Yellowtail Surgeonfish, Prionurus punctatus
The Yellowtail Surgeonfish, Prionurus punctatus, whose common Spanish name is conchinito punteado, is a species in the Surgeonfish or Acanthuridae Family, known collectively as cirujanos in Mexico. Globally, there are only seven species in the genus Prionurus, two of which are found in Mexican waters, both in the Pacific.
The Yellowtail Surgeonfish have oval compressed bodies. They are light gray with numerous small black spots covering their head and body and a bright yellow tail. They have a white bar on their head behind their eyes. Juveniles are either yellow or have a similar color as adults. They have a steep profile with eyes set high on their head and a small protrusible mouth placed low on their head with large flattened close-set teeth. Their anal fin has 3 spines and 23 soft rays; their caudal fin is straight; their dorsal fin is continuous with 7 or 8 spines and 25 rays; and their pelvic fins have one spine and 5 soft rays. A key to identification is the tail base, which has 3 bony knobs along each side of the middle of the caudal fin base. They have complete lateral lines and their body is covered with small rough scales.
The Yellowtail Surgeonfish are a coastal schooling species found in shallow waters in and around coral and rocky areas at depths up to 100 feet. They reach a maximum length of 60 cm (24 inches). They feed diurnally and primarily on benthic algae.
In Mexican waters the Yellowtail Surgeonfish have a limited distribution being found in the lower half of the Sea of Cortez and along the coast of the mainland south to Guatemala; they are absent from the northern portion of the Sea of Cortez and from the Pacific side of the Baja.
The Yellowtail Surgeonfish can be confused with the Razor Surgeonfish, Prionurus laticlavius (few small dense black spots around tail base).
Juveniles measure 2.5 cm (1.0 inch) and are very abundant within the tidal pools of the greater Los Cabos area at certain times of the year. Larger fish are, however, a very rare catch by hook and line as they are finicky nibblers. When hooked they make a fierce foe, especially on light tackle. Caution: The spines found at their tail base provide these fish with a unique defense mechanism rendering them “dangerous” to handle as these spines can inflict major slashing wounds.
Yellowtail Surgeonfish, Prionurus punctatus. Fish caught off the beach at Km 21, Cabo Real, Baja California Sur, July 2006. Length: 30 cm (12 inches). Note: this fish is a very difficult species to photograph as its coloration very quickly fades from a dark gray to a pale tan.