Invasive Non-native Species

Bonnemaisonia hamifera

Bonnemaisonia hamifera is a branched red seaweed, growing to 20-30 cm high with an erect main axis 1 mm in diameter and characteristic curved hooks. A small (2-3 cm) filamentous tetrasporophyte phase (Trailliella) also occurs.

It is found in the shallow subtidal, to depths of 15-20 m where it grows attached to rocks, or epiphytically on other seaweeds to which it attaches by its characteristic hooks. The filamentous form occurs in shaded rock pools on the lower shore and in the subtidal zone.

Native in the Pacific around Japan it was first recorded in the UK in the late 19th century. It is now so widespread and abundant in Europe that it can be regarded as fully established, with no possibility of eradication. However, there have been no negative impacts on native marine flora or marine based activities.

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Information and Identification Sheets:   Bonnemaisonia hamifera