Favoritos de davemmdave

Large aggregation in about 2m depth via snorkel. I estimate there were at least 70, and probably closer to 80-90.Most were mature adults but some older juveniles or immature younger ones were present peripheral to the main aggregation which formed a veritable mound of many individuals over many square metres of benthos.

Cropped version of the image posted earlier from this dive. (When the subject was the abalone shells found under a piece of jetty junk).The subject is now the ascidians that are brown with tinges of pink orange and mauve, and they have dark dull red 'mouths',some with a suggestion of paler red bands . They are epibiotic on this abalone (as are several other life forms but the subject Tunicates dominate).
They may be a known naturally occurring ascidian species,and are similar to several common species coating the lower parts of some jetty piles, however I wonder if they might be an introduced species?

Moderately big dense bushy shrub about 1 m high and almost 2 m wide growing in deep shade of moist understory near bank of a quiet billabong within Wirrina Resort access gully road.Some surrounding plants( of other species such as Melaleucas and possibly other genus members but no other bush pea native legumes such as Pultaenea or Dilwynia were present as natural occurrences or planted specimens) may have been planted but the wetland canopy was all naturally occurring Eucalyptus camaldulensis and the aquatic plants included many thriving Water Ribbons with various reeds sedges and rushes around edges)

This arrangement is shown as I found it. I was the only diver present AFAIK during my time underwater that afternoon but as I entered from new jetty a dive boat was just departing from much further out, and I expect that there were probably plenty of shore based divers entering and leaving via the new jetty during the morning and earlier afternoon, being good weather at this popular dive site. So I don't know if this odd looking arrangement of dead (and live) molluscs is anthropogenic (set up by divers) or a natural scene, perhaps connected to an octopus, bobtail squid or other cephalopod ,eg to attract a mate? I suspect the latter.

The abalone on the rock (upper frame) and the scallop (lower R) are alive and probably incidentally present, both being common on this dive.
But the dead bivalves within other dead bivalves of same species (queen scallops and pipis, the latter being discarded by jetty fishers and present everywhere within casting distance and more, wrt the new jetty plus the occasional trailer boat used for fishing in the vicinity) are clearly the work of an animal, humans and cephalopods being the 2 main contenders.

I'll resubmit the image for each main content species but for now the SUBJECT is the live scallop at lower R.

Images 1-8

1. Algae in a rock pool at low tide.
2. Sample taken was approximately 2cm tall.
3. Filament tips.
4. Branching.
5. Branching from a base filament bearing rhizoids.
6. Cell structure.
7. Rhizoid end cut off from pericentral cells.
8. 5 pericentral cells evident.

Images 1-6

1. Turfing algae in situ. Located in a rock pool growing on bivalves.
2. Small piece taken from a tough gristly plant still attached to a bivalve at time of sampling.
3. Slightly closer view of sample. A 10 cents coin edge just visible for scale.
4. A cross section focussing on central portion of thallus.
5. Changed focus slightly to bring outer cells more into focus.
6. An accidental oblique slice through thallus also revealing cell structure.

Images 1-10

1. Algae found in a rock pool at low tide.
2. Specimen was about 6cm tall.
3. Quite profuse spiral branching.
4. Apices tapering to a point.
5. Filament tip at higher magnification.
6. Cell structure. Longer in middle parts than near branch tips.
7. Cells.
8. Tetraspores.
9. Trichoblasts not that frequent.
10. Cross section (after many attempts) in centre of image shows 4 pericentral cells.

Images 1-7

1. Specimens on a shell washed up on beach - resident amongst other algae (Polysiphonia and Ulva).
2. Close-up of a single specimen -approx 3cm long with main blades approx 1mm across.
3. Many entangled individuals. Irregular branching. Relatively tapered branch ends.
4. Surface view of cells.
5. Branch end under higher magnification. Slightly curved.
6. Branch tip showing outer sheath.
7. Cross section revealing medullary region.

Voucher specimen D.Nicolle 6370 & M.E.French (original + F1 seedlings).

True mallee to 2 metres tall. Bark smooth throughout. Adult leaves glossy, dark green. Common on upper slopes between granite domes with Eucalyptus ligulata subsp. ligulata and E. dorotoxylon.

Seedling leaves ±ovate, ±concolorous, dull, light green, non-pruinose, scabrid. Stems terete, densely glandular/hairy.

Voucher observation D.Nicolle 8592.

Trees to 8 metres tall, many individuals several-trunked. No mature fruits in canopy.
Dominant here, forming open woodland with some Corymbia greeniana on pale orange gravelly loam.

SUBJECT for ID=the numerous bright yellow tent-shaped things lining the underside of the rock nearer the bottom.When I photographed them(with difficulty in poor light and confined space) I assumed they were small ascidians (e.g.in Pycnoclavella genus) but zooming now suggests egg capsules of some sort of mollusc.Some appear empty,also.
If they are egg capsules I've no idea what type of mollusc makes them,but one or other of the various reef-inhabiting, typically medium to large gastropod snails with solid shells would be my best guess.