Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

50.  REPRODUCTIVE BIOLOGY OF SEXUALLY MATURE FEMALE SHOVELNOSE STURGEON DURING THE SPRING SPAWNING MIGRATION IN THE WABASH RIVER, INDIANA.

Anthony J. Kennedy, Purdue University, Department of Forestry and Natural Resources, 175 Marsteller Street, West Lafayette, Indiana 47907, USA; telephone: (765) 494-5040; FAX: (765) 494-2422; email: kennedya@purdue.edu

Trent M. Sutton, Purdue University, Department of Forestry and Natural Resources, 195 Marsteller Street, West Lafayette, Indiana 47907, USA; telephone: (765) 496-6266; FAX: (765) 496-2422; email: tsutton@purdue.edu

Thomas C. Stefanavage, Indiana Department of Natural Resources, Sugar Ridge Fish and Wildlife Area, 2310 E. SR 364, Winslow, IN 47598, USA; telephone: (812) 789-2724; FAX: (812) 789-9453; email: tstefanavage@dnr.state.in.us

Brant E. Fisher, Indiana Department of Natural Resources, Atterbury Fish and Wildlife Area, 7970 South Rowe Street, P.O. Box 3000, Edinburgh, Indiana 46124, USA; telephone: (812) 526-5816; FAX: (812) 526-2892; email: bfisher@dnr.state.in.us

Shovelnose sturgeon Scaphirhynchus platorynchus are a commercially important fish species that support a viable roe fishery throughout the Mississippi River drainage.  Shovelnose sturgeon spawning behavior and recruitment dynamics are not well understood and difficult to study.  As a result, examination of their reproductive biology is the most feasible way to develop an understanding of how populations of this species are sustained.  We examined the reproductive attributes of sexually mature, spawning-phase female shovelnose sturgeon captured from the Wabash River, Indiana, from March through June 2004.  Shovelnose sturgeon were collected using boat electrofishing and experimental gill nets, measured for fork length (FL) and wet weight, sexed externally if possible (N = 3,423).  We examined the size- and age-at-maturity of female shovelnose sturgeon in the Wabash River.  In addition, we estimated fecundity, egg size, and gonadosomatic index values of 49 female shovelnose sturgeon (range: 601 to 858 mm FL).  Fecundity ranged from 14,294 to 65,490 (mean = 30,397) eggs/female fish and, when log10-transformed, was positively related to log10-transformed fork length and wet weight (FL: slope = 2.972; r2 = 0.69, wet weight: slope =0.916; r2 = 0.79).  The number of eggs/g of ovary weight ranged from 72 to 170 (mean = 98) and was negatively correlated to fork length (slope = -0.182; r2 = 0.40).  Gonadosomatic index values ranged from 9.41 to 27.24 (mean = 19.25) and were also positively correlated to fork length (slope = 0.022; r2 = 0.17).  Female shovelnose sturgeon reached sexual maturity at approximately 600 mm.  Our results can be used to assess the impact of commercial fishing on potential shovelnose sturgeon production and compliment future early life history research to better understand shovelnose sturgeon recruitment dynamics.