As aggressive, unregulated fishing continues in the South Pacific, BBC World News will broadcast this weekend a documentary that features the International Consortium of Investigative Journalists’ recent probe into the plundering of jack mackerel, once one of the world’s most abundant fish.

Jack mackerel might not be familiar at the supermarket fish counter, but you have probably eaten it unaware in bites of farmed salmon. Much of jack mackerel is reduced to feed for pigs and aquaculture. It can take more than 5 kilos of jack mackerel to raise a single kilo of salmon.

The ICIJ investigation revealed that greed, mismanagement and lack of regulation have devastated the fishery — it went from 30 million metric tons to 3 million in just two decades.

The world’s largest trawlers, after depleting other fisheries, headed south to scoop up their catch before regulations were passed. But it’s been seven years since efforts started to create a regional fisheries management organization, and key fishing nations still have not ratified the convention, notably Peru, Chile and China.

Without binding limits, industrial fleets bound only by voluntary restraints compete in what amounts to a free-for-all in no man’s water.

The documentary “Looting the Pacific” was produced by London-based tve for BBC World News.

"Looting the Pacific" will broadcast at the following times:

Saturday, April 21, at 9:30 a.m. and 9:30 p.m.

Sunday, April 22, at 2:30 am, 3:30 p.m. (all times GMT)

I set off after the vanishing jack mackerel with trepidation. Who would care? It’s hard to love a bony fish with oddly shaped fins and oily flesh that swims in shoals far away in the southern Pacific. But as oceanographer Daniel Pauly told me, they are the last buffalo. Industrial fleets, moving southward, have hammered one fishery after another. When the jack mackerel are gone, Pauly said, everything will be gone because the expansion will be finished.

Ten months later, I wrapped up tve’s BBC documentary with this alarming but unavoidable conclusion:

“People keep saying we’ll find something else .. We’re at the point where there really is nothing else ... Once these fish stocks collapse, we won’t have them. The only solution is for us to get real, to understand the problem at whatever level and whatever way — to get it, to finally get it that this is not limitless. This is not limitless.”

This was the third and final part of “Looting the Seas,” by the International Consortium of Investigative Journalists. Earlier award-winning installments looked at the Mediterranean bluefin tuna and depredation around the world by Spanish fleets.

Mar Cabra, a Spanish-based ICIJ reporter, dug deeply in Europe and plumbed arcane databases. We relied heavily on two hard-nosed investigative reporting groups, CIPER in Chile and IDL-Reporteros in Peru. I spent a month in South America and then went to New Zealand. In Hong Kong and Holland, I talked to main players: heads of giant fishing companies. On tiny islands at extremes of the earth — above the Arctic Circle and off New Zealand, eccentric ex-sailors showed me how they track fleets that catch jack mackerel.

Members of the Animal Party asked the Dutch government Wednesday to ban catches of threatened jack mackerel that vessels from the Netherlands and other European countries have overfished in the South Pacific.

"For years there have been meetings to bring to a halt the activities of big floating fish factories in whose nets whole soccer stadiums could fit," MP Anja Hazekamp of the Animal Party, said, according to the Dutch daily Trouw. “But there are still no binding fishing quotas established.”

The parliamentary debate was sparked by a recent exposé by the International Consortium of Investigative Journalists (ICIJ), which revealed that European, Asian and Latin American fleets have decimated the jack mackerel population in the once-rich waters of the southern Pacific. The stocks have declined from 30 million metric tons to less than 3 million in just two decades.

The bony, bronze-hued jack mackerel plays an important role in the marine ecosystem as food for bigger fish and is a key component of fishmeal for aquaculture. It can take more than 5 kilos of jack mackerel to raise a single kilo of farmed salmon.

Fleets compete in a free-for-all in the southern Pacific, the ICIJ investigation found, because governments have failed since 2006 to create and ratify a regional fisheries management organization that can impose binding regulations. In the meantime, quotas are only voluntary.

Fishing states meeting in Santiago, Chile, left the way open for fleets to catch jack mackerel far beyond the 390,000-metric ton limit that scientists say is vital to protect the already decimated species. In all, the actual catch could reach a whopping half-million tons.

Asian, European and Latin American nations agreed to limit catches to 40 percent of 2010 levels, a total of about 300,000 metric tons in 2012. But Peru claimed rights to an extra 120,000 metric tons within its exclusive 200-mile zone.

In addition, Chile might not be able to honor its proposed limit because government and industry had already agreed on a much higher quota. And nobody knows what Ecuador will do. The country landed almost 70,000 metric tons in 2011 but took no part in the recent South Pacific Regional Fisheries Management Organization (SPRFMO) negotiations in Santiago. The SPRFMO — an intergovernmental organization charged with protecting fish stocks — has not been ratified, so it cannot impose binding limits.

The International Consortium of Investigative Journalists (ICIJ) reported on Jan. 25 that fleets in an essential free-for-all have reduced jack mackerel from around 30 million metric tons to less than three million in two decades. The bony, bronze-hued jack mackerel is a key component of fishmeal for aquaculture. It can take more than 5 kilos of jack mackerel to raise a single kilo of farmed salmon.