FOR American fish, this is a good time to be alive. On May 14th the National Oceanic and Atmospheric Administration (NOAA) reported that a record six federal fisheries returned to health last year. After a decade of similar progress, 86% of America's roughly 250 federally monitored commercial fish stocks were not subject to overfishing; 79% were considered healthy.

This is also good for American fishermen. Commercial and recreational fishing generates an estimated $183 billion a year and supports over 1.5m full-time or part-time jobs. Rebuilding America's 45 remaining over-exploited fish stocks, NOAA estimates, could generate an extra $31 billion a year and half a million jobs.

That is a tribute to America learning a simple truth—that scientists, not fishermen or politicians, should decide how many fish can be caught—and enforcing this with simple rules. It has taken a while. America's main fishery law established the importance of scientific quotas in 1976. Yet this was routinely ignored because of poor science and weak enforcement, abetted by influential fishermen—notably in New England, which was built on once-rich Atlantic cod and haddock fisheries. The Massachusetts House of Representatives contains a conspicuous symbol of this: the “Sacred Cod”, a 200-year-old fish of solid pine, hanging from its ceiling.

Despite this totem, in the late 1980s cod fisheries in the Gulf of Maine and Georges Bank collapsed. This led to efforts to improve the fishery act, in 1996 and 2006, which forced the eight regional bodies that manage federal fisheries to introduce science-based quotas and ten-year recovery programmes for depleted fisheries. The recent recovery of species, including New England scallops, mid-Atlantic bluefish and summer flounder and Pacific lingcod, is the result. This signals another truth: given a break, the marine environment can often replenish itself spectacularly.