 Levels of large predatory fish in the global oceans were estimated to be about 10% of their pre-industrial levels by 2003.Large predatory fish are most at risk of extinction; there was a disproportionate level of large predatory fish extinctions during the Cretaceous–Paleogene extinction event 66 million years ago.Creation of marine reserves has been found to restore populations of large predatory fish such as the "Serranidae" — groupers and sea bass.