In the Arizona desert, a farm raising fish raises questions about water use

DATELAND, Ariz. (AP) — Storks scatter, white against blue water, as Dan Mohring's pickup truck rumbles down the dirt road. He's towing a trailer full of ground-up beef, chicken, fish and nutrient bits behind him, ready to be shot out of a cannon into the ponds below.

It's time to feed the fish.

Mohring fires up the machine and the food flies out in a rainbow arc. Then the water comes alive. Hundreds of thrashing, gobbling barramundi wiggle their way to the surface, all fighting for a piece. Until, in a few months, they will become food themselves.

In the desert of landlocked Arizona, where the Colorado River crisis has put water use under a microscope, Mainstream Aquaculture has a fish farm where it's growing the tropical species barramundi, also known as Asian sea bass, for American restaurants.

Mainstream sees it as a sustainable alternative to ocean-caught seafood. They say chefs and conscious consumers like that the food has a shorter distance to travel, eliminating some of the pollution that comes from massive ships that move products around the world. And they and some aquaculture experts argue it's efficient to use the water twice, since the nutrient-rich leftovers can irrigate crops like Bermuda grass sold for livestock feed.

“We’re in the business of water,” said Matt Mangan, head of Australia-based Mainstream’s American business. “We want to be here in 20 years', 30 years' time.”

But some experts question whether growing fish on a large scale in an arid region can work without high environmental costs.

That question comes down to what people collectively decide is a good use of water. In Arizona, some places manage water more aggressively than others. But the whole state is dealing with the impacts of climate change, which is making the region drier and water only more precious.

The farm uses groundwater, not Colorado River water. It's a nonrenewable resource, and like mining, different people and industries have different philosophies about whether it should be extracted.

“As long as groundwater is treated as an open resource in these rural parts of Arizona, they’re susceptible to new industries coming in and using the groundwater for that industry,” said Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University's Morrison Institute.

Some scientists believe aquaculture can play a role in protecting wild ocean ecosystems from overfishing. And it might play at least a small role in smoothing any supply problems that result from the Trump administration's tariffs on imports from dozens of countries, including those that send the U.S. about 80% of its seafood, per the United States Department of Agriculture.

In the greenhouses at University of Arizona professor Kevin Fitzsimmons' lab in Tucson, tilapia circle idly in tanks that filter down into tubs full of mussels and floating patches of collard greens and lettuce. Fitzsimmons mentored the student who started the tilapia farm eventually bought by Mainstream about three years ago where they now raise barramundi.

“I don’t think desert agriculture is going away," he said. “Obviously, we want to do it as water-efficient as possible."

But not everyone agrees it's possible.

“Artificial ponds in the desert are stupid,” said Jay Famiglietti, a professor at ASU and director of science for the Arizona Water Innovation Initiative. He worried about heavy water losses to evaporation.

Mangan says that evaporation hasn't been an issue so much as the loss of heat in the wintertime. That has required pumping more water since its warmth when it arrives at the surface helps keep the barramundi cozy. But Mangan says they've been improving pond design to retain heat better and have found, after the last year of research and development, that they can cut their water requirement by about half as a result.

Plus, he argues, the water coming out of the fish ponds is "essentially liquid fertilizer," and though it's slightly salty, they use it for crops that can tolerate it, like Bermuda grass dairy cows can eat.

But that's supporting the cattle industry, which contributes more than its share of planet-warming greenhouse gas emissions, Famiglietti said.

“Doing two suboptimal things doesn't make it better,” he said.

Purple flowers sprout alongside paddle wheels. Fish bones crunch underfoot. The faint odor of brackish water and ammonia catches in the breeze.

Without groundwater, none of it would be possible.

Some farmers in Arizona rely on water from the Colorado River, but many others use well water to irrigate crops like alfalfa for the dairy industry or the lettuce, cucumbers and melons shipped nationwide year-round.

Arizona has seven areas around the state where groundwater is rigorously managed. Dateland doesn't fall into one of those, so the only rule that really governs it is a law saying if you land own there, you can pump a “reasonable” amount of groundwater, said Rhett Larson, who teaches water law at ASU.

What might be considered “reasonable” depends from crop to crop, and there's really no precedent for aquaculture, an industry that hasn't yet spread commercially statewide.

Using numbers provided by Mainstream, Porter calculated that the fish farm would demand a “very large amount” of water, on par with a big ranch or potentially even more than some suburbs of Phoenix. And she noted that although the water use is being maximized by using it twice, it's still depleting the aquifer.

When the company scoped out Arizona to expand, Mangan said they didn’t see nearly the same kinds of regulations as back in Australia.

As part of its growth strategy, Mainstream is also hoping to work with other farmers in the area so more can use nutrient-rich fish pond wastewater to produce hay. They say a few have expressed interest.

The seafood industry needs to reduce its reliance on catching small wild fish to feed bigger farmed ones that humans eat, said Pallab Sarker, an assistant professor at the University of California, Santa Cruz, who studies sustainability in the aquaculture industry. He said seabirds and mammals rely on small species like anchovies and mackerel commonly used in fish meal.

“We should not rely on ocean fish to grow fish for aquaculture to meet the demand for humans,” Sarker said.

