Early Life History and Habitat Use of Age-0 Blue Catfish in the Unimpounded Middle Mississippi River

Recently there has been a growing interest in the management of blue catfish populations due to increased recreational and commercial fishing. However, blue catfish early-life history traits are relatively unknown and may profoundly influence management decsions. Therefore, we sought to evaluate age-0 blue catfish early life demographics (abundance, hatch time, and growth) and habitat use in an unimpounded reach of the Mississippi River during 2002-2010. We trawled several locations, collecting 7,373 age-0 blue catfish (10 to 144 mm total length) and relative abundance varied across years. Blue catfish hatch timing varied across years (30-70 d), generally begining in June and ending in August. Age-0 blue catfish growth rates differed among years (i.e. ~0.7-1.5 mm/d). In terms of macrohabitat use, catch rates of young blue catfish were highest in side channels and around islands while main channel features were infrequently used. Furthermore and in relation to mesohabitat use, age-0 blue catfish frequently occupied moderate velocity (i.e., 0.3-0.4 m/s), shallow depths (i.e., 1-4 m), and sand substrate. Knowledge of these early life characteristics plays a vital role in the management of blue catfish.