Spelling suggestions: "subject:"flatfish"" "subject:"hagfish""
1 |
Growth, survivability, and reproductive effects of pulse-dosed endosulfan on jordanella floridae (florida flagfish) over one complete life-cycleBeyger, Lindsay Alexandra 01 August 2009 (has links)
Endosulfan 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.
|
2 |
Effects of chronic exposure to ibuprofen and naproxen on Florida flagfish (Jordanella floridae) over one complete life-cycleNesbitt, Richard 01 August 2011 (has links)
Nonsteroidal anti-inflammatory drugs (NSAIDs) are a class of drugs prescribed to relieve pain, fever and inflammation, and are among the most commonly consumed medications in Ontario. Approximately 70% of the ingested dose is excreted unchanged or as an active metabolite, much of which reaches the surface waters of lakes and rivers. NSAIDs function through the inhibition of cyclooxygenase (COX), an enzyme present in two isoforms in the body; the constitutively expressed COX-1 and the inducible COX-2. Traditional NSAIDs like ibuprofen inhibit both isoforms with little selectivity while newer variants such as naproxen preferentially inhibit COX-2. Both COX isoforms share a high similarity between humans and fish creating a potential for off target effects to exposed aquatic organisms. This research investigated the chronic effects of waterborne exposure to 0, 0.1, 1, 10 and 100 μg/L of a nonselective and selective NSAID (ibuprofen and naproxen, respectively) on Florida flagfish (Jordanella floridae) over one complete life-cycle. Chronic exposure concentrations were selected by performing a short term experiment which examined the hatchability of flagfish eggs using continuous semi-static exposure conditions. Growth, survivability and reproductive endpoints were assessed in the life-cycle study. A concentration-response relationship for both NSAIDs was detected during the first 28 days post-hatch, resulting in increased body length for F1 fish and their offspring with increasing concentrations. Exposure to 0.1 μg/L of both ibuprofen and naproxen resulted in a decrease in egg fertilization providing an experimental LOEC (lowest observable effect concentration) of 0.1 ug/L and NOEC (no observable effect concentration) of < 0.1 ug/L for both ibuprofen and naproxen based on the reproductive endpoint. This indicates that either NSAID has the potential to affect
the reproductive success of flagfish at concentrations at or below those commonly found in the environment. / UOIT
|
Page generated in 0.0171 seconds