Photo -1.Cross-section of first spine of dorsal fin of young bluefin tuna showing annual growth rings

Photo -1.Cross-section of first spine of dorsal fin of young bluefin tuna showing annual growth rings. These rings are similar to tree growth rings. The wide (brown) areas represent summer growth during periods of high food intake. The narrow (white) bands represent periods of less fast growth during the winter when the fish’s metabolism slows.

Photo Category: Fisheries - Biological Oceanography
Photo Location: Atlantic Ocean, Bay of Biscay
Photo Date: 1985