Back to Completed Reports List

Species Name: 
Leiostomus xanthurus Lacepede, 1803.

Synonymy:
None.

Common Name:
Spot, flat croaker, golden croaker, silver gudgeon, goody, chub, roach, jimmy, spot croaker.
 

Species Description:
Leiostomus xanthurus is a moderately deep-bodied, compressed fish with an elevated back.  Body color is typically bluish-gray dorsally, fading to golden yellow or yellow-tan ventrally.  A set of 12 -15 dark streaks run obliquely from  the dorsal surface down the sides to about mid-body.  These tend to fade with age.  Fins are typically pale yellow in color.  The head is short, with a small, inferior mouth.  The maxilla extends to approximately the middle of the eye.  The dorsal fin is continuous, with a notch separating the spinous portion from the soft rays.  There are 9-11 dorsal spines, and 29-35 soft rays.  The anal fin has 2 spines and 12-13 rays.  The caudal peduncle is moderately deep, and the caudal fin is notched.  A large black spot is set above the upper edge of the gill cover.  There are 72-77 lateral line scales (Johnson 1978). 

Other Taxonomic Groupings:
Supeclass: Osteichthyes
Subclass: Neopterygii
Infraclass:  Teleostei
Suborder: Percoidei

Potentially Misidentified Species:
Adults are not typically mistaken for other Sciaenids due to the prominent spot and faint oblique stripes.  However, juveniles resemble a number of related species including the Atlantic croaker, Micropogonias undulatus and the silver perch, Bairdiella chrysoura.  The Atlantic croaker is differentiated from the spot by having barbells on the  lower jaw and a serrate preopercule.  The silver perch is differentiated by its rounded caudal fin and well developed teeth. 

II.  HABITAT AND DISTRIBUTION 

Regional Occurrence:
Leiostomus xanthurus is common along the Atlantic coast from Cape Cod south to the Bay of Campeche, Mexico.  It occurs irregularly in south Florida and the Florida Keys, and north of Cape Cod, Massachusetts (Bigelow and Schroeder 1953; Chao 1978). 

IRL Distribution:
Spot are common throughout the Indian River Lagoon, especially around Brevard and Indian River Counties. 

III. LIFE HISTORY AND POPULATION BIOLOGY

Age, Size, Lifespan:
Leiostomus xanthusrus grows to approximately 11 inches total length (TL).  In the first year it may reach 5.9 inches; in the second year, 8.7 inches;  and in the third year 11 inches (Townsend 1956; Welsh and Breder, 1923;  McRae et al. 1997).  The lifespan may be as long as 5 years (DeVries 1982).

Growth rates in spot show both seasonal and annual variation. In young juveniles, growth rates are fastest in late spring and early summer, with high estuarine water temperatures in late summer and early fall tending to reduce feeding and retarding growth (Weinstein and Walters, 1981).   Both juvenile and adult spot grow  more slowly during winter (Dawson, 1958).

Abundance:
Leiostomus xanthurus is one of the most common demersal fishes in coastal and estuarine waters of the Atlantic, and has both commercial and recreational importance.  In some areas, the recreational catch often exceeds the commercial harvest (Hales and Van Den Avyle 1989). 

Locomotion:
Larval spot have limited swimming abilities measured at 0.25 – 1.0 m/s for brief periods (Lewis and Judy 1983).  Adult spot have significantly slower swimming speeds than other estuarine species (Hettler 1979), with a typical speed of approximately 0.7 m/s (Rulifson 1977).   

Spot Small spot (<2.7 cm SL) are unable to orient in currents exceeding 15 cm/s.  Larger spot, (to 5 cm SL) cannot maintain orientation when currents exceed 30 cm/sec (Hales and Van Den Avyle 1989).   

Reproduction:
Spot typically migrate offshore and spawn in the relatively deep water of the outer continental shelf, though some evidently spawn in both nearshore waters and estuaries (Dawson 1958; Lewis and Judy 1983).  Ripe adults aggregate off beaches in fall and begin migration offshore, possibly migrating to more southern waters in the process (Pearson 1932).  Spot may spawn repeatedly over several weeks (Hildebrand and Cable 1930), with some individuals remaining offshore after spawning (Pearson 1932; Wenner et al. 1979, 1980). 

