Chapter 10 nine rivers of death

From the depths of the green waters of the Atlantic there are many paths leading to the shore; they are paths of fish cruising, and though these paths cannot be seen or touched, they are made by the flow of bodies of water from land-rivers.For thousands of years, salmon have become familiar with these lines of fresh water; During the summer and fall of 1953, a species of river salmon known in New Brunswick as Miramichi returned from their remote Atlantic feeding areas and entered their native river.Where this salmon reaches, there are many networks of shaded streams through which the salmon lay their eggs in the autumn on the gravel of the riverbeds, where the water flows softly and coolly.The site is a vast area of ​​coniferous forests of spruce, impatiens, thumb and pine trees, which provide suitable spawning grounds for salmon to thrive.

This has been repeated in this fashion from time immemorial to the present; in a river in the north of the United States called the Miramichi, which produces the best salmon.But by 1953, the situation was spoiled. In autumn and winter.The large, hard-shelled salmon eggs are laid in shallow gravel-filled troughs that the female fish have dug in the bottom of the river.In the cold winter, the fish eggs develop slowly, and according to their rules, the small fish hatch only when the forest stream is completely melted in spring.At first, they hid among the stones at the bottom of the river, small fish only half an inch long.They don't eat and live off a large protein sac.Until the protein sac is absorbed, the small fish start to go to the stream to find small insects to eat.

In the spring of 1954, new young fish hatched, both one- and two-year-old salmon and juveniles in the Miramichi River.These tiny fish, with their brilliant coats adorned with tiny sticks and bright red spots, hunt and devour all manner of strange insects that linger in the stream water. When summer rolls around, that all starts to change.The northwestern watershed of the Miramichi River was included in an ambitious spraying program last year.The Canadian government has been running the program for a year to save forests from the spruce aphid, a native insect that attacks many types of evergreen trees.In eastern Canada, the insect appears to undergo major developments about every 35 years.A peak in the population of this aphid was seen in the early 1950s.To combat them, DDT began to be sprayed; initially in a small area, then by 1953 the area was suddenly expanded.In an effort to save impatiens as a raw material for the pulp and paper industry, instead of spraying only a few thousand acres of forest, as in the past, it is spraying millions of acres of forest.

So, in June 1954, spraying planes visited the wooded area northwest of Miramichi; the white smoke of the spray traced the interlacing tracks of flight in the sky.Half a pound of DDT dissolved in oil was sprayed per acre, and the potion seeped through the impatiens forest, some of which ended up on the ground and into the streams.The pilots were only concerned with the task assigned to them, and did not try to avoid the river spray or close the spray gun when flying over the river; but in fact these sprays can travel a long way with even a weak air current, So even if the pilot pays attention to doing so, the result may not be much better.

No sooner had the spraying ended than there were unmistakably bad signs.Dead and dying fish, including many juvenile salmon, were found along the river within two days.Trout also appeared among the dead fish.Birds are also dying along the roadside and in the woods.All creatures in the river are silent.Prior to the spraying, the river had been rich in aquatic life, which formed the food for salmon and trout.Among these aquatic creatures are the larvae of flying grubs, which inhabit a loose but comfortable protection of leaves, grass stalks, and gravel, glued together with mucus.In the river, there are flying stone insect pupae clinging to the rocks in the eddy; there are also black flying insect larvae distributed on the edge of the stone at the bottom of the ditch or where the stream falls from the steep slope.But now that the insects in the creek have been killed by DDT, there is nothing left for the salmon to eat.

In such an environment of death and destruction, smolts themselves can hardly expect to survive, and cannot survive.Come August; not a single chub emerges on the river bed gravel where they have lingered in the spring.Slightly larger smolts, a year or more after hatching, are only slightly hit.Only one-sixth of the salmon hatched in 1953 survived in the creeks visited by the plane; almost all of the salmon hatched in 1952 went to sea, and even fewer remained. The whole of this fact is known to the world because the Fisheries Research Society of Canada has been conducting research on salmon northwest of Miramichi since the 1950's.This society conducts an annual survey of the fish living in this river.Biologists documented the number of spawning adults, juveniles of various age groups, normal numbers of salmon and other fish that inhabited the river at the time.It is precisely because of this complete record of the situation before spraying that people can determine the damage caused by spraying with great accuracy.

