Population Size and Passage Efficiency of Alabama Shad Reaching Jim Woodruff Lock and Dam

In this study, I estimated the population size of migrating Alabama shad below Jim Woodruff Lock and Dam (JWLD) in the Apalachicola River located in the central panhandle of Northwest Florida using mark recapture and relative abundance techniques. The number of marked fish was adjusted for tag loss, emigration and mortality. The population size of migrating Alabama shad near JWLD was estimated at 26,029 (95% C.I. = 15,174 - 49,040) in 2005 and as 972 (95% C.I. = 270 - 9,720) in 2006. Due to the small sample size, a relative abundance method was used to independently estimate a population size of migrating Alabama shad near JWLD in 2006 at 7,757 (95% C.I. = 5,987 - 11,012). The current population size of Alabama shad reaching Jim Woodruff Lock and Dam is relatively small when compared to both current and historic population estimates of American shad along the Atlantic coast. I also evaluated the effectiveness of the navigational lock at JWLD for upstream passage of Alabama shad using fixed-station telemetry. About 16% of Alabama shad implanted with sonic transmitters either suffered mortality or abandoned their spawning migration. Passage efficiency of the remaining study fish was 59%. I conclude that the navigational lock at JWLD can be effective in passing migrating Alabama shad