The longjaw mudsucker ''Gillichthys mirabilis'' is a

goby Goby is a common name for many species of small to medium sized ray-finned fish, normally with large heads and tapered bodies, which are found in marine, brackish and freshwater environments. Traditionally most of the species called gobies have b ...

(

Gobiidae Gobiidae or gobies is a family of bony fish in the order Gobiiformes, one of the largest fish families comprising more than 2,000 species in more than 200 genera. Most of gobiid fish are relatively small, typically less than in length, and the ...

) of the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

coast of

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

and

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

, noted for its extremely large mouth and ability to survive out of water for short periods. As the common name suggests, the upper jaw is extremely long, reaching nearly to the opercular opening. The head is broad and flat, with the eyes placed close to the top (but still widely spaced). Overall color is a dark brown to olive on the upper parts, and yellowish below; a faint pattern of vertical bars may be visible, and are prominent in juveniles. The first

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

is relatively small, with 4-8 spines, while the second dorsal fin is larger, with 10-17 rays. The

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

s are broad and rounded, with from 15 to 23 rays. They can reach lengths of 21 cm. These mudsuckers occur in estuaries, primarily in tidal sloughs with shallow mud-covered bottoms, where they often excavate burrows. When the tide goes out and the mud is exposed, they will retreat to their burrows or move into tidal channels; if trapped on the mud, they can wait for the next tide by gulping air buccopharyngeal chamber in the throat. They feed on nearly anything they can find in the mud, including small fish such as California killifish, but mostly live on invertebrates, the main choices depending on seasonal availability. Their range extends from

Tomales Bay Tomales Bay is a long, narrow inlet of the Pacific Ocean in Marin County in northern California in the United States. It is approximately long and averages nearly wide, effectively separating the Point Reyes Peninsula from the mainland of Mar ...

in the north to Bahia Magdalena in the south. There is a disjunct population of longjaw mudsuckers in the northern section of the Gulf of California; this population has been evolving independently of populations in California/western Baja for an estimated 284 thousand years. A population in the

Salton Sea The Salton Sea is a shallow, landlocked, highly saline body of water in Riverside and Imperial counties at the southern end of the U.S. state of California. It lies on the San Andreas Fault within the Salton Trough that stretches to the Gulf ...

was introduced in 1950, and now thrives there. They are considered good

bait fish 300px, Feeder Goldfish are common baitfish. Bait fish (or baitfish) are small-sized fish caught and used by anglers as bait to attract larger predatory fish, particularly game fish. Baitfish species are typically those that are common and bree ...

for freshwater fishing, such as on the

Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid watershed that encompasses parts of seven U.S. s ...

, because they can be kept alive packed in moist algae, and will not reproduce in fresh water if they happen to escape.

References

Further reading