title: Oestrogenic markers and reduced population fertile egg production in a sand goby partial life-cycle test.
abstract: Understanding the ecological significance of oestrogenic biomarker responses, seen in field surveys of some UK estuarine fish, requires a suitable model to link biochemical and reproductive effects. The sand goby (Pomatoschistus minutus) is a common inshore fish that has been successfully bred in laboratory aquaria. Juvenile sand goby were continuously exposed to 17beta-oestradiol (E2) during gonadal maturation, and their subsequent reproductive success investigated. Exposure endpoints included hepatic vitellogenin (VTG) mRNA expression and maturation (male nuptial colouration, sperm duct gland- and gonado-somatic indices (SDGSI, GSI)). Reproductive endpoints included spawning behaviour, brood size, fertility and population-level fertile egg production. Measured E2 exposure concentrations were <5 (controls), 17, 71 and 530 ngl(-1). Male maturation decreased with increasing E2 concentration. VTG mRNA expression increased with E2 concentration, but not with duration of exposure. Reproductive endpoints showed progressive impairment with increasing E2 concentration. For most endpoints, the lowest observed effect concentration (LOEC) was 71 ngl(-1), and EC50s were in the range 87-165 ngl(-1). Pre-breeding male colouration, VTG expression and SDGSI were good predictors of subsequent population-level fertile egg production, but GSI was not. The sensitivity of oestrogenic markers in sand goby are comparable to those used in other species, and feral fish populations exhibiting such oestrogenic responses at molecular and organ levels are likely to have reduced fertile egg production.
authors.affiliation: Fisheries Research Services Marine Laboratory, P.O. Box 101, 375 Victoria Road, Aberdeen AB11 9DB, UK. c.robinson@marlab.ac.uk
authors.forename: Craig D
authors.initials: CD
authors.lastname: Robinson
authors.forename: John A
authors.initials: JA
authors.lastname: Craft
authors.forename: Colin F
authors.initials: CF
authors.lastname: Moffat
authors.forename: Ian M
authors.initials: IM
authors.lastname: Davies
authors.forename: Elaine S
authors.initials: ES
authors.lastname: Brown
authors.forename: Colin
authors.initials: C
authors.lastname: Megginson
mesh_terms: D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007928:Lethal Dose 50; D008297:Male; D010473:Perciformes / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism*; D012098:Reproduction / Q000187:drug effects*; D012726:Sexual Behavior, Animal / Q000187:drug effects; D012741:Sexual Maturation / Q000187:drug effects*; D013997:Time Factors; D006113:United Kingdom; D014819:Vitellogenins / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D014819:Vitellogenins; D004958:Estradiol