The expedition not only uncovered damage to juvenile fish, but also serious changes in the river itself.Repeated spraying has completely altered the river environment, killing aquatic insects that feed on salmon and trout.It takes a long time, not months, but years, even after a single spraying, for most of these insects to repopulate enough to feed normal numbers of salmon. Smaller species of insects such as gnats and black flies recover faster and are the best food for the smallest salmon fry, only a few months old.But the larger aquatic insects that salmon in their second and third years depend on for food are unlikely to recover so quickly: the larvae of grubs, hard shells, and may chafers.Even a year after DDT entered the river, the foraging smolts had trouble finding anything more than the occasional small hard shell.In an effort to increase this natural food, Canadians have attempted to colonize the barren region of the Miramichi with grub larvae and other insects.But obviously, this kind of migration still cannot avoid the harm caused by spraying again.

Not only did the number of tree aphids not decrease as expected, but their resistance became more tenacious; from 1955 to 1957, spraying was repeated in various places in New Brunswick and Quebec, and some areas were sprayed three times as much.By 1957 nearly 15 million acres had been sprayed.When spraying was temporarily stopped, however, aphids flourished leading to the surges of 1960 and 1961.Indeed, nowhere is chemical spraying considered superfluous as a stopgap measure for aphid control (to save trees from dying from years of continuous defoliation); Arrived.In order to minimize the damage to fish, the Canadian Forestry Service has ordered the application of DDT to be reduced from 0.5 pounds per acre to 0.25 pounds in order to meet the standards recommended by the Fisheries Research Council. (In the United States, the standard application per acre and the maximum lethal rate remained unchanged.) After observing the effects of spraying for several years, Canadians saw a mixed situation; The situation offers little comfort to those involved in the salmon fishery.

A very unusual combination of events has rescued Northwest Miramichi from its projected progression toward destruction, and what used to be compelling no longer occupies the center of attention.It is important to know what is happening here and why. As we know, the watershed of the Miramichi tributary was heavily sprayed in 1954; since then, except for a narrow area that was sprayed again in 1956, the watershed has not been sprayed again. In the fall of 1954, a tropical storm intervened in the fate of the Miramichi salmon.Hurricane Edna - This violent storm reached the end of its northward course, bringing a torrential downpour to the coasts of New England and Canada.The resulting torrents and fresh water from the river ran far out to sea, attracting unusually large numbers of salmon.As a result, unusually large numbers of eggs were obtained on the gravel beds of rivers, the salmon's spawning grounds.Juvenile salmon hatched northwest of Miramichi in the spring of 1955 found conditions ideal for their survival: a year after DDT killed all insects in the river, the smallest insects, gnats and black flies, had recovered In their quantity, they are the normal food for smolts.The smolts born this year not only found plenty of food but also found little competition, since the slightly larger salmon had been sprayed to kill in 1954.So the 1955 smolts grew exceptionally fast and in surprisingly large numbers.They quickly complete their growth phase in rivers and enter the sea early. Many of them returned to the river in 1959 and produced large numbers of smolts in their native streams.

The increase in young frogs in the northwest of Miramichi is relatively good, and this is only because it has only been sprayed for one year.The consequences of years of repeated spraying have been clearly seen in other rivers in the basin, where salmon populations have declined alarmingly. In all sprayed rivers there were very few chubs of all sizes.The youngest salmon were "virtually wiped out," the biologists reported.The entire area southwest of Miramichi was sprayed in 1956 and 1957, and the number of hatchlings in 1959 was the lowest in a decade.Fishermen are talking about the sudden decline in the smallest froglets in Hume.At the sampling site in the Miramichi Estuary, the number of juvenile frogs in 1959 was only one-fourth of what it had been before. In 1959, the production of the entire Miramichi watershed was only 600,000 two and three-year-old smolts (this is young salmon that is migrating into the sea).This amount is one-third less than the output of the previous three years.

