Esox americanus, vicinity of New York City (Gmelin 1788).
Etymology/Derivation of Scientific Name
Esox, an old European word for pike; americanus, “from America” (Ross 2001).
Esox lucius americanus Gmelin1788:1390 in Mettee et al. 1987
Esox americanus Cook 1959:72.
Esox americanus vermiculatus Lesueur 1846 in Cuvier and Valenciennes 1846:335
Esox umbrosus Hay 1883:67
Esox vermiculatus Cook 1959:72
Maximum size: 381 mm TL (Ross 2001).
Life colors: Adult pattern first appears at about 130-140 mm in length. Dorsal surface and upper sides uniform pale to dark green, there is a rusty brown mid-dorsal stripe, the sides show 15-23 olive to black, thin, wavy, vertical bars separated by lightly pigmented extensions of what had in the young been a prominent golden green lateral band. Pale area between adjacent bars is wider than the bars. Ventral, vertical, suborbital and horizontal, preorbital, black bars obvious, sometimes postorbital, horizontal bar obvious; lateral edges of both jaws lightly pigmented; the pupil is yellow; the leading edge of all fins is black, the rest of the fins dusky to amber (Scott and Crossman 1973). Young grass pickerel have an unpigmented lateral band that extends from the snout to the base of the caudal fin. In addition, they have a silvery green, middorsal band that extends from the tail to the tip of the snout (Crossman 1962).
Counts: 11-13 branchiostegal rays; fewer than 115 scale rows along body (Hubbs et al. 1991); 17-21 dorsal rays; 16-20 anal rays (Crossman 1966); 13-17 pectoral rays; 8-10 pelvic rays (Ross 2001).
Body shape: Long, cylindrical, somewhat flat dorsally, shallow, greatest depth (between paired fins) is 12.1-17.4% of TL, cross section almost round; snout short (into head length 2.4-2.7; Becker 1983), rounded and concave on top, only moderately broad; eyes high, moderately large (Scott and Crossman 1973).
Mouth position: Terminal (Goldstein and Simon 1999); large canine teeth in lower jaw flattened to rear (Becker 1983).
External morphology: Opercles with scales covering most of ventral half (Hubbs et al. 1991); top of head unscaled; cheek scaled; gill rakers reduced to sharp, toothlike structures; scales cycloid; principal dorsal fin rays, principal anal fin rays, pectoral fin rays, pelvic fin rays all rounded on edge; caudal fin forked (Becker 1983).
Distribution (Native and Introduced)
U.S. distribution: Inhabits Coastal Plain from MA to south NH, Lac St. Pierre (St. Lawrence River) region of Quebec, Canada, south in Hudson River to coastal NY, from east PA south to St. Mary’s River system in GA. Waters from southwestern GA, south to Lake Okeechobee, FL, and the Gulf of Mexico systems from Suwanee River, FL and GA, to Biloxi River, MS. Pearl River, LA, west to Brazos River, TX, north through eastern OK, southeastern MO, east border of IA, to southwestern WI. East across southern MI and southern Ontario, Canada to tributaries of southwestern shore of Lake Ontario and those of Niagra River, western NY, including tributaries of Lake Ontario, some of the Finger Lakes and those of St. Lawrence, in Ontario, Canada and NY, as far downstream as mouths of Ottawa and Chateauguay rivers in Quebec, Canada. Eastern limit runs southwest from NY, west of mountains along line from northwestern PA to central MS, including Tennessee River in Northwestern AL (Crossman 1980).
Texas distribution: Primarily restricted to the eastern part of the state and coastal streams from the Red River Basin south to the Brazos River Basin (Hubbs et al. 1991). Warren et al. (2000) list the Red River drainage unit for distribution of this species in the state.
Abundance/Conservation status (Federal, State, NGO)
Not listed as threatened or endangered by Texas Parks and Wildlife Department
(2006). Populations in the southern United States are currently secure (Warren et al. 2000).
Macrohabitat: Streams, drainage canals, ponds, and bays of small lakes (Crossman 1980).
Mesohabitat: Small, quiet, heavily vegetated waters (Crossman 1980). Common in waters with neutral or slightly basic pH and sandy or rocky substrata (Crossman 1966; 1980). In Lamar Co., Mississippi, E. americanus occurs in habitat characterized by high amounts of aquatic vegetation and cover, fine substrata such as mud and silt, high litter amounts, and water depths of over 0.5 m (Ross et al. 1987). Evans and Noble (1979) noted a high relative abundance of Esox americanus, the single largely piscivorous species collected, in the headwaters of Big Sandy Creek, Texas where the streambed is mostly clay, with some silt and sand, and large, impervious clay substrate pools are found; these pools helping to negate the impact of drought in headwater areas.
Spawning season: Spring spawner, but also reported to spawn in fall with water; the two periods probably coinciding with water temperatures of about 10°C (Crossman 1980; Crossman 1966; Kleinert and Mraz 1966).
