Long-term change in the invertebrates of Zandvlei Estuary, with focus on the invasive reef worm Ficopomatus enigmaticus

Zandvlei is a small, seasonally closed, urban estuary situated 20 km south of Cape Town, and been subjected to many physical changes, including the construction of a rubble weir, canalisation of the Estuary mouth, construction of a marina and hardening of the banks with concrete. These changes have facilitated the expansion of an invasive reef-building polychaete, Ficopomatus enigmaticus. This study quantifies long term changes in the abundance of F. enigmaticus in Zandvlei and investigates historical changes in the salinity and invertebrate community. The standing stock of F. enigmaticus in the Marina da Gama has increased from 11.80 t in 1989 to 50.03 t in 2012 due both to an increase in the total area colonised by F. enigmaticus, and the dry mass of worm per m2 . There has also been a general trend of increased salinity in the system since 1989, with an increase of 4% recorded at the head of the Estuary in 2011. This study provides the first record of the infauna associated with F. enigmaticus in Zandvlei, which comprises 16 species. One of these is the hitherto unrecorded alien bryozoan, Conopeum seurati. Further research is required to understand the effects of long-term salinity change on the growth of F. enigmaticus and the role of F. enigmaticus as an ecosystem engineer.

Grantor dc:publisher.institution

Department of Oceanography

Year dc:date.issued

2013

Author dc:creator

• McQuaid, Kirsty Alexandra

Advisor dc:contributor.advisor

• Griffiths, Charles L

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/9812

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/9812