In the south Atlantic region of the U.S., spawning occurs from October through March, peaking in December and January (Townsend 1956;  Lewis and Judy 1983;  Warlen and Chester 1985).  This is later than in mid-Atlantic waters and earlier than in the Gulf of Mexico, where spawning begins in December and peaks in January and February (Nelson 1969).

Most spot reach sexual maturity in the second year, but some require 3 years (Hales and Van Den Avyle 1989).  Dawson (1958) and Music (1974) reported that spot measuring 170 -175 mm total length (TL) showed ripened gonads.  However, other research (Hildebrand and Cable 1930;  Gunter 1945;  Townsend 1956) suggests sexual maturity is attained at somewhat larger size, between 185 – 210 mm TL.  Music (1974) reported that males may reach maturity at slightly smaller sizes than do females, 170 mm TL for males vs. 205 mm TL for females. 

Dawson (1958) estimated fecundity for spot at approximately 77,000 – 84,000 eggs per season.    

Embryology:
Eggs are pelagic and buoyant.  Under laboratory conditions, eggs hatched at 20ºC within 24 hours.  Larvae absorb the yolk sac and oil globule within 5 days of hatching (Powell and Gordy 1980).  Larvae are initially found in surface waters but become more demersal as they grow (Hildebrand and Cable 1930;  Lewis and Judy 1983).  Due to the limited swimming ability of larvae, it is believed that passive mechanisms (wind, Ekman transport, tides) are the primary transporters of larvae to the nursery habitats of estuaries and bays. 

Larvae arrive at estuaries when they are approximately 10 – 24 mm Standard length (SL) and 40 – 47 days old (Warlen and Chester 1985), typically in January (Hildebrand and Cable 1983;  Lewis and Judy 1983), with recruitment peaking in  February and March (Hildebrand and Cable 1983).  Larvae continuing to enter estuaries through June. 

Postlarvae and smaller juveniles tend to congregate in shallow water areas of tidal creeks in estuaries for 3-6 months (Weinstein and Walters 1981).  Thereafter, they tend to migrate to other estuarine habitats, and often migrate to deeper waters  (Weinstein 1983;  Weinstein and Brooks 1983;  Rojas and Hackney 1984). 

Warlen and Chester (1985) examined growth characteristics of larvae and juveniles and found that initial growth is rapid while larvae remain in offshore waters, presumably due to the abundance of plankton available.  Growth then slows in the early period of estuarine residency, until approximately April.  After metamorphosis to the juvenile stage, growth is again accelerated. 

IV.  PHYSICAL TOLERANCES

Temperature:
Mass mortality of spot was observed at water temperatures of 5 – 10 ºC, but larvae and postlarvae may be more tolerant of widely ranging temperatures than are older fish  (Hildebrand and Cable 1930;  Hodson et al. 1981a). 

Under laboratory conditions (Hettler and Powell 1981) reported spawning occurred at 17-25ºC.  Spot embryos do not develop at temperatures below 14ºC; however, larvae can tolerate temperatures as low as 5 ºC. (Hettler and Clements 1978).  Burton (1979) reported symptoms of cold stress in juveniles held at 5ºC. 

Upper thermal tolerance for postlarvae and juvenile spot is approx 35 ºC, depending on the size and general condition of fish, as well as the temperature the have been acclimated to.  Generally, as acclimation temperatures increase, the critical thermal maximum also increases (Hodson et al. 1981a).

Salinity:
Low salinity does not appear to be necessary for proper development and metamorphosis to the juvenile stage; however, it may affect survivorship of larvae (Powell and Gordy 1980).  Perez (1969) found that spot tended to be more active under lab conditions when salinity changed quickly, suggesting that they may actively try to avoid areas where salinity levels change rapidly. 

Dissolved Oxygen:
Postlarval and juvenile spot have intermediate tolerance to hypoxic conditions in comparison to other estuarine species (Burton et al 1980).  Exposure of 90 mm TL spot to 0.8mg/L for 96 hours resulted in 5% mortality;  however, lowering the concentration to 0.6 mg/L resulted in 95% mortality.

