DAHLBERG: ECOLOGICAL STUDY OF GEORGIA COASTAL FISHES 



ORDER ANGUILLIFORMES 



Anguillidae - freshwater eels 



The catadromous American eel {Anguilla ro- 

 strata) was widely distributed and abundant in 

 the freshwater habitat and the high-salinity 

 pools, but absent from trawl stations. All small 

 specimens (54-170 mm) occurred in low salini- 

 ties (0-1. 9^f) in the freshwater and oligohaline 

 creeks, and the low-salinity pools. Large speci- 

 mens (230-470 mm) occurred primarily in saline 

 waters (13.1^30.3%c) but one was collected in 

 fresh water. 



Ophichthidae - snake eels 



One speckled worm eel (Myrophis punctatus) 

 was collected with a dip net in Riceboro Creek 

 under the Seaboard Railroad bridge. The 

 243-mm specimen was taken at a salinity of 0%c 

 and temperature of 24°C. Miller and Jorgenson 

 (1969) also reported it from the beach and high 

 marsh habitats. 



Three shrimp eels {Ophichthus gomesi) were 

 trawled in the lower reach at stations 4, 7, and 9. 

 They probably burrow and easily escape the 

 trawls. I have also seen specimens of the pale- 

 spotted eel (0. ocellatus) from the Georgia coast. 



ORDER CLUPEIFORMES 



Clupeidae - herrings 



Three anadromous species of shad (Alosa) are 

 listed (Table 2) for the habitats along their mi- 

 gratory route. I collected the American shad 

 (A. sapidissima) and hickory shad (A. medioc- 

 ris) only in saline waters. Both of these species 

 and the blueback herring (A. aestivalis) spawn 

 in the nearby Altamaha River (Godwin and 

 Adams, 1969). 



Young American shad were occasionally col- 

 lected from the lower reach to the upper reach 

 from December to April. Since the spawning 

 season of the American shad is from March 

 through May in the Altamaha River (Godwin 

 and Adams, 1969) , 60- to 114-mm specimens col- 

 lected from December to March were approxi- 

 mately 1 year old, and a 29-mm shad collected 

 in April was recently spawned. Both age groups 



were represented in the upper reach but only 

 individuals of age group I were taken in the 

 middle and lower reaches. 



Two species and a hybrid of menhaden {Bre- 

 voortia) (Dahlberg, 1970) occur within the es- 

 tuary. The Atlantic menhaden {B. tyrannus) 

 occurred in eight habitats. Compact schools of 

 adults occurred in the lower reach of the estuary 

 and along the beaches from spring through fall. 

 Smaller numbers were present in the sounds in 

 the winter. Juveniles (29-42 mm) were often 

 collected from June to September in the upper 

 reach where salinity ranged from 0.5 to 16.8%o 

 and temperature, from 28.4° to 30.8°C. Juve- 

 niles were also collected in the oligohaline Rice- 

 boro Creek and this species is known to occur in 

 freshwater (Gunter, 1956). Young menhaden 

 (30-99 mm) also occurred in the tidal pools and 

 tidal ditch in May and June. 



The yellowfin menhaden {B. smithi) was col- 

 lected in the high-salinity pools, tidal canal, and 

 along the beach. Its absence from trawl col- 

 lections supports my theory (Dahlberg, 1970) 

 that B. smithi is a bay or shallowwater species. 

 The occurrence of this species apparently is re- 

 stricted by low temperature as it first appeared 

 in May and was present until water temperature 

 decreased to approximately 20°C in November. 

 Its absence after November may result from a 

 southward migration since it is common along 

 Florida in the winter (Dahlberg, 1970). 



The hybrid (B. smithi x B. tyrannus) was 

 the least common of the menhadens. It was col- 

 lected with B. smithi on 5 May 1969 in the tidal 

 canal which had a salinity of 18.8%r and a tem- 

 perature of 29 °C. Hybrids were collected also 

 along the beach and in the Marine Institute's 

 boat basin at Sapelo Island. 



The gizzard shad (Dorosoma cepedianiim) 

 and threadfin shad (D. petenense) are euryha- 

 line species that are important forage fishes in 

 Georgia reservoirs. The gizzard shad is known 

 from the upper reach and the oligohaline creek 

 from two trawl collections made on 19 November 

 1969. These large gizzard shad (205-220 mm) 

 were collected at water temperatures of 15.5° 

 and 14.1°C, and others were caught in the Ma- 

 rine Institute's boat basin (lower reach habitat) 

 in the summer of 1969. 



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