Faced with this base case, the future of New Brunswick's salmon fishery can only hope to invent a future replacement for DDT to scatter forests. There is nothing special about the situation in eastern Canada. The only difference is that the area of ​​the forest sprayed is large and there are many first-hand information collected.Maine, with its spruce and impatiens forests, also has its problems with controlling forest insects.Maine also has problems with salmon migration, although it is only a remnant of the large migrations of the past.However, the river is polluted by industry and silted up with wood, so the work of biologists and conservationists is not enough to keep the remaining salmon alive in the river.While spraying has been experimented with as a weapon against the ubiquitous aphids, the area affected has been relatively small, not even including important rivers where salmon spawn.But what the Maine Department of Inland Fish and Game has observed among river fish in one area may be a harbinger of things to come. The department reported that immediately after spraying in 1958, a large number of dying carp was found in the Great Cowdard River.The fish exhibited the typical symptoms of DDT poisoning, swimming erratically, panting out of the water, trembling and convulsing.In the first five days after spraying, 668 dead carp were collected in fishing nets in two river reaches.Minnows and carp have also been poisoned in large numbers in the Little Cowdard, Cali, Ard and Black rivers.It is not uncommon to see weak, dying fish passively downstream.Sometimes, a week after spraying, blind and dying trout were still found floating in the water. [The fact that DDT can blind fish eyes has been reported by many research works.A biologist observing the spraying in North Van Cavum reported in 1957 that trout, once aggressive, were now easily caught by hand in rivers, sluggish and not fleeing.Upon investigation, their eyes were found to have been covered with an opaque white film, which weakened or completely lost their vision.Experiments conducted by Fisheries Canada have shown that almost all fish (coho) are not actually killed by low concentrations of DDT (3 parts per million), but blindness occurs with opaque eye lenses. ] Wherever there are large forests, modern methods of insect control threaten the shaded streams where fishes thrive.In the United States, one of the most famous examples of fish destruction occurred in 1955 as a result of the application of pesticides in and around Yellowstone National Park.That fall, a large number of dead fish were found in the Yellowstone River, shocking anglers and the Montana Fish and Game Service.About 90 miles of the river were affected, and 600 dead fish were counted on a 300-meter stretch of shore, including brown sturgeon, whitefish and carp.River insects, the natural bait for trout, are gone. The Forestry Service declares their mandated application of one pound of DDT per acre a "safe standard."However, the practical consequences of spraying have convinced people that this standard is far from safe. A collaborative study began in 1956 involving the Montana Fish and Game Department and two federal offices—the Fish and Wildlife Service and the Forest Service.900,000 acres were sprayed in Montana that year, and another 800,000 acres were treated in 1957.So biologists don't have to worry about finding their research sites. The fish deaths have always presented a characteristic scene: the smell of DDT in the forest, oil slicks on the water, and dead trout on the banks of the river.All fish analyzed, dead or alive, accumulated DDT in their tissues.For example, in eastern Canada, the most serious consequence of spraying is the sudden decline of organic food.In many of the areas studied, populations of aquatic insects and other river-bottom animals have declined to one-tenth of their normal numbers.Destroyed aquatic insects, which trout desperately need for survival, take a long time to recover.Even in the second summer after spraying, only very few aquatic insects were present; hardly anything was to be seen in a river formerly rich in benthic fauna.In such stretches, fish catches have decreased by 80%. Fish certainly don't die right away; in fact, delayed death is worse than immediate death.As the Montana biologists discovered, fish deaths may go unreported because the delayed mortality occurs