Coastal Power Plants:
Fishermen's Delight or Dilemma
by Nick Karas,
October 01, 2025
When Steve Nemeth of Kings Park, N.Y., on one cold, mid-January day 30 years ago, discovered that the hot-water discharge of the fossil-fueled LILCO power plant on Long Island's North Shore was packed with striped bass, he thought he had died and gone to heaven. Had he discovered fishing's mother lode? In a way he had. The bass were there just for the taking, trapped in the river-like discharge of tepid water used to cool the power plant's huge steam generators. Outside the influence of the 75-degree river, parts of Long Island Sound were capped with ice and the water beneath the frozen mantle was a frigid 36 degrees.
The fish were warm but hungry. Also trapped with the striped bass were bluefish, herring and even a few Atlantic trigger fish, The bunker had long been eaten by the bass and blues, and daily the herring numbers were dwindling. All these migrant fish had been trapped there since the previous fall when they were escaping southward from the chilly approach of a Northeast winter.
The warmer water also attracted sand eels, silversides and killies, and the lure of easy food and warm water was too much of an invitation for the predators to pass by. But, by the time they were ready to move on, water temperatures outside the flow had dropped to such a degree that the fish were hesitant to reenter the real world. And, the longer they dallied the more outside temperatures fell. Like the bait they first sought, they, too, were prisoners of the "hot water". It wouldn't be until late next spring, when outside water temperatures again rose, that they would be free. If, they survived that long.
At the time, the environment created at LILCO's (Long Island Lighting Company) Northport power plant was new, but not unique even though similar situations were limited in number. Other anglers along the coast, where power plants had been built, had also discovered these artificial environments. However, since then the number of electrical power-generating plants, either fossil-fueled or nuclear, has burgeoned. Today, nearly 100 such plants dot the Atlantic coast from Maine to Florida, and all draw in huge amounts of marine water to cool their reactors and condensers.
But, what may have first appeared to be a boon to coastal fisherman is now turning out to be a bust. The major problem these plants create is not the loss of fish being trapped on the distal end of the man-made river but fish inhaled on the opposite end, where the water is taken in to cool reactors and condensers. The great volume needed in such plants is astronomical in size and acts like a huge in-water, vacuum cleaner. As an example, the third unit, of the three-unit Millstone nuclear power plant operated by Northeast Utilities Service Company (NUSC) of Waterford, Conn., when in operation, alone draws in 600,000 gallons of Niantic River water (a tidal portion of Long Island Sound) every minute to cool its reactors. According to Ron Allen of the U.S. Geological Survey in Troy, N.Y., this is equivalent to half the annual flow of the Delaware River. And, that is only one of three integrated units.
However, it is not the volume of water that has become a problem to fishes in the area, but what such a force can suck from the environment into the cooling system. While the draw of water at Millstone continues throughout the entire year, its effect is most pronounced on fish life from early December to late May because it impinges directly upon flounder populations indigenous to the site.
The Niantic River (really a bay) is heavily used as a spawning ground for winter flounder.
The great flow of intake water affects flounder in two ways, first during the adult-spawning period and second during egg and larval periods and immature stages. The fish are acted upon by one of two processes: impingement and entrainment. The two are quite different in how they hinder flounder. Entrainment draws-in or pulls-in suspended particles though its overpowering current, At the right time, the particles can be flounder eggs and larvae, as well as small, immature fish that are entrained in the cooling system. Impingement is the striking or colliding of objects on a hard surface. In this case the hard surface is the series of intake screens that protect the cooling system from drawing in flotsam, debris and fish, Flounder, too small to pass through the screen's mesh into the cooling system, are forcefully impinged upon the screen.
According to Report 21 of the Atlantic States Marine Fisheries Commission (Feb. 1998): "Winter flounder larvae are particularly susceptible to entrainment mortality by power plant intakes during and after metamorphosis because they are weak swimmers and their benthic [bottom] habit places them near intake pipes. Mechanical forces, elevated temperatures, and chlorination cause nearly complete mortality of all fish larvae and most fish eggs drawn into the coolant water stream of power plants."
In other words, what larvae and eggs that are not chopped up while on the trip through the system are cooked by the exchange of, heat as the water they are riding absorbs the heat from the reactors and is elevated as much as 10 degrees. Mortality can occur anytime that the ambient water temperature rises above 70 degrees. And, in many such plants, the coolant water is chlorinated to reduce bacteria. Chlorine is highly toxic to many species of fish in their larval stages and in high concentrations, to post-larval fish.
