SAGARTIIDAE, Gosse, 1858

Mead, A., Carlton, J. T., Griffiths, C. L. & Rius, M., 2011, Introduced and cryptogenic marine and estuarine species of South Africa, Journal of Natural History 45 (39 - 40), pp. 2463-2524 : 2472

Family SAGARTIIDAE

Sagartia ornata (Holdsworth, 1855) Introduced

Acuna et al. (2004) report the discovery of this well-known European sea anemone in 2002 in Langebaan Lagoon on the west coast, where it is found in the intertidal zone among the cryptogenic salt marsh plant Spartina maritima and attached to stones shallowly buried in sand. Robinson et al. (2004) provide quantitative data on its abundance at Langebaan, where its populations can reach hundreds of individuals per m 2. However, we take the first record to be 1955, when Day (1955) reported a Sagartia -like species from the same location. No other native South African sea anemone could be confused with this distinctive species. The first museum records are from Langebaan in 1963 (SAM collections: catalogue numbers H1579 and H1594). Ship fouling and ballast water are the most probable vectors.

Metridium senile (Linnaeus, 1761) Introduced

This large, white Northern Hemisphere sea anemone with distinctive frilly tentacles was first detected in September 1995 in Table Bay Harbour, Cape Town ( Griffiths et al. 1996), where it occurs on a wide variety of substrata from 6 to 12 m depth. In 2006 photographic evidence was presented to the authors of a deep-water population of Metridium senile at depths up to 126 m. These populations were associated with oilrigs on the Agulhas Bank off the south coast. Ship fouling from the North Atlantic or the North Pacific is a probable vector for the harbour population .