You need forage fish to turn plankton into food for bigger fish. Take out the forage fish, and the whole food chain falls apart. This story isn’t sexy: people don’t sport fish for sardines. But we rely on these fish to feed — literally — the boom in aquaculture. Environmentalists see aquaculture as a means of reducing open sea fishing. But to feed those fish, we need open sea fishing.

Rough accounting: Looking at forage fish as merely a protein base is crude, but it highlights the value they have in both the biological and socioeconomic ecosystems.

Hard math: Managing fisheries, whether by species or by an ecosystem-based approach, involves counting fish. And counting fish is not easy, particularly due to the cyclical nature of some forage species.

Historically we’ve used menhaden, also known as bunker, for agricultural fertilizer and as an oil to grease the wheels of industry. Today, it’s used to feed livestock, make omega-3 health supplements, and as bait for the fishing industry. But the majority of the menhaden catch goes to one company: Omega Protein. To make fish meal and oil, it operates the Atlantic Coast’s lone menhaden reduction facility in Reedville, Va.

I’ll be watching: In November the fisheries commission will review public comments and consider reducing the menhaden catch by as much as 45 percent from 2010 levels. I’m interested to see the protection levels individual states pursue and Omega Protein’s position.

Back to bite us: Menhaden are small, oily baitfish. However, the species’ collapse could harm the many predator fish that feed on it and, more broadly, marine ecology because it’s a filter feeder that cleans the water.