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Avrainvillea amadelpha (Mont.) A.Gepp & E.Gepp |
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Description: Plants single or in clusters, with 1-4 terminal blades on slender stipes, and these attached to a compact basal holdfast. Stipes are branched once or twice, 2-5 mm diam and 4-15 mm long, flattened in cross-section. Blades are felt-like, asymmetrical, of green to olive color, to 4 cm wide and 3 cm high, composed of non-septate filaments in several layers, 12-25 mm diam., intertwined. Introduction and Origin: First recorded in 1981, in Koko Head Point, and Kahe Point . Possibly by boat (Brostoff). Hawaiian Distribution: Southern shores of Oahu. Kahe point to Maunalua Bay. Was not seen in Nanakuli or Makapu`u. Habitat: Subtidal, shallow to 13 m deep, on sandy reef flats with low water motion, also on rock or coral rubble. Environmental Effects: A. amadelpha decreases the heterogeneity of the reef substrate by covering holes and cracks, thus affecting recruitment of other species. It is also believed to have displaced the native seagrass Halophila hawaiiana on mudflats. World Distribution: Type locality: Indian Ocean. Mauritius, Tuamotu, Fiji, the Pilippines. Commercial Interests: Avrainvillea amadelpha decreases the heterogeneity of the reef substrate by covering holes and cracks, which in turn may affect recruitment rates of species of commercial interest, such as octopus, lobsters, and aquarium fisheries. Rate of Spread / Method: Growth rates unknown. In the Hawaiian islands, no reproductive plants have been observed. Factors likely to influence Spread and Distribution: Unsuccessful in zones with heavy surf and high water motion, A. amadelpha grows in soft sediments and calm waters. It can thrive at low light irradiance, which allows it to live in turbid waters. Reasons for Success: This species lacks predators and has a rapid growth rate. Control Methods: None used. References: www.seaslugforum.net/costsp1.htm |
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