World’s first for ARCHELON’s latest findings
World Sea Turtle Day today and we are ready to share with you an important finding. After a relevant search by ARCHELON on all the turtles that were marked in Zakynthos, it was found that they can lay eggs for at least 33 years. The result of a 33 year reproductive longevity is the biggest amongst those published for the loggerheads internationally. This may be due to the fact that the tagging program of ARCHELON is the oldest in the Mediterranean and one of the oldest in the world. The above study was accepted in a valid scientific journal and will be published within June.
Sea turtles in Zakynthos with ARCHELON tags (photo: K. Papafitsoros)
Specifically, 2 sea turtles were found with 33 years having passed from the first marking until their most recent observation. It is about the A1075 which was marked in 1984 and its most recent observation was made in 2017, and the B2494, marked in 1986 with the last observation in 2019. A total of 20 turtles with a reproductive longevity of 22 to 33 years were found in Zakynthos. Of course, this period may be actually longer since it is not known whether the first marking coincided with the first nesting of the turtle.
ARCHELON has been conducting a tagging program for the loggerhead turtles in Zakynthos since the early 1980s. Tagging is done with special tags that are placed on the flippers and carry a code and a return address. Important reproductive parameters are explored with tagging, such as the frequency of nesting during the same breeding season or after how many years the nesting turtles come back. All of these are necessary to properly estimate the size of the breeding population. Tagging also provides information on turtle movements in the Mediterranean. Another important result of the long-term tagging program is the investigation of the duration of reproductive longevity of females, i.e. for how many years females can lay eggs.
It is noted that, because the external tags get lost to a large extent or are worn out and cannot be "read", in recent years internal microchips are being installed which last much longer. So it is expected that the continuation of the long-term program of ARCHELON in Zakynthos will show that the duration of the reproductive life of loggerheads is even greater than 33 years.
Thanks are due to the Scientific Committee of ARCHELON and the authors Dimitris Margaritoulis, Christopher J. Dean, Goncalo Lourenco, Alan F. Rees and Thomas E. Riggall for this publication. A big thank you to the thousands of volunteers from all over the world who participated in the conservation projects of ARCHELON and also to ARCHELON’s staff. Without them we would not be able to know important information about sea turtles.
WE CAN ALL LIVE TOGETHER. This is the message of ARCHELON and for us it is not just about sea turtles.
photo 1. Sea turtles in Zakynthos with ARCHELON tags (photo: K. Papafitsoros)
photo 2. ARCHELON Sea Turtle Rescue Centre, rehabilitation tanks