Conflicts with Fisheries

As seen throughout the pages of this book, the Hudson River is many things to many people. So far we have reviewed the conflict between the river as food production base and sewage recipient. We now discuss, briefly, two other anthropogenic activities potentially at odds with sustainable fisheries: power generation and toxicants. For more detail on background, see Limburgetal. (1986) and Chapter 25.

water withdrawal by electric power plants

Until recently, a consortium of public utility companies (Consolidated Edison of New York, Orange and Rockland Utilities, Central Hudson Gas and Electric, New York Power Authority, and Niagara-Mohawk) owned and operated seven generating stations ranging from 59th Street on Manhattan to Albany (Table 14.1). The plants are under new ownership as a result of industry deregulation. All of the plants use Hudson River water as coolant, and recycle the water back to the river. These plants have a combined rating of 5,905 Mwe, but more relevant here, a combined total cooling water flow exceeding 23,465,000 m3 per day. This flow is on par with freshwater discharges measured at Green Island, where the average annual discharge (1918-1980) is 44 percent higher, but where meanAugust flows are 42 percent lower (Limburg et al., 1986).

Initial concern about potential impacts of power plants was that the heated effluent would cause harm to the biota, but it was soon seen that the larger potential threat was direct mortality due to two factors: entrainment, or the passage of small organisms, particularly fishlarvae, through theplants and across the heated turbines; and impingement, or the trapping of fish on intake screens designed to keep large particles out of the cooling water inlets. Gradually, attention focused mostly on the potential impacts of the power plants on a few "representative and important species," but primarily on striped bass.

Between 1974 and 1980, a protracted series of hearings and litigations by a group of plaintiffs consisting of government agencies and environmental organizations examined the utilities' environmental impact statements. During these hearings, increasingly complex mathematical models were developed to describe the potential losses of key species, especially striped bass, as a result of entrainment and impingement. At the same time, data were collected in several major programs, all funded by the utilities and continuing today. These are the Long River Survey, designed to assess egg and larval densities; the Fall Shoals Survey, to assess juvenile densities offshore; and the Beach Seine Survey, designed to assess onshore fish communities and abundance. It was determined through statistical analysis of the data sets that the level of variation in the data obscured any clear forecasting of the impacts of the plants, and that it might take as long as fifty years of data collection to observe any clear trends (Limburg et al., 1986). With no foreseeable scientific determination, all the parties to the litigation enteredinto a negotiated settlement, lasting from 1980-90, that prescribed outage (period of reduced water use) schedules to reduce larval mortality, modifications of intake screens, and the establishment of an institution (The Hudson River Foundation) to provide secure funding for future Hudson River studies.

During the fifteen years since the Hudson River Settlement Agreement expired, the utility companies continued to monitor fish communities and produce annual reports. In addition, they prepared a new draft environmental impact statement (DEIS, 1999). In the meantime, the Federal government deregulated the power industry, and over the past few years all the utilities have been purchased by private corporations (Table 14.1). Additionally, approval has been sought for another five new-generation power plants along the Hudson. The new plants will use only a fraction of the water and will be closed-cycle, i.e., will use cooling towers rather than returning thermal effluent to the river.

The socioeconomic climate for operating utilities along the Hudson appears to have changed; deregulation's intent was to produce more competition, and a potential side effect is that the companies operating the existing plants are less concerned with environmental effects than the previous owners. However, the new owners inherited the environmental issues of operating the old plants, and these are still in need of resolution. Among the issues that will likely be contested in future hearings are whether or not fish populations (particularly striped bass) have "compensatory mortality," or the ability to rebound at low densities, as when depleted by power plant mortality; whether bay anchovy, an important es-tuarine forage species that suffers up to 50 percent year class removal by the plants, truly constitutes a Hudson River population or is part of a larger, offshore stock; and whether the power plants affect species that experience other environmental stresses, for instance, Atlantic tomcod that has been stressed due to a long-term warming trend in the river (Daniels et al., in press), which could severely affect this cold-adapted species.

Table 14.2. FDA guidelines on maximum allowable levels of selected contaminants in fish

Substance

Level

Food type

Aldrin, Dieldrin

0.3 ppm

all fish

Chlordane

0.3 ppm

all fish

DDT, TDE, DDE

5.0 ppm

all fish

Heptachlor

0.3 ppm

all fish

Mirex

0.1ppm

all fish

PCBs

2.0 ppm

all fish

2,4-D

1.0 ppm

all fish

Arsenic

76 ppm

crustaceans

0 0

Post a comment