Spawning habitat: In flood plains, E. americanus spawns along grassy margins, or in other areas of heavy vegetation (Ross and Baker 1983; Kwak 1988). Phytophils; obligatory plant spawners with adhesive egg envelopes that stick to submerged dead or live plants (Kleinert and Mraz 1966; Simon 1999).
Reproductive strategy: No nest, parental care, or defense of territory (Crossman 1980; Simon 1999). Open substratum spawner (Simon 1999). Eggs are broadcast and abandoned, settling and adhering to vegetation (Becker 1983).
Fecundity: Moderately large number of small demersal, adhesive eggs (Crossman 1980). Mature eggs average 1.9mm in diameter and are golden yellow; range from 843 to 4584 mature eggs for grass pickerel of 160-325 mm TL (Kleinert and Mraz 1966).
Age at maturation: Sexually mature by at least age two, at 134-174 mm TL (Crossman 1980).
Migration: In spring adults proceed upstream and on to flooded stream margins or marshes were vegetation is plentiful. It is probable that changing water temperature and an increase in temperature stimulate spawning (Scott and Crossman 1973).
Longevity: 7-8 years (Scott and Crossman 1973; Crossman 1980).
Growth: Hatchlings 6.2 mm long (Scott and Crossman 1973; Becker 1983). In Wisconsin, early growth in different years appears to be similar and rapid; 6.5-11.5 mm TL on 24 April, 10-17 mm on 9 May, 25-29 mm on 25 May, 31-49 mm on June 3. Scale analysis of a combined sample of 280 pickerel from six Wisconsin lakes indicates average lengths at different ages as: age 0 - 145 mm; I – 208 mm; II – 251 mm; III - 287 mm; IV – 356 mm. Females are longer than males at age 0, I, and II; no males of age III were encountered, indicating females exceed males in growth and longevity (Kleinert and Mraz 1966).
Food habits: Invertivore/carnivore; benthic predator and drift/whole body feeder; trophic mode: lie-in-wait/ambush. Intestine long and undifferentiated (Goldstein and Simon 1999). Food of very young grass pickerel (to 50 mm TL) is cladocerans, amphipods, osterocods, isopods, and immature or adult insects from the orders Diptera, Plecoptera, and Hemiptera. In the size range 50-100 mm they begin to prey on fishes, but diet is mainly Trichoptera, Odonata, and crayfish. Beyond 100 mm diet is almost exclusively fish and crayfish; dragonfly nymphs form part of the food of even the largest individuals (Scott and Crossman 1973; Goldstein and Simon 1999). In a Wisconsin study, fishes found in fingerling stomachs include lake chubsuckers and smaller pickerels; in stomachs of grass pickerel 152-343 mm TL, small bluegills were one of the two predominant fishes consumed (Kleinert and Mraz 1966). In an Ontario, Canada creek, 22 species of fish were present, but grass pickerel fed on only 9 species (of which include the following species found in Texas, in descending order of importance): golden shiner, grass pickerel, creek chub, and yellow perch (Crossman 1962b).
Phylogeny and morphologically similar fishes
Hybridizes in nature with E. niger (chain pickerel; Crossman 1980). Most similar to E. niger, from which it can be readily separated from as an adult on the basis of color pattern: irregular vertical bars compared to the reticulate or honey combed pattern markings on the flank of the chain pickerel (Ross 2001).
Trematoda: Posthodiplostomum minimum; Nematoda: Agamonema (Arnold et al 1967). Contracaecum (Mayberry 2000). Protzoa: Trichodina renicola; Trematoda: Azygia angusticauda, Crassiphiala bulbglossa, Macroderoides flavus; Cestoda: Proteocephalus ambloplitis, P. pinguis; Nematoda: Spiruridae (Hoffman 1967).
Commercial or Environmental Importance
As this species is associated with heavily vegetated areas and deeper pools, it is sensitive to raparian damage from livestock or to any erosional problems resulting in increased sedimentation, bank failure, and loss of vegetation (Ross 2001). Populations negatively affected where streams are channelized and denuded of vegetation and where swamps have been drained (Boschung and Mayden 2004). E. americanus eaten by catfishes, sunfishes, yellow perch, and redfin pickerel themselves (Becker 1983).
[Additional literature noting collection of this species from Texas locations includes, but is not limited to the following: Hubbs (1957); Village Creek (Hardin Co.; Moriarty and Winemiller 1997).]
Arnold, J.G., Jr., Ph.D., H.E. Schafer, M.S., R.L. Vulliet, BSMT.1967. The parasites of the freshwater fishes of Louisiana.
Becker, G.C. 1983. Fishes of Wisconsin. University of Wisconsin, Madison. 1052 pp.
Boschung, H.T., Jr., and R.L. Mayden. 2004. Fishes of Alabama. Smithsonian Books, Washington. 736 pp.
Cook, F.A. 1959. Freshwater fishes in Mississippi. Mississippi Game and Fish Commission, Jackson.
Crossman, E.J. 1962. The redfin pickerel Esox a. americanus in North Carolina. Copeia 1962(1):114-123.
