FISHES OF THE TANGIPAHOA RIVER SYSTEM, MISSISSIPPI AND LOUISIANA Charles L. Knight Mississippi Museum of Natural Science, 111 North Jefferson Street, Jackson, MS 39202 AND Robert W. Hastings Turtle Cove Environmental Research Station, P.O. Box 585, Southeastern Louisiana University, Hammond, LA 70402 Abstract An ichthyofaunal survey of the Tangipahoa River system in the Lake Pontchartrain drainage was conducted over an 18 month period in order to compile a comprehensive list of fish inhabitants, and to compare these data with lists of species reported from other streams in the Lake Pontchartrain, lower Mississippi River, and Pearl River drainages. Eighty-five collections from 59 sites yielded 11,081 specimens including 71 species and 21 families. Over 50% of the total catch was represented by nine species of Cyprinidae followed by Centrarchidae (17%) with 14 species. Cyprinella venusta, Lythrurus roseipinnis, and Gambusia affinis were most abundant at 22.6%, 10.3%, and 9.6% of the total catch, respectively. Lepomis macrochirus (69.4%), Lepomis megalotis (64.7%), and Gambusia affinis (60.0%) displayed the greatest frequency of occurrence. Three species collected, Alosa chrysochloris, Heterandria formosa, and Etheostoma par-vipinne, were considered new records for the Tangipahoa River system. Fishes identified during our study combined with records from other sources bring the total species reported to inhabit the Tangipahoa River system to 92. Within the Lake Pontchartrain drainage, coefficient of similarity calculations indicated that the Tickfaw, Amite, and Tchefuncte rivers supported fish assemblages most similar to the Tangipahoa, while comparisions with streams from neighboring drainage systems suggested intermediate species similarity. Introduction The Mississippi River is an apparent barrier for east and west dispersal of many species of freshwater fishes in the United States (Lee et al., 1980). Douglas (1974) reported 25 species of fishes occurring in Louisiana exclusively east of the Mississippi River. Two additional fishes which may be added to this list are the northern studfish {Fundulus catenatus) (Laiche, 1978); and the broadstripe topminnow {Fundulus euryzonus), a species that is endemic to the Tangipahoa and Amite rivers of the Lake Pontchartrain drainage (Suttkus and Cashner, 1981). Tulane Studies in Zoology and Botany 29: 141-150. 1994. 141
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