Two days a week, Mike Burrell carefully sorts through drawer after drawer filled with seashells.
It’s a lot to fit in for a part-time job.
But the Collection Manager Support Officer for Marine Invertebrates at the South Australian Museum has opened a window in time, stretching back decades.
The seashell collection he is currently working on was donated to the Museum by the family of the late beachcomber and amateur naturalist Trevor John Smith.
The Museum carefully considers each donation request, but decided to accept Trevor’s shell collection, because he had meticulously recorded each specimen’s location and collection date.
This makes the collection a valuable historical resource of Adelaide’s coastal biodiversity.
Trevor’s records suggest he walked Adelaide’s metropolitan beaches almost daily, especially after storms. Between 1955 and 1985, he collected thousands of shells, representing hundreds of species.
Mike (main picture with a now uncommon frilled cockle shell - Bassina disjecta) was appointed two days a week to collate the collection, thanks to a Grassroots Grant from Green Adelaide.
He has just completed the initial progress report and the data will ultimately be uploaded to the Atlas of Living Australia — making it publicly accessible for research, conservation, and community use.
The data is revealing how Adelaide’s coastal biodiversity has changed over 70 years, filling knowledge gaps that modern surveys alone can’t close. The grant and collection have allowed Mike to track changes in molluscan sea life along the Green Adelaide metropolitan Gulf St Vincent area.
“The collection is a record of the composition of the molluscan fauna before the loss of sea grass habitat and over the period when seagrass meadow became degraded,” Mike said.
“The loss of seagrass was a gradual process which occurred with the buildup of the urban area.
“Effluent disposal, fertilizer and pollution in storm water washed into the drainage system and then out to sea which resulted in a substantial loss of seagrass meadows.”
Thanks to the collection, Mike is able to compare these historic records with the iNaturalist citizen science website that commenced in November 2015.
“There are so many records collected over the past decade or so on the platform; even more with the algal bloom,” Mike said.
In an indication just how comprehensive iNaturalist observations are, there have been 38,320 observations of 512 species of mollusc by 902 observers over the past 10 years in the Green Adelaide area.
So, what has Mike found out?
“Initial findings indicate that the molluscan species composition has changed over time,” he said.
“While most species populations appear to remain relatively healthy, sadly some species populations are reduced or even not turning up anymore.
Fortunately, there are now programs in place to rehabilitatethe seagrass meadows and introduce lost oyster reefs.
“In recent years, oyster reefs have been established along the metropolitan coast.
“These reefs attract other marine invertebrates and fish and therefore have a positive environmental effect on marine diversity.”
Mike, who expects to return to volunteering at the Museum once the project is completed, feels the rehabilitation effort can only mean good news for coastal biodiversity.
“I can remember when I was a kid there were shells everywhere, particularly after a storm,” Mike said.
“It’s exciting to continue working through this donated collection to see what other secrets it reveals.”
Visit the South Australian Museum website for more information on our Marine Invertebrates Collection.
