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 (read more on this at the link below).
I am currently wrapping up my dissertation work at the University of California, Davis. In the first chapter of my research, I asked how a fish’s natural diet affects the jaw motions it uses to eat attached prey (food that is attached to a surface, such as algae). Because jaw movements can be incredibly fast (the entire open-close jaw cycle can happen in a fraction of a second!) we used high-speed videography, filming bites at 2000 frames per second. There were two possibilities: (1) the present diet of a fish defines its feeding behaviors, or (2) fish possess a set of behaviors that they retain regardless of their natural diet, that can be deployed as-needed. We found support for the second hypothesis–regardless of their current natural diet, all the fish in our study had a shared set of underlying “latent” behaviors that they could use as-needed to eat different prey. This is really important, as it suggests that underlying behaviors form a basis for adaptation and evolution. In other words, before an animal can evolve to specialize on a new diet, it has to have the necessary behaviors to even try to eat the new food in the first place. You can see some of the films we collected for that project below.
Khalil Russell 