I know eating farm-raised fish is not as healthy as eating wild-caught fish. But is eating farm-raised fish better than eating no fish at all? Also, how often is it advisable to eat farm-raised fish? Thanks

A

Experts have raised concerns about farm raised fish, which in some cases are raised on unnatural diets and crammed into small enclosures that can breed disease, prompting aquaculture operators to rely heavily on antibiotics.

But farming practices are improving, and consumers have a number of healthy and eco-friendly farmed options, said Tim Fitzgerald, a scientist and sustainable seafood expert at the Environmental Defense Fund. He said some merchants set high standards for the farmed salmon and other fish they sell, including the supermarket chains Wegmans and Whole Foods and the producer Verlasso.

A few of the farmed varieties that are produced responsibly are also relatively high in omega 3 fatty acids, the polyunsaturated fats that promote cardiovascular health. They include arctic char, rainbow trout and oysters, he says.

Mr. Fitzgerald recommends eating a mix of farmed and wild seafood. “You paint yourself into a corner if you say you don’t want to eat any farmed fish ever,” he said. “It automatically removes 50 percent of the U.S. seafood supply from your choices.” Some good wild options are Alaskan salmon, Atlantic mackerel and sardines.

From a health perspective, farmed salmon is a good choice, said Roxanne Karimi, a research scientist at the School of Marine and Atmospheric Sciences at Stony Brook University. Dr. Karimi has found that both farmed and wild salmon are high in omega 3’s compared to shrimp, tuna and other fish, and they are generally very low in mercury, a particular concern for pregnant women and young children.

Dr. Karimi said that eating smaller types of fish is best. In her research, she has found that people who eat top predator fish like shark, swordfish and marlin have more mercury in their blood but not necessarily more omega 3’s and selenium -- a nutrient that is abundant in fish -- than people who eat seafood that is lower on the food chain, like sardines, shellfish, anchovies and herring.

When buying fish, keep your smartphone handy. You can find very helpful seafood guides on the Monterey Bay Aquarium and Environmental Defense Fund websites.