New Method Could Speed Process of Determining Fish Age and Growth Patterns
The ability to rapidly detect changes in age and growth patterns for fish populations is crucial to successfully managing them, and a new process studied by S.C. Sea Grant Consortium researchers shows promise for speeding up the previously time-consuming process.
Joseph Quattro, director of graduate studies at the University of South Carolina (USC) School of the Earth, Ocean, and Environment, USC doctoral student Michelle Passerotti, and Joseph Ballenger, a research scientist with the S.C. Department of Natural Resources, examined the effectiveness of Fourier Transform Near Infrared Spectroscopy (FT-NIRS) in predicting the age and growth of juvenile red snapper.
Otoliths are hard, calcium carbonate structures located directly behind the brain of bony fish. S.C. Sea Grant Consortium researches used otoliths to determine that a time-saving new method for determining age of juvenile red snappers works well. Photo: Florida Fish and Wildlife Conservation Commission.
In previous studies, scanning the bony structures in fish inner ears using FT-NIRS has shown promise in predicting the age of adult fish in terms of years. The research team focused on aging of juvenile red snapper in terms of days rather than years, details that can be especially important in tracking seasonal and environmental effects on species facing pressures from overfishing and climate change.
The age of a fish can be estimated by the measurement of growth increments on ear stones known as otoliths. Changes in otoliths can even be tracked at miniscule incremental scale to track daily growth. But preparing otoliths for daily age estimation using the currently most common process requires dissection, mounting, polishing of microscopic structures, and interpretation by independent readers. It’s challenging and time-consuming.
An article on the study ran in the November 23, 2019 issue of the peer-reviewed journal Fisheries Research. “The capability of FT-NIRS to generate age predictions in a fraction of the time and with improved repeatability relative to traditional methods would save significant costs and improve turnaround time for analysis while maintaining standards for age precision,” the article states.