The run

The change, for those fish that make it in, is from salt to fresh, wide to narrow, deep to shallow. Watched at Paine’s Creek in the first sheltered inland curve, the movement of those I was able to see was like the movement of tides and estuary waters, a flowing back and forth, a waving and interweaving. Some dropped back like leaves, then swam up again with the rest as they all turned together. At the start of an incoming tide—when the salt water moved in under the fresh and the creek began to rise—the fish seemed stimulated and swam faster, back and forth against it. Then gradually, though it was hard to see them in the high tide waters, they appeared to move farther up the inlet.

It was an encounter at the dramatic approaches of sea and land, on the long shoreline where continuous transitions are made between water and earth and air.

If you say the “anadromous habit” started somewhere in geologic time, it is difficult to conceive of, and it is probably not accurate, in the sense that these adaptations to environment do not start so much as develop and evolve. In any event the incredibly long history of the earth is not broken down with any facility. First of all, leaving out the question of whether fish originally evolved in fresh waters or the sea, and then blithely skipping one hundred million years or so, you have an evolved race of alewives, established residents of the sea. As to their habit of spawning in fresh water, it is possible that alewives, like other coastal fish, may gradually have explored the inland rivers and streams, until they began to use their comparative quiet and refuge in which to spawn. Along the northern coasts their inland migration would have been interrupted during the glacial epochs, and their range would have started farther to the south. There are landlocked varieties of alewife in Lake Ontario and in New York State, which also suggests a period when the continental glaciers retreated, leaving an access by water to inland lakes from the sea which was later cut off. In any case this anadromous habit was arrived at gradually, involuntarily, over a very long time. But, in a sense, what you see now, your center of history, is a routine which is neither old nor new but both various and inexorable, having in it the pull of the land, the blood of the sea.

This starting, circulatory movement of the few small schools I had seen was succeeded by the swimming of steady herds in the brown water of the channel. I couldn’t find them at first. On the ebb tide, when the water had receded enough from the banks along the inlet I walked there for a while and then cut across the tidal marsh. The day was cool and fresh, with a light northeast wind lifting in, and it smelled of the sea. (You can live a mile or so inland on the narrow peninsula of Cape Cod, in the towns or oak woods, and never smell that rich combination of salt water, shellfish, and tidal marsh, unless the wind is from the right quarter, with a special condition of the atmosphere.) Light rippled up the broad inlet—the coppery waters seemed to move slowly and reliantly. The season had hatched its enthusiasms everywhere, from flies, to crabs, to birds. The tidal ground was pitted with holes made by fiddler crabs. They backed away in front of me, the males comically holding up their one big claw—little characters of a dull metal-blue, with bubbling mouths—and disappeared into the safety of their burrows. Ahead of me nine Canada geese, which had been resting and feeding in the marshes, unfolded their wings and lunged up and out toward the Bay.

Then two black ducks flew off quacking in their deep, wild way. I saw where a deer had left fresh hoofprints in the mud; looking down at them made me notice many tiny shells, newly hatched whelks perhaps, carried in by the tide, strewn between the stiff spikes of the marsh grass; and I found a couple of empty pint bottles, sometimes as common in these parts as Kleenex beside the highways of America. Insects, shells, ducks, geese, crabs, wind, cloud rack overhead, brilliance and shadows on the tidal ground—many lifetimes of learning. Is there any man who knows the length and breadth of anything, let alone a creek? Yet such a place keeps announcing its novelties and exacting from us whatever love and discipline we are capable of; or so I felt, challenged in the keen air and the high glitter of the light.

Several hundred yards around another bend in the inlet, where it was some twelve to fifteen feet wide, I looked down into the water and saw them again. The dark channel was alive with them. It had a floor of turning, slowly moving alewives. A few at the end of this school would run quickly back, revealing their shadows on the bottom. The procession moved back and forth, as smoothly as the flow of the water, and across the entire width of the channel. They were more numerous in the areas where the sun hit the water directly.

Some of them looked torn and scarred. On that basis, and because many thousands had either been trucked off from the Herring Run in barrels by this time, or had reached the ponds, spawned, and returned to the Bay, you could not say categorically that they were all moving inland. As the season develops you can always find spent fish on their way to salt water running through those still heading up to the spawning areas. Aside from watching their movements, one method of distinguishing between the two classes of fish is to see if they bear any white patches on their backs and sides. A certain number of the spent fish will show fungus growths after a period of time in fresh water. What seems to happen is that an alewife, attacked by a gull or predatory fish or flung against sharp rocks, will at first show a “scaling” from the damage. This scaling, unless it is more than that, a mortal wound, is likely to develop into a fungus growth, which sometimes covers a large part of a fish’s body; but without, apparently, any added injury. I believe experiment proves that the fungus disappears fairly soon after the fish affected are back in salt water.

