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Dive Report

10-01-2023 Shellacey Reef

Jan 13, 2023

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

DIVE IMAGES GALLERY

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