Around 500 scientists from 44 countries have signed a letter urging a moratorium on ocean mining, an activity that researchers say could be adversely affect fisheries, in particular deep-sea catches like tuna.

Scientists made the plea recently after an ocean-mining company and its host country, the Pacific island nation of Nauru, touched off a two-year rule with the International Seabed Authority (ISA), headquartered in Kingston, Jamaica. The two-year rule – triggered by Nauru on behalf of Vancouver, Canada-based Nauru Natural Ocean Resources Inc. – means that time is short for the ISA to set a code on the specifics of seafloor mining.

But researchers like Douglas McCauley, a professor of ocean science at the University of California Santa Barbara, told SeafoodSource that not enough is known about the impacts of seafloor mining on marine life.