WESTERN AUSTRALIA's BALER SHELLS You May Occasionally

Thebountiful baler by Alan Kendrick, John Huisman and Michael Rule aler shells belong to the genus Melo extensive reefs, rock pools and tidal flats and include some of the largest that become exposed as tides recede. Band most well-known species Other northern species have more limited of the mollusc family Volutidae, which distributions, such as Melo ashmorensis, occur in many marine habitats around which was only described in 2005 and has You may occasionally chance the world. Most common in the southern so far been recorded only from offshore upon a weathered and broken hemisphere, volutes are particularly reefs of north-western Australia. In baler shell on nearly any beach diverse in Australia’s coastal seas, where contrast, only one species, the southern in Western Australia as these about a third of all known species can be baler (Melo miltonis) occurs in WA south found. While they occur around Australia, of Shark Bay. This is the largest marine large marine shells occur different baler shell species occur in the gastropod in coastal waters of Australia’s around the entire coast. While a tropical north and temperate south. south coast. Characteristically smaller beachcomber may even find a than the northern baler, this shell rarely strikingly patterned intact shell, WESTERN AUSTRALIA’S BALER exceeds 35 centimetres in length and has the more observant visitor may SHELLS a narrower shell with incurving spines on the spire and a strikingly patterned brown be lucky enough to see a living Four species are currently recognised from northern Australia, where the aptly and white body. Due to the smaller tides specimen of these distinctive named northern baler (Melo amphora) and less extensive intertidal habitats of gastropods in any of WA’s oceanic is the most prevalent. This species is WA’s south, southern balers are more marine parks and reserves. distributed across the north of Australia frequently seen alive by divers. These impressive shells are not and extends down the Western Australian Baler shells breed by producing a uncommon in intertidal and coast to Shark Bay. Northern balers large, leathery egg-mass that is fixed to can grow to about 50 centimetres in a firm structure on the seabed. The egg shallow marine habitats, but may length with highly domed shells that may mass comprises about 100 capsules (each be well camouflaged with algae become covered in algae as they age. containing an embryo) joined in rows. or partially buried in sand or The distinctive straight shoulder spines Upon hatching, the young undergo direct muddy sediments. on the spire are prominent on smaller development; that is they lack the pelagic individuals, but are often eroded or lost or free floating larval stage common to with age. Northern balers can often be many molluscs and move from the egg seen along WA’s northern coast on the directly to the seabed when they are 40 LANDSCOPE “… baler shell artefacts were also distributed far from the coast into central Australia along trade routes and examples have been found in the Great Sandy Desert in WA …” about 2.5 centimetres in length. (See also throwers and objects like pendants that Opposite page ‘Understanding marine ‘connectivity’’, had high ceremonial value. The common Main A northern baler in shallow water at the LANDSCOPE, Winter 2016.) One occurrence of baler shells in neolithic Montebello Islands Marine Park. Photo – Suzanne Long/Parks and Wildlife consequence of this lack of dispersion is burials in the Philippines and other sites Left A young southern baler showing its that genetic mixing between populations is throughout the Pacific suggests that these distinctively patterned body at Shoalwater limited, causing balers of the same species shells were ritually important. Islands Marine Park. in different locations to vary considerably The long use of baler shells by Aboriginal Photo – John Huisman/Parks and Wildlife in their shell form and colour pattern. people in WA can be seen in shell middens Above left A northern baler at Long Reef, Interestingly, baler shells with an apparent associated with human occupation along the northern Kimberley. mix of M. amphora and M. miltonis features coast over thousands of years, at locations like Photo – Clay Bryce/WA Museum occur where the ranges of these species rock shelters near Monkey Mia at Shark Bay overlap at Shark Bay, suggesting that the and Mandu Mandu on the Ningaloo coast. Above A northern baler laying an egg mass. northern and southern species may hybridise In WA’s Kimberley region, baler shells Photo – Alan Kendrick/Parks and Wildlife at this location. All volutes are thought were used to collect and store water, and to be carnivores and commonly feed on also to mark water sources. The incongruous other molluscs. Southern baler shells are presence of a baler shell in the arid interior known to feed on quite large molluscs landscape would inform traditional owners like turban shells and abalone. Baler shells or visiting people of a nearby source of themselves have been recorded as prey water. Evidence shows that baler shell consumed by tiger sharks (Galeocerdo artefacts were also distributed far from Alan Kendrick is Parks and Wildlife’s cuvier) caught off the WA coast. marine science program leader. He can be the coast into central Australia along trade contacted on (08) 9219 9793 or by email routes and examples have been found in A LONG ASSOCIATION WITH ([email protected]). the Great Sandy Desert in WA and the John Huisman is the Parks and PEOPLE Flinders Range in South Australia. Wildlife WA Herbarium curator. He can be Baler shells have provided food and So while baler shells have held value contacted on (08) 9219 9137 or by email ([email protected]). useful materials for Indigenous people for for Indigenous people throughout the Michael Rule is a Parks and Wildlife a very long time in Australia and more region over thousands of years, today they temperate research scientist. He can be broadly across south-east Asia. The shells may simply play a role in brightening up a contacted on (08) 9219 9800 or by email were formed into scrapers and adzes, walk along the beach or add interest to a ([email protected]). spoons and containers, discs for spear- swim, snorkel or dive. LANDSCOPE 41.

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