V.  COMMUNITY ECOLOGY

Trophic Mode:
Leiostomus xanthurus show 2 distinct feeding modes:  larvae are selective plankton feeders, while juveniles and adults are partly olfactory-dependent, benthic feeders that prey on infaunal and epibenthic invertebrates. 

Preferred larval foods include ciliates, invertebrate eggs, and copepod nauplii.  Individuals up to 25 mm SL feed primarily on copepods and ostracods (Hildebrand and Cable 1930).  Upon metamorphosis, the diet changes to include insect larvae, polychaetes, harpacticoid copepods and other crustaceans (Hildebrand and Cable 1930;  Townsend 1956; Hodson et al. 1981b);  however, the juvenile diet can be flexible and often is reflective of prey availability in specific areas (Hales and Van Den Avyle 1989). 

Chao and Musick (1977) reported that in Chesapeake Bay, prey for adult spot includes zooplankton and benthic infauna, with polychaetes most frequently observed in gut contents.  Other prey types included amohipods, cumaceans, gastropods, nematodes, mysids, and copepods

After growth to 10 – 15 mm SL, larvae of all sizes feed diurnally (Govoni et al. 1983). 

Competitors:
Spot likely compete with other estuarine species;  however little research has been undertaken in this area.

Habitats:
Spot are common in coastal waters during the spawning season, and in estuaries and nearshore waters during other parts of the year.  They are typically found over sandy or muddy bottoms in waters up to approximately 60 m deep. 

Activity Time:
Postlarvae feed most actively during daylight hours, with peaks in late morning (Kjelson et al. 1975).  Juveniles switch to nocturnal feeding after metamorphosis, perhaps as a predator avoidance mechanism, or to avoid high daytime temperatures in shallow marshes (Hodson et al. 1981b).  Adults tend to be nocturnal.

Associated Species:

     Predators:
Predators of spot include silversides (Menidia spp.), which may affect postlarval distribution in estuaries (Weinstein and Walters 1981).  Juveniles and adult spot are also preyed upon by many fishes, including striped bass, sharks, seatrout, bluefish, mackerels, gars, and flounders (Hollis 1952;  Rozas and Hackney 1984).

     Parasites:
Parasites of spot include copepods of the genera Lernaeenicus and Ergasilus, as well as a marine leech, Myzobdella lugubris (Sawyer et al. 1975).  Internal parasites include trematodes, microsporideans, and acanthocephalans (Sprague and Hussey 1980; Govoni 1983).

VI. SPECIAL STATUS

Special Status:
None.

Fisheries Importance:
In 2001, statewide landings in Florida were 352,786 pounds.  Of this, approximately 90% of the statewide landings were made on the Atlantic coast of Florida; with the recreational fishery for spot accounting for 86% of the total (Murphy 2003).  Commercial landings on the Atlantic are generally concentrated around Brevard, Indian River and Martin counties.

Before 1995, the commercial fishery for spot relied almost exclusively on gill nets. The ban on entangling nets enacted in late 1995 prompted a shift toward smaller gear such as cast nets and haul seines.  As reflected in the reduced commercial landings since the rule went into effect, Florida’s abolition of entangling gear use in July 1995 almost eliminated the traditional commercial fishery for spot. Reduced fishing pressure could result in higher and more stable recruitment in the future (McRae 1997b).

COMMERCIAL FISHERY:


Figure 1.  Annual dollar value of the commercial catch of spot to the 5-county area of the
             Indian River Lagoon. 

Figure 2.  Total spot  dollar value and percentage by county for the years 1987 - 2001.

Table 1.  Total dollar value of IRL spot, Leiostomus xanthurus between 1987 - 2001.

            Table 2.  By-county annual and cumulative percentages of the spot harvest for the 
                       years 1987-2001.

             Table 3.  By-county cumulative dollar value and percentage of total for the spot
                       harvest from 1987 - 2001. 

RECREATIONAL FISHERY:

Figure 3.  Survey data for the spot recreational fishery showing the number of fishes
              harvested in East Florida waters from 1997 - 2004.
 

