DAY/DATE
Thursday
02/03/2023
SITE/S
Middle Island
Bowen
PARTICIPANTS
Terry & Julie
TYPE
Subtidal
MODE
Boat Dives
VESSEL
Rebel II
DIVE
1
2
SITE/S
Middle Is. West
Middle Is. South
SPECIES #
2
4
DURATION
78 Min
44 Min
DEPTH/RANGE
8-11 m
5-10 m
TEMP.
27 C
27 C
VIS.
2 m
To 5 m
SURGE
Nil
Nil
CURRENT
Nil
Nil
COMMENTS & OBSERVATIONS
Perfect surface conditions found us again at Middle Island exploring the two sites we last visited offshore. Our dive at Middle Island West was aimed as much at finding a range of species and not just nudibranchs. Visibility was limited and we had not brought our reel which we usually run out to help with navigation in unfamiliar sites. This site is flat and difficult to navigate so we were hindered in the area we explored but happy to find two species, one of which, Baeolidia australis, we had not found here or on the Whitsundays before.
We took a slightly different approach at Middle Island South and on this dive we anchored in the shallows with the intention of swimming down the ledge to the depth we found most species of nudibranch on our previous dive here. Visibility in the shallows was reasonable but dropped dramatically as we moved to increased depth. Missing our usual navigation aid, we opted to confine our dive to the shallows and this, no doubt, contributed to the relatively low number of species recorded.
Taxonomic Diversity:
5 of the 6 species sighted were nudibranchs, with 4 being dorids comprising 4 x porostomes only (suctorial feeders – all of the Phyllidiidae family) and 1 x cladobranch comprising 1 x aeolid. A single sacoglossan rounds out the species count. If diet is considered then 4 of the 6 species sighted are spongivores.
Our Historical Data:
Middle Is West
– We have now completed three dives at this site since our first here on 13/02/2023 and have recorded two species here. Both of these species were seen on this dive.
– This is the first time we have recorded Baeolidia australis in the Whitsundays.
– Our last dive at this site was on 13/02/2023.
Middle Is South
– We have now completed two dives at this site since our first here on 13/02/2023 and have recorded 12 species here.
– This is the first time we have recorded Phyllidiella lizae or Phyllidiella pustulosa at the Whitsundays.
– We have not recorded Phyllidia elegans at this site previously.
– Our last dive at this site was on 13/02/2023.
Key to symbols
+++ New Species
+ First time sighted at this site
# Most commonly sighted at this site with %
TOTAL SPECIES SIGHTED: 6
SPECIES LIST – ALPHABETICAL
Baeolidia australis 1/- +
Elysia sp. 34 1/-
Phyllidia elegans -/1 +
Phyllidiella lizae -/1 +
Phyllidiella pustulosa -/3 +
Phyllidiopsis burni -/1
SPECIES GROUPED BY ORDER
Nudibranchia
Dorids
Phanerobranchs
–
Cryptobranchs
–
Porostomes
Phyllidia elegans -/1
Phyllidiella lizae -/1
Phyllidiella pustulosa -/3
Phyllidiopsis burni -/1
Cladobranchs
Aeolids
– Baeolidia australis 1/-
Arminids
–
Dendronotinids
–
Cephalaspidea
–
Pteropoda
–
Sacoglossa
Elysia sp. 34 1/-
Umbraculoidea
–
Pleurobranchoidea
–
Anaspidea
–