Degree Name

Master of Science (MS)

Semester of Degree Completion

2014

Thesis Director

Robert E. Colombo

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.

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