Ecology of Diloma nov Aezelandiae at Portobello,New Zealand |
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| Authors: | Sheila J Logan |
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| Institution: | 1. Portobello Marine Laboratory , University of Otago , P.O. Box 8, Portobello, New Zealand;2. Marine Science Laboratories , Menai Bridge, Anglesey, Gwynedd, LL59 5EH, Wales |
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| Abstract: | Some aspects of the biology of Diloma (Fractarmilla) novaezelandiae (Anton) (= Zediloma subrostrata), a soft‐shore trochid gastropod, were investigated in Latham Bay, Portobello, South Island, New Zealand (45° 50’ 25” S, 170° 38’ 30” E). The distribution of D. novaezelandiae during September 1973 to June 1974 was recorded along three transects; pebble distribution, macroalgal cover, grain‐size distribution and organic carbon content in the sediment, range of water salinity, and length of time of exposure to air were also recorded along the transects. The greatest population density of D. novaezelandiae occurred between 0.8 m and 1.4 m above Chart Datum. The trochid was found to prefer a hard substratum to a soft substratum, and there was a positive correlation of organic content of the sediment with density of D. novaezelandiae. As the population density decreased towards low water the individual shell size increased. Size: weight relationships were calculated and the results showed that dry flesh weight and dry shell weight were both proportional to the cube of the shell diameter. |
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| Keywords: | Tarawera River odour colour appearance panel tests threshold detection limit Kraft effluent conspicuous objectionable |
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