American Food and Game Fishes
David Starr Jordan, Barton Warren Evermann
1908

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The shad is very prolific. Single fish have been known to yield from 60,000 to 156,000 eggs, though the usual number does not exceed 30,000. The eggs are very small, semi-buoyant, and usually require 6 to 10 days for hatching, the time varying with the temperature of the water.

Unlike most other fishes shad roe is considered a great delicacy when fried; and ever since the days of George Washington and John Marshall "planked shad" has been regarded as the acme of success in the preparation of a delicious fish for the table. And a planked shad dinner at Marshall Hall, near Mount Vernon, is quite sure to constitute a feature in the spring programme of many Washington societies.
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Depoe Bay Oregon has a BBQ like this one every year. September I believe. It's called the Salmon Bake and has been going on for 60 years or so. BBQ pit looks the same though.

This started down in Texas in the late 1800's. But I noticed those silly Yankees, unlike us Texans, threw the shad aside and ate the planks, which were more flavorful and less bony.

What you have there is a good old-fashioned Maryland Eastern Shore "shad planking."

Shad are cooked as shown, smoked on standing oak boards and basted with the cook's special sauce, served with "beaten biscuits." There are two schools of thought about the menu: some think it exquisite, others think it inexcusable.

The whole ritual sparked an annual Virginia political picnic every April, where pols and their supporters gather to plank some shad and speechify.

[Thanks muchly. I knew someone out there would enlighten me. - Dave]