runoff of any watershed, 257,929 to 

 7,264,664 liters/mo and flows of 66 

 cm/sec have been recorded (Schwartz 

 et al. 1979a, b). However, that area 

 from Campbell Island, 9 km south of 

 Wilmington, North Carolina, to the 

 man-made cut, "Snows Cut," 15 km fur- 

 ther downstream is often subjected to 

 periodic freshwater runoff which pro- 

 duces ppt recordings throughout the 

 13-m deep waters for periods of 6 to 

 8 weeks (Schwartz et al. 1979a, b). 



DISCUSSION 



Hoagman and Wilson (1976), Lowe- 

 McConnell (1975), and Schubel et al. 

 (1976), have documented the natural 

 or induced downstream shift of the 

 oblique or vertical freshwater-saline 

 interface of a coastal stream or 

 river following a rain or hurricane. 

 Others (Chesapeake Res. Cons. 1976) 

 have noted the resiliency of these 

 saline-depressed waters as they re- 

 turn to nearly "normal" states within 

 short or long intervals but have not 

 resolved the question--is this dis- 

 turbed zone a truly freshwater or 

 some sort of hybrid habitat? Like- 

 wise, what happens to the freshwater 

 and marine fishes that are momentari- 

 ly "trapped" within these temporary 

 and rapidly chemically changing wa- 

 ters (Aller 1978; McHugh I960)? It 

 is to this unstable and temporary no 

 man's land between fresh and saline 

 waters that I now address this report. 



RESULTS 



To date only Schwartz (1964) has 

 compiled a list of freshwater fishes 

 that are known from runoff freshwa- 

 ter-euryhaline waters. Gunter (1942, 

 1956) compiled a similar list for 150 

 marine fishes known from euryhaline 

 waters. Otherwise the sporadic 

 occurrence of a species is usually 

 treated as a brief note that one or 

 more characteristically freshwater or 



marine fish was encountered in a 



freshwater, euryhaline, or marine 



habitat or vice versa (Rohde et al. 

 1979). 



I now add to Schwartz's 28 

 (1964) and Gunter' s 150 (1942, 1956) 

 species lists of fishes that 37 

 freshwater (Table 1) and 77 marine 

 (Table 2) fishes, within 13 fresh- 

 water and 38 marine families re- 

 spectively, are known to frequent or 

 live in "freshwater" runoff habitats 

 within the major tributaries of North 

 Carolina (Figure 1). Seven of the 

 freshwater species were found in wa- 

 ters that were or reverted to 22 ppt 

 to 31 ppt salinities following run- 

 off. These included the longnose 

 gar ( Lepisosteus osseus ) , gizzard 

 shad ( Dorosoma cepedianum ) , golden 

 shiner ( Notemigonus chrysoleucus ) , 

 white catfish (Ictalurus catus ) , 

 brown bullhead ( Ictalarus nebulo- 

 sus ) , mosquitofish ( Gambusia af finis , 

 and flier ( Centrarchus macropterus ) . 

 Of these Schwartz (1964) had, else- 

 where, collected the gar from 23.4 

 ppt, gizzard shad 22.6 ppt, golden 

 shiner 14.4 ppt, and white catfish 

 14.5 ppt (Schwartz and Kendall 1968) 

 waters. Twenty-five of the 37 fresh- 

 water fishes were found in higher sa- 

 linities, in North Carolina, than 

 previously noted by Schwartz (1964). 

 In some cases, such as the gizzard 

 shad, mosquitofish, bluegill, and 

 pumpkinseed, their occurrences were 

 recorded as abundant. Most of the 

 freshwater fishes (20) were rare cap- 

 tures in the runoff zone, which re- 

 verted to 1 ppt to 27 ppt salinities. 

 Thirteen species were common to zones 

 that had been lppt to 31 ppt salin- 

 ity Nine centrarchids and eight cy- 

 prinids were fishes that frequented 

 the runoff disturbed areas for pro- 

 longed periods of 6 to 8 weeks prior 

 to their retreat upstream into "pure" 

 freshwater habitats. No trend was 

 evident of increased number or kind 

 of fish inhabiting the runoff area. 



286 



