"There are twelve different agencies that deal with exports. There are at least five different entities that deal with housing policy. Then there's my favorite example: the Interior Department is in charge of salmon while they're in fresh water, but the Commerce Department handles them in when they're in saltwater. And I hear it gets even more complicated once they're smoked."
On the Surface he is correct - both NOAA and the U.S. Fish and Wildlife Service share jurisdiction over SOME salmon in a single region of the U.S. Atlantic Salmon - which are currently to be found primarily in Maine - are co-managed by both agencies under the Endangered Species Act (ESA). But if you actually Google their respective websites, you will find that their actions are complementary, and not overlapping. You'll also find that a significant amount of the actual work is done by the state of Maine for both agencies.
Out west, pacific salmon are regulated by NOAA alone, under both the ESA and the Magnuson-Stevens Act (which regulated U.S. Commercial Marine Fishing since pacific salmon can still be commercially harvested). Having learned how hard comanagement was, the Interior Department deferred to NOAA for the ESA, thought they still work closely with the agency on many issues relating to pacific salmon. NOAA has "sole custody" of Magnuson actions, so there is no duplication or overlap there. Bottom line - just because GAO can find the same words describing programs in similar agencies, that doesn't mean there is duplication. Often, programs that sound the same on paper are working on different parts of the same issue.
GAO's work identified three themes at the foundation of DHS's challenges Leading and coordinating the homeland security enterprise; Implementing and integrating management functions for results; and Strategically managing risks and assessing homeland security efforts. This testimony contains no new recommendations.