The following is the abstract we've submitted for the Southeastern Fishes Council (SFC) meeting in Chattanooga on Nov. 13-14. Jennifer will be the presenter, basically of her graduate work.
"Investigations into the Relationship between the Steroid Hormone 11-ketotestosterone and Reproductive Status in the Fish Lythrurus fasciolaris
Jennifer L. Schade, Department of Biological Sciences (Master’s Candidate), University of Alabama in Huntsville, Huntsville, Alabama 35899, Bruce W. Stallsmith, Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, Alabama 35899, Amy Bishop, Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, Alabama 35899.
In many fishes, 11-ketotestosterone (11KT) is a critical androgen regulating primary and secondary sex characteristics. In the sexually dimorphic Lythrurus fasciolari
s, dominant nuptial males display heavy tuberculation on the head and nape, dark dorsolateral vertical bars, and dramatic red coloration in the fins, venter, and operculum area. This study aimed to quantify 11KT circulating levels in males and determine its correlation with key reproductive status indicators such as nuptial coloration, size, and Gonadosomatic Index (GSI). Wild-caught L. fasciolaris
(15 males, 16 females) were divided into three groups according to reproductive status: dominant males (D), non-dominant males (ND) and females (F, control group). Physical measurements, digital imaging, and blood samples were used to quantify body size, GSI, nuptial coloration, and circulating levels of 11KT. Dominant males had higher 11KT levels and nuptial coloration traits compared to ND males and females (red area, hue, saturation), and a higher GSI than ND males. Non-dominant males had more 11KT and coloration than females. Increased 11KT levels corresponded to increased coloration, size and GSI.