Wednesdays from 4:30 pm – 5:30 pm in STB 226
The aim of this series is to hear about the innovative and exciting research that is taking place within our college, thus both faculty and students are encouraged to give a colloquium presentation. Talks should be either 40 - 50 minutes in length for a single presenter colloquium or 20 - 25 minutes in length for a joint colloquium event. If you would like to sign-up to give a CNHS Colloquium Talk, email Efren Ruiz.
For any questions, contact the organizers Heather Kaluna and Efren Ruiz.
Date: 8 October 2025
Speakers: Dr. Karla McDermid and Dr. Grady Weyenberg, UHH Marine Science Department and UHH Math/Data Science Departments
Title: Not Always Slow and Steady: Hawaiian Green Turtles, a New Four-Parameter Bayesian Growth Model, and the Primitive Reptilian Condition
Abstract: Growth rates, essential for understanding the demographics of sea turtle populations, vary regionally because of variability in habitat quality, food availability, turtle density, environmental conditions, and genotype. In past decades, declining green turtle (Chelonia mydas) growth rates within the Hawaiian Archipelago raised concerns about long-term population stability. From 1976 to 2018, at Punalu‘u, Hawai‘i Island, a key foraging ground, green turtles were captured, measured for straight carapace length (SCL) and mass, and released. Recaptured individuals were monitored to assess growth rates and body condition index. Of 319 turtles captured, 186 were captured at least twice during the 42 years, and 127 were captured three or more times. The average annual growth rate was 1.16 ± 0.05 cm/year based on 178 individuals. A four-parameter Bayesian growth model predicts population asymptotes at 68.6 cm SCL, and that individuals will achieve close to their final size approximately 15 years after reaching 50 cm SCL. Punalu‘u green turtles displayed a size-specific sigmoidal growth rate function characteristic of the “primitive reptilian condition” seen in extant species of alligators, crocodiles, snakes, lizards, and land tortoises, as well as extinct non-avian dinosaurs. Growth trend analyses help develop management strategies and provide comparisons with green turtle populations locally and globally.