The run

When the last adult alewife of the season drops down Stony Brook for the tidal inlet and the sea, it has left the renewal of its continuity and motion behind it. The little alewives follow out the route of their elders with a silent animism, sent by ancient habit and unknown need. The repetitive ways of the anadromous fish come out of geologic time. On the long track since then, the adults, reaching their spawning grounds, have had the drive of the sperm toward the egg. From the top of a falls to the depth of the sea there are equivalent lifts and falls in their own being. The young, tiny and perishable though they may be, have the same inalienable motion in them.

After hatching, young alewives form dense schools, and begin to feed on the plankton—tiny organisms and plant life—in the pond waters. Occasionally they can be seen flipping on the surface. They are subject to attack by all kinds of predators: perch, pickerel, frogs, herons, kingfishers, water snakes, and many others, from the time they are out of the egg. Landlocked waters are often stocked with spawning alewives for that very reason. The fry make an excellent diet for such popular game fish as bass, trout, and salmon.

The survivors begin to move out of the ponds about the beginning of July. In other areas I have heard that the majority do not start down until September. The first time I saw them was on the second of July, when they were being drawn down by the thousands through the dam opening at the head of the fishway. They were scarcely over an inch long, and as they came in from the ponds they reflected the summer-green of the water. Their eyes seemed huge in proportion to the size of their bodies. They were poured down the boiling water of the ladder, tossed around like chips and slivers, spilled down helter-skelter; but where the current slowed, farther down the brook, they held together in the fashion of their race.

There is an account, in a Report of the Alewife Fisheries of Massachusetts, 1921, of some alewives hatched out in the fisheries at Sandwich, Massachusetts, in June of 1919. The eggs were put in water of 72 degrees Fahrenheit and half of the lot, in that warm temperature, were hatched in only forty-eight hours. “In the surface water were thousands of tiny alewives with food sacs nearly transparent in appearance, and with tails resembling fine silk threads. The tiny creatures, about one-fifth of an inch in length, wiggled through the water with surprising activity. The eyes in both the egg and the hatched fish were but faintly visible. At the end of ninety-six hours their size had increased considerably, the outline of the yolk sac and the body was plainly marked, and the eyes showed prominently. By this time all the eggs had hatched. In cold water the period of development is retarded proportionately to the lowering of the temperature.”

In a month the young alewives were about three-fifths of an inch long and by autumn between two and four inches. At three-fifths of an inch they look more like a sand eel than an alewife—an observation quoted in the same report. When they are an inch and a fifth long they look more like the adults. Their bodies are shorter at that size and they have a large head and relatively large eyes. When they reach one and two-fifths inches, about the size of those I saw, they look much the same, but with the addition of the alewife’s sawbelly—“serrations of the middle abdominal scales.”

It may be that in times past little alewives have been unable to migrate out of the waters in which they were hatched, and local races of a landlocked variety were established. The landlocked alewives are much dwarfed in comparison with the salt-water variety. Some years ago there were a number of complaints from householders in New York City that small fish were coming out of the faucets. The Deputy Commissioner of the Department of Water Supply, Gas and Electricity, referred the matter to the New York Aquarium, which investigated and found that these were none other than landlocked alewives: Pomolobus pseudoharengus. They had been spawned in the Kensico Reservoir, and in the autumn they passed through the 5/8-inch mesh of the screens at the outlet. This might suggest the migrating habit of their ocean cousins. A friend of mine, getting the parent stream theory turned around, speculated as to whether a study might not show them returning from the same faucets over a period of years!

But no conclusive evidence was found that these fish were following out any consistent migration. For a period of eight years during the course of the survey hardly any fish were reported as dropping into the kitchen sinks of New York.

One interesting thing about the landlocked alewives is that they are subject to mass mortalities, or “die offs,” for reasons yet undecided. In some areas, like Cayuga Lake in New York State, this happens occasionally, but in others, Lake Ontario, for example, fairly regularly. This does not necessarily happen after spawning, so invites no analogy to the west coast salmon. Many of the dead fish have not yet reached sexual maturity.

As to the normal, coastal migration of the fry from fresh to salt water, why do they leave when they do? Is there any theory that can account for these little fish suddenly moving out of the waters in which they were born, so rich with the fresh-water food that gave them their initial growth? Are they fleeing their enemies? Yet the young of the fresh-water fish are preyed upon too, and they stay behind.

