Welcome to our blog series, Research Highlights! On the second Monday of each month, we debut newly published fisheries research by our women of fisheries colleagues. If you have research you would like to highlight and share with our readers, submit a nomination form!
This Month’s Research Highlight:
Passerotti, M.S., T. E. Helser, I.M. Benson, B.K. Barnett, J.C. Ballenger, W.J. Bubley, M.J.M. Reichert, and J.M. Quattro. 2020. Age estimation of red snapper (Lutjanus campechanus) using FT-NIR spectroscopy: feasibility of application to production ageing for management. ICES Journal of Marine Science 77: 2144–2156.
Life can be viewed as a sort of puzzle. Each part of the journey, each step along the way, is a piece of a puzzle that ultimately creates our story and illustrates our life’s purpose. This month’s research highlight is the culmination of a journey that took Dr. Michelle Passerotti to four states. Such is the life of many military spouses who must navigate multiple moves and raising a family, while also trying to pursue their own ambitions. With some ingenuity and a whole lot of perseverance, Dr. Passerotti found a way to fulfill her purpose despite the logistical challenges. One of her colleagues anonymously noted, “her journey to obtaining her PhD should give hope and inspiration to us all.” Indeed, and her work is garnering attention in the fisheries world.
The story goes a little like this.
Michelle received her Master’s Degree and a job in fisheries management around the same time she also became a military spouse and mom. After her first military relocation (and loss of her job) and the birth of her second child, Michelle chose to pay her own way to attend an international conference to, in her words, “maintain my presence and my network.” It was here that she was first introduced to FT-NIRS, or Fourier transform near infra-red spectroscopy, as a tool for ageing fish. Interested in pursuing this idea, she started seeking collaborators, ultimately landing at the University of South Carolina working with Dr. Joe Quattro after her family’s second military relocation. The pair worked together to secure funding for her PhD work, work that would end up requiring her to commute 200 miles per day! Several years, one pandemic, and yet another relocation later, she completed her work. One piece of that larger puzzle is the subject of this month’s research highlight.
Typically, fish are aged by counting growth rings on any number of structures from otoliths to scales to fin rays and beyond. Often, as is the case with red snapper Lutjanus campechanus, otoliths are removed and processed before annuli are counted by at least two readers. This can be a very time consuming process. Just for the 2017 assessment of the Gulf of Mexico stocks of red snapper, almost 50,000 otoliths were removed and aged by scientists at 10 different agencies! For anyone who has aged fish before, there is also a certain amount of subjectivity, an “art” of sorts, involved. What if there was a quicker and less subjective option?
That’s what makes the FT-NIRS tool so inviting. It uses near infrared light and measures the absorption pattern to create a spectral signature based on the type and number of chemical, specifically organic, bonds present. It’s not as simple as popping a whole otolith into a machine and reading its predictive age on a screen, but through Dr. Passerotti and her colleagues’ work, this tool shows promise not just for red snapper but other species and age structures as well. In her own words, “This study found compelling evidence that FT-NIRS can provide ages from whole otoliths that are equivalent to traditional ages on a large scale for assessment, and can do so more quickly than traditional methods. As a whole, error rates for FT-NIRS ages were not different to those derived from traditional methods using multiple growth band counts.” Keep an eye out for another publication by Dr. Passerotti that is in the works describing some of the theory behind why FT-NIRS is successful at predicting age.
If you’re involved with ageing fish and are interested in learning how to get started, Dr. Passerotti first suggests locating a university or research institution with access to a spectrometer and reaching out to fisheries partners to see if anyone has started evaluating this approach for your species of interest. Or, if you’re not sure where to turn, you can reach out to her personally at mpasserotti@gmail.com.
We wish Dr. Passerotti all the best as she and her family moves to their fifth state. This time, not for a military assignment, but to fill her role as Fish Biologist for the NOAA Fisheries Apex Predators Program in Narragansett, Rhode Island. We know there is more to come in Dr. Passerotti’s fisheries journey, and pieces of the puzzle left to her story. That certainly “give(s) hope and inspiration to us all.”
And Mr. Passerotti, we at the Women of Fisheries organization salute you and thank you for your service in the United States Air Force!
The full manuscript can be found and downloaded here:
https://doi.org/10.1093/icesjms/fsaa131