after the fishing season.Massive die-offs of spawning fish in the rivers studied occurred in autumn, including brown trout, grayling and whitefish.This is not surprising, because for living things—whether fish or humans—during their physiological orgasm, they store up fat as a source of energy.From this, it can be seen that DDT stored in adipose tissue has a sufficient lethal effect on fish. It is therefore clear that spraying at the rate of one pound of DDT per acre constitutes a serious threat to fish in forest streams.But to make matters worse, aphid control has been missed, while many fields are registered to continue spraying.The Montana Fish and Game Department has expressed strong opposition to further spraying, expressing its reluctance to jeopardize game and fish stocks for spraying programs whose necessity and success are questionable.In any case, the agency announced that it would join forces with the Forest Service to "identify ways to minimize side effects."But can such a collaboration actually succeed in saving fish?An experience in British Columbia sheds some light on this issue.There, a large population of black-headed aphids has been rampant for many years.Concerned that another seasonal fall of the leaves might kill large numbers of trees, the Forest Service decided to implement an aphid control program in 1957.Discussed with the Bureau of Fish and Game many times, but the Management Office of the Bureau of Fish and Game is more concerned about the migration of salmon.The Forest Biology Division has agreed to modify the spraying program to reduce the risk to fish by taking every possible approach to neutralize its effects. In spite of these precautions, and despite the fact that there was a real effect, in the end almost 100 percent of the salmon in the four rivers were killed. In one of the rivers, the young of 40,000 returning adult coho salmon were all but wiped out.So has the fate of thousands of young steelhead and other trout.Coho salmon have a three-year life cycle, and migratory fish are almost all of the same age group.Like other species of salmon, coho have a strong homing instinct, allowing them to return to the rivers of their birth.Salmon from different rivers will not mess with each other.That means salmon will only be able to return to rivers every three years if careful management can restore the vital migration of this prolific fish through captive breeding and other methods. There are some solutions to the problem of protecting both forests and fish.It would be succumbing to despair and defeatism if we allowed our rivers to become rivers of death.We must make wider use of now known alternatives and must mobilize our ingenuity and resources to develop new ones.There are documented instances where natural parasites have conquered aphids and are better controlled than sprays.This natural control method needs to be applied on the widest scale.Low-toxicity pesticides can be used, or better yet, microbes introduced that will cause disease in aphids without affecting the overall forest biological structure.We'll see later what these alternatives are and what they require.By now we should realize that chemical spraying of forest insects is neither the only nor the best way. Pesticides that pose a threat to fish can be divided into three categories.One, as known above, is the insecticides associated with individual problems in spraying forested areas, which have affected fish in migratory rivers in boreal forests, almost entirely as a result of the action of DDT.The other is a high volume, spreadable and diffuse insecticide that affects many different species of fish such as bass, sunfish, sunfish, carp, etc. that inhabit a variety of water bodies throughout the United States , even in flowing water bodies, this class of pesticides includes almost all pesticides currently used in agriculture, but only the main culprits such as endrin, toxaphene, dieldrin, and heptachlor can easier to detect.There is another issue that must now be fully considered, namely, that we can logically imagine what will happen in the future, and that the research work to reveal these facts is only just beginning to be done, which is related to salt marshes, bays and estuaries related to the fish in it. With the widespread use of new organic pesticides, it is inevitable that the fish world will be severely damaged.Fish are exceptionally