The returning alewives will stay for a while in the brackish water of the inlet, resting and feeding. They are spare and hungry and will feed on shrimp, small eels, and small fish. Alewives that by chance stay longer than the others in fresh water have been known to chase and eat their own young, if they were small enough to swallow.

Their basic salt-water diet is plankton. The copepods and amphipods—tiny animals similar to the well-known sand hoppers, beach fleas, water fleas, or small shrimp—provide the staple part. On their inland migration they will not eat much of anything. They are in the service of a mission, and they fast. Still there may be occasions when they snap at lures. I have heard of some, migrating inland, that were caught by fishermen casting with flies at the Herring River in Harwich, on the south side of the Cape.

Those herds now in the brown waters of the channel seemed to be gradually moving inland as the day advanced, and I guessed that for most of them it was the journey up.

As I watched them there was a slight, quick change of wind, a shift in the breeze that flicked the water, and in the crosshatches this made on the bright surface all the fish disappeared. Then the surface cleared and I could see them again, swimming through a rippling weave of light that was reflected on the channel floor.

They meandered along, an occasional lively one dashing through the rest, or rushing up to the surface. I could hear light plops, faint flips along the water. I walked closer to the edge so that my shadow fell across them, and they turned back in one quick and graceful stampede, some of them dashing to deeper water under the opposite bank. That so many separate entities should have such an immediate response to one another that they all moved like the beat of a wing was hard for one individual to understand.

Alewives are able to stand the quick change from salt to fresh water without any trouble. It would kill some other kinds of fish, but neither the alewife fry growing up in fresh water nor adults growing up in the sea seem to mind being taken out of one medium and plunged into another. They are adapted to both. On the other hand, repeated changes, such as occur sometimes under certain conditions in tidal estuaries, are said to be able to kill them.

These changes, incidentally, are registered in an alewife’s scales. To read them is difficult and requires a competent biologist. In general they mark physiological changes, such as occur when young alewives go from fresh to brackish water, or when the adults spend some time in fresh water before returning to the sea. An alewife’s age can be determined because a record of each spawning migration is etched on the scales.

I had seen them flashing and swarming inland up in the Herring Run area, but in this wide channel were new motions that needed more patience and information to be understood. For example, where the fish eddied and wheeled under the dazzling rays, I noticed one group idling in front of a submerged sand bar or reef that ran across the channel. I waited there for three-quarters of an hour before the fish showed signs of any common impulse to cross over it. One or two dashed over sportively to chase a minnow and then sped back, but the rest of them—a hundred or more—would make no move. Finally, after many circling approaches by the whole crowd, the measure of their circle came closer and closer out of the brown water to the brightly lit, coppery bar, until some of the vanguard spilled over. Then more and more sped and skittered over until the move was accomplished. Why? Were they afraid of the brightness? Did the contrast in light stop them in some way? This would hardly seem consistent with what I had found out so far. Perhaps it was just routine to their motion. Evidently alewives idle in the deeper channels where the velocity of the water is slower and easier to swim in. They respond to the relative force of the flow. Where the current is more uniformly rapid, and they are going up against it, they progress steadily. And perhaps the bar formed an eddy behind it, so that the water where they swam moved against the current in the channel and they were unable to tell their direction.

The alewife hordes puzzled me as they moved slowly but definitely through the channel. A new animal, moving to unknown needs is hard to understand. You grasp for some translation between you that will not come. Relationships in the water world seem to need other senses than your own. It could be said that to understand the transition of the alewives from salt to fresh water and back you must know about the effect of the endocrine glands on the reproductive system, as well as adaptations of the kidney, along with the temperature, the time of the tides, and the chemical composition of a particular stream—just to begin with. If you are wise and devoted enough to put all the known factors together, you may come out with a unified interpretation, and be abreast of the latest theories of process. Knowledge is the motion by which the human animal may come closest to a fish. Still I looked in my ignorance for another familiarity in which we shared. Where the sea pushed inland and the alewives moved ahead or returned, I saw an indefinite route, of surpassing, complex elaboration; but in their pulse and tempo I felt something that gave me present assurance, and a touch of joy.