Published online by Cambridge University Press: 20 March 2001
Prevalence of the parasite Hemioniscus balani (Isopoda: Cryptoniscidae) was determined in intertidal barnacles Semibalanus balanoides collected from north-east England during winter 1989–1990 and March 2000. Infection by female and male stages of the parasite were low (0·0–13·6% and 0·0–9·9%, respectively). Female stages were usually more prevalent lower down the shore, and were more common among larger barnacles. The observed rates of parasitism are similar to those recorded in the region 40–50 years ago.