Forensic Markers of Lampricide Toxicity & Mortality in Non-Target Fishes

Science Center Objects

The pesticides 3-trifluoromethyl-4-nitrophenol  (TFM) and niclosamide selectively target larval sea lampreys (Petromyzon marinus) because they have a much lower capacity to detoxify these lampricides by forming glucuronide conjugates compared to typical non-target fishes.  However, if lampricide uptake overwhelms a fish's detoxification capacity, non-target mortality can result.  Non-target mortality following lampricide treatments can result from sudden drops in water pH or changes in water flow, but may go unobserved due to time of day and/or treatment location (e.g. lentic treatments).  We propose to use forensic toxicology approaches to test the hypothesis that there are readily quantifiable post-mortem markers of TFM and niclosamide toxicity in fishes that can facilitate non-target mortality investigations.

Objective

This collaborative research effort will use rainbow trout (Oncorhynchus mykiss), blue gill  (Lepomis macrochirus), white sucker (Catostomus commersonii), and lake sturgeon (Acipenser fulvescens) to determine:

 

1. What concentrations of internal TFM/niclosamide and their glucuronide metabolites are sub-lethal or fatal in fishes, including different life stages of the lake sturgeon?

2. Which tissues (blood, liver, muscle, heart) are most suitable for measuring post-mortem TFM/niclosamide and their metabolites?

3. How stable are TFM/niclosamide and their metabolites in tissues following death in decomposing fish, and how is lampricide stability influenced by time, temperature, immersion (in water) or air exposure?

4. What sampling, handling and storage protocols should be used in the field after unexplained fish kills?