South Australian Bivalves
Amongst the seashells of South Australia, Bivalves are a common feature of the intertidal zone. Some are very common and found by thousands whilst others can be very elusive.
Here are a few that are interesting and make nice display pieces for a collection
This species was originally named as above and the later renamed and sold/traded as Pinna bicolor. Recent work has shown this latter name to be incorrect and the
name has reverted to Pinna dolabrata.
It is endemic to Southern Australia.
It’s common name is ‘Razor Fish’ because of the sharp lips that can be easily stepped on amongst sea weeds at low tide and would cause a very significant cut to bare feet.
it is an intertidal species but usually only found near the extreme low tide area or in shallow water.
It is quite abundant in South Australia, living in silty sand and often completely hidden by seaweed. Beds of Pinna can extend for some way given the sand surface a very brown rough surface.
It’s shell is a great habitat for other shells such as Chama ruderalis, Lepsiella flindersi, Haliotis cyclobates, Patelloida insignis and Ischnochiton contractus.
The muscle of the animal is quite small compared with the relatively large shell but is regarded as a delicacy and often collected and then pickled in vinegar.
Shells can grow quite large ( in excess of 200mm) but as they get older the shell surface seems to get rougher and often the younger, smaller shells are the nicest for specimens. They are a reasonably heavy shell but never easy to send around the world because of their fragile lips.
You may be surprised to find me writing about a shell in a relatively common genus in the VENERIDAE family. However, I have always found this species to be quite interesting as most that I have seen are quite rough and unattractive and yet, in our area (Upper Spencer Gulf, South Australia) it has a very nice pinkish brown periostracum which makes the shell quite attractive.
Circe rivularis occurs close to the low tide mark or in shallow water, usually in sand. It emerges from the sand on the incoming tide.
It is never common with stories that the ethnic population have decimated its numbers by collecting as a food delicacy. It is always an interesting find.
When does a seashell look more like a shed insect shell?…when it’s a Solemya!
It is a glossy black shell with frilled edges and in very thin and fragile.
After a storm, many dead shells can be cast onto the beach but they are almost always damaged.
As the tide starts coming in, these can occasionally be found live, emerging from the intertidal side.
An amazing example of the variety of shape and structure found in the seashell world.
I remember in my early years finding my first live Glycymeris. I thought, at the time, I had found something rare, only to later learn that these are not uncommon. I guess, however, this species has sentimental value for me with the first find still being in my collection.
Glycymeris radians is a very attractive intertidal shell, usually found on sand bars at extreme low tides. It always looks nice in a collection with its dark brown/white colour pattern.
It is interesting that this shell is found in South Australia but also in tropical areas such as Philippines.
These seem to be a sub-tidal species which occasionally occur in shallow water at extreme low tides and, in my collecting area, can turn up on the beach after rough weather.
They are always a pink/purple usually turning to pink in the collection. Other colour forms are said to exist in our State but I am yet to find any.
Another common bivalve and easily dismissed by collectors because of this. These have been used as fish-bait for many years and are now becoming very expensive to purchase for that use. It seems that they have been over-fished and the supply has diminished. The Government has now applied non-collecting periods to the beaches to help preserve the species and hopefully, invrease the available numbers.
Some interesting colour variations can be found amongst the usually pinkish shells.
I have to admit to having too many of these in my collection….I just cannot resist adding the different colours and shells from different locations when I find them.
Like most scallop shells, these can be very beautiful and occur in a broad range of colour patterns.
Deep violet is the most common but occasionally the collector can be lucky enough to find various orange-yellow shells. A pure Yellow shell is the prize colour, particularly if found in a large size
Mimachlamys asperrima is sometimes washed ashore after storms and do not seem to continuously occur at any locality on a consistent basis.
Just a small sample of the many species of Bivalves that South Australia has to offer the Collector
As I sit here sorting and cataloguing shells, I am also pondering where my collecting is heading. I have basically collected everything but specialise in South Australian and Philippine shells.
The future for collecting South Australian shells is under a huge cloud at present!
For some time South Australian Fisheries departments have had plans out to the public for the creation of new Marine Reserves. Whilst this has been prompted mainly beacause of concerns for the fishing industry and conservation of fish stocks, there is little doubt that it will be applied to other marine creatures e.g. shells.
Conservation methods are not new..there are already size limits on most fish species, also on crabs and bag limits on common shellfish such as razor fish (Pinna dolabrata) in our State
Currently there is a bag limit of collecting of Cypraea thersites on one per person per day (not that that has any effect on the unscrupulous collectors)
Rumours suggest that a blanket ban on collecting shells in marine parks could apply. As these parks could cover in excess of 70% of our coastline, it will be the death of collecting South Australian shells if the rumours are correct.
There is also talk of stopping the selling of South Australian shells and even the swapping of these. The rumours also suggest the creation of completely protected species……Cassis fimbriata is one example.
So what does all this mean?
Well until the marine parks and legislation is completed we cannot be sure. My best guess is that even common South Australian shells will disappear from the market sometime next year. Of course I could be wrong ( and I hope that some thought is given to the hobby by the Fisheries officials), but if you have an interest in South Australian shells, be warned that they may become items that are not as readily available as they are now.
On another topic it seems all sorts of negotiations and discussions are also being held re Philippine shells and conservation and more prosecutions for collecting of protected species is now occurring……..a sign of the times for shell collecting as a hobby?
Phasianella australis was one of the first ever seashells that I found on a beach when I started collecting. What is surprising is that, dead shells of this species regularly wash onto our local beaches (top end of Spencer Gulf – South Australia) and yet I am still to find a live specimen in this area.
Having explored many Yorke Peninsula beaches, it is fairly obvious from beach drift that this is a common species in this area and yet live specimens can prove to be quite elusive!
Phasianella australis Gmelin, 1791 is known by the common name Pheasant shell. It is tall-spired with a teleoconch of six whorls. It is reported as living from Bass Strait (Victoria) to about Geraldton (Western Australia).
I would briefly like to touch on three topics relating to this species (more…)