For one thing, an estimated 400,000 tons of anchoveta caught annually goes unreported. "That's the entire (annual) catch of Spain, or Italy," said Juan Carlos Sueiro, a Cayetano Heredia University economist. It's value: about $200 million.
There are also huge loopholes.
Anchoveta quotas only apply to boats in the commercial fleet that works within Peru's 200-mile territorial waters. Those vessels have been responsible for about 94 percent of the catch.
But when boat-by-boat quotas were imposed in 2008, trawlers under 32 tons were exempted. Unrestricted, their numbers swelled.
"Everybody around here got into fishing. Farmers sell their cattle and get into fishing. Engineers and doctors, they have their profession. But on the side, they buy boats," said Juan Ponce, administrator of the artisanal, or small-time, fishing pier in Pisco, a three-hour drive south of Lima.
With so much overfishing, particularly of anchoveta, fresh fish of all sizes are now scarcer than ever for Peruvians, and seafood prices have risen since 2009 at a rate four times that of other foods.
People "buy more chicken than fish because chicken is cheaper," said Pedro Diaz Sanchez, a wad of bills in his hand thickening as he sells hake by the crate at Lima's Villa Maria del Triunfo fish market.
In fact, whole anchoveta hasn't been available for years. Rendering factories now pay roughly twice as much for anchoveta as wholesalers who cater to human consumption. Peru earns about $2,000 a metric ton for fishmeal and $2,800 a ton for fish oil, a popular ingredient in nutritional supplements, and prices have more than doubled over the past decade.
Local supplies of fish also are hurt by laws that subsidize exports.
"It's cheaper to export fish to Africa than to haul it to Huancavelica," said Carlos Paredes, a San Martin de Porres University economist, referring to a highlands Peruvian province where 55 percent of children under age 5 suffer from chronic malnutrition.
The powerful fishing industry has fought efforts to trim quotas and raise taxes, while some commercial fleet owners challenge in court a backlog of millions of dollars in fines. Last year, fishermen in the northern port of Paita blocked highways and sacked city hall to protest a quota on hake that they considered too low. Two people died in clashes with police.
Hoping to forestall similar unrest, and to get more fish to local markets, the government in September mixed new restrictions on the big anchoveta fleet with incentives for smaller boats. It barred the big, commercial trawlers from within 10 miles of the coast. Previously, the first five miles had been off-limits. Then it created a new category of "medium-sized" boats — between 10 and 32 tons — with exclusive rights to the 5-to-10-mile corridor.
The artisanal fleet of boats of less than 10 tons was given exclusive rights to the first five miles, where most anchoveta spawn.
The government decreed that the small and medium-sized boats would only be permitted to catch fish for human consumption.
But there is blatant cheating amid an almost complete absence of government policing.
At Pisco's artisanal pier on a recent morning, workers removed six tons of anchoveta from the turquoise-hued wooden trawler "El Tio" as pelicans and boobies picked at the scraps.
The oily fish were loaded onto a flatbed truck that navigated Pisco's dusty streets before disappearing through a eucalyptus grove into an illegal fishmeal factory, one of 15 that Sueiro says operate up and down the coast.
Ponce, the pier administrator, said dozens of the 300 boats at his pier similarly sell anchoveta illegally, especially in these slow days of the Southern Hemisphere summer when people aren't catching much else.
"The anchoveta is the only resource available year-round," said Ponce.
Sueiro, the economist, fears it could one day disappear as an industry, as other fisheries have.