DAY/DATE
Tuesday
10/01/2023
SITE/S
Shellacey Reef
Gneering Shoals
PARTICIPANTS
David
TYPE
Subtidal
MODE
Boat Dives
VESSEL
Li’l Mischief
DIVE
1
2
SITE/S
Shellacey Reef
Shellacey Reef
SPECIES #
12
13
DURATION
68 Min
63 Min
DEPTH/RANGE
14.5-17.7 m
14.5-18.5 m
TEMP.
26 C
26 C
VIS.
10 m
10 m
SURGE
Slight
Slight
CURRENT
Nil
Nil
COMMENTS & OBSERVATIONS
A small window of opportunity presented itself for an offshore excursion in between all the days of strong onshore winds. The recent heavy seas, no doubt, reduced the visibility at inshore sites so the Gneering Shoals were again the best choice. There was some surge but no current. Visibility was about half that experienced two weeks previously. Large schools of bait fish are still around. A 5 mm specimen of Thorunna halourga was recorded. An unusual characteristic of this species is the distinctive mantle spicules of calcium carbonate arranged in a chevron pattern on the dorsum. These are readily visible in the image below, taken in studio lighting conditions, however, they are not always so readily visible from in situ images. The spicules are also dissolved away when specimens are placed in preserving fluid.
Taxonomic Diversity:
18 of the species sighted were nudibranchs, with 16 being dorids comprising 0 x phanerobranch (non-retractile gill), 5 x porostomes (suctorial feeders and all Phyllidiidae family), 11 x cryptobranchs (retractable gill) (all belonging to the Chromodorididae family) and 2 x cladobranchs comprising 2 x aeolids. The balance of sightings were made up of 1 x cephalaspidean (headshield slugs) and 1 x sacoglossan. If diet is considered then 17 of the 20 species sighted are spongivores.
Our Historical Data:
– This excursion brings the number of survey dives to 68 at this site since we commenced fully recording data here on 26/01/2010.
– 182 species have been recorded at this site.
– The most regularly recorded species at this site are Chromodoris elisabethina (91%), Doriprismatica atromarginata (84%), Phyllidiella pustulosa (84%) and Phyllidiella lizae (86%).
– This is the first time that we have recorded Hypselodoris bullockii and Thorunna halourga at this site within the survey period.
– We have only recorded Tenellia sibogae here on one previous occasion (27/03/2021).
– As seen in the graph, in the image gallery below, Chromodoris elisabethina is our most prolific species recorded at this site with around 5 species recorded on each dive.
– This site last surveyed on 24/12/2022.
(Historical data courtesy of Terry Farr, who extracts it from his comprehensive database.)
Key to symbols
+++ New Species
+ First time sighted at this site
# Most commonly sighted at this site with %
TOTAL SPECIES SIGHTED: 20
SPECIES LIST – ALPHABETICAL
Chromodoris elisabethina 8/4 #91%
Chromodoris joshi -/1
Chromodoris lochi -/3
Doriprismatica atromarginata 4/- #84%
Glossodoris vespa 1/-
Hypselodoris bullockii 1/- +
Hypselodoris jacksoni -/1
Hypselodoris lacuna -/1
Hypselodoris whitei -/1
Mexichromis trilineata 3/-
Phyllidia elegans 1/1
Phyllidia varicosa 3/1
Phyllidiella lizae 1/- #86%
Phyllidiella pustulosa 5/2 #84%
Phyllidiopsis burni 1/-
Sagaminopteron psychedelicum -/1
Samla bicolor 2/-
Tenellia sibogae -/1
Thorunna halourga -/1 +
Thuridilla cf. splendens 1/-
SPECIES GROUPED BY ORDER
Nudibranchia
Chromodoris elisabethina 8/4
Chromodoris joshi -/1
Chromodoris lochi -/3
Doriprismatica atromarginata 4/-
Glossodoris vespa 1/-
Hypselodoris bullockii 1/-
Hypselodoris jacksoni -/1
Hypselodoris lacuna -/1
Hypselodoris whitei -/1
Mexichromis trilineata 3/-
Phyllidia elegans 1/1
Phyllidia varicosa 3/1
Phyllidiella lizae 1/-
Phyllidiella pustulosa 5/2
Phyllidiopsis burni 1/-
Samla bicolor 2/-
Tenellia sibogae -/1
Thorunna halourga -/1
Cephalaspidea
Sagaminopteron psychedelicum -/1
Pteropoda
–
Sacoglossa
Thuridilla cf. splendens 1/-
Umbraculoidea
–
Pleurobranchoidea
–
Anaspidea
–