An 81-Year-Old Snapper | Hakai Magazine

“The age of a scaly fish may be told by the size and the hardness of its scales.” - Aristotle ca. 340 B.C.

“From whence I conclude, that every year, the scale encreased [sic] one circular line...” Leeuwenhoek, 1685.

“… and concluded that the rings that could be discerned on them were growth rings that could be used to determine the fish’s age.” Hans Hederström, 1759.

and so the process of discovery of fish age determination methods continued. A historical overview can be found at “Earliest References to Age Determination of Fishes and Their Early Application to the Study of Fisheries” by James. J. Jackson (2007)

Why did I start to think about fish age determination? I read an article in Hakai Magazine that an 81-Year-Old Snapper was discovered off the coast of Broome, Australia and, obviously, the first question was “How do they know? “ There is no shame in saying “I don’t know”, right? I might start to think about it, come with some ideas but before that it is simple - I don’t know.

“Researchers from AIMS and the Western Australian Fisheries and Marine Research Laboratories determined the age of the snappers by dissecting them and examining their otoliths—the small calcium carbonate structures, also known as ear stones, found in the inner ears of fishes that aid in balance and hearing. Otoliths contain growth rings, similar to those found in trees, that scientists can use to determine a fish’s age.”

Read the Article | Hakai Magazine | Annie Roth

If somebody has an interest in errors, accuracy and precision related to the methods of fish age determination they can spend some time going through “Accuracy, precision and quality control in age determination, including a review of the use and abuse of age validation methods” by S.E. Campana published in Volume 59, Issue 2 (August 2001) of the Journal of Fish Biology. Of course, spending time would require an access to the full text which I don’t have so … let’s say that an abstract is better than nothing.

And since we are talking about fishes, enjoy colorful drawings from 1754 via The Public Domain Review

“Originally published in 1719, with a second edition in 1754, Poissons, Ecrevisses et Crabes can lay claim to being the earliest known publication in colour on fish — in this case, celebrating those hailing from the waters of the East Indies. This wonderful book is the creation of Louis Renard — a publisher, bookseller, and spy for the British Crown (employed by Queen Anne, George I and George II).”

Image via The Public Domain Review.