Dive Report

16-11-2021 Clown Reef

Nov 22, 2021

DAY/DATE

Tuesday

16/11/2021

SITE/S

Clown Reef
Outer Gneerings

 

PARTICIPANTS

Terry, David

 

TYPE

Subtidal

 

MODE

Boat Dives

 

VESSEL

Rebel II

 

DIVE

1

2

SITE/S

Clown Reef

Clown Reef

SPECIES #

26

14

DURATION

71 Min

50 Min

DEPTH/RANGE

14-20 m

14-20 m

TEMP.

22 C

22 C

VIS.

15 m

15 m

SURGE

Nil

Nil

CURRENT

Southerly

Southerly

COMMENTS & OBSERVATIONS

Mid-week diving and the La Balsa ramp trailer park is not as crowded so a Mooloolah River departure beckoned. With such little swell the trip to the Outer Gneerings was smooth and quick. Blue water greeted us at the Clown Reef site as did a southerly current carrying many and varied sea jellies. (The hope is that it also carries sea slug larvae from the tropical north to stock our reefs.) The first dive rewarded us with an excellent quantity of sea slugs to record however the 2nd dive was shorter due to time spent and air wasted searching for a lost weight pocket. Sloppy preparation brings its penalties.

Taxonomic Diversity:
Of the 27 sea slugs sighted that belong to the Order Nudibranchia, 24 were dorids, comprising 19 cryptobranchs (retractable gill), being more than three-quarters of the dorids, (18 from the Chromodorididae Family, being three quarters of the dorids) 1 x phanerobranch (non-retractile gill) and 4 were porostomes (suctorial feeders and all Phyllidiidae Family). The other 3 nudibranchs were cladobranchs all being aeolids. The balance of 5 were spread across other orders as follows: 1 x Sacoglossa, 1 x Cephalaspidea, 1 x Umbraculoidea and 2 x Pleurobranchoidea. The nudibranchs dominate the overall sea slug count, the dorids dominate the nudibranchs, the cryptobranchs dominate the dorids and the Chromodorididae dominate the cryptobranchs. In fact, the Chromodorididae Family dominates the overall species count, comprising more than half of the species total, a trend we have been noticing. If diet is considered 25 of the 32 species, more than three-quarters the total, are spongivores.

Our Historical Data:
– We have now undertaken 39 survey dives at Clown Reef since we first commenced keeping records here on 10/07/2011.
– We have recorded 149 species at this site.
– The most commonly sighted species are Chromodoris elisabethina (90%), Phyllidiella pustulosa (90%), Doriprismatica atromarginata (82%), and although not sighted on this survey, Phyllidiella lizae (69%).
– Our recording of Ceratosoma sp. 02, Diversidoris sp. 02, Favorinus sp. 02, Mexichromis pusilla, Hypselodoris sp. 04 and Tornatina sp. 01 are first recordings by us at this site.
– The numbers of species recorded on a survey and the overall organisms recorded has remained relatively constant over the period of time we have been conducting surveys here.
– This site last surveyed on 19/03/2021.

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

TOTAL SPECIES SIGHTED: 32

 

SPECIES LIST – ALPHABETICAL

Berthella martensi -/1
Cadlinella ornatissima 2/1
Ceratosoma sp. 02 1/- +
Chromodoris elisabethina 8/6 #90%
Chromodoris lochi -/1
Cratena lineata 1/-
Cratena simba 1/-
Diversidoris sp. 02 1/- +
Doriprismatica atromarginata 7/3 #82%
Favorinus sp. 02 1/-
Glossodoris hikuerensis 1/-
Glossodoris rufomarginata 2/2
Goniobranchus splendidus 6/4
Halgerda aurantiomaculata 1/-
Hypselodoris emma 1/-
Hypselodoris jacksoni 1/-
Hypselodoris maculosa -/1
Hypselodoris maritima 2/1
Hypselodoris obscura 1/-
Hypselodoris sp. 04 2/- +
Hypselodoris whitei 1/-
Mexichromis pusilla -/1 +
Mexichromis trilineata 2/-
Phyllidia varicosa 3/-
Phyllidia ocellata -/1
Phyllidiella annulata 1/-
Phyllidiella pustulosa 4/5 #90%
Pleurobranchus peronii -/1
Roboastra luteolineata -/1
Thuridilla carlsoni 1/-
Tornatina sp. 01 1/- (Live animal) +
Tylodina corticalis 3/-

SPECIES GROUPED BY ORDER

Nudibranchia
Cadlinella ornatissima 2/1
Ceratosoma sp. 02 1/- 
Chromodoris elisabethina 8/6 
Chromodoris lochi -/1
Cratena lineata 1/-
Cratena simba 1/-
Diversidoris sp. 02 1/- 
Doriprismatica atromarginata 7/3 
Favorinus sp. 02 1/-
Glossodoris hikuerensis 1/-
Glossodoris rufomarginata 2/2
Goniobranchus splendidus 6/4
Halgerda aurantiomaculata 1/-
Hypselodoris emma 1/-
Hypselodoris jacksoni 1/-
Hypselodoris maculosa -/1
Hypselodoris maritima 2/1
Hypselodoris obscura 1/-
Hypselodoris sp. 04 2/- 
Hypselodoris whitei 1/-
Mexichromis pusilla -/1 
Mexichromis trilineata 2/-
Phyllidia varicosa 3/-
Phyllidia ocellata -/1
Phyllidiella annulata 1/-
Phyllidiella pustulosa 4/5 
Roboastra luteolineata -/1

Cephalaspidea
Tornatina sp. 01 1/- (Live animal) 

Sacoglossa
Thuridilla carlsoni 1/-

Umbraculoidea
Tylodina corticalis 3/-

Pleurobranchoidea
Berthella martensi -/1
Pleurobranchus peronii -/1

Anaspidea

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