Lead faculty: Dr. Ethan Grossman (Texas A&M University, Department of Geology and Geophysics)
Research topic: Impacts of prehistoric harvesting on conch growth rates in Panama.
Presentation:
Research topic: Impacts of prehistoric harvesting on conch growth rates in Panama.
Presentation:
- Berger, A., Fuchs, K., Ramey, E., Wehbe, C. “Impacts of Prehistoric Harvesting on the Evolution of Strombus Growth Rates in Panama,” presented at the Environmental Programs poster session at Texas A&M University (2015).
In April 2015, I had the opportunity to go to Panama as part of the capstone course for my major. We spent some time at the Smithsonian Tropical Research Institute (STRI) research station in Bocas del Toro, collecting samples for our capstone research projects.
We used West Indian fighting conch (Strombus pugilis) shell samples from pre-human (~7 ka), pre-Columbian (~1 ka), and modern times to investigate whether persistent harvesting over the past 7000 years has impacted species evolution. This size-selective evolution would either favor younger individuals at sexual maturity, or individuals with slower growth rates. We estimated S. pugilis growth rates and age at sexual maturity from seasonal variations in the oxygen isotopic signal of shell samples. Our results showed that neither growth rates nor age at sexual maturity had evolved significantly since pre-human times. The use of data from previous studies, however, suggested that a more extensive dataset might provide support for decreasing growth rates as an explanation for the observed smaller size at sexual maturity.
We used West Indian fighting conch (Strombus pugilis) shell samples from pre-human (~7 ka), pre-Columbian (~1 ka), and modern times to investigate whether persistent harvesting over the past 7000 years has impacted species evolution. This size-selective evolution would either favor younger individuals at sexual maturity, or individuals with slower growth rates. We estimated S. pugilis growth rates and age at sexual maturity from seasonal variations in the oxygen isotopic signal of shell samples. Our results showed that neither growth rates nor age at sexual maturity had evolved significantly since pre-human times. The use of data from previous studies, however, suggested that a more extensive dataset might provide support for decreasing growth rates as an explanation for the observed smaller size at sexual maturity.