摘要：By the 1900s, the ichthyofauna of Pennsylvania's Monongahela River basin was decimated by a combination of discharges from industrial, coal extraction, and municipal sources. Over the past half-century, water quality improvements resulting fiom federal and state mandates have initiated a continuing recovery of fish populations throughout the mainstem. We compiled the results of recent (2003-06) collections from the river and its tributary network by a number of state, federal, and academic agencies employing a variety of gear. The combined sampling methods yielded 32,999 fishes on the mainstem, representing 14 families and 64 species/hybrids, while 6,825 fishes representing 10 families and 51 species/hybrids were captured from the tributaries. Tributary species richness ranged from 24 to 0 concomitant with declining water quality. Members of the families Ictaluridae and Cyprinidae dominated mainstream communities, while the Percidae and Cyprinidae were prevalent in its tributaries. Twenty-two species were captured only from the Monongahela mainstem, while 11 were unique to its tributaries and 39 were cosmopolitan. Overall, the Monongahela Basin ichthyofaunal complement currently numbers 75 species/hybrids.