Figure 4.  Summary of the spot recreational harvest and percentage of total by area from
             1997 - 2004. 

               Table 4.  Summary data for recreational fishery in Eastern Florida waters for
                          the spot, Leiostomus xanthurus, from 1997 - 2004.   Data provided by
                          National Marine Fisheries Service, Fisheries Statistics Division, NOAA.

                          Table 5.  By-county annual and cumulative percentages of the spot
                                     harvest for the years 1997 - 2001.  Data provided by National Marine
                                     Fisheries Service, Fisheries Statistics Division, NOAA.

                          Table 6.  Summary of the spot recreational harvest and percentage of total
                                   fish captured in each area from 1997 - 2004.  Data provided by National
                                   Marine Fisheries Service, Fisheries Statistics Division, NOAA.

VII.  REFERENCES 

Bigelow, H.B., and W.C. Schroeder. 1953. Fishes of the Gulf of Maine. U.S.
     Fish Wildl. Serv. Fish. Bull. 74:1-577.

Bullock, W.L. 1957. The acanthocephalan parasites of the fishes of the Texas
     coast. Publ. Inst. Mar. Sci. Univ. Texas 4:278-283.

Burton, D.T. 1979. Ventilation frequency compensation responses of three
     eurythermal estuarine fish exposed to moderate temperature increases. J. Fish
     Biol. 15:589-600.

Burton, D.T., L.B. Richardson, and C.J. Moore. 1980. Effect of oxygen
     reduction rate and constant low dissolved oxygen concentrations on two
     estuarine fish. Trans. Am. Fish. Soc. 109:552-557.

Chao, L.N., and J.A. Musick. 1977. Life history, feeding habits, and functional
     morphology of juvenile sciaenid fishes in the York River estuary. U.S. Natl.
     Mar. Fish. Serv. Fish. Bull. 75:657-702.

Chao, L.N., 1978 Sciaenidae. In W. Fischer (ed.) FAO species identification
     sheets for fishery purposes.  West Atlantic (Fishing Area 31). Volume 4.
     FAO, Rome.

Dawson, C.E. 1958. A study of the biology and life history of the spot,
     Leiostomus xanthurus Lacepede, with special reference to South Carolina.
     S.C. Wildl. Mar. Res. Dep. Contrib. Bears Bluff Lab. No. 28. 48 pp.

DeVries, D.A. 1982. Age and growth of spot in North Carolina. Northeast Fish
     Widl. Conf., April 13-15, 1982 Cherry Hill, NJ (Abstract).

Govoni, J.J. 1983. Helminth parasitism of three larval fishes in the northern Gulf of
     Mexico. U.S. Natl. Mar. Fish. Serv. Fish. Bull. 81:895-898.

Govoni, J.J., A.J. Chester, D.E. Hoss, and P.B. Ortner. 1985. An observation of
     episodic feeding and growth of larval  Leiostomus xanthurus in the northern
     Gulf of Mexico. J. Plankton Res. 7:137-141.

Govoni, J.J., D.S. Peters, and J.V. Merriner. 1982. Carbon assimilation during
     larval development of the marine teleost  Leiostomus xanthurus Lacepede. J.
     Exp. Mar. Biol. Ecol. 64:287-299.

Gunter, G. 1945. Studies on the marine fishes of Texas. Publ. Inst. Mar. Sci.
     Univ. Texas 1:9-190.

Hales, L.S. and M.J. Van Den Avyle.  1989.  Species profiles: life histories and
     environmental requirements of coastal fishes and invertebrates (South Atlantic)
     Spot.  U.S. Fish and Wildlife Service Biological Report 82(11).  U.S. Army
     Corps of Engineers TR EL-82-4.

Hettler, W.F. 1979. Swimming speeds of juvenile estuarine fish in a circular flume.
     Proc. Ann. Conf. Southeast. Assoc. Fish Wildl. Agencies 31:392-398.

Hettler, W.F., and L.C. Clements. 1978. Effects of acute thermal stress on marine
     fish embryos and larvae. Pages 171-190 in Fourth National Workshop on
     Entrainment and Impingement, Ecological Analysts Communications, Melville,
     New York.

