摘要：Pugnose shiner (Notropis anogenus) and blackchin shiner (N. heterodon) are classified as endangered and of special concern, respectively, in New York and were thought to be rare in the Thousand Islands area of the St. Lawrence River. Both species were caught in 1993-1995, at historic Thousand Islands collections sites (in 1931 and 1983) and at new locations. Blackchin shiner occurred in 11 of 50 samples and pugnose shiner in 4 of 50 in 1993-94. In 1995, sampling extended 93 km downstream and neither species were collected there. When blackchin shiner were collected, there was a high probability of also catching pugnose shiner (regression coefficient of P=0.006). Other species commonly associated with these included tessellated darter, bluntnose minnow, banded killifish and bluegill. The population status for pugnose and blackchin shiners seems unchanged in the Thousand Islands area since the 1930's. The downstream area to Massena, Middle Corridor and Lake St. Lawrence, had no pugnose shiners and is apparently outside their range. Blackchin shiner was not collected here in 1995, and but it did occur at three sites in 1976. Farther downstream yet, in Lake St. Francis blackchin and two other members of this dark-lined shiner group, bridle and blacknose shiner, were collected by others in Ontario's waters.
