Lost Woods (8 page)

As the young mackerel grows rapidly during the first months of life, sea animals that were once deadly enemies become his prey as he, too, joins the ranks of sea hunters. After spending the summer in a sheltered New England harbor, he and other young mackerel wander out into the open sea again. There new and larger enemies await them: fish-eating birds, swordfish, tunas, and fishermen. In the concluding chapter of this series, I described the setting of a mackerel seine from the viewpoint of a fish – something that I do not believe has been done before.

In many ways, I found this section the hardest to write, and so I get a good deal of satisfaction out of the fact that most reviewers and readers seem to like it best. I believe it was hard because of the endless waste of waters – no fixed points around which to orient one’s characters. I said a few minutes ago that I really lived the things I wrote about, and I don’t mind admitting that I was very thankful to climb out on dry land in beginning the concluding section.

Book III – River and Sea

For the last section of the book, I had left the gently sloping sea bottom from the tidelines out to the edge of the continental shelf, and the deep Atlantic abyss. There was one fish whose migrations include all that varied undersea terrain – the eel. I know many people shudder at the sight of an eel. To me (and I believe to anyone who knows its story) to see an eel is something like meeting a person who has travelled to the most remote and wonderful places of the earth; in a flash I see a vivid picture of the strange places that eel has been – places which I, being merely human, can never visit.

Every eel that lives along our Atlantic coast began life in the distant Sargasso Sea. It lived, at first, so far below the surface that only the faintest blue haze ever penetrates there. For the most part, the water in which the baby eels are born is eternally dark and still and cold. The pressure is so great that it would instantly crush our unaccustomed bodies to nothing. All about the baby eels are the strange animals that live permanently in the abyss. Many of them carry their own lights, perhaps to help them see their way about in the darkness and find food.

As the young eels grow they work up toward the surface, and as they move up the light becomes stronger. By this time they look like tiny willow leaves, flat, oval, and transparent. In a few months’ time, they begin their thousand-mile journey toward the American coast. At first, probably, they are carried along by the ocean currents; later, they must swim independently. But here is the really remarkable part of the story. In the Sargasso, the young of eels from America mingle with the young of European eels, for the eels from all the European Atlantic coast make the long westward crossing to spawn in the Sargasso. But although many of the two species of young are intermingled during their first weeks or months of life, soon after the migration begins the travelers separate. They form two great bands, one company proceeding westward toward America, the other eastward to Europe. The two kinds of eels are so similar that a scientist can distinguish them only by counting the number of vertebrae in the backbone, but the little eels themselves never make a mistake. They always return to the continent from which their parents came.

In the spring the young eels begin to arrive in our coastal waters. They are, by this time, a little more than a year old, but they are no longer than a man’s finger and so transparent that one could read print through their bodies. They move into the bays and river estuaries, and some begin to ascend the rivers and streams. It is thought that the young males remain in salt or brackish water, and that it is only the females that ascend the fresh-water streams. There they live for 8, 10, or 12 years before they reach physical maturity. Then the awakening of some race instinct causes them to begin a downstream migration. This happens in the fall of the year. Usually the eels migrate at night, and apparently dark, stormy nights are times of large movements of eels. In the estuaries of the rivers the migrating females are joined by the males and together they enter the sea and pass out through the coastal waters. Fishing boats take a few; then the eels completely disappear from sight and never are seen again. We know, though, that they returned to their birthplace a thousand miles out in the Atlantic, because, very early in the spring, the eggs of the new generation of young can be found there. Evidently the old eels die after they spawn, for they never return to the coast. They begin and end their lives in the deep abyss.

General

Each of these stories seems to me not only to challenge the imagination, but also to give us a little better perspective on human problems. They are stories of things that have been going on for countless thousands of years. They are as ageless as sun and rain, or as the sea itself. The relentless struggle for survival in the sea epitomizes the struggle of all earthly life, human and nonhuman. As one reviewer said: “Our own battles for existence seem less a matter for dismay and more a simple reason for fortitude when compared in the mind with the ceaseless ebb and flow of life and death that are under all the sea winds.”

