Anonymizing Health Data

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The animals on the cover of Anonymizing Health Data are Atlantic Herring (Clupea harengus), one of the most abundant fish species in the entire world. They can be found on both sides of the Atlantic Ocean and congregate in schools that can include hundreds of thousands of individuals.

These silver fish grow quickly and can reach 14 inches in length. They can live up to 15 years and females lay as many as 200,000 eggs over their lives. Herring play a key role in the food web of the northwest Atlantic Ocean: bottom-dwelling fish like flounder, cod, and haddock feed on herring eggs, and juvenile herring are preyed upon by dolphins, sharks, skates, sea lions, squid, orca whales, and sea birds.

Despite being so important to the ecology of the ocean, the herring population has suffered from overfishing in the past. The lowest point for the Atlantic herring came during the 1960s when foreign fleets began harvesting herring and decimated the population within ten years. In 1976, Congress passed the Magnuson-Stevens Act to regulate domestic fisheries, and the Atlantic herring population has made a great resurgence since then.

Herring fisheries are especially important in the American northeast, where the fish are sold frozen, salted, canned as sardines, or in bulk as bait for lobster and tuna fishermen. In 2011, the total herring harvest was worth over $24 million. Fisheries in New England and Canada do especially well because herring tend to congregate near the coast in the cold waters ...