Short answers, pulled from the story.
The word sardine entered English in the 15th century via French sardine, from Latin sardina, which traces back to the Ancient Greek sardinos or sardinos. The name may derive from Sardinia, the Italian island, or from the Greek root sardion, meaning red, related to the gemstone sard obtained from Sardis in ancient Lydia.
The FAO and WHO Codex standard for canned sardines recognizes 21 species that may be labeled as sardines. FishBase lists over a dozen species as sardines proper, at least six as pilchards, and many more with compound names. The genus Sardinella alone contains 25 species.
A 100 g serving of canned sardines supplies 185 calories, 21% protein, and 10% fat. The same serving provides 375% of the recommended daily value of vitamin B12, 29% of phosphorus, and about 7 g of combined monounsaturated and polyunsaturated fatty acids.
Pilchard fishing in Cornwall thrived from around 1750 to around 1880, when it went into decline. The catch reached 47,000 hogsheads in 1871 but fell to 9,477 hogsheads by 1877. Cornish sardines gained Protected Geographical Status under EU law in March 2010.
The Stinson Seafood plant in Prospect Harbor, Maine closed on the 15th of April 2010, after 135 years of operation. It was the last large sardine cannery in the United States.
In April 2015 the Pacific Fishery Management Council voted to direct NOAA Fisheries Service to halt the commercial sardine season in Oregon, Washington, and California because of a dramatic collapse in Pacific sardine stocks. The ban affected roughly 100 permitted fishing boats and was expected to last more than a year.