An experimental investigation of the burrowing behaviour of Paphies australis (bivalvia: Mesodesmatidae)*

Partly supported by Port of Tauranga Ltd., P.O. Box 1, Mount Maunganui, New Zealand.

Abstract

Laboratory and field experiments examining the burrowing behaviour of the estuarine infaunal bivalve Paphies australis (Bivalvia: Mesodesmatidae) were conducted in two areas of northeastern New Zealand. Field experiments examining reburial showed that when exposed on the sediment surface most P. australis were able to bury within 40 min. Slightly fewer pipi buried during high‐tide trials than during mid‐tide trials. Laboratory experiments established the ability of P. australis of various sizes to burrow up to the sediment surface after being inundated with sediment to a depth of up to 40 cm. P. australis buried under 10 cm of sediment burrowed to the surface at a slower mean rate than those buried under lesser depths of sediment, and variability in ascension rates increased with increasing burial depth. P. australis with an initial upright orientation burrowed and ascended at a greater rate than P. australis placed laterally or inverted. Though capable of ascending through as much as 50 cm of sand in laboratory experiments, there was evidence of decreased ability to respond to repeated burials over 5 and 8 day periods. P. australis is an active burrower which is capable of responding rapidly to inundations and uncoverings by sediments.

Keywords:

• Pipi
• Paphies australis
• burrowing
• orientation
• sediment

Notes

Partly supported by Port of Tauranga Ltd., P.O. Box 1, Mount Maunganui, New Zealand.

Corresponding author. National Institute of Water and Atmospheric Research, P.O. Box 893, Nelson, New Zealand. Tel: [phone]. Fax: [phone]. E‐mail: [email protected].

Leigh Marine Laboratory and School of Environmental and Marine Science, University of Auckland, P.O. Box 349, Warkworth, New Zealand.