There is an explanation about salmon fry which has them gradually going seaward in order to escape the brighter light in the shallow fresh waters; but is there anything in the constitution of an alewife that is not accustomed to sunlit waters? They do not escape them so much as seek them, because of their warmer temperature. Aside from that, I would think, from my own observation, and the comments of others, that they have no preference between the dark and light along their way—they run through both—but do not like a sudden change. For example, they waited all one morning before coming out of the shaded waters under Stony Brook Road to go into the brightness of the seining pool, only moving when a shadow fell across it that was cast by the old mill.

If the adults swim toward the coast in the spring because of some change in their make-up consonant with changes in the waters where they swim, is there also some change in food and temperature which makes the young start to leave fresh water at a particular time? The little alewives are creatures of such sensitivity to their medium, to its changes, and to what they eat, that a factor in the timing of their migration might be some internal discomfort, or so it was suggested to me. To begin to find out, a scientist would have to follow all the stages of a little alewife’s birth and growth, tracing where it goes, what it eats, and what the temperature, depth, and density of the water is along the way. He would also have to do this for every age group that leaves the three ponds from July through October, analyzed pond by pond, since conditions differ in each one. During this period the little fish leave at all stages in the seasonal development of the ponds, while not all of one age group seem to go with the others. Many appear to stay in the ponds for several months. So attempting consistency with such findings might result in more indigestion for the investigator than the fish themselves.

From the outward evidence all I can say is that these little ones do not start schooling to move out of the ponds until they are over an inch in length. I have seen them, still not much more than pin size, circling a few hundred yards above the outlet, but neither swimming with the flow nor letting themselves be drifted on. Logically then, the point at which they are stimulated to leave must coincide with growth, the rate of which depends on food and temperature in the ponds.

Warm-water ponds are more favorable to growth than cold-water ponds. They turn out better fish, larger and healthier. By the same token a cold spring and summer will result in a poorer crop of alewives. They will probably be hatched later. The colder pond waters will bring down the “plankton bloom,” in other words less food for the fish. As a result, young alewives going to salt water that year will be smaller, weaker, more subject to disease, and less able to escape their enemies.

It is just possible, then, that some spring when the annual run of alewives is smaller than usual, for no apparent reason, you might find an answer to the mystery in a cold season, four years before.

After the first young alewives have moved out, having attained the size and response necessary for it, you can see a gradual increase in size from early summer until autumn. One of the unsolved questions is why the earliest to go will not stay longer in the ponds. Why not relax, if a fish can, and eat well until autumn, as in fact large numbers of them do. Were they nearest the outlet? Perhaps the larger fish that begin to appear later on were hatched earlier and therefore came from farther back in the chain of ponds.

Of course there is nothing rigid about their timetable, nothing exact about their migratory behavior. Whatever stimulates it, their new momentum takes the form of a gradual circling out. I have heard that in some areas they will start down and then return when they can swim back up the outlet, if the force of the water is not too strong for them. They may be in a state of indecisive action for a while, or so it sounds, but most of them are moved to go at some time before winter sets in, though there have been many exceptions to the rule. John Burns, of the Massachusetts Division of Marine Fisheries, tells me that he saw a “generous school of fry” one January, coming down under the ice of a frozen pond at Bournedale.

Perhaps this phenomenon of migration in the young fish is not susceptible of final analysis. Might that be because it is so simple, however complex in detail and circumstance, simple though intangible in the life rhythm it embodies? However slow or fast their response to it may be, the little fish must be obeying an organic, directional drive that goes back beyond history. As a part of their growing up they may develop the same kind of built-in response to the waters in which they find themselves as their parents schooling offshore in the spring; and they come to have an intercommunication that knows its way. It is not the adult call of sexual maturity that moves them, and yet they must have a biological need to start out together on the same living track.

I recognize how much an amateur may leave out of his calculations, and only proffer my individual guess that they follow the outward flow of the ponds when they grow to feel a rhythmic, habitual motion in them that responds to it and that belongs in its balance to the whole race of alewives between land and sea. The fresh-water minnows stay where they are, no matter how hard the pull of the waters may be. I have seen them lazing in the shallows while a school of little alewives darted over them, restlessly moving on. And as I followed the young migrants I saw in them a roaming, roving sweep like sea birds made for distant journeys.

