COMMENTS & OBSERVATIONS

A prolonged spell of strong winds and other commitments on the rare good days has meant that we have not had the boat in the water since late April. We were keen to get back out to the offshore reefs and jumped at this chance with very light winds forecast. We motored out around the exclusion zone established for the military exercises around Bowen and watched with interest as the USA Coast Guard rushed to prevent an ‘attack’ from a local fishing boat evidently unaware of the exclusion zone. The fishing boat  veered away from the exclusion zone and war between the USA and Australia was thankfully avoided.

We were serenaded by whales during our first dive to the east along the drop off and were pleased with the new species that we found. Problematically at this site, there is always a range of other marine life that draws attention away from the search for nudibranchs. On this occasion there was plenty to look at and the variety of sea cucumbers was especially interesting. Two species not recorded by us in Australia previously – Halgerda batangas and Phyllidiella sp. 05 were sighted on this dive. The Phyllidiella sp. 05 presented us with a bit of a conundrum. It would be easy enough to consign this specimen to Phyllidiella pustulosa but there are a number of characteristics that prevent it from fitting the mould.

On the second survey, to the west along a wall, we recorded fewer species but our ‘hunt’ was limited by the cold and cramps which meant that a lot of our focus was on returning to the warmth of the surface. However, the Marionia sp. 10 and Phyllodesmium briareum were both highlights as we have not recorded either in Australia previously.

Taxonomic Diversity:
Fourteen of the fifteen sighted species were nudibranchs, with 10 being dorids comprising 2 x phanerobranch (non-retractile gill), 5 x porostomes (suctorial feeders  of the Phyllidiidae family), 3 x cryptobranchs (retractable gill – all belonging to the Chromodorididae family) and 4 x cladobranch comprising 3 x aeolids, 0 x arminid and 1 x dendronotinid. A single sacoglossan completes the species count. If diet is considered then 8 of the 15 species sighted are spongivores.

Our Historical Data:
– We have now completed 5 survey dives at this site since we commenced fully recording data here on 13/03/2023.
– We have recorded 31species 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 to observe. The most regularly recorded species at this site are: Phyllidiella pustulosa (100%), Thuridilla gracilis (80%), Phyllidiella lizae (60%) and Phyllidia varicosa (40%). 
– As could probably be expected with so few surveys at this site, a large number of the species recorded were first for us. The species not previously recorded by us at this site are Cadlinella ornatissima*, Halgerda batangas**, Hypselodoris bullockii, Kaloplocamus acutus*, Marionia sp. 10**, Phyllidia picta, Phyllidiella sp. 5**, Phyllodesmium briareum**, Samla bicolor, Tenellia sp. 33* and Trapania vitta.
– Those species marked with an asterisk have not been recorded by the team in the overall Whitsundays region previously and those with a double asterisk have not been recorded by us in Australia previously.
– This site last surveyed on 6/04/2023.
(Historical data courtesy of Terry Farr, who extracts it from his comprehensive database.)

Key to symbols
+++ New Species
+ First time sighted at Whitsundays
# Most commonly sighted at this site with %

TOTAL SPECIES SIGHTED: 15

DIVE IMAGES GALLERY

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