Crossman, E.J. 1962b. Predator-prey relationships in pikes (Esocidae). J. Fish. Res. Board Canada 19(5):979-980.
Crossman, E.J. 1966. A taxonomic study of Esox americanus and its subspecies in eastern North America. Copeia 1966(1):1-20.
Crossman, E.J. 1980. Esox americanus (Gmelin), Redfin Pickerel and Grass Pickerel.pp.131 in D.S. Lee et al. Atlas of North American Freshwater Fishes. N.C. State Mus. Nat. Hist., Raleigh, i-r+854 pp.
Cuvier, G. and Valenciennes  1969. Histoire naturelle des poisons. Vol. 19. A. Asher and Co., Amsterdam. 544 pp.
Evans, J.W., and R.L. Noble. 1979. The longitudinal distribution of fishes in an east Texas stream. American Midland Naturalist 101(2):333-343.
Gmelin. 1788. Systema naturae, Laurentii Salvii, Holmiae, 13 ed.
Goldstein, R.M., and T.P. Simon. 1999. Toward a united definition of guild structure for feeding ecology of North American freshwater fishes. pp. 123-202 in T.P. Simon, editor. Assessing the sustainability and biological integrity of water resources using fish communities. CRC Press, Boca Raton, Florida.
Hay, O.P. 1883. On a collection of fishes from the lower Mississippi Valley. Bull. U.S. Fish Comm. 2:57-75.
Hoffman G.L. 1967. Parasites of North American Freshwater Fishes. University of California Press. Berkeley and Los Angeles, CA 1-486.
Hubbs, C. 1957. Distributional patterns of Texas fresh-water fishes. The Southwestern Naturalist 2(2/3):89-104.
Hubbs, C., R.J. Edwards and G.P. Garret. 1991. An annotated checklist of freshwater fishes of Texas, with key to identification of species. Texas Journal of Science, Supplement 43(4):1-56
Kleinert, S.J. and Mraz. 1966. Life history of the grass pickerel (Esox americanus vermiculatus) in southeastern Wisconsin. pp.1-40. Tech. Bull., no. 37, Wisconsin Conservation Department, Madison.
Kwak, T.J. 1988. Lateral movement and use of floodplain habitat by fishes of the Kankakee River, Illinois. Amer. Midl. Nat. 120(2):241-249.
Mayberry, L.F., A.G. Canaris, J.R. Bristol, and S.L. Gardner. 2000. Bibliography of parasite and vetebrate hosts in Arizona, New Mexico, and Texas (1893-1984). University of Nebraska Harold W. Manter Laboratory of Parisitology Web Server. January 11, 2000; published on the World-Wide-Web. pp. 1-100.
Mettee, M.F., P.E. O’Neil, R.D. Suttkus, and J.M Pierson. 1987. Fishes of the lower Tombigbee River system in Alabama and Mississippi. Geol. Surv. Ala. Bull. 107:1-186.
Moriarty, L.J., and K.O. Winemiller. 1997. Spatial and temporal variation in fish assemblage structure in Village Creek, Hardin County, Texas. Texas Journal of Science, Supplement 49(3):85-110.
Ross, S.T. 2001. Inland fishes of Mississippi. University Press of Mississippi, Jackson Mississippi. 335-336 p.
Ross, S.T. and J.A. Baker. 1983. The response of fish to periodic spring floods in a southeastern stream. Amer. Midl. Nat. 109(1):1-14.
Ross, S.T., J.A. Baker, and K.E. Clark. 1987. Microhabitat partitioning of southeastern stream fishes: temporal and spatial predictability, pp. 42-51. In: Evolutionary and community ecology of North American stream fishes. W.J. Mathews and D.C. Heins, eds. Univ. Oklahoma Press, Norman.
Scott, W.B., and E.J. Crossman. 1973. Freshwater Fishes of Canada. Bulletin 184. Fisheries Research Board of Canada, Ottawa. 966 pp.
Simon, T. P. 1999. Assessment of Balon’s reproductive guilds with application to Midwestern North American Freshwater Fishes, pp. 97-121. In: Simon, T.L. (ed.). Assessing the sustainability and biological integrity of water resources using fish communities. CRC Press. Boca Raton, Florida. 671 pp.
Texas Parks and Wildlife Department, Wildlife Division, Diversity and Habitat Assessment Programs. County Lists of Texas' Special Species. [30 May 2006]. Available online at: http://gis.tpwd.state.tx.us/TpwEndangeredSpecies/DesktopModules/AcountyCodeKeyForWebESDatabases.pdf
Warren, L. W., Jr., B. M. Burr, S. J. Walsh, H. L. Bart, Jr., R. C. Cashner, D. A. Etnier, B. J. Freeman, B. R. Kuhajda, R. L. Mayden, H. W. Robison, S. T. Ross, and W. C. Starnes. 2000. Diversity, Distribution, and Conservation status of the native freshwater fishes of the southern United States. Fisheries, Conservation. 25(10):7-29.