2015-11-10 - P&O Agenda - Item 7, Attach 2 - Assessment of Oyster Recruitment

3 Results

A variety of organisms colonised the settlement tiles including two species of oyster (P.
pestigris & Pinctada maculata); hairy mussels (Trichomya hirsuta); barnacles (Amphibalanus
variegatus & A. amphitrite); bryozoans (Biflustra sp., Hippopodina sp., & Schizoporella
unicornis) ascidians (Leptoclinides sp. & Ascidia sp.), sponges (Ircinia sp. & Batzella sp.) and
serpulid polychaete worms (Spirorbis sp.). There was no recruitment of rock oysters
(Saccostrea glomerata) onto settlement tiles or deployment structures at any of the sites
examined, despite adults being present in the estuary. Numerous mobile species were also
associated with the sessile organisms, including amphipods, crabs and polychaetes. The
abundance and distribution of mobile species were not examined further as part of the
assessment.

Predators such as the mulberry whelk (Morula granulata) were absent from observations by
the field team and were not recorded on any of the intertidal or subtidal settlement tiles (note
that specific surveys for predatory species were not completed as part of this preliminary
assessment, and these species may have dropped off when retrieving the settlement arrays).
Mulberry whelks are typically very common on intertidal shores, particularly where oysters
are present (e.g. intertidal shore on Stradbroke Island Figure 4).




    Figure 4    Sydney rock oysters and predatory mulberry whelks on an intertidal shore at North
                Stradbroke Island




Restoration of Noosa Estuary: An Assessment of Oyster Recruitment                                   8