Cetacean research pioneers David and Melba Caldwell wrote in their 1972 book “The world of the bottlenosed dolphin” that the earliest example of the practice of prolonged observation of cetaceans based on the recognition of individuals over extended time was that of Pelorus Jack - a Risso’s dolphin observed between 1888 and 1912 swimming near ships crossing Cook Strait, between the northern and southern portions of New Zealand.
Recently my attention was pointed to a writing by Pliny the Elder which moves back the clock of such scientific method by 1,811 years!
In the 9th book of his Naturalis Historia, published in 77 A.D., the ancient naturalist wrote about dolphins: "They grow fast, and it is believed that they reach their maximum size at 10 years of age. They can reach the age of 30, as discovered through the experimental cutting of nicks on their tails" (Adolescunt celeriter, X annis putantur ad summam magnitudinem pervenire. Vivunt et tricenis, quod cognitum praecisa cauda in experimentum).
Giuseppe Notarbartolo di Sciara