Welcome to the world of alternative biodiversity records.
Since the last Edo period, around the middle of the 19th century, recreational fishers in Japan have recorded memorable catches with fish impressions or rubbings, known as gyotaku.
As well as an image, each traditionally includes information such as the species, sampling date and locality, the fisherman, the tackle used, and any witnesses to the catch.
It’s a dying art in a world of smartphones but it definitely still exists, researchers have found, and it can provide important information.
Yusuke Miyazaki, from Shiraume Gakuen College, Tokyo, and Atsunobu Murase, from the University of Miyazaki, surveyed fishing shops in different regions of Japan and found 261 rubbings with 325 printed individual specimens. All are now part of a gyotaku database.
Notably, the observed species reflected the biogeography of the regions and can be representative enough to identify rare Red-listed species in particular areas.
Given the rarity of these threatened species in some regions, the researchers suggest, gyotaku are probably important vouchers for estimating historical population status and factors of decline or extinction.
The research is described in the journal ZooKeys. Currently, the oldest known material is the collection of the Tsuruoka City Library, dating back to 1839.