Not necessarily a "new" idea as past presidents of both parties have proposed the same idea (even Obama)
Trump Admin proposals:
Move the Department of Commerce’s National Marine Fisheries Service (NMFS) to the Department of the Interior (DOI), and merge it with DOI’s Fish and Wildlife Service (FWS). This idea, which has been proposed in various forms over the past few decades, is aimed at streamlining the administration of two major environmental laws—the Endangered Species Act and the Marine Mammal Protection Act. The White House notes that the “jurisdictions under these two laws is generally split based on habitat type, with FWS covering species that spend time on land or in inland fisheries, while NMFS covers mostly marine species. This split jurisdiction … creates a confusing permitting landscape for project proponents.” Dam operators, for example, often have to seek permits from both agencies to operate their facilities.
In 2012, then-President Barack Obama proposed a more sweeping version of this merger, which would have involved moving NMFS as well as its entire parent agency, the National Oceanic and Atmospheric Administration, from the Commerce Department to DOI. But the effort never gained headway.
Conservation groups are not wild about the idea. Although there might be efficiencies to be gained in a merger, “there are also a lot of benefits to having divided authority among executive branch agencies,” says Brett Hartl, government affairs director for the Center for Biological Diversity in Washington, D.C. “One agency can help check an egregious mistake by another.” Hartl also questions the motives behind the proposal. White House officials are “not proposing this because they love endangered species,” he says, but rather because the current “division of power makes it harder to railroad decisions through one agency.”
Interior would also take on certain duties of the Army Corps of Engineers Civil Works, such as flood and storm damage reduction, aquatic ecosystem restoration, and other regulatory activities. This realignment would allow for more rational public policy outcomes and better investments.
Additionally, some of Interior’s environmental cleanup programs would be consolidated into the Environmental Protection Agency’s Superfund program, which would reduce the number of decisions and approvals, eliminate policy inconsistency among agencies, and expedite the cleanup of contaminated sites.