The report goes on, using Millstone as an example: "The relatively large volume of seawater required to cool multiple-unit power plants makes entrainment mortality a major concern. The three-unit nuclear station at Millstone Point (Waterford, Conn.) draws an average of 2.7 billion gallons per day from Long Island Sound. Full operation entrains an estimated 79 to 102 million winter flounder larvae annually. The four-unit fossil fuel station at Brayton Point (Somerset, Mass.) entrains an estimated 266 to 686 million winter flounder larvae annually. In comparison, the smaller Pilgrim nuclear power station (Plymouth, Mass,) entrains an estimated 15 million flounder larvae annually, comparable to an older fossil fuel plant, United Illuminating in New Haven, Conn., which entrains an estimated 18 million flounder larvae annually.
"The ultimate effect of entrainment mortality (adult equivalent losses) can easily be underestimate if entrainment numbers are not examined by larvae age group. Because entrained larvae are often disproportionately older metamorphosing stages, this additional mortality targets the small percentage of larvae which have survived the very high natural mortality rates experienced by [flounder in] younger planktonic stages.
"Extensive study at the Millstone plant has shown that, on average, 75% of entrained larvae are late stage. Although there is uncertainty concerning the stock origin of entrained larvae, the conditional mortality due to entrainment could be as much as 35% if all entrainment is from the local Niantic River stock. Such mortality factors, added to high fishing pressure, may severely erode the spawning stock, resulting in recruitment failure."
"The degree of entrainment and its affect on the overall population can be argued," said Penelope T. Howell, a marine fisheries biologist with the Fisheries Division of Connecticut's Dept. of Environmental Protection. "Thirty, or even 20 years ago, it might not have hurt the overall flounder population in the Niantic area but today, with reduced populations caused by both recreational and commercial fishing for this species, it can be the factor that determines whether the population can bounce back. In the last two years, we have seen an increase in spawning production but a failure of these fish to reach a size where they can reenter the fishery. The stock is low and one more blow is having an effect on the fish."
While entrainment is a major problem for immature flounder, it is only one of two power-plant activities that threaten the reestablishment of flounder stocks in the Northeast. The other, impingement, affects juvenile and adult flounder and this is also addressed in the Atlantic States Marine Fisheries' report: "A second concern related to power plant removals is impingement of juveniles and adults on intake screens. Impingement losses can be substantial if plant intakes are located in nursery grounds, as impinged fish are usually young-of-the-year fish unable to escape intake currents."
As and example, the report highlights a relatively small plant near spawning flats in upper New Haven harbor, Conn. that impinges 27,000 juvenile flounder each year. It also calls attention to impingement by larger power stations at Brayton Point and Millstone Point that annually have been documented removing 6,000 and 16,700 flounder, respectively. The report suggests that retrofitting plants located near spawning areas with fish return systems (FRS) would reduce this unnecessary mortality. They list as an example the FRS that were added to two of three units [Units 1 and 3] at the Millstone Power Station, Waterford, Conn. These, according to NUSC biologists, reduced impingement mortality of winter flounder by more than half.
Fish return systems are ingenious devices that, when properly installed and adjusted to the situation unique at each intake, can reduce fish mortality in some species by 80 to 90 percent. They are, what one biologist calls, "a technical fix." A FRS is a system of parallel channels or troughs placed across the outside of an intake screen. Usually, the intake is protected from inhaling debris by several screens with various size meshes placed one behind the other. The largest mesh is first and the largest pieces of debris are stopped from entering the system.
The parallel troughs rotate constantly, using centrifugal force, and backed up by water jets or sprayers, to move trapped fish to the outer edges of the screen. Here, additional sprayers, some behind the screen, but most on the periphery, wash the trapped fish out of the troughs and hopefully outside the influence of the intake waters. The fish are battered about a bit but round-bodied species and flatfish like flounder seem to be able to take the abuse, Soft-bodied species like anchovies, or squid, do no survive the effects of impingement and being washed away.
All nuclear power plants were required to have such fish washing systems. Only where the construction and arrangement of intakes make them impossible to install, are exceptions made. One is Unit 2 of the Millstone plant. Millstone is considered an old plant without the state-of-the-art cooling systems. Most older power plants have been retrofitted with these systems. However, some older plants received exemptions because they were somehow able to demonstrate that they were not having an impact on the fish populations.
