We’re excited to share a new instructional video now available on the FishAge YouTube channel, featuring otolith extraction for Ruddy Bowfin (Amia calva).
Ruddy Bowfin are a unique, basal ray-finned fish with cranial anatomy and otolith morphology that differ from many commonly aged teleost species. These differences can make otolith extraction challenging, especially for students or labs encountering Ruddy Bowfin for the first time. This video walks through key anatomical landmarks and species-specific considerations to support accurate and repeatable otolith removal.
The Ruddy Bowfin video is part of a growing FishAge instructional video series designed to support fisheries professionals, students, and researchers working in age and growth. The goal of this series is to provide clear, practical demonstrations of otolith extraction methods, processing techniques, and ageing approaches across a wide range of species.
All fish featured in FishAge instructional content are handled according to approved handling protocols and institutional guidelines.
This is just the beginning. Additional videos are currently in development and will cover otolith extraction for other fish species, as well as otolith processing and ageing techniques. Together, these resources will complement the FishAge image database by supporting training, consistency, and best practices in fish ageing.
Interesting Facts about bowfin
Bowfin are ancient fishes, part of a lineage that stretches back over 150 million years, making them one of the few remaining representatives of the order Amiiformes. While they were long thought to consist of a single species (Amia calva), recent research using genomic data has revealed that at least two distinct living species exist within what was previously considered one.
A 2022 phylogenomic study by Wright et al. demonstrated that modern bowfin actually comprise at least two distinct species, which diverged millions of years ago:
- Amia calva — commonly referred to as the Ruddy Bowfin, occurring primarily in western portions of the range
- Amia ocellicauda — the Emerald Bowfin, found more frequently in eastern regions and often exhibiting greener coloration and a pronounced caudal eyespot
This discovery highlights how cryptic diversity can persist even in well-known freshwater fishes and underscores the importance of continued taxonomic and genetic research. The authors also suggest that additional, unrecognized species diversity within Amia may exist, warranting further investigation.
Read the primary research here.
Photographer credit: Tim Bonvechio, Georgia Department of Natural Resources.
Do you have known-age fish structures
or a validation study to share?
We’d love to feature them! If you have known-age fish structures (i.e., otoliths, scales, fin spines) or an age validation paper you’d like highlighted on our blog, please Contact Us!
Stay tuned as we continue to expand the image database and instructional resources to support the fisheries ageing community, and don’t forget to subscribe to our blog to stay up to date with the FishAge project!
