Conservation And Management Of Paddlefish In Mississippi With Emphasis On The Tennessee-Tombigbee Waterway
O'Keefe, Daniel Mark
AdvisorJackson, Donald C.
CommitteeTaylor, Christopher M.
Jones, Jeanne C.
Miranda, Leandro E.
Paddlefish are long-lived large river fish which are declining in many areas of their range due to habitat modifications and overfishing. A framework for management of paddlefish in Mississippi is proposed and a case study of its application to the paddlefish population of the Tennessee-Tombigbee Waterway (TTW) is presented. The framework includes four phases: (I) distribution and stock assessment; (II) determination of limiting factors; (III) design and implementation of management actions; and (IV) review and monitoring. Phase I of management in the TTW consisted of gill-net surveys in four impoundments. Paddlefish abundance was estimated at 1,581 to 8,851 in Demopolis Lake, Alabama. In Gainesville Lake, Alabama, CPUE was 16.8 times less than Demopolis Lake. No paddlefish were caught in Aliceville Lake, Mississippi/Alabama, or Columbus Lake, Mississippi. Demopolis Lake paddlefish grew faster than more northern populations, but slower than more southern populations (Lt = 971.8 [1 − e−0.2844 (t+0.6962)]) and had a high annual mortality rate (A = 0.406) comparable to other southern populations. Potential limiting factors related to spawning in Demopolis Lake and stocking programs in Columbus Lake were investigated pursuant to Phase II. Paddlefish eggs were collected in the Noxubee River and a unique flowing bendway habitat in Demopolis Lake during early April when discharge was ¡Ý2.74 m above 50% exceedance. Flow timing and magnitude in the Noxubee River was related to paddlefish year-class strength (linear regression P = 0.089; R2 = 0.830). Radio-tagged paddlefish exhibited seasonal site fidelity and 4 of 10 translocated fish returned to their area of initial capture.,Columbus Lake provides food resources and physiochemical characteristics adequate for paddlefish survival, but depth and zooplankton density are more favorable in Demopolis Lake. Emigration of stocked juvenile paddlefish was low in Columbus Lake habitats; survival (percent after one month ¡À SE) was 5 ¡À 5 in backwaters and 28 ¡À 9 in the mainstem after one month. Phase III recommendations include further investigation of early life history requirements and protection of bendway and tributary habitat in Demopolis Lake. The annual stocking of 4,000 juvenile paddlefish in the mainstem of Columbus Lake and up to 1 million larval paddlefish in a tributary is recommended.