9

[1949]

Lost Worlds: The Challenge of the Islands

DESPERATELY IN NEED
of money to support her family – her mother, and her two young nieces – and to further her publishing ambitions for the book that would become
The Sea Around Us,
Carson engaged Marie Rodell, a New York literary agent, in the spring of 1948. One of their publishing strategies was to sell individual chapters as soon as Carson completed them. The chapter dealing with the creation of oceanic islands was one of the most scientifically challenging and one Carson judged from the outset could stand alone as an independent essay.

The story of how islands are formed and inhabited went through many versions before Carson was satisfied. Her research on island evolution was aided by F. Raymond Fosberg, a tropical botanist at George Washington University and the Smithsonian’s National Museum, and a world expert on atoll formation. Fosberg read an early draft of Carson’s chapter which he later described as “the finest account of the creation and colonization of an oceanic island” he had ever read.

This version, titled “Lost Worlds,” was published in the magazine of the D.C. Audubon Society
, The Wood Thrush,
edited by Carson’s friend Shirley Briggs, in the spring of 1949. It is distinguished by Carson’s undisguised anger at the human destruction of the rare ecology of island habitats, her advocacy of island ecosystem preservation, and her delight in the mysterious processes of species migration to distant Atlantic atolls. Although a later version published in the
Yale Review
was awarded the Westinghouse Science Writing Prize from the American Association for the Advancement of Science, “Lost Worlds” brought Carson favorable notice from the small but influential Washington, D.C., science community whose support was crucial to her expanding literary career.

DR. ERNST MAYR
of the American Museum of Natural History recently compiled a list of all species of birds known to have become extinct anywhere in the world during the past two centuries. This was his score: on all continents combined, eight species; on islands, at least ninety-two – probably more than a hundred when all reports from war areas are in.

This report epitomizes the tragedy of island life that is playing out what may well be its last act before our eyes. Each of the ninety-two species named by Dr. Mayr represents a loss that will never be replaced. For most of these island species have been created once, and only once, in all the world, the products of the slow processes of the ages. Destroyed by man’s careless abuse of the most delicately balanced environment in the world, an oceanic island, they are lost forever.

The problem of the islands is not one that can be put off until later; it is not one that will solve itself if we adopt a comfortable policy of laissez faire. Our own generation is in all probability the last that will have an opportunity to save any of the original island faunas and floras. The Atlantic islands, whose discovery and colonization began back in the sixteenth century, were despoiled so long ago that we scarcely realize what was lost. The islands of the Indian Ocean and parts of the Pacific came in for their turn a little later. The immense distances of the vast Pacific, the remoteness of many of its islands from the routes of whalers and traders, for a time saved some of the Pacific islands, but not for long. Today there are in all the world only a few islands whose original life remains.

Islands present a conservation problem that is absolutely unique, a fact that is not generally realized. This uniqueness stems from the nature of the island species, and from the delicately balanced relationships between island animals and plants and their environment. And going back still farther, these things are related to the origin of the islands themselves, and to the amazing manner in which they acquired their faunas and floras.

The islands of the deep ocean, far from the continents, are the products of an extraordinary process of earth-building. With few exceptions, they are the result of the violent, explosive, earth-shaking eruptions of submarine volcanoes, working perhaps for thousands or millions of years. In eruption after eruption the mass of an undersea mountain takes form on the floor of the ocean, builds up toward the surface, emerges as an island.

On their first emergence from the sea, these islands are bare, harsh, and repelling beyond human experience. No living creature moves over their volcanic hills; no plants cover their naked lava fields. By what miracle are these islands, isolated by hundreds or thousands of miles from other land, transformed into forested hills and fertile valleys, bright with birds and stirring with life?

The stocking of the islands has been accomplished by the strangest migration in earth’s history – a migration that began long before man appeared on earth and must still be continuing, a migration that seems more like a series of cosmic accidents than an orderly process of nature. Little by little, riding on the winds, drifting on the currents, or rafting in on logs, floating brush, or trees, the plants and animals that are to colonize them arrive from the distant continents.

So deliberate, so unhurried, so inexorable are the ways of Nature that the stocking of an island may require thousands or millions of years. It may be that no more than half a dozen times in all these eons does a particular form, such as a tortoise, make a successful landing upon its shores. To wonder impatiently why man is not a constant witness of such arrivals is to fail to understand the majestic pace of the process.

