My Research
From Carbonate to Climate
Arctica islandica (ocean quahog) is the longest-lived bivalve on Earth. Individuals on the deep continental shelf of the Mid-Atlantic (US) can survive for centuries, and when found in the colder, boreal waters of Iceland, ages over 500 years can be reached. Ocean quahog age-at-length data are famously inconsistent both within and across regions preventing the development of a comprehensive age-length key, an essential component to understanding the population dynamics of a species. Ocean quahog landings in the United States represents a $24 million industry, yet very little is known about the resiliency of the ocean quahog stock to fishing activity, and ocean quahog recruitment patterns over time. Results by Pace et al. (2017) indicate that age at length data are extremely variable for this species and a robust age-length key cannot be created from a sparse data set (i.e. ~20 animals per 5-mm size class). Furthermore, the longevity of this animal ensures that an individual will encounter centuries of changing bottom water conditions over a single lifespan. Environmental changes are then manifested as growth signatures within the shell itself and a clear acceleration of growth rate over time is documented. Unfortunately, aging ocean quahogs is an extremely time-intensive process which limits the number of ages commonly used to generate an age-length key, an essential component to understanding the population dynamics of a species.
Age-Reader Error
2020/2021
When developing an age-length key, the validity of such a key is only as credible as the age determinations used to create it. Understanding the precision of each age reader and any underlying bias present in the age estimates allows researchers to report error and identify age drifts produced by such biases. A triple-method error protocol was developed for Arctica islandica which also established species-specific error thresholds. This is the first known, comprehensive examination of aging error for A. islandica on record.
Population Dynamics
2021
Error-validated, age-at-length data for two Mid-Atlantic populations were used to estimate population age frequencies, sex ratios, mortality rates, and longevity estimates.
Growth Dynamics
Fall 2022
Invertebrates such as A. islandica grow in synchrony with their ambient environmental conditions. Due to the longevity of this species, modern populations contain centuries of cohorts whose growth rates change with the changing bottom water temperatures and food availability. We applied wavelet analyses to A. islandica growth residuals versus climate temperature residuals in the Northwest Atlantic.
