For these 2 images the SUBJECT fish is the adult, but please note that there is a small juvenile facing camera to R of the adult.
(On this roughly 2 hours dive from new jetty to outer old jetty including all of the eastern arm of the T section and the "grid " in about 10m depth alongside that section, I saw the greatest number of blue devils I've ever seen for the location. Ranging from small juveniles to large adults. Within the past decade or so there has clearly been considerable recruitment of the species on site. Can but guess why, as I've been saying in some of my observations from some earlier dives here. Possibly the increased protection of nearby populations-Rapid Head Green Sanctuary Zone in particular-,possibly ocean warming, possibly both, and perhaps there are other reasons yet to be considered.,eg the collapse of much of the inshore section of the old jetty has prevented recreational fishers from having shore access to the outer old jetty, and perhaps anthropogenic reduced predation eg by over extraction of many likely predator species such as Snapper and Harlequin Fish).

In these images the same two large adults are shown interacting, probably a territorial tiff given the "kissing " action of one in the 3rd image.
I nominate the nearer of the two as the SUBJECT individual for this series (the individual ideally should be specified for any inat observations where images include more than one individual, because every individual has unique facial markings. Therefore an individual can be tracked over time, in similar fashion to leafy seadragons and probably other species eg? Harlequin Fish).

For those who have read the Notes in my preceding observation of the juvenile Dusky Morwong, these Bullseyes (not a target species) were photographed as near as I can tell to the exact line on the map that marks the southern (SW more specifically) limit of the disappointingly tiny "No Spearfishing " area for this iconic little coastal enclave.
(Declaration of personal interest:-I started my 6 decades of exploring SA marine life as an amateur spearo under age 10 years. Like many of my generation, I soon moved on. But I still recall the stark fact that after our small group of teenage snorkellers had hammered our favourite shore access Spearfishing sites (not Second Valley, but nearby eg Normanville, Carrickalinga and Willunga) each summer school break, after even a few days of intensive forays early each warm season, our favourite spots became virtual deserts. The hapless 'sitting duck ' species we were spearing seemed to vanish for some months. But next summer we would repeat the slaughter,with the same outcome. The key factors that made this phase of our lives blissfully brief- less than a decade- were that we were able at age 16 to do entry level scuba training, and the fact that underwater cameras had just become widely available (and affordable for most),notably the Nikonos series.
Not forgetting that in SA (and most other States I think) it was already illegal to spear anything while using SCUBA or hookah equipment.
Now that was a great example of timely and progressive legislation, if ever there was one.
Not that I have become cynical with age...).

Snorkel in Kaurna pool Lady Bay platform reef some months after dreadful black silt catchment outflows temporarily blanketed most of littoral zone in this lower energy corner of Yankalilla Bay
Depth half a metre or so
(Makes me wonder why the black headed zebrafish adult variants became evident around that time ,after I'd never seen anything like it for preceding half decade ,approx.)

Cropped and heavily cropped versions of this photo, originally posted with the leatherjacket as subject (Toothbrush I think).Now the subject is the few pencil weed whiting (which appear adult rather than juvenile),several being close to the leatherjacket (which I recall was almost stationary).And one on the R is probably actually cleaning the Leatherjacket, best seen at centre in 2nd image.

I've just noticed that this Castelnau's Wrasse which was the Subject of an earlier submission from this dive is being cleaned by a young Pencil Weed-Whiting. So, the head up bobbing posture so often associated with this Wrasse species is also used as a client posture during cleaning. (Juvenile Pencil Weed Whiting are known facultative cleaner hosts, but are harder to capture in the act than eg Western Cleaner Clingfish which are effectively full time hosts, as far as is known).

This leatherjacket convinced me that it was actually eating bits of the jellyfish (an Australian Sea Nettle which are currently very common here),although I admit that I can't be certain. Another possibility could be that by disabling the jellyfish, any juvenile trevallies would be vulnerable to predation, because they would face a long swim in open water to find another intact Australian Sea Nettle (, despite this jellyfish being common distances between individuals on this dive was still many, many metres).

Note the Western Cleaner Clingfish on the sea tulip at upper R. This is another typical cleaning services host client interface, but my presence has probably interrupted proceedings.

[As is often the case when any diver, knowingly or unknowingly, gets too close to a cleaning station. The 2 most frequently observed consequences are #1: the current or prospective client(s) back off, fearing predation, and perhaps accepting the likelihood that a much larger prospective client hovering nearby is more appealing to the host cf #2.

2: The host abandons the current client, even though that fish still has parasites requiring removal, and swims actively towards the bigger "fish aka diver"-sometimes latching directly onto camera, face mask or other external surfaces including neoprene and exposed skin.

