title: Effects of atrazine and chlorothalonil on the reproductive success, development, and growth of early life stage sockeye salmon (Oncorhynchus nerka).
abstract: The effects of 2 currently used commercial pesticide formulations on Pacific sockeye salmon (Oncorhynchus nerka), from fertilization to emergence, were evaluated in a gravel-bed flume incubator that simulated a natural streambed. Embryos were exposed to atrazine at 25 µg/L (low atrazine) or atrazine at 250 µg/L (high atrazine) active ingredient (a.i.), and chlorothalonil at 0.5 µg/L (low chlorothalonil) or chlorothalonil at 5 µg/L a.i. (high chlorothalonil) and examined for effects on developmental success and timing, as well as physical and biochemical growth parameters. Survival to hatch was reduced in the high chlorothalonil group (55% compared with 83% in controls), accompanied by a 24% increase in finfold deformity incidence. Reduced alevin condition factor (2.9-5.4%) at emergence and elevated triglyceride levels were seen in chlorothalonil-exposed fish. Atrazine exposure caused premature hatch (average high atrazine time to 50% hatch [H50] = 100 d postfertilization [dpf]), and chlorothalonil exposure caused delayed hatch (high chlorothalonil H50 = 108 dpf; controls H50 = 102 dpf). All treatments caused premature emergence (average time to 50% emergence [E50]: control E50 = 181 dpf, low chlorothalonil E50 = 175 dpf, high chlorothalonil E50 = 174 dpf, high atrazine E50 = 175 dpf, low atrazine E50 = 174 dpf), highlighting the importance of using a gravel-bed incubator to examine this subtle, but critical endpoint. These alterations indicate that atrazine and chlorothalonil could affect survival of early life stages of sockeye salmon in the wild. Environ Toxicol Chem 2017;36:1354-1364. © 2017 SETAC.
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Du Gas
authors.affiliation: Ocean Pollution Science Program, Vancouver Aquarium Marine Science Center, Vancouver, British Columbia, Canada.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Ross
authors.affiliation: Department of Biology, University of the Fraser Valley, Abbotsford, British Columbia, Canada.
authors.forename: Janessa
authors.initials: J
authors.lastname: Walker
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Marlatt
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kennedy
mesh_terms: D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D004625:Embryo, Nonmammalian / Q000187:drug effects; D012739:Gonadal Steroid Hormones / Q000378:metabolism; D006540:Herbicides / Q000633:toxicity*; D009570:Nitriles / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects*; D012474:Salmon / Q000254:growth & development* / Q000378:metabolism; D013739:Testosterone / Q000378:metabolism; D060753:Water Quality
chemical_list: D012739:Gonadal Steroid Hormones; D006540:Herbicides; D009570:Nitriles; D013739:Testosterone; C005806:tetrachloroisophthalonitrile; D001280:Atrazine
keywords: Commercial formulations; Emergence; Hatch; Pesticides; Salmon