Sheepshead minnow, continued 



1 972), and are demersal in shallow coastal and inland 

 waters (Reid 1955, Harrington and Harrington 1961, 

 Springer and Woodburn 1960, Tabb and Manning 

 1961, Peterson 1990). 



Habitat 



Ty pe: All life stages are estuarine and are restricted to 

 bays and coastal inland areas, preferring quiet, shal- 

 low waters. They are found in salt marshes, sloughs, 

 coves, bays, creeks, canals, and ditches (Hildebrand 

 and Schroeder 1 928, Simpson and Gunter 1 956, Breuer 

 1957, Gunter 1958, Gunter 1967, Strawn and Dunn 

 1967, Franks 1970, Martin 1972, Swift et al. 1977, 

 Loftus and Kushlan 1 987). Sheepshead minnows are 

 uncommon in heavily vegetated marsh areas (Loftus 

 and Kushlan 1987). Larvae often occupy the water's 

 edge while larger individuals (7 mm) may stay on the 

 bottom (Ward and Armstrong 1980). This fish is 

 generally found in depths ranging from 0-1 .5 m (Raney 

 et al. 1953, Phillips and Springer 1960). 



Substrate : All life stages occur over bottoms areas 

 where vegetation is generally, but not strictly, absent. 

 Bottoms can consist of rock, sand, mud, detritus mud, 

 or mud with shell fragments (Reid 1 955, Simpson and 

 Gunter 1956, Franks 1970, Martin 1972, Swift et al. 

 1977, Loftus and Kushlan 1987), occasionally with 

 turtle grass, shoal grass, or algae present (Hudson et 

 al. 1970). 



Physical/Chemical Characteristics 

 Temperature - Eggs: Egg development has been ob- 

 served to occur at 17.4-27.5°C (Renfro 1960) and 

 >26°C (Schimmel and Hansen 1974). Optimal devel- 

 opment occurs at 22.8-28.9°C (Ward and Armstrong 

 1980). 



Temperature - Larvae, Juveniles, and Adults: These 

 life stages are all eurythermal. Their reported tempera- 

 ture range in Texas is 8.8-34.9°C (Gunter 1945, 

 Simmons 1 957, Strawn and Dunn 1 967, Pineda 1 975), 

 5.0-33.5°C in Mississippi (Christmas and Waller 1 973; 

 Franks 1970), and 7.2-43.0°C in Florida (Reid 1954, 

 Odum and Caldwell 1955, Kilby 1955, Phillips and 

 Springer 1 960, Harrington and Harrington 1 961 , Hudson 

 et al. 1970, Wang and Raney 1971, Subrahmanyam 

 and Drake 1975). The sheepshead minnow has been 

 observed to be resistant to near freezing conditions, at 

 least for short periods (Gunter and Hildebrand 1951, 

 Simpson and Gunter 1956). Laboratory and field 

 observations found that it begins burrowing into the 

 substrate between 7° and 9° C possibly to escape 

 predation (Loftus and Kushlan 1987, Frederick and 

 Loftus 1993). 



Salinity: The sheepshead minnow is a euryhaline spe- 

 cies recorded from freshwater to hypersaline condi- 



170 



