Holdway, DouglasBeyger, Lindsay Alexandra2009-10-132022-03-292009-10-132022-03-292009-08-01https://hdl.handle.net/10155/36Endosulfan is a commonly used organochlorine in Durham Region, Ontario Canada which has known toxic effects on non-target organisms including fish. This research investigated the effects of endosulfan on Florida flagfish (Jordanella floridae), using both continuous and pulse-exposure. The 96 hour continuous exposure LC50 in larval flagfish was 4.35 μg/L; sub-lethal observations included hyperactivity, convulsions, and some axis malformation. The effects of a 4 hour endosulfan pulse-exposure on 7-8 day-old larval growth, reproduction, and survivability were investigated over one full life-cycle. The 4 hour pulse-exposure LC50 value for larval flagfish was 49.7 μg/L; there were no growth or reproductive effects of endosulfan pulse-exposure up to the highest exposure concentration of 10 μg/L. Thus, the life-cycle 4-h pulse-exposure no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) were 3.2 and 10 μg/L endosulfan, respectively, due to significantly higher mortality.enEndosulfanLife-cycleReproductionFlagfishThesis