Stock Structure and Dynamics of Longnose Gar and Shortnose Gar in the Wabash River, Indiana-Illinois

ABSTRACT

Little information exists on the stock characteristics and dynamics of longnose gar (Lepisosteus osseus) and shortnose gar (Lepisosteus platostomus). We examined the size and age structure, mortality, growth, and condition of both species from the Wabash River, Indiana-Illinois, from June through August 2006. Longnose gar ranged from 492 to 1,224 mm in total length (TL) and from 250 to 5,600 g in wet weight (WW), while shortnose gar ranged from 498 to 776 mm in TL and from 350 to 1,900 g in WW Longnose gar and shortnose gar ranged in age from 2 to16 and 2 to12 years, respectively. Total annual mortality ranged from 13 to 17% for longnose gar and from 25 to 29% for shortnose gar. Annual growth in length was most rapid through age 6 for longnose gar (range, 18 to 100 mm/yr) and age 4 for shortnose gar (range, 9 to 48 mm/yr). Variation in relative condition of longnose gar and shortnose gar was heterscedastic over the size range of fish collected, but there was no significant relationship between relative condition and total length.