Deep-Water Ninespine Sticklebacks, Pungitius pungitius, in the Mississippi Drainage, Crooked Lake, Indiana

Abstract

A population of Pungitius pungitius was found in 1966 in Crooked Lake, Noble-Whitley counties, Indiana, the southernmost locality for the species in inland North America. This is the first population to be described indigenous to the Mississippi drainage, one of the postulated refugia for the species during Wisconsin glaciation. Morphological comparisons with populations thought to have been derived from a Mississippi refugium agreed in most respects, but Crooked Lake and Lake Michigan populations differed in pelvic girdle shape and caudal peduncle width. The full number of dorsal spines and caudal scutes were first present at 13 and 21 mm standard length, respectively, in Crooked Lake Pungitius. The pelvic spine first appeared at 14 mm. Pungitius was found between five and 30 m by collecting with rotenone, monofilament gillnets, and Plexiglas traps. Young specimens were most common just within, and a few meters below, the rooted aquatic zone while the adults occurred in greatest numbers in deeper water. Fully ripe females were found from 9 June to 22 July in 1966 and from 9 April to 24 August in 1967. The temperature ranged from 50 to 250 C at the stratum where Pungitius lived in the summer. Most adults were caught in 6?-120 C water, but were able to survive one week in live boxes at surface shore temperatures of 24?-28? C.