Dive Report

24-07-2021 La Balsa Park

Jul 24, 2021

DAY/DATE

Saturday

24/07/2021

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 #

13

 

DURATION

77 Min

 

DEPTH/RANGE

To 6.2 m

 

TEMP.

19 C

 

VIS.

5 m

 

SURGE

 

CURRENT

Usual tidal run

 

COMMENTS & OBSERVATIONS

We met up with experienced divers, Tom & Nicola from Nelson Bay (currently at Coffs Harbour) who joined us for the river dive. We are still disappointed with the invertebrate life in the river of late, knowing from past experience how vibrant and diverse it can be. Cratena sp. 07 is still in the river following its first appearance in May of this year. Flabellina sp. 09 was a not-so-common find as was the Knoutsodonta maugeansis found on the turfing algae rather than the encrusting bryozoans that are its food.

Taxonomic Diversity:
Aeolids continue to dominate the river species count and population levels. More than half of the total species count were aeolids with the other 6 being dorids (2 x cryptobranchs & 4 x phanerobranchs).

Our Historical data:
– 80 surveys conducted at this site since 22/03/2014.
– Last surveyed 18/06/2021
– 225 species recorded by us at this site.
– Patterns of abundance are a little difficult to determine without proper statistical analysis but it would appear that Flabellina lotos  and Goniodoridella sp. 01 are most abundant at this site in April to July whereas the other species we see regularly seem to have relatively consistent abundances throughout the year. Unidentia sp. 01 numbers seem to peak around June but this may be skewed because we have still not separated out all of the variations of the earlier dives. Pteraeolidia semperi also has a high sighting percentage here of 81%, but no specimens were to be found this time.

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

TOTAL SPECIES SIGHTED: 13

 

SPECIES LIST – ALPHABETICAL

Bulbaeolidia alba -1
Cratena lineata -4
Cratena sp. 07 -2
Flabellina lotos -30
Flabellina rubrolineata -6
Flabellina sp. 09 -2 +
Goniobranchus daphne -1 #76%
Goniodoridella savignyi -2
Goniodoridella sp. 01 -12 #85%
Gymnodoris sp. 10 -3
Hypselodoris obscura -1 #89%
Knoutsodonta maugeansis -1 +
Unidentia sp. 01 -2

SPECIES GROUPED BY ORDER

Nudibranchia
Bulbaeolidia alba -1
Cratena lineata -4
Cratena sp. 07 -2
Flabellina lotos -30
Flabellina rubrolineata -6
Flabellina sp. 09 -2 
Goniobranchus daphne -1 
Goniodoridella savignyi -2
Goniodoridella sp. 01 -12 
Gymnodoris sp. 10 -3
Hypselodoris obscura -1 
Knoutsodonta maugeansis -1 
Unidentia sp. 01 -2

Cephalaspidea

Sacoglossa

Umbraculoidea

Pleurobranchoidea

Anaspidea

DIVE IMAGES GALLERY

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