Deepwater Serrano, Serranus aequidens
The Deepwater Serrano, Serranus aequidens, whose common Spanish name is serrano de aqua profunda, is a species in the Sea Bass or Serranidae Family, known as collectively serranos in Mexico. Globally, there are twenty-seven species in the genus Serranus, thirteen of which are found in Mexican waters, ten in the Atlantic and three in the Pacific.
The Deepwater Serranos have elongated bodies that are covered with large rough scales. They have an overall tan coloration and a white belly. Their head is long yet features a short snout, their eyes are disproportionately large, their mouth is large, and their lower jaw is projecting. They have a narrow tail base and a series of characteristic markings that include a large blue-gray spot on their gill covers and six irregular bars on their upper body; the second of these bars has a large blotch on the lateral line. Their first dorsal fin has a yellow margin with spines one to four increasing in size and spines four to nine decreasing in size; their second dorsal fin has a black margin and a black stripe along its base. The third anal spine and the first anal ray are the longest of the anal spines and rays. Their caudal fin is slightly concave. Their anal and caudal fins are transparent; their pectoral fins are long and narrow and extend past their anal fin origin; both pectoral and pelvic fins are yellow.
The Deepwater Serranos are found over sandy bottoms at depths between 225 and 800 feet. They reach a maximum length of 24.5 cm (9.6 inches) and are virtually weightless. They are a small and rare deep water species and very little is known about their behavioral patterns.
In Mexican waters the Deepwater Serranos are found in all waters of the Pacific, with the exception that they are absent from the east coast of the mainland within the Sea of Cortez.
The Deepwater Serrano is similar in size, shape, and habitat to the Flag Serrano, Serranus huascarii (large yellow blotch behind pectoral fins; tail with black margin) but the markings and colors of the two species are very different.
The Deepwater Serrano is too small and too rare to be of interest to most.
Deepwater Serrano, Serranus aequidens, juvenile. Fish caught from coastal waters off Point Palmilla, Baja California Sur, June 2016. Length: 8.5 cm (3.3 inches). This is a highly colored fish which was caught in atypical relatively shallow water perhaps indicative the juveniles settles out in shallower waters and then move to deeper waters. Identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.
Deepwater Serrano, Serranus aequidens. Fish caught from coastal waters off Point Palmilla, March 2008. Length: 18 cm (7.0 inches). Identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.