I have to admit to being a huge John McPhee fan. His books and essays are always interesting and Founding Fish about the American shad is no exception. McPhee always does his homework, seeking out the knowledgeable and then going further to double-check even their information. For example, one little tidbit is the myth surrounding the role of shad in saving the Revolutionary Army at Valley Forge. The prevailing wisdom, cited in numerous sources is that the shad run was early that winter and without the abundance of fish the army would have starved. Often cited as a source is a letter purportedly by Nathan Hale who, McPhee, points out had died in September of 1776, and so could have had little knowledge of Valley Forge events. (I was pleased to see that the Valley Forge Historical Society does not perpetuate the myth(link.)
The idea that early settlers also feasted on fish appears doubtful even though it was plentiful. Archaeological studies reveal few fish bones except for slaves. It appears that, coming from beef loving England, they were eager to have a beef laden diet in the colonies as well. Washington caught thousands of shad at Mount Vernon, but used them mostly as fertilizer and slave food. It's a bony fish, and like the lobster, took many decades to be accepted as "upscale" in restaurants.
Like salmon, the shad is anadromous (running upstream,) but differs in that while the salmon dies after spawning at the end of its run, the shad can make the trip up and back to the ocean several times.
Only McPhee could take such an arcane subject and weave culture, history, physiology, and natural science so ably together.