Figures for the reduction of intake mortality at Millstone were provided by biologists employed by NUSC and are the result of their interpretation of the data. Howell, however, interpreting the data differently, has come up with figures that cause her to doubt the effectiveness of the fish-washing system used by NUSC to clean the intake protection screens. And, these figures, if valid, refer to the operation of Units 1 and 2. Subsequently, Unit 1 had been permanently shut down and the configuration and relationship between Units 2 and 3 are totally different.
NUSC was criticized for having no screens on Unit 3's intake. Howell, however, said there are screens, with a 2-inch mesh. "What they don't have on one of their units," she said, "is a fish return system (FRS). The reason they didn't install one is because they realized it wouldn't work. The configuration of the three units is like a horseshoe, and Unit 2 is in the middle. There is a minimal FRS on Units 1 and 2. When the built Unit 3, by far the largest of the three units, we looked at their configuration for the FRS. They [NUSC's biologists and engineers] told us the FRS, from 1 and 2, would drop the fish physically in front of Unit 3's intake so it wasn't going to accomplish anything. We agreed with that assumption.
"They [NUSC] did a follow-up study after start-up of Unit 3 and found that the fish never made it into Unit 2's [FRS], or never even made it that far. We're talking about one- to three-year-old fish that get entrained-when on their way to spawn or change locations because of temperature-because the draw of water is so great.
"We came to the realization that they couldn't physically put in an effective FRS. Now that Unit 1 is not going to be activated, their permit was changed and now requires that they have the physical space where they can put in a FRS for impingement where the fish will be returned safely and not be redrawn back into the cooling system. There is, however, no technological fix for the larvae and eggs entrained into their system because they are so small, almost microscopic. There is nothing NUSC can do about it, other than build cooling towers."
NUSC official, when contacted, refused to be interviewed and to comment on any part of the plant's operation or if they were making future considerations to protect flounder and other fishes affected by the plant's operation. Nor would they allow their head biologist, Dr. Donald Danila, answer a series of questions that were presented to him about the plant's operation with regard to fish. They claimed it would be inappropriate for them to discuss anything because of continuing litigation.
Ed Radle, the New York's DEC power plant impact specialist in Albany also isn't sure that the NUSC's screen debris (including fish) washing technique is very effective because there is no real data on what happens to the impinged fish. He has been working with cloth screening material, the kind road constriction project use to control runoff waters while work is being done. However, the mesh is so small that such a large area would be need to maintain a sufficient intake volume for a power plant that it would be impractical. The only real solution to the dilemma, as he and others see it, is for NUSC to build cooling towers. Most European power plants recycle their coolant waters through such towers and they have proven economically feasible.
There are other problems for the environment inherent in any power plant, either fossil fueled (coal and petroleum) or nuclear. Heated water and its affect on fish, a problem common to both systems, was described in Report 21. However, there are problems unique to nuclear plants that include radiation, radio-active waste, chemical by-product pollution, and accidental discharges. The affects of these, however, manifest themselves over the long term and are not immediately recognizable in fish. And, while they can contribute to increases in fish mutation, no one has established that they have caused any lasting change in the overall population of a species. Simply put, there is a lack of data on the long-term effects of power plants on the entire environment and no one is coming forth with funds to support such research.
The Millstone plant has been froth with both accidental and intentional discharges of nuclear waste into nearby waters and NUSC has been fined for the action. The March I 999 issue of Estuaries, the Journal of the Estuarine Research Federation, contained an article by three researchers who studied sediments in the bottom of Jordan Cove, a part of L.I. Sound on the east side of Millstone Point, at the power plant's outflow pipe. They found, along with other deposits, small amounts of the radio-active isotope cobalt-60, By measuring its half-life, they determined it had been deposited 20 years ago, about the time Unit I began operating at Millstone. Cobalt-60 is a by-product of power production with a half-life of about five years.
Terrance McIntosh, a spokesman for NUSC, had earlier acknowledged that cobalt-60 was deposited in L.I. Sound in the late 70's, but said it never was in danger or harming fish or people. He said the. concentrations always were within the Nuclear Regulatory Commission's (NRC) legal limits of the late 1970's. Gaboury Benoit of the Yale School of Forestry, who headed the research project, believes that there is too little cobalt-60 in the sediment to be of any real danger to the public. The NRC, which required the test, said the test NUSC provide to the commission showed that no cobalt-60 was found in any of the fish tested from the area.