sensitive to chlorinated hydrocarbons, and most modern insecticides are composed of chlorinated hydrocarbons.As millions of tons of chemical poisons are dropped on the earth's surface, some will find their way into the endless water cycle between land and sea. Reports of tragically poisoned fish have become so common that the U.S. Public Health Survey has sent people to the states to collect such reports as an indicator of water pollution. This is an issue that concerns the broad masses of the people.Nearly 25 million Americans view fish as their primary source of recreation, and at least another 15 million are occasional anglers.These people spend $3 billion a year on licenses, tackle, boats, tenting gear, gas, and lodging.Other issues that keep people from playing sports also affect a lot of economic interests.People who depend on fishing see fish as an important source of food, and they represent a larger good.Inland and coastal fishers (including sea fishers) catch at least 3 billion pounds of fish each year.Yet as we have seen, pesticide pollution of streams, ponds, rivers, and bays has threatened recreational and professional fishing. Everywhere there are examples of the destruction of fish by the spraying or powdering of agricultural crops.For example, in California, nearly 60,000 catchable fish, mainly blue whales and other sunfish, were lost to attempts to use dieldrin to control a rice leaf pest.In Louisiana, there were more than two dozen deaths of large fish in one year in 1961 due to the application of endrin to sugar cane fields.In Pennsylvania, fish were also mass-killed with endrin in order to eradicate rats in orchards.The use of chlordane to control grass fleas in the western highlands resulted in the death of many stream fish. There is perhaps no other program like the one in the southern United States that sprayed millions of acres extensively to control a species of fire ant.The main pesticide used is heptachlor, which is slightly less toxic to fish than DDT.Dieldrin, another drug that kills fire ants, has a bad reputation of being very harmful to all aquatic life.Endrin and toxaphene alone pose a great danger to fish. Everywhere fire ant ranges are controlled, either heptachlor or dieldrin have been reported to have catastrophic effects on aquatic life.It only takes a few excerpts to get the smell of these reports, written by biologists who specialize in hazards: The state of Texas reported "a severe loss of aquatic life in its efforts to preserve the canal," "in all treatment Dead fish appeared in the waters where it was sprayed”, “Fish mortality was severe and continued for more than three weeks”; Alabama reported that “within a few days after spraying, most of the adult fish were killed. (in Wilkes County)", "Fish in temporary water bodies and small tributaries have been completely extinct". In Louisiana, farmers complained of losses in ponds on their farms.In one canal, more than 500 dead fish were found floating on the water or lying on the banks in just under a quarter of a mile.In another parish 150 sunfish died, a quarter of the original number.Five other fish species were completely wiped out. In Florida, heptachlor residues and a secondary chemical, heptachlor oxide, were found in fish taken from ponds in sprayed areas.Among these fish are sunfish and bass; of course, sunfish and bass are favorite fish among anglers, and both are often found on the dinner table.The chemicals contained in these fish are considered by the Food and Drug Administration to be the kind that can pose a great danger to humans within minutes of ingestion. So many areas reported killing fish, frogs, and other aquatic life that the American Society of Ichthyologists and Herpetologists, a respected scientific organization that specializes in fish, reptiles, and amphibians, A resolution was passed in 1958 calling on the Department of Agriculture and its state offices "to suspend area spraying of heptachlor, dieldrin, and such agents until irreparable damage is done."The society calls attention to the wide variety of fish and other creatures that live in the southeastern United States, including those not found anywhere else in the world."Many species of these animals live in very small areas and could be wiped out quickly and completely," the society warned. Insecticides used to kill cotton insects have also hit fish in southern