smiths Lake are typically estuarine, and resemble communities in other lagoons along the N.S.W. coast. The absence of several benthic and fish species commonly associated with N.S.W. estuaries is attributed to intermittent closure of the lagoon to oceanic influence. K. I. M. Robinson and J. L. May, School of Zoology, University of New South Wales, Kensington, Australia 2033, P.J. Gibbs, N.S. W. State Fisheries, Sydney, Australia 2000, and J. B. Barclay, formerly School of Botany, University of New South Wales, now The Scots College, Victoria Road, Bellevue Hill, Australia 2030; manuscript received 21 July 1982, accepted for publication in revisedform 9 February 1983. Introduction In recent years there has been an accumulation of ecological data on the aquatic flora and fauna of New South Wales coastal lagoons. Although some data have been published (Maclntyre, 1959; Thomson, 1959; Wood, 1959; Higginson, 1965, 1970; Weate and Hutchings, 1977; Hutchings et ai, 1978; Povvis and Robinson, 1980; Harris el ai, 1980; Collett et ai, 1981; Atkinson et ai, 1981), much still remains in the form of theses and student reports. This paper combines unpublished data on Smiths Lake with surveys of the macrobenthic fauna and flora of that lagoon undertaken in the summer of 1979/1980. Study Area Smiths Lake is a marine-dominated coastal lagoon (32°24'S, 152°22'E), 130 km north of Newcastle, N.S.W. The lake is 10 km^ in area with its catchment extending just beyond its perimeter (Bell and Edwards, 1980). Freshwater input is provided by swamps on the southern shore, and during rainy periods by several small creeks (Fig. 1). The median annual rainfall in nearby Bulahdelah is 1251 mm, the wettest months being in late summer and early autumn (Atkinson etai, 1981). The lagoon is divided into two main regions by a sandbar at Simons Point. The seaward end comprises a wide shallow lagoon (1-2 m deep) with deeper holes (3-4 m) at its northern and southwestern extremities. The western region of the lagoon is twice the area of the seaward region with an average depth of 3-4 m and a maximum depth of 5 m off Big Island. Proc. Linn. Soc. N.S.W. 107 (1), (1982) 1983
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