Dive Report

18-06-2021 La Balsa Park

Jun 18, 2021

DAY/DATE

Friday

18/06/2021

SITE/S

La Balsa Park

 

PARTICIPANTS

Julie, Terry, David

 

TYPE

Subtidal

 

MODE

Shore Entry

 

VESSEL

 

DIVE

1

 

SITE/S

La Balsa Park (Toilet Block Entry)

 

SPECIES #

19

 

DURATION

112 Min

 

DEPTH/RANGE

To 6.2 m

 

TEMP.

21 C

 

VIS.

6 m

 

SURGE

 

CURRENT

Usual tidal run

 

COMMENTS & OBSERVATIONS

From the shore the visibility looked inviting. As we were gearing up though, it appeared as if we might have to dodge several anglers both on the shore and sitting in dinghies over our dive site. Fortunately, one of the boats soon shifted and the shore based angler left, allowing us room to manoeuvre around the remaining dinghy. Cratena lineata, Flabellina lotos and various Unidentia were abundant. A small, juvenile cryptobranch dorid was found under a rock that we are unsure of genus placement so have called our Discodorid sp. 01 for now. The mantle is covered with knobbly pustules.

Taxonomic Diversity:
Possibly due to the high level of hydroid growth, aeolids often figure prominently in our river species list as occurred on this dive. 12 or almost 2/3rds of the total species count were aeolids the balance being made up by 5 phanerobranchs (almost a 1/3rd) and 2 cryptobranchs. This preponderance of aeolids and phanerobranchs might be indicative of the high current (swift tidal habitat) preference of their food sources available in the river – hydroids, anemones and arborescent bryozoans, the gymnodorids of course taking advantage of the high population levels of their prospective prey. A Gymnodoris sp. 10 was photographed consuming a Cratena lineata.

Our Historical data:
– 79 surveys conducted at this site since 22/03/2014.
– 222 species recorded by us at this site.
– Apart from those marked out below Goniobranchus daphne, although not recorded upon this dive, is also commonly sighted (76%).
– This is our second record of Cratena sp. 07 at this site since first recording on 28/04/21.
– This is our second record of Flabellina sp. 04 at this site since our first recorded sighting here on 02/03/16.

Guide to Symbols:
+++ New Species
+ First time sighted at this site
# Most commonly sighted at this site with %

TOTAL SPECIES SIGHTED: 19

 

SPECIES LIST – ALPHABETICAL

Cratena lineata -15
Cratena simba -1
Cratena sp. 07 -4
Discodorid sp. 01 -1 +++
Flabellina lotos ->41
Flabellina rubrolineata ->28
Flabellina sp. 04 -3
Goniodoridella savignyi -3
Goniodoridella sp. 01 ->11 #85%
Gymnodoris sp. 09 -1
Gymnodoris sp. 10 -4
Hypselodoris obscura -1 #89%
Pteraeolidia semperi -1 #82%
Tenellia sibogae -4
Tenellia sp. 23 -1
Trapania brunnea -2
Unidentia sp. 01 ->28
Unidentia sp. 02 -3
Unidentia sp. 08 -3

SPECIES GROUPED BY ORDER

Nudibranchia
Cratena lineata -15
Cratena simba -1
Cratena sp. 07 -4
Discodorid sp. 01 -1 
Flabellina lotos ->41
Flabellina rubrolineata ->28
Flabellina sp. 04 -3
Goniodoridella savignyi -3
Goniodoridella sp. 01 ->11 
Gymnodoris sp. 09 -1
Gymnodoris sp. 10 -4
Hypselodoris obscura -1 
Pteraeolidia semperi -1 
Tenellia sibogae -4
Tenellia sp. 23 -1
Trapania brunnea -2
Unidentia sp. 01 ->28
Unidentia sp. 02 -3
Unidentia sp. 08 -3

Cephalaspidea

Sacoglossa

Umbraculoidea

Pleurobranchoidea

Anaspidea

DIVE IMAGES GALLERY

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