River Sloop Clearwater and the Clearwater Festival to draw attention to the problem. Environmental activism in New York and across the country, and increased attention from members of Congress led to passage of the CWA in 1972. Extensive remediation actions on the river began in the 1970s with the issuance and enforcement of CWA wastewater discharge permits and consequent control or reduction of discharges from industrial facilities and municipal sewage treatment plants. In 1984, EPA declared a 200-mile (320 km) stretch of the river, from Hudson Falls to New York City, as a Superfund site requiring cleanup, one of the largest such site designations in the country. Sediment removal operations by GE, pursuant to the Superfund orders, have continued into the 21st century. Flora and fauna Plankton Zooplankton are abundant throughout both fresh and saltwater portions of the river, and provide a crucial food source for larval and juvenile fish. Invertebrates The benthic zone has species capable of living in soft bottom habitats. Within freshwater regions, there are animal species including larvae of chironomid flies, oligochaete worms, predatory fly larvae, and amphipods. In saline regions, there are abundant polychaete annelids, amphipods, and some mollusks such as clams. These species burrow in the sediment and accelerate the breakdown of organic matter. Atlantic blue crabs are among the larger invertebrates, at the northern limit of their range. The entire Hudson was once far more populated with native suspension-feeding bivalves. Freshwater mussels were common in the river's limnetic zone, but populations have been decreasing for decades, probably from altered habitats and the invasive zebra mussel. Oyster beds were once pervasive in the saltwater portion, but are now reduced through pollution and exploitation. Fish About 220 species of fish, including 173 native species, currently are found in the Hudson River. Commercial fishing was once prominent in the river, although most were shut down in 1976 due to pollution; few survive today. American shad are the only finfish harvested for profit, though in limited numbers. Species include striped bass, the most important game fish in the Hudson. Estimates of the striped bass population in the Hudson range to nearly 100 million fish. American eels also live in the river before reaching breeding age; for much of this stage they are known as glass eels because of the transparency of their bodies. The fish are the only catadromous species in the Hudson's estuary. The Atlantic tomcod