states hard. The summer of 1950 devastated the cotton-producing regions of northern Alabama.Prior to this year, organic insecticides had been used sparingly to control the weevils.But because of several mild winters, a large number of weevils appeared in 1950; thus, about 80-95% of the farmers, at the instigation of local brokers, turned to insecticides.The most common chemical used by these farmers is toxaphene, one of the most destructive to fish. The summer rains this year were abundant and concentrated.Rainwater washes these chemicals into rivers; and farmers counteract this by spraying more on their fields.During the year, an average of 63 pounds of toxaphene was received per acre of farmland.Some farmers applied as much as 200 pounds to an acre; one overzealously applied more than a quarter ton of insecticide to an acre. The results are easily foreseeable.What happened in the Flint River, which flows 50 miles through Alabama's farm country before flowing into Wheeler Reservoir, is typical for the region. On August 1, heavy rain fell on the Fulin River Basin.This rainwater is poured from the land into rivers in trickles, creeks and torrents.The Flint River rose 6 inches.The next morning, I saw many other things appearing in the river besides the rain.Fish floated blindly in circles near the surface of the water; sometimes a fish would jump out of the water toward the bank by itself.They can be caught easily.A farmer picked up many fish and put them into a pool fed by a spring.There, in the clear water, some fish came to life.And in rivers, dead fish float down the current all day long.But this one fish kill is only the prelude to more fish to come, as each subsequent rain washes more pesticides into the river, killing even more fish. The rains on 10 August took a toll on the entire river, nearly killing the fish.When it rained again on August 15 and washed the poison into the river, there were almost no fish left as victims again.However, evidence of the chemical's mortality was obtained by placing cages of experimental goldfish in rivers: the goldfish all died within a day. Among the fish that have been devastated in the Flint River are the large white crappie, a favorite among anglers.Large numbers of dead bass and sunfish were also found in Wheeler Bay, where the Flint River flows.All trash fish in these water bodies - carp, bison fish, drum fish, gizzard fish and catfish, etc. have also been eliminated.None of the fish showed symptoms of disease, they only showed abnormal movements at the time of death and a strange dark wine color on the gills. When pesticides are used near warm penned fish ponds on farms, fish in the ponds are likely to be killed or killed.As many examples illustrate, poisons are carried by rainwater and runoff from surrounding land to rivers.Sometimes these fish ponds are not only polluted by runoff, but when pilots spraying fields fly over the ponds and forget to turn off the sprinklers, the ponds literally receive the poison.It doesn't even need to be this complicated, the normal use of pesticides in agriculture also exposes fish to large quantities of the chemical in far greater quantities than would kill them.In other words, even a drastic reduction in the cost of medication would hardly change this deadly situation, since usage above 0.1 pounds per acre is generally considered harmful to fish ponds.This poison is very difficult to remove once introduced into the pond.One pond that had been treated with DDT to get rid of unwanted silvery fish retained the toxin through repeated drainage and flow, killing 94 percent of sunfish as it later accumulated.Apparently, these chemical poisons are stored in the silt at the bottom of the pond. Clearly, conditions are no better than they were when these new insecticides first came into use.The Oklahoma Department of Wildlife announced in 1961 that reports of fish losses in farm ponds and small lakes had been coming in at least once a week and were now increasing.A heavy rain falls immediately after applying pesticides to crops, so that the toxins are flushed into ponds. — This kind of loss-making situation has become accustomed to people in Oklahoma because of its repeated occurrence over the years. In some parts of the world, pond fish provide essential food for people.In these places, insecticides were used without regard to the effect on the fish, and problems