Terry & Julie
COMMENTS & OBSERVATIONS
Finally after a month of Blowin’ in Bowen (except for the one day we were packing to head south), we got one day of awesome conditions forecast before the winds started again so the boat was loaded and camera batteries charged. Following the continual strong winds, inshore visibility was expected to be low so we headed up to Holbourne Island. We decided to concentrate on the northern side in a pretty area tucked into a small “bay”. Whilst the water colour looked amazing, visibility was disappointing.
The area hosts large bommies with a variety of hard corals and occasional condensed patches of soft corals, with a large number of large crown-of-thorns starfish. Interestingly there are very few hydroids in this area and the one aeolid we found was on a piece of dead coral. A big school of barracuda kept us company and, when we looked up, we observed several large fish species and anemone fish. Whilst the overall sea slug species count is low, most of these are first sightings for us in this region.
Seven of the eight sighted species were nudibranchs, with 4 being a dorids comprising 1 x phanerobranch (non-retractile gill), 2 x porostomes (suctorial feeders of the Phyllidiidae family), 1 x cryptobranch (retractable gill) and 3 x cladobranchs comprising 2 x aeolid, 1 x arminid and 0 x dendronotinid. A single cephalaspidean completes the species count. If diet is considered then only 3 of the 8 species sighted are spongivores.
Our Historical Data:
– This excursion brings the number of survey dives to 5 at this site since we commenced fully recording data here on 13/03/2023.
– We have recorded 23 species at this site.
– Although too early to draw any conclusions regarding relative abundance or prevalence of species at this site, the changes over time as we complete more surveys may be interesting. The most regularly recorded species at this site are: Phyllidiella lizae (80%), Phyllidiella pustulosa (80%), Phyllidiella annulata (60%) and Aegires gardineri (60%) with the last two not sighted during these surveys.
– As noted above, a large number of the species recorded were a first for us at this site. The species not previously recorded by us at this site are Chelidonura electra, Coryphellina pannae*, Hypselodoris tryoni*, Nembrotha purpureolineata* and Pteraeolidia semperi*. Those species marked with an asterisk have not been recorded previously by us in the overall Whitsundays region.
– This site last surveyed on 30/04/2023.
Key to symbols
+++ New Species
+ First time sighted at Whitsundays
# Most commonly sighted at this site with %
TOTAL SPECIES SIGHTED: 8
SPECIES LIST – ALPHABETICAL
Chelidonura electra 1/-
Coryphellina pannae -/1 +
Dermatobranchus rodmani -/1
Hypselodoris tryoni 2/- +
Nembrotha purpureolineata -/1 +
Phyllidiella lizae 2/1 #80%
Phyllidiella pustulosa 2/1 #80%
Pteraeolidia semperi -/1 +
SPECIES GROUPED BY ORDER
Nembrotha purpureolineata -/1
Hypselodoris tryoni 2/-
Phyllidiella lizae -/1
Phyllidiella pustulosa 6/-
Coryphellina pannae -/1
Pteraeolidia semperi -/1
Dermatobranchus rodmani –/1
Chelidonura electra 1/-