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 W y r ) and age 4 for shortnose gar (range, 9 to 48 mndyr). 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.

Relative Bias and Precision of Age Estimates among Calcified Structures of Spotted Gar, Shortnose Gar, and Longnose Gar

“…; Sutton et al. ; Kelley ), we found that this structure underestimates the ages of young fish and overestimates the ages of old fish relative to age assignments from the pectoral fin rays, sagittal otoliths, and cleithra of gars collected in Illinois. Branchiostegal rays from older specimens became opaque making it difficult to view annuli, which likely contributed to more relative bias between readers of older age classes in our study.…”

“…; Sutton et al. ; Kelley ). Previous research assumed that branchiostegal rays provide accurate age estimates based on the high precision between readers (Netsch and Witt ; Murie et al.…”

Age, Growth, and Reproduction in Two Coastal Populations of Longnose Gars

“…To date, no peerreviewed published study provides a comprehensive description of the age, growth, and reproduction of Longnose Gars. There are a few studies examining population age structure in Longnose Gars, which all utilized branchialstegal rays for age estimation (Netsch and Witt 1962;Klaassen and Morgan 1974;Johnson and Noltie 1996;Sutton et al 2009;Kelley 2012), even though it has been demonstrated that otoliths provide better estimates of age in fish than do other structures (Buckmeier et al 2002;Sylvester and Berry 2006;Ma et al 2011;Buckmeier et al 2012). A few studies have described some aspects of reproduction in Longnose Gars (gonadosomatic index and fecundity), but none utilized histological techniques to describe the reproductive cycle (Netsch and Witt 1962;Johnson and Noltie 1996;Zeug and Winemiller 2007).…”

Age and Growth of Spawning Longnose Gar (Lepisosteus osseus) in A North Central Texas Reservoir

“…Comparative data from lacustrine systems (Klaassen and Morgan 1974), however, are lacking, particularly in the southern portion of the gar's range. While electrofishing is widely used to capture many fish species, including longnose gar (Sutton et al 2009), it has produced poor results for lepisosteids from Lake Arrowhead (Howell andMauk 2004, 2008). The tendency of stunned gar to sink rather than float up for visible dip net captures (Burr 1931) may bias catch rates.…”