Marine Biology

, Volume 147, Issue 4, pp 943–953

Burrow morphology, biometry, age and growth of piddocks (Mollusca: Bivalvia: Pholadidae) on the south coast of England


    • School of Biological SciencesUniversity of Southampton
    • Joint Nature Conservation Committee
  • C. A. Richardson
    • School of Ocean SciencesUniversity of Wales Bangor
  • R. C. Thompson
    • School of Biological SciencesUniversity of Plymouth
  • S. J. Hawkins
    • School of Biological SciencesUniversity of Southampton
    • The LaboratoryMarine Biological Association
Research Article

DOI: 10.1007/s00227-005-1582-0

Cite this article as:
Pinn, E.H., Richardson, C.A., Thompson, R.C. et al. Marine Biology (2005) 147: 943. doi:10.1007/s00227-005-1582-0


Biometry and growth of three piddock species Pholas dactylus, Barnea candida and B. parva, from chalk and clay substrata were investigated between 1999 and 2000 at five low shore locations along the south coast of England. Piddock burrow shape was significantly different (P<0.01) amongst the locations. Burrows at Lyme Regis showed the largest (height/maximum diameter) ratio (4.86±2.00) whilst those at Compton the lowest (3.73±1.62). Using the method of Bhattacharya, the population structure of P. dactylus, B. candida and B. parva was separated into eight, three and five modal size classes, respectively. Age and shell growth were determined from the number and spacing, respectively, of annual growth lines present in acetate peel replicas of shell sections. The von Bertalanffy growth (VBG) equation fitted the size at age data obtained for P. dactylus and B. candida (L and K were 79.3±13.8 mm and 0.0011±0.22 and 29.6±1.5 mm and 1.17±0.47, respectively) whilst the size at age data for B. parva were linearly related and did not fit the assumptions of the VBG equation. Male and female gonads were mature and piddocks competent to spawn between June and September 1999, with settlement of juveniles observed between November 1999 and February 2000. A significant relationship between burrow aperture diameter and age of the occupant piddock was established for the three species. Burrow morphology and spatial distribution of burrows were influenced by substratum hardness and population density. Based on estimates at Lyme Regis, piddocks are capable of removing up to 41% of the shore substratum to a depth of 85 mm over their lifespan (12 years), significantly compromising the structural stability of the soft rock shores they inhabit and contributing to bioerosion.

Copyright information

© Springer-Verlag 2005