arose immediately!In Rhodesia, for example, DDT at concentrations of just 0.04 parts per million killed juveniles of kaffy bream, an important food fish in shallow water.Many other insecticides can kill even in smaller doses.The shallow water in which these fish live is a good breeding ground for mosquitoes.The problem of eradicating mosquitoes while also protecting food fish in Central Africa has clearly remained unresolved. Milkfish farmed in the Philippines, China, Vietnam, Thailand, Indonesia and India face the same problem.The fish is farmed in shallow ponds along the coasts of these countries.Schools of juveniles of this fish appear suddenly in coastal waters (no one knows where they come from), are scooped up and placed in holding tanks where they grow up.The fish is so important as a source of animal protein for the rice-eating millions of people in Southeast Asia and India that the Pacific Science Congress has recommended an international effort to find this hitherto unknown spawn land, in order to develop the breeding of this fish in a wide area.However, the spraying of insecticides has caused severe damage to the existing impoundments.In the Philippines, area spraying to eradicate mosquitoes has cost fish pond owners dearly.In one pond of 120,000 milkfish, more than half the fish died after spraying planes visited, despite the fish farmers' best efforts to dilute the water with currents. In 1961, the largest fish kill in recent memory occurred in the Colorado River downstream of Austin, Texas.On January 15, a Sunday, shortly after dawn, dead fish suddenly appeared on Xintang Lake and the river within about 5 miles downstream of the lake.Before this day, no one had discovered this phenomenon.Fish were reported dead 50 miles downstream on Monday.By this time it became clear that some poisonous substance was spreading down the river.By January 21, fish had also been poisoned 100 miles downstream near Le Grange.And a week later, the chemicals were working their way back 200 miles downstream from Austin.During the last week of January, the locks of the inner coast channel were closed to prevent the poisonous water from entering the Matagoda Bay and thereby diverting it into the Gulf of Mexico. Investigators in Austin smelled odors related to the pesticides chlordane and toxaphene at the time.The smell was especially strong in the sewage of a sewer.The sewer has been the cause of accidents in the past due to the discharge of industrial waste; when officials from the Texas Game & Fish Association moved up from the lake and down the river, they noticed what appeared to be an odor of hexachlorobenzene, which came from a chemical factory. A branch of it drifted far away.The plant mainly produces DDT, HCB, chlordane and toxaphene, but also produces small amounts of other insecticides.The plant manager recently allowed large quantities of insecticide powder to be flushed down drains; what is more, he acknowledged that this treatment of pesticide overflow and residue had been done routinely for the past decade. In further research, fisheries officials found that stormwater and domestic water from other factories may also carry pesticides into drains.However, the final link in this chain reaction was the discovery that several million gallons of water flowed through the entire storm sewer system days before the water quality in the river and lake became fatal to fish. , which flushes the stormwater system under pressure.This flow has undoubtedly washed out the pesticides stored in the gravel, sand and tile deposits, and carried them into the lake and further into the river, where the chemical poison was later reintroduced show up. As this mass of deadly poison came downriver to Colorado, they brought death to it.Nearly all fish were killed for a distance of 140 miles downstream from the lake, and seines were later used in an effort to find out if any survived, but they found nothing.Twenty-seven species of dead fish were found, totaling 1,000 pounds of dead fish per mile of river.There is a canal catfish that is a major catch in this river, along with blue and flathead catfish, loach, four species of sunfish, silverfish, tapefish, rollerfish, largemouth bass Fish, mullet, sucker, eel, gar, carp, river sucker, gizzard and buffalo are all dead fish.Some of them are the elders of the river. Many flathead catfish weigh more than 25 pounds. Judging