Friday, March 3, 2017

Heather Williams-- the fish girl in the fire lab!

Hello. My name is Heather Williams and I am a graduate student in the TTU fire ecology lab, with a focus on aquatic sciences – “the fish girl in the fire lab”! Dr. Verble graciously took over as lead advisor on my project in June 2016 after my PI, Tim Grabowski, took on an exciting job opportunity to lead the Hawai’i Cooperative Fishery Research Unit in Hilo. Dr. Verble was an important mentor for me during my undergraduate career at Texas Tech and I am so pleased to have her overseeing my project. She is teaching me how to be a scientist, and hopefully I can teach her a little about fish.

My research focuses on flow ecology of Guadalupe Bass throughout their native range. Guadalupe Bass is the official freshwater state fish and endemic to regions of the Edwards Plateau in central Texas. Adapted to riffle-run habitat with higher-current velocities, this species is considered to be flow dependent, requiring a relatively undisturbed mosaic of stream habitat in order to persist. This habitat need is threatened by our ever increasing water demand, and the Guadalupe Bass range is home to some of the fastest growing urban centers in the country. However, the influence of flow regime on growth, recruitment, and mortality of this species is not well known. So the objective of my study is to evaluate these relationships in order to develop instream flow recommendations to benefit both Guadalupe Bass as well as other flow-dependent species.

Flow-growth relationships are determined through examination of a fish’s otolith. Much like tree-ring dating, fish also have hard structures which can be used to determine age and growth. Otoliths are calcium carbonate structures in the inner ear that aid in balance and movement for all vertebrates. (Yes, you have otoliths too!) Counting the annual growth rings (annuli) on otoliths is a common technique for estimating age of fish. Annuli are reflective of seasonal growth patterns – fish grow faster in the summer than in the winter. Thus summer zones are wide and translucent while zones representing winter growth are narrow and opaque. This data is then used to reconstruct year classes and estimate mean growth rates related to flow conditions.

I am currently staying really busy, processing our age data and gearing up to sample more river sites throughout the Texas Hill Country. An additional benefit of being a student in the fire ecology lab is that I have the opportunity to stay up to date on my NWCG certifications and continue volunteering on prescribed burns in the region. Here is a photo of Michael Tynes and myself on a burn at the Rolling Plains Quail Research Center. It was a great day!