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Dive Reports

21-01-2024 Trench

DAY/DATE

Sunday

21/01/2024

SITE/S

Trench
Inner Gneerings 

 

PARTICIPANTS

David

 

TYPE

Subtidal

 

MODE

Boat Dives

 

VESSEL

Li’l Mischief

 

DIVE

1

SITE/S

Trench

SPECIES #

5

DURATION

63 Min

DEPTH/RANGE

14-16.7 m

TEMP.

26 C

VIS.

<4 m

SURGE

Mod

CURRENT

Nil

COMMENTS & OBSERVATIONS

I can handle surge and I can handle poor visibility but I cannot be bothered with both at the same time so I called it after the first dive. I avoided the Island due to both visibility and surge concerns and the Outer Gneerings as strong surface currents have been reported out there of late. 

Traffic into the La Balsa boat ramp was backed up to Point Cartwright Drive. The last weekend of the school holidays, the best surface conditions so far this summer and an influx of northside-ramp users that could not get a park over there. No ramp rage was evident but several could not bring themselves to fall into line astern as we all motored down the river at 6 knots. They sped past at 20 knots to get in front and then slowed down???? Pulled over by the water-police on my way back. I kept trying to avoid a collision with an approaching boat but it kept turning across my bow – then the penny dropped. They said they were very interested to take a look at my boat as it locked so much like another “enforcement” boat. I said, is that what you call it – enforcement? They laughed, and then asked to see all my safety equipment.

Taxonomic Diversity:
All five, of the low count of sighted species, were nudibranchs, with all being dorids comprising 0 x phanerobranchs (non-retractile gill), 1 x porostome (suctorial feeders  of the Phyllidiidae family), 4 x cryptobranchs (retractable gill – all belonging to the Chromodorididae family) and zero cladobranchs comprising 0 x aeolids, 0 x arminids and 0 x dendronotinids. Only 11 specimens in total were recorded due to the combination of surge, low visibility and a single dive.

Our Historical Data:
– This excursion brings the number of survey dives to 41 at this site since we commenced fully recording data here on 10/07/2010.
– 137 species have been recorded at this site.
– The most regularly recorded species at this site are: Doriprismatica atromarginata (98%), Phyllidiella pustulosa (95%), Thuridilla cf. splendens (80%) and Chromodoris elisabethina (78%). 
– All of the species recorded on this survey are regularly recorded by us at this site;
– Our records show that the abundance of Glossodoris vespa is consistent throughout the year. Refer to graph in Image Gallery, below.
– This site last surveyed on 21/12/2023.
(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: 5

 

SPECIES LIST – ALPHABETICAL

Chromodoris elisabethina -1 #78%
Doriprismatica atromarginata -1 #98%
Glossodoris vespa -2
Hypselodoris jacksoni -6
Phyllidiella pustulosa -1 #95%

SPECIES GROUPED BY ORDER

Nudibranchia
Dorids
Phanerobranchs

Cryptobranchs
Chromodoris elisabethina -1
Doriprismatica atromarginata -1
Glossodoris vespa -2
Hypselodoris jacksoni -6
Porostomes
Phyllidiella pustulosa -1 

Cladobranchs
Aeolids

Arminids

Dendronotinids

Cephalaspidea
– 

Pteropoda

Sacoglossa

Umbraculoidea

Pleurobranchoidea

Anaspidea

DIVE IMAGES GALLERY

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