Alabama shad, continued 



Table 5.16. Relative abundance of Alabama shad in 

 31 Gulf of Mexico estuaries (Nelson et al. 1992, 

 Mettee pers. comm.). ^ Q siaQe 



Relative abundance: 



% Highly abundant 



® Abundant 



O Common 



a/ Rare 



blank Not present 



Life stage: 



A - Adults 

 S - Spawning 

 J - Juveniles 

 L - Larvae 

 E - Eggs 



anadromous (Laurence and Yerger 1 967, Turner 1 969. 



Habitat 



Ty pe: Eggs and larvae are riverine and have been 

 collected only at night in areas with appreciable current 

 (Mills 1972). Young juveniles are freshwater riverine 

 and nektonic. Older juveniles descend rivers and 

 move into estuarine and Gulf waters (Mills 1972). 

 Adults are anadromous, inhabiting neritic waters of the 

 Gulf and migrating into estuaries and then up major 

 river systems to spawn. They occur in fresh to euhaline 

 waters in both rivers and bays (Hildebrand 1963, 

 Laurence and Yerger 1967, Moore 1968, Swingle 

 1971, Mills 1972, Douglas 1974, Swift et al. 1977). 



Substrate : Eggs and larvae have been collected over 

 coarse sand and gravel (Mills 1972). Juveniles and 

 adults are found over a wide variety of substrates due 

 to their anadromous nektonic life history. 



Physical/Chemical Characteristics : Eggs and larvae 

 have been collected from freshwater at 1 9-23°C (Mills 

 1 972). Juveniles have been found in a water tempera- 

 ture range of 13.3 to 28.1 °C and are considered 

 euryhaline along with adults (Mills 1 972, Douglas 1 974, 

 Walls 1 976) because they occur in both freshwater and 

 seawater at different times in their life cycle (Laurence 

 and Yerger 1967, Mills 1972). Adults occur in water 

 temperatures of 1 2. 1 to 23°C. Below 1 7°C, males are 

 reported to outnumber females, but at 1 9.5°C, females 

 may occur in larger numbers than males (Laurence 

 and Yerger 1967, Mills 1972). 



Migrations and Movements : The Alabama shad is an 

 anadromous species, and could be considered the 

 only anadromous clupeid along the Gulf coast (Mettee 

 et al. 1 996). Juveniles are present in freshwater rivers 

 and streams from late May to early July. They leave 

 these areas to enter saltwater at the end of their first 

 summer when they reach a fork length (FL) of 1 20 mm, 

 but they will migrate at smaller sizes in cold weather 

 (Hildebrand 1963, Laurence and Yerger 1967, Mills 

 1 972). Juvenile shad have been taken in the rivers as 

 late as November (Mills 1972, Beecher and Hixson 

 1 982). Adults leave salt water and ascend freshwater 

 rivers and streams in the spring to spawn (Hildebrand 

 1963, Eddy and Underhill 1982). Adults first begin to 

 arrive at freshwater spawning areas in Apalachicola 

 River during late January and February when water 

 temperatures are 1 5° (Laurence and Yerger 1 967). In 

 Alabama's Choctawhatchee and Conecuh Rivers, adult 

 shad are reported to arrive in March, spawn in April, 

 then migrate seaward (Mettee et al. 1 995, Mettee et al. 

 1 996). In the Mississippi River valley, arrival has been 

 reported from May to July (Fischer 1980). Abundance 

 in the Apalachicola River generally peaks during late 

 March through late April when water temperatures are 



131 



