COMMENTS & OBSERVATIONS

Early morning dive at Horseshoe Bay to beat the winds. Conditions were partly cloudy and we had an outgoing tide but reasonable visibility (once past the carpet of sunken Trichodesmium that was covering the sand). Although the swell was very small, we had a slight surge which increased as the tide fell.

Numbers of sea slugs are still down but we did find a few, some of which we have only seen once before. The Pelagella joubini looked like a bit of algae but the colour hinted at something different and closer inspection paid off. Even the Hypselodoris tryoni was small, things never seem to grow up here! We exited just in time as the winds were picking up and the surge increasing, but still a nice dive.

Taxonomic data:
Four of the five species sighted were nudibranchs, all four being dorids comprising 1 x porostomes (suctorial feeders), 1 x phanerobranchs (non-retractile gill), 2 x cryptobranch (retractable gill); and nil cladobranchs comprising 0 x aeolids, 0 x arminids and 0 x dendronotinids. A single sacoglossan completes the sightings. A total of 6 specimens were sighted. If diet is considered, three of the five were spongivores.

Historical Data:
– We have now completed 29 survey dives at Horseshoe Bay since our first survey here on 12/06/2018.
– We have recorded 69 species at this site.
– The species we record most often at this site are Gymnodoris sp. 35 (38% of dives), Samla bicolor (28%), Hypselodoris tryoni (28%) and Elysia sp. 30 (28%).
– The most prevalent species we record here are Elysia sp. 30 (0.9 per dive), Elysia sp. 31 (0.8), Gymnodoris sp. 35 (0.8), and Samla bicolor (0.7).
– We have recorded all of the species seen on this survey at this site before. However it is only the second time we have recorded Pelagella joubini in the Whitsundays. The previous occasion was at this site on 24/04/2025.
– Our last survey at this site was on 13/02/2026.
(Historical data courtesy of Terry Farr, who extracts it from his comprehensive database.)

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

TOTAL SPECIES SIGHTED: 5

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