Did PCB's Save the Stripers? A Fish Story
Did PCB's Save the Stripers? A Fish Story
By James Gorman
This was an amusing and interesting article deserving of reprint from a March 2003 NY Times Story
The dredging of the Hudson River for PCB's will be starting a year later than expected (in 2006 instead of 2005), but the striped bass season in the river opened this month, right on time.
There is no direct connection between the two events. The Environmental Protection Agency needs more time to plan the dredging. And the fishing for stripers has been going on for years with PCB's in the river. In fact, there are more stripers in the river now than there have been in decades. They migrate up the river in the millions to spawn. It is almost as if PCB's are good for them.
That is not the case, of course, not directly. No one can be sure exactly why fish populations rise and fall, but one obvious and important ingredient is fishing pressure. Greatly restricted fishing has reduced that pressure on Hudson River stripers. Changes in regulations were prompted partly by the health risk to people of the PCB's that accumulate in the fat of fish, and partly by a general decline in striper populations.
There is now no commercial striped bass fishing on the Hudson above the George Washington Bridge and there has not been for quite a few years.
Sport anglers can keep one striper a day in the river above the bridge, but health recommendations suggest eating no more than one a month, and none for children and women of childbearing age. Many anglers could care less, since they like to catch the fish and let them go. So the stripers, from a fisherman's point of view, are doing great.
Other rivers have improved as sport fisheries after problems with PCB's were uncovered. The Housatonic in Connecticut is one of them. It has catch and release stretches for trout that provide some of the best freshwater fly-fishing in the Northeast.
I have fished both rivers and had started to think of PCB's in stripers as something like the cardiac glucosides in milkweed that monarch butterflies ingest. The glucosides are not bad for the butterflies, but they make birds that eat the butterflies sick, so birds do not eat them. PCB's can make people sick, causing cancer or interfering with embryonic development, so people ? at least people who worry about what they eat ? do not eat the stripers. Although the consequences of pollution are all unintended, surely protective inedibility of game fish would be among the least expected.
What was left out of this equation was the effect of PCB's on the fish themselves. I called Dr. Adria Elskus, an assistant professor of environmental toxicology at the University of Kentucky, who has done research on the effects of various pollutants on fish.
Are PCB's bad for fish? I asked. Unequivocally yes, she said. They are not at all the equivalent of glucosides. Monarchs are well adapted to ingesting those chemicals and do not suffer from them. But, Dr. Elskus said, PCB's and other chlorinated substances like dioxin can hurt the ability of fish to reproduce, affect hormones, decrease the chances of survival for the offspring and cause skeletal deformities and devastating defects in heart development.
The studies that showed these effects, Dr. Elskus said, were mostly done not on striped bass, but "on the lab rats of the fish world" ? species that are easy to study in the lab, like rainbow trout, zebra fish and Japanese medaka. It is, however, quite sensible to expect stripers to experience similar effects. The reason is that when it comes to these chemical effects "Fish Is Fish," as the children's author Leo Lionni so presciently announced in his story with that title.
The actual effect of PCB's on Hudson River fish has not been clearly established, said Dr. Emily Monosson, an independent toxicologist who did a study of just this subject for the National Oceanic and Atmospheric Administration that was published in 1999. But PCB's are present in the river at levels that should be causing some damage to fish.
Why then, are the fish doing so well? The answer is that the effects of unrestrained fishing ? mass fishicide ? are much worse than the effects of current levels of PCB's.
Suppose that people were in the position of striped bass. Aliens ? to whom we were the equivalent of striped bass, in both intelligence and taste ? came to Earth to harvest us by the hundreds of millions. This went on for many generations until the human population was really dwindling, at which point the aliens realized that the exhaust from their spaceships included a chemical that accumulated in our tissues and posed a danger to them. What would they do? Turn to catch and release, probably. Oddly this is an exact description of alien abductions, which makes you wonder: do fish have trouble making other fish believe that they have been hooked, reeled in, photographed, and then, inexplicably, released?
This is a very limited analogy, of course, because fish cannot talk. In addition, and more important, PCB's affect all sorts of life, not just fish. Mammals suffer and birds and reptiles. PCB's are only one nasty pollutant among many. And we are looking at the effects after they are no longer being dumped and after decades of struggle to clean up the Hudson of a variety of pollutants. Thirty years ago, sections of the river were dead. It is a tribute to environmental activism that from the stripers' point of view, fishing is now more frightening than the remaining pollutants.
There are fish, Dr. Elskus said, that have found a way to cope with devastating pollution. In Newark Bay, some populations of the little baitfish known as mummichogs or killifish have become resistant to a variety of pollutants, including mercury and PCB's. Exposed to the same poisons, they do not show the developmental problems that nonresistant fish do.
Exactly how the fish resist the effects of these poisons is not known. "We're trying to figure that out," Dr. Elskus said, referring to the small network of scientists who do similar research. The resistance seems to have to do with the activity of an enzyme that breaks down pollutants, releasing damaging toxins.
The killifish do not migrate, however. Striped bass move around, from the Hudson to the sea, from the sea to the Hudson. The killifish were pretty much stuck in Newark Bay. And so, they were not able to wait for cleanup and dredging. They had to survive the truly old fashioned way, by evolution.
For them, Dr. Elskus said, it was "die or adapt."