Fish Intersexuality as Indicator of Environmental Stress summarizes a presentation about using intersexuality in fish as a bioindicator for detecting endocrine disrupting chemicals in bodies of water. The presentation describes research on mosquitofish and least killifish exposed to kraft-mill effluent that showed masculinized features in female fish, including gonopodial elongation of the anal fin in mosquitofish and increased segmentation at the fin ray tips in least killifish. The study demonstrates that examining reproductive systems in fish can help identify substances interfering with hormone-mediated processes and that poeciliid fish make useful subjects for detecting endocrine disruptors.

1. Fish Intersexuality as Indicator
of Environmental Stress
By: Stephen A Bortone and
William P. Davis.
Faith Warren
Presentation Date:
04/29/2014
Dr. Pease

2. Picture 1 Picture 2
Picture 3
Eleven Mile Creek
Fenholloway River ^^

3. Figure 1: “Normal female (top) and
male mosquitofish (bottom). A
masculinized female is pictured in
the center, showing the gonopodial
elongation of the anal fin.”

4. Figure 2: “An array of anal fins from the least killifish. A.) Normal
female. B.) Fish exposed to kraft-mill effluent; note the increased
segmentation at the tips of the rays. C.) Another example of a
fish exposed to kraft-mill effluent with some elongation of the fin
rays. D.) Normal male.”

5. Hermaphroditism: “describes a subcategory of
intersexuality where the primary reproductive
characters (testes and ovaries) are found in a single
individual.”
“The study shows that reproductive systems in fishes
are useful bioindicators for detection of substances that
interfere with endocrine modulated processes…
Poeciliid fishes such as the mosquito fish and the least
killifish can be useful to detect endocrine disruptors.”

6. What does this mean for managers of
aquatic resources?
“Developing a well-documented and well-referenced
system to recognize the subtle changes in intersexuality in
fishes represents a step in the right direction to better
monitor the health of aquatic ecosystems.”

7. For more information here is the full paper:
http://eds.b.ebscohost.com.lib-
e2.lib.ttu.edu/eds/pdfviewer/pdfviewer?sid=d0ccf185
-bab2-42f7-af4e-
06c1b1baee53%40sessionmgr112&vid=4&hid=119