Pacific Fat Sleeper

Pacific Fat Sleeper, Dormitator latifrons

The Pacific Fat Sleeper, Dormitator latifrons, whose common Spanish name is puyeki, is a member of the Sleeper or Eleotridae Family, known collectively as guavinas in Mexico. Globally, there are five species in the genus Dormitator, two of which are found in Mexican waters, one in the Atlantic and one in the Pacific.

The Pacific Fat Sleepers have elongated compressed bodies with a depth that is 31 to 35% of standard length; they are widest before their second dorsal fin. They vary in color from jet black to shiny red-brown to yellow-brown with seven or eight oblique bars on their upper sides. They have a dark bar under their eyes and several dark brown stripes on the side of their head behind the eyes that extend to the end of their gill cover. They have a pale line at the base of their anal fin and a dark line at the base of their pectoral fins. Their anal and second dorsal fins have rows of spots. Some fish have a prominent blue “ear spot” behind the upper edge of their gill cover. Their head is flat with small beady eyes, a blunt snout, and a large slightly oblique mouth. Their mouth extends to the eyes and is equipped with slender teeth with straight tips set in bands on the jaws. Their anal fin has one spine and 9 or 10 rays; their caudal fin is straight; their first dorsal fin has seven spines; their second dorsal fin has a short base with one spine and 8 or 9 rays; their pectoral fins are relatively short and do not reach the anus; and their pelvic fins are long and widely separated. They have 83 to 114 gill rakers. They lack a lateral line and are covered with large scales.

The Pacific Fat Sleepers are found demersal in both freshwater and marine environments over sandy and muddy substrates, such as estuaries, stagnant ditches, and low current velocity coastal creeks in water depths up to 6 feet and in coastal areas with elevations of under 100 feet. They reach a maximum length of 61 cm (24 inches) and weight of 1.2 kg (2.6 pounds). Males are slightly bigger than females. They prefer water temperatures between 25oC (77oF) and 33oC (91oF). They have the ability to migrate from freshwater to the ocean. They are bottom feeders that will sift through the substrate consuming detritus, plankton, and small fish. They are extremely tolerant of dramatic changes in salinity even up to 50%. They are very hardy and capable of surviving for up to ten hours out of water due to their ability to absorb oxygen through their broad and highly vascularized forehead. They have a lifespan of up to 12 years.

In Mexican waters the Pacific Fat Sleepers are found in all coastal lagoons and freshwater systems of the Pacific.

The Pacific Fat Sleepers are sold commercially and raised via aquaculture. Within some South American cultures they are considered an important food fish. They are attractive for marketing due to their long shelf-life without refrigeration. From a conservation perspective they are considered of Least Concern being widespread and common with stable populations. They are a component of the aquarium trade on a limited basis.

Pacific Fat Sleeper, Dormitator latifrons. Fish collected by locals with a cast net at the mouth of the San José River, Baja California Sur, July 2005, during a breach in the barrier caused by Hurricane Hilary. Length: 25 cm (10 inches). The identical species in very non-photogenic red-brown and jet black colorations were also in this collection.