The US Fish and Wildlife Service is in charge of the National Wildlife Refuge System , which was created in 2010 to, “strategically and collaboratively address… the mounting challenges faced by conserving America’s wild plants, fish, animals and their habitats in our rapidly changing world” (https://www.fws.gov/refuges/). One way in which this is done is by focusing on the natural diversity of an area: “Natural diversity means the existence of all fish, wildlife, and plant populations within a particular wildlife refuge system unit in the natural mix and in a healthy condition for the long-term benefit of current and future generations. Managing for natural diversity includes avoiding emphasis of management activities favoring some species to the detriment of others and assuring that habitat diversity is maintained through natural means, avoiding artificial developments and habitat manipulation programs whenever possible” (https://www.federalregister.gov/documents/2016/08/05/2016-18117/non-subsistence-take-of-wildlife-and-public-participation-and-closure-procedures-on-national). The purpose of these refuges is to maintain a healthy ecosystem, with all elements in the ecosystem participating in the delicate web of life. Thus specifically taking out one species is not allowed for this will disrupt and damage the ecosystem. However there were some issues in Alaska, namely predators were being specifically hunted and thus the ecosystem was being tilted.
Due to these intentions of the US Fish and Wildlife Service and the National Wildlife Refuge System and the problems within Alaska’s refugees, a Federal Regulation (81 Fed. Reg. 52247) was created that prohibited the hunting of predators, primarily grizzly bears, wolves, coyotes and wolverines, in the National Wildlife Refuges in Alaska by specific means – such as killing the animals over bait, steel leg hold traps, scouting via airplanes (then landing and killing the animals), killing animals in their dens and at specific times – such as denning season (https://www.federalregister.gov/documents/2016/08/05/2016-18117/non-subsistence-take-of-wildlife-and-public-participation-and-closure-procedures-on-national). It should be noted that the regulation did not take away hunting for subsistence reasons (source: same as above).
However HJ Res 69 (https://www.congress.gov/bill/115th-congress/house-joint-resolution/69/text) took away this regulation on the arguments of state’s rights and that somehow this regulation egregiously damaged hunters. The NRA was a massive supporter of this law and lobbied on its behalf (https://www.nraila.org/articles/20170217/nra-backed-resolution-to-stop-obama-attack-on-state-wildlife-management-passes-house) and a lawsuit has already been filed against this law (http://www.environews.tv/042117-center-biological-diversity-sues-trump-signing-hjr-69-allowing-slaughter-bear-cubs-wolf-pups/). To read an article in support of this law: http://www.sitnews.us/0417News/040517/040517_overturning_usfw_reg.html and an article opposing it: https://www.nrdc.org/experts/nora-apter/congress-oks-ruthless-killing-iconic-wildlife-what-next .
As you can probably guess, Feinstein and Harris voted no while Hunter voted yes.