2009 Proc. Annu. Conf. SEAFWA Weight-length Relationships and Growth Data for Blue Catish from Four Tennessee Waterbodies David R. Stewart, Florida Fish and Wildlife Conservation Commission, 601 West Woodward Avenue, Eustis, FL 32726 George W. Benz, Middle Tennessee State University, P.O. Box 60, Murfreesboro, TN 37132 George D. Scholten, Tennessee Wildlife Resources Agency, P.O. Box 40747, Nashville, TN 37204 Abstract: he blue catish (Ictalurus furcatus) is an important sport and commercial species in Tennessee for which state-speciic biological data are lacking. We report weight-length relationships and age and growth data for blue catish (n = 773) collected from three exploited and one un- exploited Tennessee waterbodies: Lake Barkley, Kentucky Lake, and the Mississippi River, and Fort Loudoun Reservoir. here were signiicant diferences between blue catish weight-length relationships between waterbodies. Catish age ranged from age 0 to 34 and length at age estimates were signiicantly diferent among some, but not all studied waterbodies. Recommendations are provided regarding research necessary to ill blue catish data gaps that hinder management of this widespread and economically important species. Key words: blue catish, Ictalurus furcatus, weight-length relationships, length at age, growth, otoliths, Tennessee Proc. Annu. Conf. Southeast. Assoc. Fish and Wildl. Agencies 63:140–146 hroughout much of the southeastern and midwestern United States, the blue catish (Ictalurus furcatus) is an important sport and commercial species (Graham 1999, USFWS and USCB 2006). Blue catish comprises the heaviest annual commercial catch of any catish in Tennessee (unpublished data, Tennessee Wildlife Resources Agency, TWRA), with its white lesh being preferred by consumers relative to that of other catishes (D. Shelton, Cool Cats Fish Market, personal communication). Based in part on sport an- gler feedback, the TWRA modiied commercial and sport-ishing regulations in 2003, making Tennessee the irst state to impose a maximum size limit on catish of any species (Tennessee Wildlife Resources Commission Proclamation 03–02). Given the recre- ational and commercial importance of catish in Tennessee, it is notable that basic, state-speciic biological information is gener- ally lacking for catishes. his report presents blue catish weight- length relationships and age and growth data for ish representing three exploited and one unexploited Tennessee waterbodies. Methods Study Area Lake Barkley, Kentucky Lake, and the Mississippi River were selected for study as exploited waterbodies based on high levels of catish harvest there from 1988 through 2006 (unpublished data, TWRA). Fort Loudoun Reservoir was added to the study to rep- resent an unexploited reservoir, as recreational harvest has been discouraged and commercial harvest prohibited there since 1979 due to PCB (polychlorinated biphenyls) contamination (B. Wil- son, TWRA, personal communication). Sample Collection Catish samples from Lake Barkley and Kentucky Lake were collected from commercial ish wholesalers (Hart’s Fish Market, Paris, Tennessee; B&F Fish Market, Perryville, Tennessee; Quillen’s Fish Market, Paris, Tennessee; Cool Cats Fish Market, McKinnon, Tennessee) during May–October 2007 and 2008. Fish were un- selectively gathered from wholesaler swim tanks or from live wells of commercial ishing boats as catches were being oloaded. Com- mercial ishers selling to wholesalers ished mainly with gill nets, but they occasionally used trot-lines to harvest catish. Processing procedures used by commercial ish wholesalers prevented our ef- forts to gather ish sex information. Mississippi River sampling occurred during November 2006 and 2007. hree sampling methods were used at each of three collection locations along the Mississippi River (Caruthersville, Missouri; Ashport, Tennessee; Randolph Point, Tennessee). Boat electroishing using low-frequency pulsed-DC (15 pulses/sec) was carried out in 10-min passes around wing dikes, rip-rap, and sand bars, with an electroishing boat accompanied by two chase boats to increase netting eiciency (Travnichek 2004). A 4.88-m knotless shrimp trawl (complete shrimp trawl, model TRL16C, Memphis Net and Twine Co., Inc, Memphis, Tennessee) was towed for 5 min around wing dikes, rip-rap, and sand bars. Two experimental gill nets (46-m net with stretched mesh sizes ranging 2.54–10.16 cm; 55-m net with stretched mesh sizes ranging 6.35–8.89 cm) were ished behind wing dikes for 4–8 h during the day. Fort Loudoun Reservoir was sampled in January and February 2007 using 38- to 91-m long trot-lines set at various locations. A total of nine lines were set at once (total of 36 sets) and various 140