Mainstream gets its fish feed from two suppliers, Skretting and Star Milling, but Mangan and Mohring said they didn't know for certain where those suppliers got their base ingredients from.

Fitzsimmons, of the University of Arizona, also pointed out that between pollution, overfishing and oceanfront development for recreation, the commercial fishing industry had already been facing problems. He doesn't think that Trump's moves this spring to open up marine protected areas for commercial fishing will improve that situation the way aquaculture could.

“We can’t keep hunting and gathering from the ocean,” Fitzsimmons said.

Follow Melina Walling on X @MelinaWalling and Bluesky @melinawalling.bsky.social. Follow Joshua A. Bickel on Instagram, Bluesky and X @joshuabickel. Follow Annika Hammerschlag on Instagram @ahammergram.

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Artificial ponds for farmed fish operate near crop fields Saturday, April 19, 2025, at a Mainstream USA fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

An adult barramundi reaches for food Saturday, April 19, 2025, at a Mainstream USA fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

Sunlight reflects off artificial ponds Saturday, April 19, 2025, at a Mainstream USA fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

Kevin Fitzsimmons holds a farmed tilapia Sunday, April 20, 2025, at a research lab in Tucson, Ariz. (AP Photo/Joshua A. Bickel)

Groundwater fills artificial ponds for barramundi Saturday, April 19, 2025, at a Mainstream USA fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

Fish food flies into a pond Saturday, April 19, 2025, at a Mainstream USA fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

Juvenile barramundi fish sit in a net Saturday, April 19, 2025, at a Mainstream USA fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

Juvenile barramundi thrash in a pond after being fed Saturday, April 19, 2025, at a Mainstream USA fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

Matt Mangan, president of Mainstream USA, feeds juvenile barramundi fish Saturday, April 19, 2025, at a fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

Matt Mangan, president of Mainstream USA, prepares to feed juvenile barramundi fish Saturday, April 19, 2025, at a fish farm in Dateland, Ariz. (AP Photo/Joshua A. Bickel)

BOSTON (AP) — Alex Bregman’s first game back with the Red Sox since late May had a dramatic flair to it.

Bregman went 1 for 4 with a double off the Green Monster as the Red Sox rallied for their eighth straight win when Ceddanne Rafaela's ninth inning homer lifted them over the Tampa Bay Rays 5-4 on Friday night.

Boston manager Alex Cora said after the game that there are ground rules in place to make sure the All-Star third baseman doesn’t suffer a setback after missing 43 games with a quad strain.

Bregman won’t play on Saturday as the team is taking a long-range view with a player who was sidelined since May 24 when he sustained an injury that occurred when he rounded first base and felt his quad tighten up to the point where leaving the game was the best option.

A clear indication of the restrictions placed on Bregman came in the fifth inning Friday night when he hit a sharp grounder to third base but didn’t hustle down the line.

“When he hits a groundball, he’s not going to go all-out to first,” Cora said. “It might look bad, but we need him healthy and we’re going to keep him healthy.”

It’s a new reality that figures to take some getting used to, since Bregman is known for being a foot-on-the-gas-pedal-at-all-times ballplayer.

“Yeah, it sucks,” Bregman said. “But the first few weeks especially, just got to be smart out of the box. When I first got out there, my legs weighed like five pounds. Later in the game, it felt like they weighed a little more than that."

Bregman returned to his customary spot in the field and was slotted in the No. 2 spot of Boston’s lineup for the second of a four-game series against the Rays. A two-time World Series winner who spent the first nine seasons of his big league career with the Houston Astros, Bregman signed a $120 million, three-year contract in February.

At the time of the injury, he was hitting .299 with 11 homers and 35 RBIs. Those numbers led to Bregman being named an American League All-Star for the third time.

Earlier this week, Bregman said he was trending in a direction where he didn’t believe he would require a minor league rehab assignment. With three games left before the All-Star break, the Red Sox clearly agreed that the time was right to reinstate a player to a team that entered Friday in possession of one of the AL’s three wild-card berths.

“My body feels good. Super thankful to the training staff and strength and conditioning staff for allowing me to get back this quick,” said Bregman. “Initially, we thought it would be more like 12 weeks. To get back in seven weeks is awesome, but we’ve got to take it slow. On the days we’re not playing, we’re going to make sure my full hip complex is staying strong and my hamstrings and quads are good.”

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Boston Red Sox third baseman Alex Bregman dives for the ball on a left field single hit by Tampa Bay Rays' Junior Caminero during the first inning of a baseball game Friday, July 11, 2025, in Boston. (AP Photo/Mark Stockwell)

Boston Red Sox's Alex Bregman runs to second base on an infield double during the seventh inning of a baseball game against the Tampa Bay Rays, Friday, July 11, 2025, in Boston. (AP Photo/Mark Stockwell)

Boston Red Sox's Alex Bregman gestures after hitting an infield double during the seventh inning of a baseball game against the Tampa Bay Rays, Friday, July 11, 2025, in Boston. (AP Photo/Mark Stockwell)

FILE - Boston Red Sox's Alex Bregman heads for the dugout after injuring himself on a single against the Baltimore Orioles during the fifth inning in the first baseball game of a doubleheader on May 23, 2025, at Fenway Park in Boston. (AP Photo/Winslow Townson, File)