Not long ago, 2017 was looking good for the shrimp fishermen of Texas. Fuel prices are low, and—thanks to heavy spring rains and unseasonably high temperatures—federal agencies had predicted above-average shrimp harvests in the state’s portion of the Gulf of Mexico.

But in Brownsville, Texas, a coastal city right across the border from Matamoros, Mexico, many vessels remain tied to their docks during the height of this year’s shrimping season. Their owners have no choice: There’s not enough workers around to help them man their boats.

A shortage of foreign workers has left the local industry reeling, the Brownsville Times reports. But what’s become an urgent local issue originated last year in the halls of Capitol Hill, when the Republican-led Congress failed to pass an exemption to the H-2B visa program. (These visas are for temporary, non-agricultural workers in industries that hire extra staff during peak seasons, like hotels, landscaping, and seafood processing.) The number of H-2Bs available nationwide had been capped at 66,000, but the “Returning Worker Exemption” meant that workers who’d been hired via H-2B between 2012 and 2015 could be brought back without counting towards the limit.

Then Congress didn’t renew the provision in its budget for fiscal year 2017. The exemption expired on September 30, 2016. And for the shrimp fishermen of Brownsville and Port Isabel, it’s a potentially devastating blow.

“The same people that they employed on the visas would come back every year, working for the same people year after year after year,” John Williams, executive director of the Southern Shrimp Alliance, an organization that represents the industry from Texas to North Carolina, tells me. “When they did not return that returning worker exemption, that really put them in a bind.”

That’s because the 66,000 visas are given out on a first-come, first-served basis—but businesses can apply for them with only about a month’s lead time. By the time shrimpers need extra staff in July, many of the H-2Bs have already been snapped up by landscapers and other industries that peak earlier in the year.

Still, the question remains: Why rely on foreign labor in the first place, when plenty of American citizens are looking for work? How is it possible that fishermen in the Brownsville shrimp basin can’t staff their boats when poverty in surrounding Cameron County is up to 32 percent, and unemployment hovers around 7 percent?

It’s not for lack of trying. Andrea Hance, executive director of the Texas Shrimp Association, told the Brownsville Herald that the local shrimp industry would prefer to hire American citizens. The visa program requires a lot of paperwork, and it’s expensive, requiring “a couple thousand dollars” per worker, she said.

The fact is that American citizens simply aren’t willing to do the work.

“A lot of folks just don’t want to do that type of job,” Williams tells me. He explains that shrimp boats are often out on the water for 30, even 40 days at a time. “That’s a long time to be gone from the family and a lot of people just don’t want to do that,” he says, especially to be on a boat. For the unaccustomed, seasickness is an issue. And the work itself—hauling up giant net traps full of shrimp, chopping off their heads by the thousands, and hand-packing them in crates—can be grueling. Williams says that “clocking” is a common practice: working in 24-hour shifts, with only intermittent naps.

Williams thinks that giving these jobs to foreign workers isn’t stealing jobs from U.S. citizens. Americans just won’t take the positions, even when they’re wide open.

For the fishermen he represents, the situation is an emergency that transcends ideological battles on immigration: It’s a simple matter of survival.

“You have a choice,” he says. “You can leave the boat tied up and end up losing your business, or you can work with the system to hire a legal H-2B worker to work on your boat.”

That won’t stop the issue from being politicized. Just this week, the Department of Homeland Security’s decided to raise the cap on H-2B visas from 66,000 to 81,000, citing the need to help businesses in danger of “suffering irreparable harm due to a lack of available temporary nonagricultural workers.” Partisan media decried the decision. The right-wing blog Breitbart (formerly run, of course, by Trump administration advisor Steve Bannon) predictably argued that the decision made businesses less likely to hire and train American workers. ThinkProgress, the liberal news activism site, basically agreed—suggesting the move is a hypocritical betrayal of Trump’s “America First” platform, while also pointing out that H-2B workers can fall prey to low wages and other forms of exploitation.

Meanwhile, in an op-ed in the Houston Chronicle, business columnist Chris Tomlinson points out the irony that scaling back HB-2—far from helping American industry—opens up new opportunities for foreign competition.

“A shortage of Gulf Coast shrimp will be a boon for foreign suppliers who will meet market demands,” he writes. “Serious business people have been warning Congress for years about exactly this kind of unintended consequence from dumb, knee-jerk immigration policies.”

Meanwhile, the increased cap probably won’t help fishermen of the Brownsville Shrimp Basin. According to Williams, they usually make 70 percent of their annual income in the first two or three months of the high season. The clock is ticking: “I’m sure some boats are suffering pretty bad right now.”