Variations in sampling procedure and frequency affect estimates of recruitment of barnacles

For Semibalanus balanoides on an intertidal rocky shore at Sandy Cove, Nova Scotia, the effect of sampling procedure (removing or not removing barnacles after sampling) on estimates of recruitment varied with intertidal height. There was no effect of sampling procedure in the mid-intertidal zone, but in the low zone, where recruitment was on average four times larger, the estimate of recruitment was significantly greater from quadrats where barnacles had been removed after sampling. Estimates of recruitment and post-settlement mortality decreased exponentially as the sampling frequency decreased. -from Authors