Overall Research Project Description We are studying how fish populations change when individuals are removed due to harvest, and how this might depend on the amount of food/prey available to the fish. When fish are removed due to harvest, the fish remaining are often (depending on the type of harvest) younger and smaller, but there is sometimes more food and space left over for fish remaining and they may start to grow more quickly. Over multiple generations, the population gene pool may change as fish with certain genetics survive and breed better in the new conditions, and change in fishes’ traits may occur even without genetic change. To study this, we use the very small (the smallest fish in North America!) and fast-growing fish Heterandria formosa as a model organism. We keep lab-bred populations of hundreds of these fish at the FSU Biology Department’s Mission Road greenhouse near campus (off the Osceola bus route)–however, depending on students’ interests, most of the work for a UROP project can be completed on our lab on campus in the King building. At the greenhouse, we are imposing different types of harvest and levels of food on the different populations to observe what happens to the individuals and populations over time. UROP students in the lab this year will have the opportunity to measure differences in length, size, reproduction, and growth of individual fish between these experimental populations, and to study how population size and demographic characteristics are changing.