We believe that in such cases the Western Cleaner Clingfish thinks such a large client must have more parasites etc ie is a better food source.Until its investigated, and learns otherwise.
Anecdotally I think that at places like Rapid Bay jetty, where divers have become so numerous as to be ubiquitous, WCCs are less likely to allow divers to jump a client queue. They have learned that with divers size doesn't equate with more food, so they don't bother checking us out.
Perhaps they have plans B and C?
Plan B= leave their station and follow an existing client a short distance to where the client has retreated, to continue where it left off.
Plan C=wait impatiently for diver to move on, so the WCC can resume normal services.
(And I could speculate on a Plan D,etc, but enough is enough!)]

I don't often see juvenile Scalyfin in cup sponges, FWIW.
And on close zooming I think there's a (probably also juvenile) Western Cleaner Clingfish at the scalyfin's gill slit.
Makes sense, as Scalyfin adults are known to use the services of WCCs, so juveniles would surely need the same.

Older juvenile near centre ,heading towards a Silver Drummer and a Sea Sweep,and there's a small female Brownspotted Wrasse not far beyond the Moonlighter. Feasibly a host client cleaning interaction; not that convincing but I am adding it to the Temperate Marine Cleaner project. It may be worth noting that we saw reasonable numbers of older juvenile or adolescent Moonlighters on this snorkel close to the cliffs, but very few decent sized adults. Since we were in about the middle of the shoreline section of this Green Sanctuary Zone, there should be no shortage of mature adults. So perhaps the cliffs base nooks and crannies encourage the younger Moonlighters to provide cleaning services there, especially towards low tide, while the full adults spend more time on the offshore reefs at such times? Pure speculation, hmm...🫢.

As found in shallowest subtidal at low tide.
Note:-Flat calm, no wind, partial to full sun,so water close to shore was surprisingly warm for time of year. I didn't feel cold even after almost 3 hours in the water and I wore only a 2mm wetsuit. I saw no dead or overtly heat stressed motile lifeforms.
But I suspect that if there'd been a dodge tide (prolonged lack of tidal exchange akin to " missing a tide",being a phenomenon essentially unique to SA's main gulfs),many of the shallowest subtidal and intertidal lifeforms would have suffered severely. This is known to occur occasionally on dodge tides during any warm season, and until recently acute dieoffs of littoral zone reef lifeforms during dodge tides were considered natural phenomena. However, climate change will surely exacerbate the number and severity of such events.
Also worth noting is the trend in SA and other parts of southern Australia towards increased 'monsoonal ' warm season rainfall.(Along with lower cool season rainfall: average annual rainfall in SA is expected to decrease slightly, but the % occurring in the warm season will increase considerably, according to meteorological forecasts. The rapidity of these changes means they are largely anthropogenic.)
So, inevitably we will experience dodge tides (normal) coinciding with abnormally big summer rain events.
This warm season trend (combinations of lower salinity due dilution via catchment outflows with higher water temperatures ( without even mentioning anthropogenic nutrient excess!) means that catastrophic die-offs on intertidal and shallow subtidal reefs in the upper to mid Gulfs will become more frequent.
So monitoring of the shallowest parts of the Great Southern Reef is a high priority.
Currently in SA most of the modest funding available for monitoring and protecting coastal ecosystems focuses on seagrass retention, restoration of shellfish reefs,mitigation of beach sand loss, and maintenance of commercially important fish stocks.All hugely important facets, but not yet a holistic approach.
Whew, that is enough from the pessimistic side of this ecodiver 🫢.

Freshly beach washed on receding early morning tide. Still alive with intermittent symmetrical gasps (gills open and close several times in 1-2 seconds then no sign of life for 2-5 seconds). Arched body sideways when 1st touched with tip of a boot then no further overt response to touch.
About 56cm TL.
I returned it to the water as carefully as possible and it appeared to show some recovery within 15-30 seconds, eventually swimming a few metres, right way up. But I don't think it will survive, based on the unknown reason(s) for its being weakened to the point of stranding. Its now nearly a week since the last decent local rain event, which did open the mouths of the local estuaries including the Bungala River and Carrickalinga Creek, so it may have suffered from the dilutional or other effects of these point source discharges. It doesn't look emaciated eg from certain types of internal parasites, and has no external evidence of traumatic injury, certainly no penetrative wounds.

With a Striped Sea Louse male on mouth. This was one of many adult smooth toadies seen on this shallow intertidal and subtidal snorkel(in image 2 a second one is almost fully buried in lower frame),but was the only one with a visible parasite externally.

Smallish adult (estimated TL 40cm), at 8 to 8.5m at the T Junction. Quite inquisitive but also suitably wary; would flee whenever I turned towards it with camera. If I've ever seen adults or juveniles here before, I don't remember, but I definitely wasn't able to get images, or I'd certainly have posted those here.
Otherwise, I have only ever seen adults (one or two) off KI's NW coast.
And small juveniles at the Salmon Hole Beachport.

NB: Perhaps the species is moving into upper GSV, perhaps it's just a vagrant, or perhaps it's been established here long-term i.e. at extreme edge of range.