COMMENTS & OBSERVATIONS

Good conditions and the lack of commitments meant that we were able to venture out to Holbourne Island for the first time since moving here. Not having any marks for dive sites at the Island, we have created our own names for the survey sites. The first dive was at Manta Reef, named after the Manta Rays that visited us during our safety stop and during our surface interval. The site has an abundance of coral cover and ledges that look like they should hold more species of nudibranch than we found. However, we were happy with what we did record at this site, including a species, Dermatobranchus phyllodes, that we have not recorded in Australia previously. After playing with the Mantas during the surface interval, we moved to explore another site we named The Gap. Situated on the south-eastern side of the island in a gap between the main island and a large rocky outcrop, the area we dived is heavily covered in coral so our choice of anchoring spots was limited. We managed to find a sandy/rubble area in around 7 m and explored the coral covered tommies and rubble bottom in the immediate vicinity. The area was not as rich in non-target species (i.e. species other than nudibranchs) but an area well worth exploring nevertheless. One worrying observation was the number of large Acanthaster planci (Crown-of-Thorns) seen under the overhangs of bommies in the area. Great to explore some new sites and experience some good visibility.

Some of  the other species we recorded during these surveys, Aegires gardineri, Coryphellina flamma, Cratena simba, Favorinus japonicus, Phyllidiella annulata and Thuridilla gracilis have not been recorded by us previously in the Whitsundays.

Taxonomic Diversity:
11 of the 12 species sighted were nudibranchs, with 7 being dorids comprising 1 x phanerobranch (non-retractile gill), 2 x cryptobranchs (retractable gill), 4 x porostomes (suctorial feeders – all of the Phyllidiidae family) and 4 being cladobranchs comprising 3 x aeolids, 1 x arminid. A single sacoglossan rounds out the species numbers. If diet is considered then 7 of the 12 species sighted are spongivores.

Our Historical Data:
No formal historical data is supplied for this dive/site as these were the first surveys conducted here.

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

TOTAL SPECIES SIGHTED: 12

DIVE IMAGES GALLERY

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