Longjaw Mudsucker

Gillichthys mirabilis





As part of the bony fish Gobiidae family, the Longjaw mudsucker is characterized by its smaller size with a common length of 13cm at maturity (4). It may have a gray to olive body coloration marked with black striations and a yellow hue on its ventral side (1). This species is distributed along the northern California coast to the Gulf of California of saline water habitats in sloughs, bays and tidal flats (2). This estuarine goby has a vascularized buccopharynx for aerobic respiration without emerging activity in the shallow waters it occupies (2). When an increase in oxygen levels is required, the fish will travel to the water/air interface where it consumes oxygen and proportionally excretes carbon dioxide (3). Unlike an obligatory aquatic breather, oxygen is consumed through a gulp of air while the carbon dioxide waste is released through the gills and skin in a single gulp interval (3).


  1. Eschmeyer, W.N., E.S. Herald and H. Hammann, 1983. A field guide to Pacific coast fishes of North America. Boston (MA, USA): Houghton Mifflin Company.
  2. Martin, K.L.M. and C.R. Bridges, 1999. Respiration in water and air. p. 54-78. In M.H. Horn, K.L.M. Martin and M.A. Chotkowski (eds.) Intertidal fishes. Life in two worlds. Academic Press. 399.
  3. Todd, E. S., & Ebeling, A. W. (1966). Aerial respiration in the longjaw mudsucker Gillichthys mirabilis (Teleostei: Gobiidae). The Biological Bulletin, 130(2), 265-288.
  4. Hugg, D. O. (1996). MAPFISH georeferenced mapping database. Freshwater and estuarine fishes of North America. Life Science Software. Dennis O. and Steven Hugg, 1278.


(Photograph) Tom Turner.  https://www.inaturalist.org/observations/22488167