by their size, they must be very old. Local residents along the river have reportedly picked up 60 pounds. , and according to official records, a giant blue catfish can weigh up to 84 pounds.Even if no further pollution occurs, it may take years to change the fish population in the river, the state's Fish and Game Association predicts.Some of the species remaining in their natural range may never recover, and others are likely to recover only through a widespread increase in farming activities in the state. The apocalypse of Austin's fish is now known, but it's certainly not over, the poisonous river still has the ability to kill fish after traveling 200 miles downstream.若这一极其危险的毒流被允许放入玛塔高达海湾，它们就会影响那里的牡蛎产地和捕虾场；所以将这整个有毒的洪流转引到了开阔的墨西哥湾水体中。但在那儿它们的影响如何呢？也许还有从其他河流来 的、带着同样致命的污染物的洪流吧？ 当前我们对这些问题的回答大部分还得凭猜测；不过，对江口、盐沼、海湾和其他沿海水中农药的污染作用愈加关心。这些地区不仅有污染了的河水流入，而且，尤为常见的是为消灭蚊子及其它昆虫而直接喷洒农药。 没有什么地方能比佛罗里达州东海岸的印第安河沿岸乡村更加生动地证实了农药对盐沼、河口和所有宁静海湾中生命的影响了。1955年青天，那里的圣鲁斯郡有2000英亩盐沼被用狄氏剂处理，其目的是试图消灭沙蝇幼虫，用药量为每英亩一磅有效成份。对水生生物的影响真是一场大灾难。来自州卫生部昆虫研究中心的科学家们视察了这次喷药后造成的残杀现场，他们报告说鱼类的死亡是“真正彻底的”。海岸上到处乱堆着死鱼。从天空中可以看到鲨鱼游过来吞食着水中垂死无助的鱼儿。没有一种鱼类得以幸免。死鱼中有鲻、锯盖鱼、银鲈、食蚊鱼。 “在除印第安河沿岸而外的整个沼泽区中所有直接被杀死的鱼至少有20一30吨，或约1，175，000条，至少有30种。”(调查队R，W·哈林顿和w·L·彼得令梅叶等报告)“软体动物看来未受狄氏剂伤害。本地区的甲壳类实际上已完全被消灭。水生蟹种群彻底毁灭；提琴手蟹除了在明显漏掉喷药的沼泽小地块中暂时地活着外，也全部被杀死了。” “较大型的捕捞鱼和食用鱼迅速地死了……蟹在腐烂的鱼体上爬行和吞食，而第二天它们也都死了。蜗牛不断地、狼吞虎咽地吃着鱼的尸体，两周之后，就没有一点儿死鱼残体遗留下来了。” 这样一幅阴沉的图画是后来由H·R·米尔斯博士在佛罗里达对岸的塔姆帕湾进行观察后描述出来的，国家阿杜邦学会在那儿建立了一个包括威士忌据点在内的海鸟禁猎区。在当地卫生权威们发动了一场驱赶盐沼地蚊子的战役之后，这一禁猎区具有讽刺意味地变成了一个荒凉的栖息地，鱼和蟹又一次成了主要的牺牲品。提琴手蟹是一种小巧、雅致的甲壳动物，当它们成群地在泥地或沙地上爬过时，宛如正在放牧的牛群。它们现已无法抵御撒药人的袭击了。在这一年的夏、秋季节里进行了大量喷药(有些地方喷了16次之多)之后，提琴手蟹的状况曾由米尔斯博士进行了统计：“这一次，提琴手蟹的进一步减少已变得很明显了。在这一天(10月12日)的季节和气候条件下，这儿本应有100，000只提琴手蟹群居，然而在海滨实际上只见到不足100只，而且都是死的和有病的，它们颤抖着，抽动着，沉重地、勉勉强强地爬行；然而在邻赶的未喷药的地区中的提琴手蟹仍然很多。” 这个有提琴手蟹存在的地方是这种生物栖居世界的生态学中不可缺少的一个地方。对许多动物来说，它们是一种重要的食物来源。海岸浣熊吃它们，象铃舌秧鸡、海岸鸟这样一些居住在沼泽地中的鸟和一些来访的候鸟也吃它们。在新泽西州的一个喷洒了DDT的盐化沼泽中，笑鹅的正常数量在几周内减少了85%，推测其原因可能是由于喷药之后使这些鸟再也找不到充足的食物了。这些沼泽提琴手蟹还有其他方面的重要性，它们通过它们到处挖洞的活动而使沼泽泥地得到清理和充气。它们也给渔人提供了大量饵料。 提琴手蟹并不是潮汐沼泽和河口中唯一遭受农药威胁的生物，有些对人更为重要的其他生物也受到危害。切撒皮克湾和大西洋海岸其他地区中有名的蓝蟹就是一个例子。这些蟹对杀虫剂极为敏感，在潮汐沼泽、小海湾、沟渠和池塘中的喷药杀死了那里的大部分蓝蟹。不仅当地的蟹死了，而且从其他海洋来到撒药地区的蟹也都中毒死亡。有时中毒作用是间接发生的，如在即第安河畔的沼泽地中，那儿的蟹象清道夫一样地处理了死鱼，然而它们本身也很快中毒死去了。人们还不太了解大红虾受危害的情况；然而它们与蓝蟹一样属于节足动物的同一族，它们具有本质上相同的生理特征，因而推测可能会遭到同样影响。对直接具有人类食物经济重要性的蟹和其他甲壳类来说可能出现同样的情况。 近岸水体——海湾、海峡、河口、潮汐沼泽——构成了一个极为重要的生态单元。这些水体对许多鱼类、软体动物、甲壳类来说如此关系密切和不可缺少，以致于当这些水体不再适宜于生物居住时，这些海味就从我们的餐桌上消失了。 甚至在那些广泛地生活在海岸水体的鱼类中，有许多都依赖于受到保护的近岸区域来作为养育幼鱼的场所。幼小的大鰽白鱼大量地存在于所有栲树成行的河流及运河的迷宫之中，这些河流在佛罗里达州西岸三分之一的低地中婉蜒环绕。在大西洋海岸，海鳟、叫鱼、石首鱼和鼓鱼在岛和“堤岸”间的海湾砂底浅滩上产卵，这条堤岸象一条保护性键带横列在纽约南岸大部分地区的外围。这些幼鱼孵出后被潮水带着通过这个海湾，在这些海湾和海峡(卡里图克海峡、帕勒恰海峡、波桂海峡和其他许多海峡)中，幼鱼发现了大量食物，并迅速长大。若没有这些温暖的、受到保护的、食料丰富的水体养育区，各种鱼类种群的保存是不可能的。然而我们却正在容忍让农药通过河流和直接向海边沼地喷洒而进入海水。而这些鱼在幼年阶段比成年阶段更容易化学中毒。 另外，小虾在幼年时期依存于近海岸的觅食区。丰富而又广泛巡游的虾类是沿南大西洋和墨西哥湾各州所有渔民的主要捕捞对象。虽然它们在海中产卵，但幼虾却游入河口和海湾，这种几周龄的小虾将经历形体连续的蜕皮和变化。从5－6月份到秋天，它们停留在那儿，在水底碎屑上觅食。在它们近岸生活的整个期间，小虾的安全和捕虾业的利益都全仰仗于河口的适宜条件。 农药的出现是否对捕虾人和市场供应是一个威胁呢？由商业捕渔局最近所做的实验室试验可能会提供答案：发现刚刚过了幼年期的、具有商业意义的小虾对杀虫剂的抗药性非常低——其抗药性是用十亿分之几来衡量的，而不是通常使用的百万分之几的标淮。例如在实验中，当狄氏剂浓度为十亿分之十五时，即有一半的小虾被杀死。其他的化学药物甚至更毒。异狄氏剂始终是最致命的农药之一，它对小虾的半致死量仅为十亿分之零点五。 这种威胁对牡蛎和蛤更是加倍严重，这些动物的幼体同样是十分脆弱的。这些贝壳栖居在海弯、海峡的底部，栖居在从新英格兰到得克萨斯的潮汐河流中及太平洋沿岸的庇护区。虽然成年的贝壳定居不再迁移，但它们把它们的卵子散布到海水中。在海水中，在几周时间内幼体就可以自由运动了。在夏天的日子里，一个拖在船后的细跟拖网可以收集到这种极为细小、象玻璃一样脆弱的牡蛎和蛤的幼体，与它们一同打捞起来的还有许多组成浮游生物的漂流植物和动物。这些牡蛎和蛤的幼体并不比一粒灰尘大，这些透明的幼体在水面上游泳，吃微小的浮游植物；如果这些细微的海洋植物衰败了，这些幼小的贝壳就要饿死。而农药能有效地杀死大多数浮游生物。通常用于草坪、耕地、路边，甚至用于岸边沼泽的除草剂只要有十亿分之几的浓度，即可成为这些构成软体贝壳幼虫食物的浮游植物的强烈毒剂。 这种娇弱的幼体被各种极微量的常用杀虫剂杀死了。即使它们暴露于不足致死的浓度情况下最终也会引起死亡，因为它们的生长速度不可避免地将受到阻滞，这必将延长幼贝在致毒的浮游生物环境中生活的时间，这样就减少了它们发育成为成鱼的机会。 对于成年软体动物来说，看来至少对某些农药直接中毒的危险要少得多。但这也不一定是很保险的。牡蛎和蛤可以在其消化器官及其他组织中蓄集这些毒素。人们吃各种贝壳时一般都是把它们全部吃下去，有时还吃生的。商业捕渔局的菲利浦·巴特勒博士曾提出了一个不吉祥的比喻，在这个比喻中我们可能发现我们本身已处于一种类似知更鸟的同样处境。巴特勒博士提醒我们说，这些知更鸟并不是由于受到DDT的直接喷洒而死去的，它们死亡是由于它们吃了已在其组织中蓄积了农药的蚯蚓。 消灭昆虫使用农药的直接作用是明显的；它造成一些河流和池塘中成千上万的鱼类或甲壳类突然死亡。虽然这种事故是悲惨的、令人吃惊的，但间接到达江湾、河口的农药所带来的那些看不见的、人们还不知道的和无法测量的影响却可能最终具有更强大的毁灭性。这全部情况涉及到一些问题，而这些问题至今还没得出圆满的答案。我们知道，从农场和森林中出来的洪流中含有农药，这些农药现正通过许多、也许是所有的河流被带入海洋。但我们却不知道这些农药的全部总量是多少；而且一旦它们汇入海洋，我们当前还没有任何可靠的方法在高度稀释的状况下去测出它们。虽然我们知道这些化学物质在迁移的漫长时间里肯定发生了变化，但我们却无法知道最终的变化产物究竟比原来毒物的毒性更强，还是更弱。另外一个几乎未被探查过的领域是化学物质之间的相互作用问题，考虑到当毒物进入海洋之后，那儿有很多的无机物质与之混合和转化，这个问题就变得更为急迫。所有这些问题急需得到正确回答，只有广泛的研究才能提供这些答案，然而用于这一目的的基金却少得可怜。 内陆和海洋的渔业是一项关系到大量人民收入和福利的非常重要的资源。这些资源现已受到进入我们水体的化学物质的严重威胁，这一情况已毋容置疑了。如果我们能把每年花在试制愈来愈毒的喷撒剂上的钱的零头转用在上述建议的研究工作上去，我们就能够发现使用较少危险性物质的办法，并从我们的河流中将毒物清除出去。什么时候公众将充分认清这些事实而去要求采取这一行动呢？