Tuesday, June 29, 2010

Shad Migration

The water just upstream from the Shuresville road bridge over Deer Creek sporadically boiled as the early evening darkened. Must be shad I thought, and after a few minutes of looking, confirmed my suspicion: the shad had arrived to spawn, and their tails rapidly beat the shallow riffle into a boil. I needed to get into the water to witness this eons old rite from the perspective of these fish. Shad are in the herring family and are anadramous. Like salmon, they spend their lives at sea and endure an arduous spring journey as they swim inland to spawn in smaller creeks. Many shad are declining in number and some are endangered. Dams, which sever migration routes, and sediments, which cover gravel spawning beds, are the two current reasons for the ongoing lack of recovery.
The negative affect dams had on migratory shad was recognized early. The state of Pennsylvania has required fish passages on dams since the 1800s. Unfortunately, the passages installed were poorly designed and did little to restore fish migration routes. Even today, many passages are only marginally effective. A steady increase in the number of shad traveling through the Conowingo dam was celebrated in the years following the installation of a second fish lift, a kind of elevator that carries fish 100 feet up where they swim under route 1 into the water behind the dam. I thought shad were going to be the second fisheries success story of the Chesapeake Bay, behind rockfish. But then the numbers of shad passing through Conowingo significantly declined and demonstrated how interconnected all things are. Menhaden are an oily fish that are taken in huge numbers from the Chesapeake in what is effectively an unregulated fishery. They are turned into fertilizers and cosmetics and are a staple part of the rockfish diet. It has been theorized that as menhaden numbers decline, rockfish are eating more shad, which results in a decline in the number of shad making their way back up the Susquehanna.
Historically, ridiculously huge quantities were fished from our rivers. There are stories and pictures of a net strung across the entire mouth of the Susquehanna that captured a large part of the migration, back when we called these fish resources and thought they were inexhaustible. There aren’t any dams between this stretch of Deer Creek and the Atlantic, so shad can make the 175 mile journey from the ocean to this riffle unimpeded by concrete walls. These fish returned, driven by the primal urge to ensure their immortality by passing their genes on to the next generation. I want to witness this incredible act.
I slip into the water downstream of the shad and fight a heavy current. I don’t see any fish as I crawl my way against the flow. A fisherman from shore directs me to where the fish are spawning - a little further upstream and a little further out in the current. Ghostly blurs appear on my periphery as shad shoot past, then I feel a slap on my shoulder. I am right in the middle of the spawning school. I can barely hang onto the bottom against the current, and shad dart by with effortless but strong tail strokes. It is obvious their compressed bodies and powerful deeply forked tails make them perfectly designed for their reproductive task at hand. Silver tails flash over a particular spot in the stream bed just upstream, as females release eggs and males release sperm while fish continue to rush upstream. From above their olive backs make them invisible against the bottom. From beneath the surface their silver bodies are obvious through the early spring hazy water.
Shad are a kind of teleost fish which, based on the fossil record, first appeared 65 million years ago, so I figure shad have been making treks like this for 60 million years or so. And yet we might take them away in my lifetime. I feel fortunate to have experienced the timelessness of this event, timeless in relation to my fleeting human life span. Knowing these fish are here and spawning this year gives me hope that more will follow, and that maybe the great mythic shad runs I have heard of that occurred before I was born may once again fill our streams. And I hope that maybe my grand kids can snorkel with the descendants of the Deer Creek shad.

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