Demographics and Seasonal Diet Composition of Shovelnose Sturgeon (Scaphirhynchus platorynchus Rafinesque) in Wabash River

Abstract

Shovelnose sturgeon Schaphirhynchus platorynchus Rafinesque, one of the only sturgeon species that support a sustainable commercial harvest, are fished in a substantial caviar fishery in the lower Wabash River. However, ecological information on the population is sparse. In this thesis, I present information on the status and seasonal diet characteristics of the population. A 14-year long shovelnose sturgeon monitoring survey conducted by Illinois Department of Natural Resources shows that the population is in relatively good condition, faces low mortality rates, and has a high potential for recruitment. Study of the seasonal composition of diet suggests that shovelnose sturgeon generally get enough food throughout the year, and are thus, in good condition. I found that shovelnose sturgeon are opportunistic benthic invertivores, with Hydropsychidae and Chironomidae as the staple prey taxa for the fish. However, the sex-ratio of the population is highly male-biased, and the proportion of memorable-size fish is decreasing, likely due to the ongoing commercial harvest of ripe-and-running females. This poses potential problems regarding the sustainability of this fishery, and thus, management policies should be conservative until more information on optimal harvest of this fish is available.

Date of Award	2014
Original language	American English
Awarding Institution	Eastern Illinois University
Supervisor	Robert E. Colombo II (Supervisor)