The iconic images belie a troubled reality, with pressures coming for them on land and at sea. For the families involved in the pursuit, bluefin tuna are the defining element of their existence and the key to their economic survival. The series follows the struggles of five fishing boats, their captains and crews, revealing the stunning difficulty of their grueling work lives. There’s nothing high tech about the way they fish; it’s rod and reel, strength and determination. It costs about $3000 to provision a boat for a three-day outing on Georges Bank. They need to catch at least one fish just to break even, more than one if they’re small. Their language is salty, to say the least, and their anger at the elements or at each other is unconcealed. But underneath the “man talk” are a grittiness and entrepreneurial commitment to survive and succeed that is impressive.

National Geographic’s stated goals are to tell the human stories behind the macro descriptions of the fishing industry and to educate people about the increasing scarcity of bluefin tuna. (According to its press material, the adult bluefin population has declined by as much as 83 percent in the Atlantic since 1950.) Marine biologists say it is a victim of overfishing. Governments have tried to set quotas for fish and regulate fishing methods, creating other problems for the fishermen.