The long-finned albacore (Thunnus alalunga) is a member of the tuna family, and is a brilliant blue above and bluish silver below. It is readily distinguishable by the extremely long pectoral fins which fit into depressions on each side of the body to reduce resistance when the fish is being propelled at speed by the sculling action of the powerful tail. The pectoral fins are employed for sudden turning motions.

by Arthur William Baden Powell, Assistant Director, Auckland Institute and Museum.