Contributions to the Life History of the Longnose Gar, (Lepisosteus osseus) in Missouri

Abstract

The age and growth of the longnose gar in Central Missouri were determined from the branchiostegal rays. Males and femmes differed markedly in growth and longevity. One‐year‐old males were 19.5 inches long, and females were 22.0 inches long. Females continued to grow approximately one inch a year for 13 to 14 years, and outlived the males. Males matured between 3 and 4 years of age, and females at about 6 years of age. Sex ratios changed with the age of the fish; initially they were in favor of the males, and after 10 years, they were in favor of females. The average number of eggs per female was 27,830; range 4,273 and 59,422. The mature eggs are toxic to mice and other higher vertebrates, but are probably not toxic to fishes. Twenty young‐of‐the‐year gar were raised experimentally for 52 days, and grew at the rate of 2.95 millimeters per day. Their gross metabolic efficiency during this time was 43.1 percent, and their food conversion factor was 2.34. Young‐of‐the‐year gar ate an average of 9.1 percent of their body weight per day, and digestion was completed at the end of 24 hours. These factors, in part, cause the longnose gar to be one of the fastest growing freshwater fishes, growing up to 6 times faster than other common, large, freshwater fishes.

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

“…Few longnose gar less than 625 m m TL and shortnose gar less than 525 mm TL were captured from the Wabash River, which is also consistent with results from previous studies (Netsch and Witt 1962, Klaassen and Morgan 1974, Tyler et al 1994, Johnson and Noltie 1997. Although a lack of recruitment may be one reason for not capturing smaller fish, differences in habitat use among life stages most likely had a greater influence on size at capture.…”

“…Tyler et al (1994) also noted that the greatest proportion of longnose gar captured from the Red River and East Cache Creek, Oklahoma, ranged from 600 to 700 mm TL. The ranges in total length and wet weight for both gar species in the Wabash River were also consistent with observations in other U.S. river systems (Trautman 1957, Netsch and Witt 1962, Walburg 1964, Klaassen and Morgan 1974, Jenkins and Burkhead 1994, Tyler et al 1994, Johnson and Noltie 1997, Pflieger 1997, Vokoun 2000. Our study also supports results from previous studies that shortnose gar are heavier for their length than longnose gar, but do not reach the size (both length and weight) of longnose gar (Trautman 1957, Walburg 1964, Vokoun 2000.…”

“…The age range of longnose gar in the Wabash River was within those reported for other gar populations (Netsch and Witt 1962, Klaassen and Morgan 1974, Johnson and Noltie 1997. In addition, the maximum age of longnose gar from the Wabash River (age 16) was also similar to estimates from Tuttle Creek Reservoir, Kansas (age 15).…”

“…The left, largest branchiostegal ray, located just beneath the preopercle and most distal to the isthmus, was removed and dried for subsequent age analysis. This branchiostegal ray was selected because it is easy to remove, does not have to be sectioned before examination, and the distal end of the bone remains relatively thin and translucent throughout the life of the fish which allows for annuli identification (Netsch andWitt 1962, Johnson andNoltie 1997).…”

“…Longnose gar (Lepisosteus osseus) and shortnose gar (Lepisosteus platostomus) are distributed widely throughout the eastern two-thirds of the United States (Netsch and Witt 1962). Gars comprise one of North America's oldest fish groups, being an ancient species from approximately 215 million years ago (Scarnecchia 1992).…”