Select Page

Dive Reports

06-12-2023 Bornella Reef

DAY/DATE

Wednesday

06/012/2023

SITE/S

Bornella Reef
Mudjimba Island 

 

PARTICIPANTS

David

 

TYPE

Subtidal

 

MODE

Boat Dives

 

VESSEL

Li’l Mischief

 

DIVE

1

2

SITE/S

Bornella Reef

Bornella Reef

SPECIES #

12

15

DURATION

86 Min

80 Min

DEPTH/RANGE

10-13 m

8.5-12 m

TEMP.

26 C

26 C

VIS.

12 m

12 m

SURGE

Nil

Slight

CURRENT

Nil

Nil

COMMENTS & OBSERVATIONS

Finally, back in the water after 4 months. A long trip through Europe, catching Covid along the way and the after effects of that, have kept my dive gear in the bucket and the boat on the trailer. Decided on Mudlimba Island for the long overdue return to the water and dropped the pick at Bornella Reef at the southeast corner. Two great dives were enjoyed with almost perfect conditions above and below. Aegires flores and the always photogenic Miamira magnifica were the highlights of the sea slug search. Interestingly, no aeolids were sighted. Surface interval entertainment was provided by several inquisitive turtles. With all the dive gear, camera gear and the boat and its equipment working flawlessly, plus a lack of operator error (always a hovering risk), a most pleasant excursion was completed.

Taxonomic Diversity:
Sixteen of the nineteen sighted species were nudibranchs, with 14 being dorids comprising 2 x phanerobranchs (non-retractile gill), 2 x porostomes (suctorial feeders  of the Phyllidiidae family), 10 x cryptobranchs (retractable gill – all bar one belonging to the Chromodorididae family) and 2 were cladobranchs comprising 0 x aeolids, 1 x arminid and 1 x dendronotinid. A single head-shield slug, a single sacoglossan and a single pleurobranch complete the species count. If diet is considered then 15 of the 19 species sighted are spongivores. 59 specimens in total were recorded.

Our Historical Data:
– This excursion brings the number of survey dives to 34 at this site since we commenced fully recording data here on 19/07/2010.
– 138 species have been recorded at this site.
– The most regularly recorded species at this site are: Goniobranchus splendidus (97%), Phyllidiella pustulosa (79%), Doriprismatica atromarginata (76%) and Hypselodoris jacksoni (68%). 
– The number of species recorded seems to be fairly constant given a single recorder on recent dives.
– This is the first time we have recorded Aegires flores, Hypselodoris decorata or Jorunna parva at this site.
– The number of Goniobranchus splendidus specimens recorded has dropped from the peaks seen in earlier months of this year while the number of species recorded has climbed slightly.
– The graph, in the image gallery below, shows the number of G. splendidus  against the total species count recorded at this site on our dives here for the period January 18th, 2021 to the current date.
– This site last surveyed on 31/07/2023.
(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: 19

 

SPECIES LIST – ALPHABETICAL

Aegires flores -/1 +
Aegires gardineri 1/2
Bornella anguilla -/3
Chromodoris lochi -/1
Dermatobranchus sp. 07 1/-
Doriprismatica atromarginata 8/6 #76%
Glossodoris vespa 1/1
Goniobranchus splendidus 1/2 #97%
Hypselodoris jacksoni 1/5 #68%
Hypselodoris obscura -/1
Hypselodoris decorata 1/- +
Hypselodoris whitei 1/-
Jorunna parva -/1 +
Miamira magnifica 2/1
Phyllidiella lizae -/1
Phyllidiella pustulosa 3/5 #79%
Pleurobranchus peronii -/2
Sagaminopteron ornatum 3/2
Thuridilla cf. splendens 2/-

SPECIES GROUPED BY ORDER

Nudibranchia
Dorids
Phanerobranchs
Aegires flores -/1
Aegires gardineri 1/2
Cryptobranchs 
Chromodoris lochi -/1
Doriprismatica atromarginata 8/6
Glossodoris vespa 1/1
Goniobranchus splendidus 1/2
Hypselodoris jacksoni 1/5
Hypselodoris obscura -/1
Hypselodoris decorata 1/-
Hypselodoris whitei 1/-
Jorunna parva -/1
Miamira magnifica 2/1
Porostomes
Phyllidiella lizae -/1
Phyllidiella pustulosa 3/5

Cladobranchs
Aeolids

Arminids
Dermatobranchus sp. 07 1/-
Dendronotinids
Bornella anguilla -/3

Cephalaspidea
Sagaminopteron ornatum 3/2

Pteropoda

Sacoglossa
Thuridilla cf. splendens 2/-

Umbraculoidea

Pleurobranchoidea
Pleurobranchus peronii -/2

Anaspidea

DIVE IMAGES GALLERY

PUT CURSOR ON IMAGE FOR SPECIES NAME
CLICK IMAGE TO ENLARGE & SCROLL