Distribution and population recovery of Arenicola marina and other benthic fauna after bait digging

Effects of bait digging on distribution and population recovery of Arenicola marina, Hydrobia ulvae and Macoma balthica have been investigated on trial plots at Blackness, Forth estuary (Scotland). A. marina rapidly recolonised the basins created by digging, but had reduced populations on the dug mounds. Its populations were dislocated for over 3 mo after digging. H. ulvae and M. balthica showed enhanced populations on the mounds for up to 2 wk, but were otherwise unaffected by digging. Factors influencing the mode of population recovery are discussed; it is suggested that enhanced basin populations of recolonising A. marina are due substantially to above-surface migration of worms into areas with increased levels of organic matter.