Plebidonax deltoides

Plebidonax deltoides, known as pipi in the eastern Australian states, and goolwa cockle in South Australia, is a small, edible saltwater clam or marine bivalve mollusc of the family Donacidae, endemic to Australia. It was previously known as Donax deltoides. Other names for the shellfish are Coorong cockle and ugari or eugarie. Plebidonax deltoides is a moderate-sized bivalve that is strong, triangular, and wedge-shaped, with both valves equal in size and a mirror image of one another. The sculpture on the shell consists of numerous very fine radial striations. Shell colour is bluish-white, tinted with cream, brown, olive, pink, yellow or rose. It is covered with a greenish-brown periostracum. The shell interior may be purple-mauve, dark violet or a pink tinge. It is found on sandy shores on surf beaches, between rocky headlands. It usually occurs 5 cm below the surface near low water level. There are two breathing siphons, one a little larger than the other. The larger siphon has a ring of papillae around its entrance to protect it from washed in sand. The smaller siphon is for the outgoing water. Plebidonax deltoides is greatly valued by beach fishermen as bait. It is also collected commercially for human consumption, and in some areas they have been sold as "Butter Clams". There is a bag limit of 50 for each collector along New South Wales shores, while in South Australia, goolwa cockles should not be taken between 1 June to 30 November. The two major threats are over-collecting and recreational vehicles travelling along long sandy beaches near the low-water mark. Although the shellfish appear to be very common on most sandy beaches, many are killed by fishermen for bait, collected for food, or crushed by 4WD vehicles. Maximum length is 60 mm.

References

• Australian Government Department of Environment
• WikiSpecies