There are plenty of fish in the sea, so the old saying goes. But that’s not as true as it used to be: Climate change, pollution and overfishing have slashed global fish populations . Now a new study suggests the problem may be worse than expected. It finds that global fish populations have been overestimated by an average of 11.5 percent — highlighting “that governments need to take more precautions to protect fish populations,” Manuela Andreoni wrote in The New York Times . To reach these results, researchers sifted through nearly four decades of data from 230 of the world's most important fisheries. “We’ve worked across all of these stocks and see this signal that tells us we’re basically overestimating, on average, how much is out there,” Amanda Bates, a marine ecology professor at the University of Victoria and one of the authors of the study, told The New York Times. “And we’re making management decisions based on that.” Scientists’ reactions to the study have been mixed.…