Understanding Larval Fish

Dr. Simon Geist's Lab
Texas A&M University-Corpus Christi
Texas State Aquarium Teen STEM Cafe


In September of 2019 at the Texas State Aquarium, the Teen STEM Cafe hosted Dr. Simon Geist’s lab from Texas A&M University-Corpus Christi. They are currently working on a variety of studies with larval fish, including one that identifies the relationship to the environment and the juvenile and adult stages of the fish. Their goal throughout their lab is to learn how to conserve and protect local fish species.

Hands on Activity

There were three stations set up for hands-on activities. One station was to observe fish cadavers through a microscope. The fish were injected with a protein that caused their different body parts to change colors depending on how it reacted to the protein injection. The second station was a microscopic viewing of otoliths (the fish’s ear bones). A fish was placed under a microscope and the professionals hunted for their ear bones. The third station was measuring the respiration rates of larval fish. A lower or fast respiration rate reveals that the fish is uncomfortable and stressed in their environment, and a constant rate reveals that the fish is comfortable. This information can be used to find which environment a fish can mature the best in. When a fish is comfortable in their environment they mature at a constant, steady rate leading to a healthy adult. The data collected by the respiration rates can lead to the construction and protection of the fish species.