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Dive Report

29-09-2022 Bornella Reef

Oct 1, 2022

DAY/DATE

Thursday

29/09/2022

SITE/S

Bornella Reef
Mudjimba Island

 

PARTICIPANTS

Julie, Terry, David

 

TYPE

Subtidal

 

MODE

Boat Dive

 

VESSEL

Li’l Mischief

 

DIVE

1

SITE/S

Bornella Reef

SPECIES #

18

DURATION

71 Min

DEPTH/RANGE

9-13 m

TEMP.

21 C

VIS.

Up to 6 m

SURGE

Slight

CURRENT

Nil

COMMENTS & OBSERVATIONS

This excursion was the inaugural dive trip on Li’l Mischief, the 6 m RIB now operating in place of Mischief the 11.5 m Scimitar cat. We left the Mooloolah River mid-morning, after sorting stowage arrangements, and deciding to limit the excursion to a single dive. In general, the set-up worked fairly well with just some minor tweaking and hopefully becoming acclimatised to less personal space. Surface conditions were excellent but the visibility below was less than ideal, the whole vista having a green tinge. Nevertheless a good number of species were sighted for a single dive including one not recorded here previously.

Taxonomic Diversity:
16 of the 18 species sighted were nudibranchs, 14 being dorids comprising 0 x phanerobranch (non-retractile gill), 4 x porostomes (suctorial feeders and all Phyllidiidae family) and 10 x cryptobranchs (retractable gill) all belonging to the Chromodorididae family. The other two nudibranchs were dendronotid cladobranchs. The other two non-nudibranch sea slug species were a cephalaspidean (headshield slug) and one sacoglossan. If diet is considered then 15 of the 18 species sighted are spongivores.

Our Historical Data:
– This excursion brings the survey number to 22 at this site since we commenced fully recording data here on 28/09/2011.
– 119 species have been recorded at this site.
– Our most common sightings at this site are: Goniobranchus splendidus (95%), Thuridilla cf. splendens (91%, but interestingly, not sighted on this survey), Doriprismatica atromarginata (86%) and Phyllidiella pustulosa (86%).
– There is no clear seasonal pattern to the sightings of any of the species recorded on this survey.
– The overall number of organisms and species recorded is within the range normally recorded by us at this site.
– As noted above Doriprismatica atromarginata is one of the most frequently recorded species at the site and is also the most abundant species recorded on most of our surveys here (see graph below in image gallery).
– This is the first time we have recorded Verconia decussata at this site and the second occasion on which we have recorded Verconia romeri here.
– This site last surveyed on 18/01/2021.

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

TOTAL SPECIES SIGHTED: 18 

 

SPECIES LIST – ALPHABETICAL

Bornella anguilla 1
Chromodoris kuiteri 1
Diversidoris crocea 1
Doriprismatica atromarginata 6 #86%
Glossodoris rufomarginata 4
Goniobranchus splendidus 8 #95%
Hypselodoris jacksoni 3
Hypselodoris obscura 6
Phyllidia ocellata 1
Phyllidia varicosa 1
Phyllidiella lizae 1
Phyllidiella pustulosa 4 #86%
Sagaminopteron ornatum 1
Thuridilla albopustulosa 1
Tritoniopsis elegans 1
Verconia decussata 1 +
Verconia norba 1
Verconia romeri 1

SPECIES GROUPED BY ORDER

Nudibranchia
Bornella anguilla 1
Chromodoris kuiteri 1
Diversidoris crocea 1
Doriprismatica atromarginata 6
Glossodoris rufomarginata 4
Goniobranchus splendidus 8
Hypselodoris jacksoni 3
Hypselodoris obscura 6
Phyllidia ocellata 1
Phyllidia varicosa 1
Phyllidiella lizae 1
Phyllidiella pustulosa 4
Tritoniopsis elegans 1
Verconia decussata
Verconia norba 1
Verconia romeri 1

Cephalaspidea
Sagaminopteron ornatum 1

Sacoglossa
Thuridilla albopustulosa 1

Umbraculoidea

Pleurobranchoidea

Anaspidea

DIVE IMAGES GALLERY

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