Under outside pressure, the Nuclear Regulatory Commission , which issues licenses for such plants as Millstone to operate, has been leveling fines on them for disregarding NRC's rules for operating. Unit 1 was permanently closed and NUSC was fined $2.1 million for blatant license violations. A few years later, it was again fined, this time for $1.2 million for willfully dumping more than 1,000 gallons of radioactive wastewater into Long Island Sound.
Maybe what NRC should do to NUSC what it did two years ago to the San Onofre nuclear power plant operated by Southern California Edison (SCE). The cooling system damaged the immediate environment around the discharge. As compensation, SCE agreed to build the world's largest artificial kelp reef at San Mateo Point, north of the plant, and enhance 150 acres of wetlands at San Dieguito Lagoon near De] Mar. SCE will first build only 15 acres of the reef and have it monitored for five years by scientists. If it proves effective, the remainder of the reef will be built. The San Dieguito Lagoon will require extensive dredging to improve tidal flushing, as well as excavation, to provide suitable habitat for inshore marine species such as halibut, sand bass, croakers, sand sharks.
One of the more vociferous opponents to reopening the Millstone power plant is Bill Smith, head of the Shelter Island-based conservation organization Fish Unlimited. Smith has been instrumental in gathering together like-minded groups that oppose Millstone because of its affects on fish and the environment. He has even suggested that Millstone be required to establish and maintain a flounder hatchery that would replace fish lost to cooling the nuclear reactors.
"For decades now," said Smith, "regulatory agencies charged with managing our fisheries have pointed the finger toward easy targets-the fishing community-as the culprit in the decline of our fisheries. While there is no doubt that improved technologies responsible f or finding and catching fish have impacted our fisheries more than we realize, a newly and equally disturbing culprit has emerged, power plants, and in particular nuclear power plants that are impacting our fisheries on an alarming basis."
"There's a direct interest in those fish," said Scott Cullen, a spokesman for the East Hampton(NY)-based STAR (Standing for Truth About Radiation). "Commercial fishermen are highly regulated in what they can catch and where they can catch it. I live in Montauk and a lot of fishermen there are going out of business because regulations are so intense. But this plant kills fish all the time."
Aside from a group of former plant workers and citizens fighting the plant, only a few of its neighbors, who privately harbor reservations about the plant's safety, appear to be actively opposing it. "I'd rather be right next door to it, because if it melts down, I'll never know it," said Capt. John Wadsworth, who skippers the fishing boat Sunbeam, out of Niantic, Conn.
The problem with Millstone, is that its EIS (Environmental Impact Statement) was not fully scrutinized, and its relation to the proposed structure did not demonstrated that its construction would have no impact on fish. Maybe unwittingly, NUSC was allowed to build three units that could not accommodate workable fish return systems. Now that that plant is built, modifications, from an economic standpoint, are impractical. In reality, NUSC, from the point of fish, has done about all it can. Its team of scientists at the NU Environmental Laboratory, nearly a dozen, produced a I 00-page report on winter flounder that is especially complete and seemingly unbiased, though it interpretation can be multifaceted. However, this still does not correct the situation.
NUSC has two alternatives if it cares to save the fish, either shut down the plant or build cooling towers. At the last NRC hearing, NUSC claimed that if it cannot open Unit 3 it will have to declare bankruptcy. Fish Unlimited has suggested a third alternative, build a flounder hatchery. However, nowhere in the history of mariculture has a hatchery to restock an unfettered marine fish population proven successful. One mature, gravid female, spawning in a hospitable environment, can far surpass the best efforts of any hatchery.
If there is a lesson to be learned here, is that it cannot be left up to the Nuclear Regulatory Commission, a body of politically appointed individuals, to be solely responsible for reviewing an EIS that will affect how and where we fish, and the fish we seek.
Note: As of this writing (May 26th), a Hartford (Conn.) judge ruled against the Fish Unlimited, et al, suit and will allow the opening of Unit 3. However, since then, another accident has occurred at the plant and its opening is again in limbo. NK
Article reprinted from the STAR Foundation website: www.noradiation.org
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