Emerald Wrasse, Thalassoma virens
The Emerald Wrasse, Thalassoma virens, whose common Spanish name is señorita esmeralda, is a member of the Wrasse or Labridae Family, known collectively as doncellas, señoritas, and viejas in Mexico. Globally, there are twenty-eight species in the genus Thalassoma, four of which are found in Mexican waters, one in the Atlantic and three in the Pacific.
The Emerald Wrasses have elongated compressed bodies with a depth that is 33 to 36% of standard length. Females and males in the Initial Phase (IP) have a dull green coloration with red-brown spots that afford a vertical pattern of wide broken stripes. Their head is covered with small red spots and vertical broken stripes. Their caudal fin is concave and their fins are darker than the body. Terminal phase (TP) males have a uniform greenish-blue coloration which extends to the fins. They have a small terminal mouth equipped with enlarged canine teeth at the front of both jaws (one pair above and one pair below). Their caudal fin is concave with long pointed lobes and their dorsal fin has eight spines and twelve or thirteen rays.
The Emerald Wrasses are coastal residents found within rocky shores exposed to surges from the intertidal zone at depths up to 30 feet. They reach a maximum length of 30 cm (12 inches). They feed diurnally on small crustaceans, sea urchins, mollusks, and brittle stars. IThey are a very rare shallow-water species and very little is known about their behavioral patterns.
n Mexican waters the Emerald Wrasse has a very limited distribution being found from the tip of the Baja, as established by fish that I have caught, northwards to La Paz within the Sea of Cortez, and around the Revillagigedo Islands.
The Emerald Wrasse is a fairly easy identification and cannot be confused with any other species due to its unique colorations.
The Emerald Wrasses are small and of limited interest to most but they are a gorgeous fish! They are retained by subsistence fishermen.
Note: several productive discussions with Dr. Benjamin Victor (www.coralreeffish.com) related to the lifestyle of this species are acknowledged. Dr. Victor believes that the Emerald Wrasse “settled out” in the Los Cabos area during periods of El Niño and these are mostly similar to 1998–1999 fish. He also indicated that they are elusive, secretive, and exceedingly fast swimmers that spend a significant amount of time in the high surge zones very close to shore.
Emerald Wrasse, Thalassoma virens, initial phase (IP) female. Fish caught from shore at Km 21, Cabo Real, Baja California Sur, December 2004. Length: 30 cm (12 inches).
Emerald Wrasse, Thalassoma virens, initial phase (IP) female transitioning to a terminal phase (TP) male. Fish caught from shore at Km 21, Cabo Real, Baja California Sur, January 2005. Length: 30 cm (12 inches). Identification courtesy of Milton Love, University of California, Santa Barbara, CA.
Emerald Wrasse, Thalassoma virens, initial phase (IP) female transitioning to a terminal phase (TP) male. Fish caught from shore at Km 21, Cabo Real, Baja California Sur, January 2016. Length: 29 cm (12 inches).
Emerald Wrasse, Thalassoma virens, terminal phase (TP) male. Fish caught from shore at Km 21, Cabo Real, Baja California Sur, December 2015. Length: 25 cm (10 inches).