COMMENTS & OBSERVATIONS

While the viz is up and the surge is down dive sites around Mudjimba Island will be surveyed. Saturday the first day of April was just such a day. It seemed like everybody who had something that floated was out on the water making the most of the glorious conditions. Goniobranchus splendidus were sprinkled all over the site many quite small so they will be there for some time. Two Aegires gardineri were recorded, one almost totally covered with black pigment over the yellow but the other only had a few large spots. A different porostome (suctorial feeder) other than the usual phyllidiids was recorded, Dendrodoris fumata under a rock. Thorunna daniellae and Verconia haliclona were nice finds.

Taxonomic Diversity:
20 of the 21 species sighted were nudibranchs, with 15 being dorids comprising 2 x phanerobranch (non-retractile gill), 5 x porostome (suctorial feeders – all bar one (Dendrodoris) of the Phyllidiidae family), 8 x cryptobranchs (retractable gill – all belonging to the Chromodorididae family) and 5 x cladobranchs comprising 2 x aeolid, 1 x arminid and 2 x dendronotinids. One Sacoglossa rounds out the species numbers. If diet is considered then 14 of the 21 species sighted are spongivores.

Our Historical Data:
– This excursion brings the number of survey dives to 13 at this site since we commenced fully recording data here on 18/11/2011.
– 97 species have been recorded at this site.
– The most regularly recorded species at this site are: Doriprismatica atromarginata (100%), Hypselodoris jacksoni (92%), Phyllidiella pustulosa (92%) and Goniobranchus splendidus (85%).
– The last surveys conducted at this site were exceptional because of the number of new species recorded here (1/3 of the sightings). On these surveys, 3 species (Dendrodoris fumata, Dermatobranchus oculus and Verconia haliclona) were recorded here by us for the first time.
– The number of Goniobranchus splendidus specimens remains high.
– At the time of the last survey at this site we noted a slight downturn in the number of species and organisms sighted and noted some cautions in interpreting this. The current surveys show a reversal in this trend. The increase in the number or organisms being largely the result in the large number of Goniobranchus splendidus sighted (see graph in image gallery below). We have sighted large numbers of this species on a number of our recent surveys around Mudjimba Island.
– Gymnodoris sp. 30 was also recorded. We have previously called this species Gymnodoris alba but have changed the name to indicate this as an undescribed species following a review of a paper by Knutson & Gosliner (2022). We have recorded this species under the previous name at this site on 25/11/2011. [Knutson, V. L. & Gosliner, T. M. (2022). The first phylogenetic and species delimitation study of the nudibranch genus Gymnodoris reveals high species diversity (Gastropoda: Nudibranchia). Molecular Phylogenetics and Evolution 171.]
– This site last surveyed on 24/11/2022.
(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: 21

DIVE IMAGES GALLERY

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