Dive Report

20-07-2021 Trench

Jul 20, 2021

DAY/DATE

Tuesday

20/07/2021

SITE/S

Trench

 

PARTICIPANTS

Terry, David

 

TYPE

Subtidal

 

MODE

Boat Dives

 

VESSEL

Rebel II

 

DIVE

1

2

 

SITE/S

Trench

Trench

 

SPECIES #

21

18

 

DURATION

78 Min

68 Min

 

DEPTH/RANGE

14 – 18 m

14 – 18 m

 

TEMP.

20 C

20 C

 

VIS.

15+ m

15+ m

 

SURGE

Nil

Nil

 

CURRENT

Nil

Nil

 

COMMENTS & OBSERVATIONS

The forecast was for the wind to increase before noon however it was to be westerly in direction so we opted for a short trip (less fetch) to the Inner Gneerings. While it was breezy from the NW when we anchored, that dropped away almost completely until the expected westerly came in during our second dive. Fabulous visibility was enjoyed as we worked one way along the Trench for the first dive and the opposite direction for the second. We searched the opposite side of the Trench to our last survey out there just over a week ago. Two species deserve special mention because of their not-so-common appearance and these are Aegires hapsis and Phyllidiopsis shireenae.

Taxonomic Diversity:
20 of the 24 species sighted were dorids (4/5ths the total) comprising 2 x phanerobranchs, 6 x porostomes (all belonging to Phyllidiidae) and 12 x cryptobranchs (all belonging to Chromodorididae). The other 4 species comprised 0 x aeolids, 1 x dendronotid, 1 x arminid, 1 x pleurobranch and 1 x sacoglossan sea slug. If diet is considered then 20 of the 24 species sighted are spongivores.

Our Historical Data:
– This survey is number 18 at this site since 27/06/2011
– Last surveyed on 10/07/2021
– 103 species have been recorded here
– 5 first-time sightings were recorded for this site on top of the 8 from last week.

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

Total Species Sighted: 24

SPECIES LIST – ALPHABETICAL

Aegires hapsis -/1 +
Berthellina delicata 1/- +
Bornella anguilla 2/2
Chromodoris elisabethina 3/7 #94%
Chromodoris kuiteri 2/1
Chromodoris sp. 5 1/1 +
Dermatobranchus rodmani 1/-
Diversidoris sp. 1 1/1 +
Doriprismatica atromarginata 7/8 #94%
Glossodoris rufomarginata 3/3
Glossodoris vespa 1/-
Goniobranchus geometricus 1/-
Goniobranchus kuniei 1/- +
Goniobranchus splendidus -/1
Hypselodoris jacksoni 2/2
Phyllidia ocellata 1/3
Phyllidia varicosa 2/3
Phyllidiella lizae 2/-
Phyllidiella pustulosa 4/5 #94%
Phyllidiopsis burni 1/2
Phyllidiopsis shireenae -/1
Roboastra luteolineata 1/1
Thuridilla cf. splendens 3/4 #89%
Verconia norba 1/1

SPECIES GROUPED BY ORDER

Nudibranchia
Aegires hapsis -/1 
Bornella anguilla 2/2
Chromodoris elisabethina 3/7
Chromodoris kuiteri 2/1
Chromodoris sp. 5 1/1
Dermatobranchus rodmani 1/-
Diversidoris sp. 1 1/1 
Doriprismatica atromarginata 7/8 
Glossodoris rufomarginata 3/3
Glossodoris vespa 1/-
Goniobranchus geometricus 1/-
Goniobranchus kuniei 1/- 
Goniobranchus splendidus -/1
Hypselodoris jacksoni 2/2
Phyllidia ocellata 1/3
Phyllidia varicosa 2/3
Phyllidiella lizae 2/-
Phyllidiella pustulosa 4/5 
Phyllidiopsis burni 1/2
Phyllidiopsis shireenae -/1
Roboastra luteolineata 1/1
Verconia norba 1/1

Cephalaspidea

Sacoglossa
Thuridilla cf. splendens 3/4

Umbraculoidea

Pleurobranchoidea
Berthellina delicata 1/-

Anaspidea

Pteropoda

DIVE IMAGES GALLERY

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