Probably so. Mercury is the key pollutant people think about when considering polluted fish. Mercury toxicity isn’t on the list of top 10 killers in the U.S., but heart disease is.
Heart disease is #1 on the list of top causes of death, followed by cancer and chronic lower respiratory tract disease. “Heart disease” is a broad category; the primary killer is heart attacks.
Eating fish regularly seems to reduce your risk of heart attack. I favor the cold-water fatty fish like salmon, trout, herring, and sardines.
I quote the NYT:
“Numerous studies have found that people who eat fish on a regular basis are less likely to die of a heart attack than those who don’t eat it or eat it less than once a month, and a 2006 Harvard review concluded that eating one to two servings of fish rich in omega-3s every week cut the risk of dying of a heart attack by one-third.”