American Shad are Running out of Luck

Every spring growing up in Pennsylvania, my grandmother-any many other people of Pennsylvania Dutch descent-would make us Shad and Dandelion. If you haven’t had this delicacy (served over boiled potatoes with generous amounts of mustard sauce and bacon), you’re missing out. Although shad can be an oily fish if not eaten right away, it is a delicate, flaky white fillet, that (according to my grandmother) would purify our blood and give us good luck for the coming year.

American Shad. Photo: USFWS.

American shad (Alosa sapidissima) are an extremely important fish, both culturally and in terms of its role in the ecosystem. Culturally, shad have always been a significant seasonal food source, signaling the beginning of spring, and were at one time used as currency by Native Americans. But their numbers declined as loss of habitat and overfishing depleted their stocks. In spite of numerous recovery efforts, numbers remain unfortunately low. In the early 1900s, commercial landings along the eastern seaboard measured around 50 million pounds. By 1980, they declined to 3.8 million. According to the Atlantic States Marine Fisheries Commission, approximately 349,942 pounds of American shad were landed in 2017 (ASMFC, 2020). Additionally, most rivers have closed to shad fishing, and ocean catches have been largely prohibited since 2005 (Cox and Harp, 2020)

As an anadromous species, shad require freshwater and marine habitats throughout their life-cycle, which means they face a plethora of challenges at nearly every life stage including dams, pollution, and now predation by invasive species. To address some of these challenges,  several mid-Atlantic states have removed dams to increase access to spawning grounds and hatcheries have launched massive efforts to rebuild swindling stocks. In fact, more than 1,000 additional miles of Chesapeake Bay tributaries have been opened to migrating shad since the early 1990s. Unfortunately, where dams remain, shad use installed fish passages at relatively low rates (ASMFC, 2020).

Although many theories exist, scientists are not confident as to why populations have failed to achieve growth since 2005. Among their top hypotheses, however, are the impacts of invasive species such as blue catfish (Ictalurus furcatus) and northern snakeheads (Channa argus) that are likely predating on young shad. When a population remains at a low level, predation impacts are disproportionately large. However, scientists do agree on one thing: opening additional habitat to migrating fish is necessary for the persistence of this species. Scientists and environmental advocates have identified that the Conowingo Dam on the Susquehanna River is a barrier to the largest untapped spawning ground for  fish on the East Coast (Chesapeake Bay Program, 2020). It is the focus of attention for many conservationists because of its status as a barrier to migration, sediment trap, and nutrient leach (ie: the reservoir is full and can no longer contain the pollution from agricultural and other run-off behind the dam). This year, shad passage through the Conowingo dam only lasted four days: operations were delayed due to Covid-19 and prematurely shut down  because northern snakeheads invaded the fish ladder (Wheeler, 2020)

Conowingo Dam. Photo: Chesapeake Bay Program.

Anadromous species like shad are considered indicator species for environmental issues that will eventually impact life in all marine environments. The precipitous shad decline is more than just a cautionary tale, it’s a story that we’ve heard dozens of times throughout the past 30 years with other fish species. It is a call for more dramatic action, such as dam removals (which are proven and effective methods to counter the loss of anadromous species) to take place or else we will no longer be able to share in the rich cultural and environmental benefits that these species provide. I hope future generations can enjoy shad with dandelion like my grandmother shared with me, but in order for the shad to pass on good luck, we need to give the species a fighting chance.

The full 2020 Benchmark Assessment for American Shad can be viewed here: http://www.asmfc.org/uploads/file/5f43ca4eAmShadBenchmarkStockAssessment_PeerReviewReport_2020_web.pdf

References

Atlantic States Marine Fisheries Commission. (2020). Shad and River Herring. Retrieved October 06, 2020, from http://www.asmfc.org/species/shad-river-herring

Cox, J., & Harp, D. (2020, September 30). Shad recovery efforts not paying off, study shows. Retrieved October 06, 2020, from https://www.bayjournal.com/news/fisheries/shad-recovery-efforts-not-paying-off-study-shows/article_db0d59c0-f1e7-11ea-8f6f-7b37af284b72.html

Chesapeake Bay Program. (2020). Conowingo Dam. Retrieved October 06, 2020, from https://www.chesapeakebay.net/issues/conowingo_dam

Wheeler, T. B. (2020, May 29). Snakeheads shut down late-starting shad lift at Conowingo Dam. Retrieved October 06, 2020, from https://www.bayjournal.com/news/fisheries/snakeheads-shut-down-late-starting-shad-lift-at-conowingo-dam/article_6d5a8c22-a057-11ea-a85b-97553e018b62.html


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