The next time you’re looking to add some lox to your bagel or perhaps make salmon en papillote, you may have to fork over a bit more cash than before. Salmon populations are down amid recent “acute” outbreaks of sea lice, driving prices upstream.

According to the Nasdaq Salmon Index, salmon prices are at historic highs, reports Quartz, because sea lice — a parasite also known as a sea louse or salmon louse — have been chomping down extra hard on fish populations in Scotland and Norway this year.

Norway, the world’s biggest salmon producer, exported 5% less by volume in 2016 than it did in 2015, while global production fell around 9%.

Sea lice infestations are a pricy problem for the farmed Atlantic salmon industry, costing around $550 million in lost output each year, expert Ian Bricknell from the University of Maine told Quartz.

Adult salmon can handle the lice, but a dozen or so of the parasites can wear down a younger fish’s immune system, opening the door to other infections and ultimately, killing it. And although wild salmon may get a few parasites in open waters, the lice are killed when they spawn in freshwater streams. By comparison, farms — with salmon confined in smaller spaces — can create a breeding ground for the pests.

While scientists are at work trying to come up with various methods of combating such outbreaks, sea lice are likely doing enough damage to create higher prices for consumers in 2017. Maybe you don’t need that second slice of lox, after all.

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