Zaca Blenny

Zaca Blenny, Malacoctenus zacae

Zaca Blenny, Malacoctenus zacae.  Fish collected from a tidal pool at Km 17, El Tule, Baja California Sur, January 2007. Length: 1.2 cm (0.5 inches). Fish identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, California.

Zaca Blenny, Malacoctenus zacae, Female.  Underwater photograph taken in the greater Los Cabos area, Baja California Sur, October 2019. Photograph courtesy of Bob Hillis, Ivins, Utah.

Zaca Blenny, Malacoctenus zacae, Males. Underwater photographs taken in Zihuantanejo Bay, Guerrero, in December 2019 and January 2023. Photographs and identifications courtesy of Ron Woheau, Zihuantanejo.

The Zaca Blenny, Malacoctenus zacae, is a member of the Labrisomid Blenny or Labrisomidae Family, and is known in Mexico as trambollo aletiamarilla. The Zaca Blenny was named after one of the world’s finest yachts, the Zaca (www.zaca.com) which is the subject of extensive myths and legends. In 1946 actor Errol Flynn took the Zaca on a scientific expedition to the Sea of Cortez and coastal Mexican waters. The crew included Carl Hubbs, the then curator of the Scripps Institute of Oceanography fish collection. The trip was a fiasco as all hands, including crew, jumped ship in Acapulco. The Zaca is also featured in the movie The Lady from Shanghai starring Orson Wells and Rita Hayworth and is currently moored in Monte Carlo. Globally, there are eighteen species in the genus Malacoctenus, of which fourteen are found in Mexican waters, six in the Atlantic and eight in the Pacific Ocean.

The Zaca Blenny has a shortened elongated body with a uniform depth throughout that tapers gradually at the rear into the tail. The sexes have similar coloration being pale olive with five faint dark saddles on their back, a dark greenish-brown stripe from the eye to the caudal fin base, and a dark spot where the stripe is crossed by the dark bars. They also have 6 greenish-brown lines along their lower body. Their belly and pectoral fins are yellowish, their anal fin is transparent or has dark bars, their caudal fin is transparent or with elongated spots on the rays, and their dorsal fin may or may not have spotting. Their head is slender with a pointed snout, large eyes, a branched cirrus over each eye, and a pair of closely set and heavily branched cirri. Their mouth is small, opens at the front, and is equipped with one row of large teeth on the upper jaw. Their anal fin has 2 spines and 18 to 20 rays; their caudal fin is square; and, their dorsal fin has 10 spines and 9 to 11 rays with a slight notch in between. They have 9 to 11 gill rakers. They are covered with small scales.

The Zaca Blenny is a shallow water coastal species found at depths up to 11 m (35 feet). They reach a maximum of 6.5 cm (2.6 inches) in length. They are diurnal highly territorial predators that feed mostly on benthic crustaceans including small crabs. Reproduction is oviparous with females depositing eggs in protected areas. The Zaca Blenny is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Zaca Blenny is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from Guerrero Negro, Baja California, southward along the central and southwest coasts of Baja and from Mazatlán, Sinaloa, southward along the west coast of the mainland; they are absent from the Sea of Cortez.

The Zaca Blenny can be easily confused with the Fishgod Blenny, Malacoctenus ebisui (small white spots covering body), the Glossy Blenny, Malacoctenus zonifer (throat and belly covered with dark spots), and the Redside Blenny, Malacoctenus hubbsi (flank with narrow stripes).

From a conservation perspective the Zaca Blenny is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature and of limited interest to most.