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New Zealand Journal of Marine and Freshwater Research abstractsBENTHIC COMMUNITY STRUCTURE IN LYTTELTON HARBOURG. S. KnightZoology Department, University of Canterbury, Christchurch, New ZealandAbstract Benthic communities in the upper regions of Lyttelton Harbour, Christchurch, New Zealand (43° 38' S, 172° 41' E), are defined by correlating the species present with the sediment types and their organic carbon content. Lyttelton Harbour has been a major port since the 1860s, and is extensively dredged. It is in the crater of an ancient volcano, the walls of which are covered with loess, which is the principal source of bottom, sediments. The sampling characteristics of an orange peel grab, a box. dredge, and an epibenthic sledge, determined in comparable working conditions, proved sufficiently different to justify the use of all three in taking the 71 benthic fauna samples for this study. Sediment grades were determined from dredge samples by sieving and pipetting, and 40 of them were classified into coarse sand ( - 2.0 to +0.250), fine sand (0.25 to 3.0 <t>), muddy sand (3.0 to 4.75 <j>), and mud (>4.75 <p). Determination of sediment organic carbon was by a modified wet combustion method. Data were analysed by Pager's recurrent species analysis and by a discriminant function computer program derived from the IBM set of scientific subroutines and run on. the University of Canterbury's IBM 360/44 computer. Three benthic communities were identified. The first, associated with muddy substrates, was called the Hemiplax hirtipes - Virgularia gracillima community. The second, the Zeacolpus vittatus-Pectinaria australis community existed on sandy substrates. Between these two communities a continuum of about 12 species was postulated. A Chione stutchburyi community was also present in restricted sandy areas. Also, an association of opportunist species was found to occur sporadically with little regard to the substrate. In comparison with other New Zealand inshore benthic faunas, the Hemiplax hirtipes-Virgularia gracillima community of Lyttelton Harbour closely parallels the Maoricolpus roseus roseus community in both. Otago and Auckland Harbours; the Chione community parallels a Chione association in Otago Harbour, but characterised communities in the Marlborough Sounds were very different from (hose found in Lyttelton Harbour.
N.Z. Journal of Marine and Freshwater Research 8 (2): 291-306.
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