Mugil cephalus

Geographic Range

Mugil cephalus occurs in the coastal waters of the tropical and subtropical zones of all seas. Striped mullet are found in the western Atlantic Ocean, from Nova Scotia, Canada south to Brazil, including the Gulf of Mexico. They are absent in the Bahamas and the Caribbean Sea (Robins and Ray 1986). In the eastern Atlantic Ocean, striped mullet occur from the Bay of Biscay (France) to South Africa, including the Mediterranean Sea and the Black Sea (Thomson 1951). The eastern Pacific Ocean range includes southern California south to Chile (Eschmeyer et al. 1983).

• Biogeographic Regions
• indian ocean
  • native native
• atlantic ocean atlantic ocean
  • native native
• pacific ocean pacific ocean
  • introduced introduced
  • native native
• mediterranean sea
  • native native

• Other Geographic Terms
• cosmopolitan cosmopolitan

Habitat

Mugil cephalus are found in highly salty to fresh waters that are warm or temperate from 8 to 24 C. They spend a great deal of time close to shore around the mouths of streams and rivers or in brackish bays, inlets, and lagoons with sand or mud bottoms (Texas Parks 2005). They often enter estuaries and freshwater environments. Adult mullet have been found in waters ranging from 0 ppt to 75 ppt salinity. Adults form huge schools near the surface over sandy or muddy bottoms and dense vegetation (Bester 2004).

• Habitat Regions
• temperate temperate
• tropical tropical
• saltwater or marine saltwater or marine
• freshwater freshwater

• Aquatic Biomes
• benthic benthic
• rivers and streams
• coastal coastal
• brackish water brackish water

• Other Habitat Features
• estuarine estuarine

Physical Description

The maximum length of striped mullet is 120 cm, with a maximum weight of 8 kg. The body of striped mullet is subcylindrical and anteriorly compressed. They have a small, terminal mouth with inconspicuous teeth and a blunt nose. The lips are thin, with a bump at the tip of the lower lip. The adipose eyelid is prominent with only a narrow slit over the pupil. The body is elongate and the head is slightly wider than deep. Pectoral fins are short, not reaching the first dorsal fin. The origin of the second dorsal fin is posterior to the origin of the anal fin. The lateral line is not visible. This mullet is often confused with white mullet, Mugil curema . However, white mullet have scales extending onto the soft dorsal and anal fins while striped mullet do not. They may also be identified based on the anal ray fin counts of 8 for striped mullet and 9 for white mullet. The body is grayish olive to grayish brown, with olive-green or bluish tints and sides fading to silvery white towards the belly. Dark longitudinal lines, formed by dark spots at the center of each scale on the upper half of the body, run the length of the body. Young fish smaller than 15 cm in length lack stripes. There is a large dark blotch at the base of the pectoral fin. The pigmentation in the iris is dispersed and brown, a character that also helps to distinguish it from M. curema . The mouth is triangular in shape when viewed from above, with small, close-set teeth arranged in several rows on the jaws (Bester 2004).

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Development

The eggs are transparent and pale yellow, non-adhesive, and spherical with an average diameter of 0.72 mm. Each egg contains an oil globule, making it positively buoyant. Hatching occurs about 48 hours after fertilization, releasing larvae approximately 2.4 mm in length. These larvae have no mouth or paired fins. At 5 days of age, they are approximately 2.8 mm long. The jaws become well-defined and the fin buds begin to develop. At 16 to 20 mm in length, the larvae migrate to inshore waters and estuaries. At 35 to 45 mm, the adipose eyelid is obvious, and by 50 mm it covers most of the eye. At this time the mullet is considered to be a juvenile. These juveniles are capable of osmoregulation, being able to tolerate salinities of 0 to 35 ppt. They spend the remainder of their first year in coastal waters, salt marshes, and estuaries. In autumn, they often move to deeper water while the adults migrate offshore to spawn. However, some young mullet overwinter in estuaries. After this first year of life, mullet inhabit a variety of habitats including the ocean, salt marshes, estuaries, and fresh water rivers and creeks (Bester 2004).

Reproduction

Striped mullet are catadromous, that is, they spawn in saltwater yet spend most of their lives in freshwater. During the autumn and winter months, adult mullet migrate far offshore in large aggregations to spawn. In the Gulf of Mexico, mullet have been observed spawning 65 to 80 km offshore in water over 1,000 m deep. In other locations, spawning has been reported along beaches as well as offshore.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Estimated fecundity of striped mullet is 0.5 to 2.0 million eggs per female, depending upon the size of the individual (Bester 2004). Female mullet reach sexual maturity in their fourth year, when they are between 40 to 42 cm. Males mature in their third year, once they reach a size of 33 to 38 cm. The minimum spawning size of females is between 31 to 34 cm. Striped mullet are oviparous fish (Hill 2004). Beginning in the early fall, large schools of mullet aggregate in the lower reaches of estuaries and at river mouths in preparation for offshore migration to spawning grounds. Environmental cues such as falling water temperatures, passage of cold fronts and falling barometric pressure are thought to trigger aggregation and subsequent migration. Spawning occurs in deep, offshore waters from mid-October through late January, with peak spawning occurring in November and December. Larvae and prejuveniles then migrate to inshore estuaries where they inhabit shallow, warm water in the intertidal zone. Mugil cephalus are isochronal spawners, with all oocytes reaching maturity at the same time. However, based on the size of the female body cavity, it is unlikely that a female's entire store of eggs is hydrated at the same time in preparation for spawning. Rather, females are likely to hydrate eggs in batches and spawn on successive evenings until their supply of yolked eggs is depleted (Hill 2004).

