The Case of the Missing Shad

Submitted by Catherine Schmitt on Wed, 07/13/2016 - 08:45

hand holding a shad fish above water backgroundShad are the largest member of the herring family, which includes Atlantic herring, blueback herring, and alewives. They are among the 12 species of native sea-run or diadromous fish expected to benefit from efforts to restore free-flowing rivers, efforts like the Penobscot River Restoration Project, which recently completed a bypass channel around the Howland Dam, the project’s final milestone.

Shad inhabited most of Maine’s larger coastal rivers, ranging far upriver in search of the fresh water they need to ensure survival of eggs and juveniles. In the Penobscot watershed, Wabanaki ancestors harvested and consumed American shad 8,000 years ago along the banks of the Sebec River. Historical records place them up the East Branch to Wassataquoik Stream, up the West Branch to “Shad Pond” near Grand Falls and North Twin Lake. The Mattawamkeag, Passadumkeag, Piscataquis, and Orland Rivers all had shad. They were the most abundant fish in terms of biomass (estimated at nearly two million fish), and supported a valuable commercial food fishery.

Dams were the death knell for shad, as they don’t have the leaping ability of a salmon or the sheer numbers of the alewife. Faced with a timber or concrete barrier, or the tricky turbulence of a fishway entrance, shad flinch and retreat. And so their population quickly dwindled.

It’s a story shared by other migratory fish that need free passage up and down flowing water to complete their life cycle. By the middle of the twentieth century, most people assumed Maine’s shad were lost.

US Fish and Wildlife chief biologist Clinton Atkinson stated that Maine shad were “almost extinct” in 1951. Bigelow and Schroeder reported that “the only Maine rivers that see regular runs of a few shad are the Nonesuch and the Sheepscot.” US Fish and Wildlife repeated the refrain in 1967: “Shad have all but disappeared from Maine streams.” As recently as 2009, the State considered the Penobscot River shad population a “remnant” numbering in the hundreds.

The shad had gone missing. No one knew where they were.

Would the Penobscot River Restoration Project help shad numbers increase? Were there any shad left?

With Sam Chapman’s shad hatchery in Waldoboro closed due to lack of funding, managers could not “jump start” the shad return with stocking (as they did in the Kennebec). Instead, they had to hope the shad would do it on their own.

Before dam removal, scientists monitored the river with sonar and trawl nets, electrified fishing boats and old-fashioned seines.

Joseph Zydlewski, a fisheries biologist with the USGS Maine Cooperative Fish & Wildlife Unit at the University of Maine, looked for shad. Joe and his student Ann Grote found a few shad, and saw many more on the fuzzy screen of their sonar. Sampling results accumulated. The static came into focus: there were thousands of shad in the Penobscot River, all crowded below the Veazie Dam. Grote conducted nighttime “splash surveys” and observed spawning activity. Confident this was no remnant, she published her findings.

The Veazie Dam was dismantled in 2013; Great Works came out in 2012. Joe continued his studies, taking on Ph.D. student George Maynard.

I heard the rumors of shad.
Shad was a fish I did not know.
I went shad fishing with George and Joe.

I met them early in the morning on June 2 at the public boat ramp in Brewer, Maine. After some unpacking and packing of gear and outfitting of waders and launching of the vessel, we motored upriver toward Eddington Bend.

The aluminum boat was wired: two retractable booms dangling off the bow send 20 hertz of electrical current per second into the water, stunning any fish within six feet of their charged tentacles.

George Maynard is building on the work of Ann Grote, collecting the post-dam removal data. He steered the boat while Joe and I stood in the bow, nets in hand, watching.

The fish were hard to see at first, things were quiet, and then a golden flash as a shad went broadside in the electric current. I fumbled with the long-handled net as Joe snagged the fish.

We paused for sampling. George measured the length of each fish, scraped a few scales for analysis of age and spawning history (unlike shad in the Southeastern states which tend to die after spawning, northern shad will spawn up to six times in their lifetime). He then tagged the fish by inserting a radio device into the fish’s gut. Then, using cars and boats and antennas in trees and on buildings along the river's edge, he'll track the fish, recording the movements of each individual.

Back in the rapids and pools, we saw other fish temporarily stunned by the electrical field: alewives, sea lamprey, eels, suckers. But the shad were big, and shiny. Joe netted a few more, and each time we pulled into an eddy to measure and tag them.

We ventured as far as the site of the former Veazie Dam, whitewater rushing through centuries-old remnants of cribwork and cement, old wing dams and mill channels. Where the dam’s brick powerhouse once stood, a new park greened with the growth of young grasses. The river sparkled and roared.

A loon dove in the rapids ahead of us. A kingfisher swooped along the west bank, and sandpipers poked along the shore.

I did net a shad eventually, and several more. Each one was measured, scaled, tagged, and released, 11 fish in all, bringing George’s total to 61. His permitted limit is 100 fish; after that, he'll wait for the signals to come across the antenna array. He won't have to wait long. The fish are not missing. Maybe they never were.

As of July 11 this year, 7,559 shad had passed through the fish lift at the Milford Dam.
Someday, shad could once again number in the millions.

References

Atkinson, C.E.. 1951. Preface to A Survey of Former Shad Streams in Maine by C.C. Taylor. Special Scientific Report: Fisheries No. 66. Washington, DC: US Fish & Wildlife Service.

Bailey, M.M., and J.D. Zydlewski. 2013. To stock or not to stock? Assessing the restoration potential of a remnant American Shad spawning run with hatchery supplementation. North American Journal of Fisheries Management 33.3:459-467.

Collette, B., and G. Klein-MacPhee. 2002. Bigelow and Schroeder’s Fishes of the Gulf of Maine. Washington, DC: Smithsonian Institution Press.

Grote, A.B., et al. 2014. Multibeam sonar (DIDSON) assessment of American shad (Alosa sapidissima) approaching a hydroelectric dam." Canadian Journal of Fisheries and Aquatic Sciences 71.4:545-558.

Grote, A.B., M.M. Bailey, and J.D. Zydlewski. 2014. Movements and demography of spawning American shad in the Penobscot River, Maine, prior to dam removal. Transactions of the American Fisheries Society 143.2:552-563.

MacKenzie, C., L.S. Weiss-Glanz, and J. Moring. 1985. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic).  Biological Report 82(11.37) TR EL-82-4. Vicksburg, MS: US Fish and Wildlife Service.

Maine Department of Marine Resources and Department of Inland Fisheries and Wildlife. 2008. Strategic Plan for the Restoration of Diadromous Fishes to the Penobscot River. Augusta, ME.

Walburg, C.H., and P.R. Nichols.1967. Biology and Management of the American Shad and Status of the Fisheries, Atlantic Coast of the United States, 1960. US Fish and Wildlife Service Special Scientific Report, Fisheries No. 550. Washington, DC: US Fish and Wildlife Service, Department of the Interior.