My research is focused on cichlids (a group of fishes which includes the Tilapia), but also includes other freshwater fishes. My journey in research started in high school, where I worked at the Virginia Tech Seafood and Agricultural Research Extension Center in a lab that focused on ornamental fishes (as opposed to food fish). My first real project looked at whether a species of freshwater fish, the Cherry Barb, laid more or fewer eggs based on the water temperature to see how climate change might impact their populations. Although that project ended up being a bust, I pressed on to a lab in college in my first semester, undeterred from research.
In college at William & Mary, I started in a lab that looked at how fish filter food from the water without clogging their gills (using a technique called vortical crossflow filtration, which is used widely in industry). From there, I went on to study the Ocean Quahog, a clam native to the northeastern US and the longest-lived animal on the planet (the oldest ever recorded was 507 years old!), at the Virginia Institute of Marine Science. Quahog shells have lines like tree trunks have rings, and those lines look different based on qualities of the year in which they were created. So, in theory (and, I discovered, in practice) you can use quahog lines to figure out what the weather was like in the oceans from before we kept written records of weather in North America (cool stuff, I know!).
After this work, I looked at whether invasive cichlids in Florida had changed in body shape from their native counterparts back in their original environments. I hypothesized that the novel Floridian environment might have caused them to change in some way or another. As it turned out, they changed in a variety of ways, and I am currently working to publish this work with Dr. Eric Hilton.
I am currently working on two projects at the University of California – Davis. The first looks at what fish body shapes can tell us about competition between native and invasive fish. The premise for this project is the assumption that the body shape of a fish reflects how it uses its environment. For example, long slender fish might inhabit faster flowing water than taller, fatter fish, and fish with downturned mouths might feed on the bottom while those with upturned mouths might feed at the surface. Using this body shape information, we can then predict that fishes with similar body shapes might use their environments in similar ways, leading to increased competition and less invasive success when introduced species are similar in body shape to already established native species (or at least that’s what I’m predicting!).
My second project looks at plasticity. Phenotypic plasticity is basically what happens when a change in how you use a body part causes a change in that body part. For example, working out more causes your muscles to grow, and using their jaws in certain ways causes fish mouths to change shape in the same way (plasticity!). I’m looking at whether the amount of shape change varies between species and across families of fishes, and how that variation affects rates of evolution and invasiveness.
Khalil Russell 