Hildebrand, S.F., and L. Cable. 1930. Development and life history of fourteen
     teleostean fishes at Beaufort, North Carolina. Bull. U.S. Bur. Fish.
     46:383-488.

Hildebrand, S.F., and W.C. Schroeder. 1928. Fishes of Chesapeake Bay. Bull.
     U.S. Bur. Fish. 43, Part 1.  366 pp.

Hodson, R.G., R.G. Fechhelm, and R.J. Monroe. 1981a. Upper temperature
     tolerance of the spot, Leiostomus xanthurus, from the Cape Fear River
     Estuary, North Carolina. Estuaries 4:345-356.

Hodson, R.G., J.O. Hackman, and C.R. Bennett. 1981b. Food habits of young
     spot in nursery areas of the Cape Fear River Estuary, North Carolina. Trans.
     Am. Fish. Soc. 110:495-501.

Hoss, D.E., W.F. Hettler, and L.C. Clements. 1974. Effects of thermal shock on
     larval estuarine fish - ecological implications with respect to entrainment in
     power plant cooling systems. Pages 357-371 in: J.H.S. Blaxter, ed. The Early
     Life History of Fish.  Springer-Verlag, New York.

Houde, E.D. 1978. Critical food levels for growth and survival of laboratory
     reared larvae of three species of subtropical marine fishes. Bull. Mar. Sci.
     28:395-411.

Johnson, G.D. 1978. Development of Fishes of the Mid-Atlantic Bight. Volume
     IV, Carangidae through Ephippidae. U.S. Fish. Wildl. Serv. Biol. Serv.
     Program FWS/OBS-78/12. 416 pp.

Kjelson, M.A., and G.N. Johnson. 1976. Further observations of the feeding
     ecology of postlarval pinfish, Lagodon rhomboides, and spot, Leiostomus
     xanthurus. U.S. Natl. Mar. Fish. Serv. Fish. Bull. 74:423-432.

Kjelson, M.A., D.S. Peters, G.W. Thayer, and G.N. Johnson. 1975. The general
     feeding ecology of postlarval fishes in the  Newport River estuary. U.S. Natl.
     Mar. Fish. Serv. Fish. Bull. 73:137-144.

Lewis, R.M., and M.H. Judy. 1983. The occurrence of spot, Leiostomus
     xanthurus, and Atlantic croaker, Micropogonias undulatus, larvae in
     Onslow Bay and the Newport River estuary, North Carolina. U.S. Natl. Mar.
     Fish. Serv. Fish. Bull. 81:405-412.

Murphy, Michael D.  2003.  Species account for spot (Leiostomus xanthurus)
     in:  Florida.  Florida Fish and Wildlife Research Institute, Florida Fish and
     Wildlife Conservation Commission. Available on the Internet at:
     http://www.floridamarine.org/features/view_article.asp?id=5573

Music, J.L. 1974. Observations on the spot Leiostomus xanthurus in Georgia's
     estuarine and close inshore ocean waters. Ga. Dep. Nat. Resour. Contrib. Ser.
     28. 29 pp.

Nelson, W.R. 1969. Studies on the croaker, Micropogon undulatus Linnaeus,
     and the spot, Leiostomus xanthurus Lacepede, in  Mobile Bay, Alabama. J.
     Mar. Sci. Alabama 1:4-92.

Neumann, D.A., J.M. O'Conner, and J.A. Sherk, Jr. 1981. Oxygen consumption
     of white perch (Morone americana), striped bass (Morone saxatilis), and
     spot (Leiostomus xanthurus). Comp. Biochem. Physiol. 69A:467-478.

Pacheco, A.L. 1962. Age and growth of spot in lower Chesapeake Bay, with
     notes on the distribution and abundance of juveniles in the York River system.
     Chesapeake Sci. 3:18-28.

Parker, J.C. 1971. The biology of the spot, Leiostomus xanthurus, and the
     Atlantic croaker, Micropogon undulatus, in two Gulf of Mexico nursery
     areas. Tex. A&M Univ. Sea Grant Publ. NOAA-TAMU-SG-14, College
     Station, TX.

