title: Intersex in the clam Scrobicularia plana (Da Costa): Widespread occurrence in English Channel estuaries and surrounding areas.
abstract: Estuarine clams Scrobicularia plana were sampled from 108 intertidal locations around the English Channel and adjacent areas. Although S. plana is believed to be a strict gonochorist, 58% of the populations sampled included intersexed individuals (described as male clams exhibiting ovotestis). Over the entire region, on average, 8.6% of male clams exhibited intersex, although proportions of affected males ranged from 0% to 53% depending on location. The severity of intersex was assessed using a simple classification scale, with the majority of individuals showing low levels of impact. Sex ratios were significantly skewed at some sites. There were no significant relationships between incidence or severity of intersex; or with size or parasitism of individual clams. Intersex in S. plana is a useful tool to assess endocrine disruptive effects in estuaries, although mechanisms of impact and causative agents remain uncertain.
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK. Electronic address: ndpo@mba.ac.uk.
authors.forename: N D
authors.initials: ND
authors.lastname: Pope
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: K
authors.initials: K
authors.lastname: Childs
authors.affiliation: Laboratory of Ecotoxicology, Universite du Havre, BP540, 76058 Le Havre, France.
authors.forename: C
authors.initials: C
authors.lastname: Dang
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: M S
authors.initials: MS
authors.lastname: Davey
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: S C M
authors.initials: SC
authors.lastname: O'Hara
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: K
authors.initials: K
authors.lastname: Langston
authors.affiliation: Laboratory of Ecotoxicology, Universite du Havre, BP540, 76058 Le Havre, France.
authors.forename: C
authors.initials: C
authors.lastname: Minier
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: P L
authors.initials: PL
authors.lastname: Pascoe
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: E
authors.initials: E
authors.lastname: Shortridge
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: W J
authors.initials: WJ
authors.lastname: Langston
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000502:physiology*; D012734:Disorders of Sex Development; D004784:Environmental Monitoring; D063366:Estuaries; D005260:Female; D005602:France; D008297:Male; D012744:Sex Ratio; D006113:United Kingdom; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical
keywords: Endocrine disruption; English Channel; Intersex; Scrobicularia plana; Sex ratio