Yet we have occasional glimpses of the method. Natural rafts of uprooted trees and matted vegetation have frequently been seen adrift at sea, hundreds of miles off the mouths of such great tropical rivers as the Congo, the Ganges, the Amazon, and the Orinoco. Such rafts could easily carry an assortment of insect, reptile, or mollusk passengers. Some of these involuntary passengers might be able to withstand long weeks at sea; others would die during the first stages of the journey. Probably the best adapted for travel by raft are the wood-boring insects, which, of all the insect tribe, are most commonly found on oceanic islands. The poorest raft travelers must be the mammals, yet even a mammal might cover short inter-island distances.

No less than the water, the winds and the air currents play their part in bringing inhabitants to the islands. With special nets and traps, scientists have now collected from the upper atmosphere many of the forms which inhabit oceanic islands. Spiders, whose almost invariable presence on these islands is an intriguing problem, have been captured nearly three miles above the earth’s surface. Airmen have passed through great numbers of the white, silken filaments of spiders’ “parachutes” at heights of two to three miles. At altitudes of 6,000 to 16,000 feet, and with wind velocities reaching 45 miles an hour, many living insects have been taken. At such heights and on such strong winds, they might well have been carried hundreds of miles. Seeds have been collected at altitudes up to 5,000 feet. Among those commonly taken are members of the Composite family, typical of oceanic islands.

The wide-ranging birds that visit islands of the ocean in migration may also have a good deal to do with the distribution of plants, and perhaps even of some insects and minute land shells. From a ball of mud taken from a bird, Charles Darwin raised eighty-two separate plants, belonging to five distinct species! Many plant seeds have hooks or prickles, ideal for attachment to feathers. Such birds as the Pacific Golden Plover, which annually flies from the mainland of Alaska to the Hawaiian Islands and even beyond, probably figure in many riddles of plant distribution.

Isolated from the great mass of life on the continents, with no opportunity for the cross-breeding which tends to preserve the average, to eliminate the new and unusual, island life has developed in a remarkable manner. On these remote bits of earth, Nature has excelled in the creation of strange and wonderful forms. As though to prove her incredible versatility, almost every island has developed species which are endemic; that is, they are peculiar to it alone, and are duplicated nowhere else on earth.

The strange plants and animals of the Galapagos Islands – giant tortoises, black, amazing lizards that hunted their food in the surf, birds in extraordinary variety – moved Charles Darwin, years after his visit to the islands, to write in reminiscence: “Both in space and time we seem to be brought somewhat near to that great fact – that mystery of mysteries – the first appearance of new beings on earth.”

Of the “new beings” evolved on islands, some of the most striking examples have been birds. In some remote age before there were men, a small, pigeon-like bird found its way to the island of Mauritius, in the Indian Ocean. By processes of change at which we can only guess, this bird lost its power of flight, developed short, stout legs, grew larger until it reached the size of a modern turkey. Such was the origin of the fabulous Dodo, which did not long survive the advent of man on Mauritius. New Zealand was the sole home of the Moa, an ostrich-like bird that stood twelve feet high. Moas had roamed New Zealand from the time of the Pliocene, but they died out soon after the arrival of the Maoris.

Besides the Dodo and the Moa, other island forms have tended to become large. The loss of wing use and even of the wings themselves (the Moa had none) is a common result of insular life. Insects on small, wind-swept islands lose the power of flight. The Galapagos Islands have a flightless cormorant. There have been at least fourteen species of flightless rails in the islands of the Pacific alone.

One of the most interesting and engaging characteristics of island species is their extraordinary tameness, a lack of sophistication in dealings with the human race which even the bitter teachings of experience do not quickly alter. When Robert Cushman Murphy visited the island of South Trinidad in 1913 with a party from the brig
Daisy
, terns alighted on the heads of the men in the whaleboat and peered inquiringly into their faces. Albatrosses on Laysan, whose habits include wonderful ceremonial dances, allowed naturalists to walk among their colonies, and responded with a grave bow to similar polite greetings from the visitors. When the British ornithologist David Lack visited the Galapagos Islands, a century after Darwin, he found that the hawks allowed themselves to be touched, and the flycatchers tried to remove hair from the heads of the men for nesting material. “It is a curious pleasure,” he wrote, “to have the birds of the wilderness settling upon one’s shoulders, and the pleasure could be much less rare were man less destructive.”