McRae, G., R.G. Muller, and R. Paperno.  1997.  Update on Florida's Spot
     Fishery Report to the Marine Fisheries Commission, July 10, 1997. 
     Department of Environmental Protection Florida Marine Research Institute,
     100 Eighth Avenue Southeast, St. Petersburg, FL 33701-5095.

Pearson, J.C. 1932. Winter trawl fishery of the Virginia and North Carolina
     coasts. U.S. Bur. Fish. Investigative Rep. 10. 31 pp.

Powell, A.B., and H.R. Gordy. 1980. Egg and larval development of the spot,
     Leiostomus xanthurus. U.S. Natl. Mar. Fish. Serv. Fish. Bull. 78:701-714.

Roberts, M.H., Jr. 1980. Survival of juvenile spot (Leiostomus xanthurus)
     exposed to bromochlorinated and chlorinated sewage in estuarine waters.
     Mar. Environ. Res. 3:63-80.

Roelofs, E.W. 1954. Food studies of young sciaenid fishes, Micropogon and
     Leiostomus, from North Carolina. Copeia 1954:151-153.

Rozas, L.P., and C.T. Hackney. 1984. Use of oligohaline marshes by fishes and
     macrofaunal crustaceans in North Carolina. Estuaries 7:213-224.

Rulifson, R.A. 1977. Temperature and water velocity effects on the swimming
     performances of young-of-the-year striped mullet (Mugil cephalus), spot
     (Leiostomus xanthurus), and pinfish (Lagodon rhomboides). J. Fish. Res.
     Board Can. 34:2316-2322.

Sawyer, R.T., A.R. Lawler, and R.M. Overstreet. 1975. Marine leeches of the
     eastern U.S. and the Gulf of Mexico with a key to the species. J. Nat. Hist.
     9:633-667.

Townsend, B.C., Jr. 1956. A study of the spot, Leiostomus xanthurus
     Lacepede, in Alligator Harbor, Florida. M.S. Thesis. Florida State University,
     Tallahassee. 43 pp.

Warlen, S.M., and A.J. Chester. 1985. Age, growth and distribution of larval
     spot; Leiostomus xanthurus, off North Carolina. U.S. Natl. Mar. Fish. Serv.
     Fish Bull. 83:587-599.

Weinstein, M.P. 1983. Population dynamics of an estuarine dependent fish, the
     spot (Leiostomus xanthurus), along a tidal creek-seagrass meadow
     coenocline. Can. J. Fish. Aquat. Sci. 40:1633-1638.

Weinstein, M.P., and M.P. Walters. 1981. Growth, survival, and production in
     young-of-year populations of Leiostomus xanthurus Lacepede residing in
     tidal creeks. Estuaries 4:185-197. Tech. Rep. 40. 78 pp.

Welsh, W.W., and C.M. Breder, Jr. 1923. Contributions to the life histories of
     Sciaenidae of the eastern United States coast.  Bull. U.S. Bur. Fish.
     39:141-201.

Wenner, C-A., C.A. Barans, B.W. Stender, and F.H. Berry. 1979a. Results of
     MARMAP otter trawl  investigations in the South Atlantic Bight. I. Fall, 1973.
     S.C. Dep. Wildl. Mar. Res. Center Tech. Rep. 33. 79 pp.

Wenner, C.A., C.A. Barans, B.W. Stender, and F.H. Berry. 1980. Results of
      MARMAP otter trawl investigations in the South Atlantic Bight. V. Summer,
     1975. S.C. Dep. Wildl. Mar. Res. Center Tech. Rep. 45. 57 pp.

Yoder, J.A., L.P. Atkinson, J.O. Blanton, D.R. Deibel, D.W. Menzel, and G.A.
     Paffenhofer. 1981. Plankton productivity and the distribution of fishes on the
     southeastern U.S. continental shelf. Science 214:352-353.

Report by:  K. Hill, Smithsonian Marine Station
Submit additional information, photos or comments to:
irl_webmaster@si.edu
Page last updated: June 9,  2005