dorsal

In Oregon, when a survey team first spotted a large fish rise to the surface, they saw only its dorsal fin, said Mark Hereford, Klamath fisheries reintroduction project leader for the Oregon Department of Fish and Wildlife.

Winter had put a life vest on the dog resembling a shark, with a dorsal fin protruding from its back.

Yet sea robins are most notable for their distinctively large, fan-shaped dorsal fins and for their six leg-like appendages.

Tadamichi Morisaka, a cetology professor at Japan's Mie University, said the dorsal fin of a dolphin spotted biting a man's fingers at a beach in Tsuruga - a port city next to Mihama - matched those of a 2.5m long dolphin observed off the coast of Fukui province last year.

The dorsal fin is like a dolphin's fingerprint, as each has distinctive notches, ridges and pigmentation.