Rep. Pete Sessions yesterday pulled a tiny glass jar out of his pocket, holding it up for the members of the House Natural Resources subcommittee to see. Inside sat a number of striped shells, most just a couple of inches long.

"I wanted to make sure that you had an adequate idea of what we're talking about," the Texas Republican said before the Subcommittee on Fisheries, Wildlife, Oceans and Insular Affairs.

Sessions' display began a contentious discussion about H.R. 6007, a bill sponsored by Rep. Ralph Hall (R-Texas) that would authorize water transfers out of Lake Texoma, a lake on the Texas-Oklahoma border that has become threatened by invasive zebra mussels. While the Texas congressmen and community officials supported the bill, the Obama administration came out against it, saying it would set a bad precedent for a federal law.

As much of the United States continues to experience a drought, northern Texas has been hit particularly hard. James Parks, executive director and general manager of the North Texas Municipal Water District, said he has seen the water levels drop at water sources around the region. Water remained more abundant at nearby Lake Texoma, but that supply was cut off when zebra mussels were discovered in its waters.

Along with the Greater Texoma Utility Authority, the water district Parks oversees pledged to build a nearly $300 million pipeline that would transfer water out of the lake to a treatment facility, where the zebra mussels would be killed and the water could be distributed to about 500,000 customers.

"Such a conveyance system would provide safe and dependable means for the district to access water they have legal rights to while ensuring, with 100 percent reliability, that zebra mussels will not be transferred to Texas waters," Sessions said.

One of the main hurdles, however, is that such a transfer is illegal under a federal regulation that prohibits the interstate transfers of invasive species. Because of a recent resolution that fixes the state border between Oklahoma and Texas, the water would actually come from Oklahoma and would fall under the provision.

Hall's legislation would exempt the utility authority and the water district from the regulations, a move that was praised by Mayor Phil Dyer of the northern Texas city of Plano.

But in his testimony, Tom Melius, acting deputy policy director for the Fish and Wildlife Service, said creating a legislative exception would be a bad precedent for the federal law and "must be considered carefully."

"While the facts and policy issues surrounding this complicated water supply and management situation are compelling, the [Obama] administration believes a non-legislative solution is possible and that the precedent set by a legislative exemption to the Lacey Act would be very costly to America's fish and wildlife resources," Melius said.

He explained that a non-legislative way to allow the transfers would be a non-prosecution agreement between the U.S. attorney in the area and the water district.

But Parks called this proposal inadequate, as the agreement would only last for five years and would only prevent one district attorney office in the region from filing charges. This would leave it open for prosecutions by other district attorney offices and the Justice Department.

Rep. Steve Southerland (R-Fla.) called the administration's approach to the situation "dangerous."

"I see this thing where [the administration] chooses to follow this particular law, and this statute we'll ignore, and this one we'll enforce," he said. "It seems like what you're proposing is more of that, and that's awful confusing. ... It's a very slippery slope."

The subcommittee also heard testimony on H.R. 6096, a bill offered by Rep. Jon Runyan (R-N.J.) that would reauthorize a number of Atlantic fisheries statutes. Samuel Rauch of the National Oceanic and Atmospheric Administration said his agency would continue to work with Congress on the proposed measure, as it authorizes new requirements that are not in the administration's fiscal 2013 budget.

Also reviewed by the subcommittee was H.R. 3906, which would allow for fishing in the Block Island sound transit zone off Rhode Island. Rauch said requiring the Commerce secretary to open the area to fishing could limit state and federal law enforcement in the area in the future.