Istiophorus platypterus

Blue Marlin
Makaira nigricans

Longbill Spearfish Tetrapturus pfluegeri

White Marlin
Kajikia albida

Blue Marlin Makaira nigricans. First dorsal fin not sail-like, slightly higher to lower than body depth at level of midbody. Pelvic fins not as long (far from reaching to anus), with a moderately-developed membrane. Lateral line not straight, usually not visible in adults, characteristically a chicken wire-like pattern. Anterior part of dorsal fin lower than body depth. Profile of head between preorbital region and origin of first dorsal fin steeply elevated. Body not strongly compressed.

Longbill Spearfish Tetrapturus pfluegeri. First dorsal fin not sail-like, slightly higher to lower than body depth at level of midbody. Pelvic fins not as long (far from reaching to anus), with a moderately-developed membrane. Lateral line visible, a simple straight line. Anterior part of first dorsal fin slightly higher than, or nearly equal to, body depth. Body strongly compressed. Profile of head between preorbital region and origin of first dorsal fin nearly flat. Anterior part of dorsal fin nearly equal to body depth. Pectoral-fin length nearly equal to pelvic-fin length.

White Marlin Kajikia albida. First dorsal fin not sail-like, slightly higher to lower than body depth at level of midbody. Pelvic fins not as long (far from reaching to anus), with a moderately-developed membrane. Lateral line visible, a simple straight line. Anterior part of first dorsal fin slightly higher than, or nearly equal to, body depth. Body strongly compressed. Profile of head between preorbital region and origin of first dorsal fin slightly elevated. Anterior part of dorsal fin slightly higher than body depth. Pectoral fin longer than pelvic fin.