Grampians Clam Shrimp Day – June 18


Bill Gardner

In June 2016 a new species of Clam Shrimp was found in a rock pool at Flat Rock, in the Northern Grampians. and Professor Brian Timms who studies invertebrate biodiversity in a variety of temporary waters across the inland was interested in investigating further. FOGGs decided to assist this June.

In the morning, armed with instructions from Bill and Professor Timms, volunteers went to several different high up areas across the park to collect samples of water and inhabitants. Then we met up at Laharum for Brian to check what was found and to tell us more about these surprising creatures.

  1. Lots were found on Flat Rock, Hollow Mountain and Mt Stapylton…including another new species…limited to that area? None found at Mt William or Lost Lake or track from Beehive falls to Briggs bluff. However the museum has recorded species from Mt Difficult in the past.
  2. One person brought in a sample from Arapiles which was actually a different species (pea shrimp….more rounded clam shape…widespread species)…Arapiles people are going to look harder in that area
  3. FOGG will monitor the Flat Rock pools at monthly intervals until they disappear and let Brian know how the population proceeds over time. Brian is an emeritus professor and is volunteer funding this research largely personally, so FOGG can be very helpful in taking this work in the Grampians forward. So, if you are interested, head out to look for some yourself.
  4. Samples can be posted to Brian in vials with cotton wool moistened with metho.

Some information about clam shrimps:

  1. Live in gnammas…rock pools formed by chemical dissolution of the sandstone at water/ air interface…overhanging brows typical and flat bottoms. Other gnammas in other rock types evolve differently.
  2. Gnammas need to be min 15 cm deep and a couple of metres across to be likely habitat for clam shrimp. Filamentous algae seems to clog them up and is not a hopeful sign in a gnamma…but still worth looking.
  3. Require dry period to mature eggs, so not found in permanent water.
  4. About 30% of eggs hatch on the first rain after dryness…lifecycle is about 6 weeks so limited time to see them.
  5. Hard to see, shadows on sunny days often easier…need to get your eye in.
  6. Filter feeders
  7. Mate guarding…clasp females until they moult when they can be mated with…so often seen joined together. Claspers diagnostic of different species (prevents wasting time trying to mate with wrong species?)
  8. Detailed egg surface structure diagnostic of species. Eggs often lock together to reduce blowing round.

More information on Brian’s other research interests and posters of Brian’s work on gnammas and various shrimp genera are available.

Contact Bill Gardner

  1. Email
  2.  Phone 0438838286

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