I watched them coming down from July through October and into November, from the lush green of early summer to the red and brown of dry weeks in August, and on to the cool days of autumn when the sea turned a brighter blue and winds and clouds blew full—all the way almost to the hardening in of winter and its sullen skies. The alewife is a part of the life of Stony Brook and the ponds above it for at least seven months out of the year. And the fact that so many return again to the particularity, the uniqueness of these waters is a reminder of the power of living form and place together, the welding of those strands of near and far in the body of a fish, the body of the world. The fish egg rolls around on a greater axis than its own.

So the first of the tiny fish came down by the thousands during the first week in July. After that there was hardly a day until the middle of August when there were not at least a few to be seen in the brook. Gradually they grew larger, so that in August they were up to two inches on the average. The next big movement, after an August lull, began on September 6 and 7. Their size by then had increased to between two and two and one-half inches. A few were considerably larger. I measured one at the surprising length of four and one-half inches, and another, which escaped my net, looked to be well over five.

It was easy enough to get a sampling, because they had a tendency, owing to their very light weight perhaps, to be caught at the bottom of the little falls that poured out of each resting pool in the ladder. They were tossed, turned, tumbled in the bubbling water, flung out from it but returning to be tossed again. On the surface of that turbulence they sometimes managed like gulls riding drafts of wind, but then they would drop down and under and be carried off to the edge once more. This would go on for a long time, although they were very gradually dropping down the brook. Because of this tendency of theirs I was able to scoop them out of the falls with a sieve—although the larger they were the more elusive.

I noticed their absence during a number of cloudy and rainy days in September and their return when the sun shone; which is not to say that I did not see them on overcast days too, but the good days started them going. They responded to warmth like the adults. Beginning in October the next schools of fish coming down had increased in size, so that the average seemed to have gone up to about two and three-quarters to three inches. This movement, off and on, kept up until the end of the month. I saw one last small group coming in to the upper falls on November 16.

In the larger individuals I noticed a wider radius of response, even though they circled with fish much smaller than themselves. They were faster. They were gaining more control, and more apparent ability to see what was coming, my hand or sieve, for example, and to avoid it. These later age groups were not tossed downstream so helplessly as the earlier one-and-a-half-inchers had been. They showed more strength against the current. Yet the motion of them all was consistent with what I had seen in the adults going the same course.

I would see a little gray school of fish circling above the dam between the two outlets, with a beautiful, light swinging, and running by. There might be a sudden split in the middle of them when a leaf fell or a dragonfly touched close to the surface of the water. Then one or two of the tiny fish would fall back over the outlet with an almost electric beat, while the rest stayed. Then four or five more dropped over, and suddenly all the rest spilled over after them. They were tumbled down the first steep ladder; then they followed out the longer stretches farther on, sometimes running with the current, sometimes turning back against it; and on the down side of the road they were caught in the in-boiling waters of the second fishway, before the uninterrupted flow ahead.

A minority came down the side or waste stream instead of swimming down the second fishway, and, because they were not contained there as they were in the resting pools, I could see more clearly what happened to them as they approached a falls. The current was consistently smooth and swift, but it was a long, level, calm stretch of water. I watched them swimming straight down with it and then, quite close to the sudden tug of the high falls, they would turn back. They felt it, and had a quick response to it. It was as though they suddenly had their equilibrium tested, and that they were like trapeze artists feeling wrists, body, and rope, before swinging out and over.

Then down where Stony Brook was broad, shallow, and swift, they ran, or were carried on, like sticks and leaves. Where the water lost some of its force they swam up against it, in little schools together, or they swam off to the side of the main flow for a while, sometimes lingering in deeper water, or the shelter of rocks and banks, but continually returning to it, always a part of that outward seagoing rhythm. Gradually they traversed the swirling, eddying, long-stretching waters. They moved toward the influence of the tides where the brook ran through the marshes. They held position or circled back when the brackish water came in against them. Finally they swam, or were pulled out, from Paine’s Creek on an ebb tide, and moved toward the new shelter of the sea and its many dangers.