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • external external
• broadcast (group) spawning
• oviparous oviparous

Once eggs are laid, adult striped mullet do not provide any further parental care (Texas Parks 2005).

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning
  • protecting
    • female

Lifespan/Longevity

The lifespan of striped mullet is seven years for males and eight years for females, with a probable average lifespan of five years. The oldest striped mullet on record is one that lived 13 years (Texas Parks 2005).

Behavior

Striped mullet tend to school for protection from predators in the daylight hours, although they feed around the clock (Texas Parks 2005). Striped mullet leap out of the water frequently. Biologists aren't sure why these fish leap so often, but it could be to avoid predators. Another possibility is that the fish spend much of their time in areas that are low in dissolved oxygen. They may quickly exit the water in order to clear their gills and be exposed to higher levels of oxygen (Bester 2004).

• Key Behaviors
• natatorial natatorial
• diurnal diurnal
• nocturnal nocturnal
• motile motile
• social social

Home Range

Home ranges of these animals in the wild have not been reported.

Communication and Perception

The communication and perception of striped mullet has not been reported. They are likely to use chemical and visual cues.

• Perception Channels
• visual visual
• tactile tactile
• chemical chemical

Food Habits

Mullet are diurnal feeders, consuming mainly zooplankton, dead plant matter, and detritus. Mullet have thick-walled gizzard-like segments in their stomach along with a long gastrointestinal tract that enables them to feed on detritus.

They are an ecologically important link in the energy flow within estuarine communities. Feeding by sucking up the top layer of sediments, striped mullet remove detritus and microalgae. They also pick up some sediments which function to grind food in the gizzard-like portion of the stomach. Mullet also graze on epiphytes and epifauna from seagrasses as well as ingest surface scum containing microalgae at the air-water interface. Larval striped mullet feed primarily on microcrustaceans. One study found copepods, mosquito larvae, and plant debris in the stomach contents of larvae under 35 mm in length. The amount of sand and detritus in the stomach contents increases with length indicating that more food is ingested from the bottom substrate as these fish mature (Bester 2004).

• Primary Diet
• planktivore planktivore
• detritivore detritivore

• Animal Foods
• insects
• aquatic crustaceans
• zooplankton zooplankton

• Plant Foods
• algae

• Other Foods
• detritus detritus

Predation

Major predators of striped mullet include larger fish, birds, and marine mammals. Spotted seatrout, Cynoscion nebulosus , feed on mullet up to 13.8 to 35 cm long. Off the coast of Florida, sharks often feed on large mullet. Pelicans and other aquatic birds as well as dolphins also prey on striped mullet. Humans are also significant predators of striped mullet (Bester 2004).

Ecosystem Roles

Striped mullet are an ecologically important link in the energy flow within marine communities. They serve as prey for their predators. Striped mullet are hosts for many parasites including flagellates, ciliates, myxosporidians, monogenean and digenean trematodes, nematodes, acanthocephalans, leeches, argulids, copepods, and isopods (Bester 2004).

Economic Importance for Humans: Positive

Striped mullet are regarded as an excellent food fish. They are also used as bait for a variety of fishes, including billfish, commonly bringing a higher price as bait than as food fish. These fish are prized for their roe. Striped mullet are marketed fresh, dried, salted, and frozen with the roe sold fresh or smoked. This fish is also used in Chinese medicinal practices. It is a very important commercial fish in many other parts of the world (Bester 2004).

• Positive Impacts
• food food
• source of medicine or drug source of medicine or drug

Economic Importance for Humans: Negative

No negative effects on humans have been reported for striped mullet.

Conservation Status

Striped mullet are not listed as endangered or vulnerable with the World Conservation Union (IUCN), CITES, or the U.S. Endangered Species Act. These are common and abundant fish.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Roy Pullukat (author), University of Michigan-Ann Arbor, Kevin Wehrly (editor, instructor), University of Michigan-Ann Arbor.

References

Bester, C. 2004. "Ichthyology at the Florida Museum of Natural History" (On-line). Accessed October 16, 2005 at http://www.flmnh.ufl.edu/fish/Gallery/Descript/StripedMullet/StripedMullet.html .

Eschmeyer, W., E. Herald, H. Hammann. 1983. A field guide to Pacific coast fishes of North America . Boston: Houghton Mifflin Company.

Hill, K. 2004. "Smithsonian Marine Station at Fort Pierce" (On-line). Accessed October 16, 2005 at http://www.sms.si.edu/irlspec/Mugil_cephal.htm .

Man, S., I. Hodgkiss. 1981. Hong Kong freshwater fishes . Hong Kong: Wishing Printing Company.

Robins, C., G. Ray. 1986. A field guide to Atlantic coast fishes of North America . Boston, U.S.A.: Houghton Mifflin Company.

Thomson, J. 1951. Growth and habits of the sea mullet, Mugil dobula Günther, in Western Australia . Australia: Aust. J. Mar. Freshwat..

2005. "Texas Parks and Wildlife Department" (On-line). Accessed December 02, 2005 at http://www.tpwd.state.tx.us/huntwild/wild/species/mullet/ .