There appears to be some confusion here. The seasonal shrimping restrictions (ban) and the contamination last summer at the shrimp farms are two completely unrelated issues. The shrimping issues are in the papers frequently, but I realize that newcomers or tourists aren't generally able to read the papers or follow the TV news, so here goes.
The ban referred to is quite likely addressing the shrimping season and much like a hunting season it is just that, a limited season for conservation of said species. It is a controversial issue here every fall since tourist season has passed, yet shrimp season has yet to begin. How early the season starts and how late it goes are much awaited dates, and always hotly debated with the shrimpers protesting for a longer season and the conservationists trying to slow down the depletion of marine life.
Shrimping the ocean is a major industry and many families depend on it as their only source of income. Last fall when the season began, they no sooner got out to sea when the threat of a hurricane brought them swiftly back to port delaying the season even further. Much of the shrimp is caught from the middle of the Sea of Cortez south and brought to port in Mazatlan.
Fish farming, which has become big industry recently, now makes up about half of all Mexican shrimp production, and is done in the states of Sonora, Sinaloa and Nayarit.
It seems someone is confusing the "veda" or ban that was temporarily put in place back last summer because of the contaminated shrimp from the shrimp farms in Agua Verde and Caimanero (located south between Mazatlán and El Rosario). A so-called "cerco sanitario" or sanitary fence was implemented so no shrimp could leave.
Those are estuary-raised shrimp and their season is during summer so it would be difficult to get ill from them at other times of the year. Locals believe that the feed used (Purina as it is called here) is what makes them go bad. Incidentally, they are not dangerous if cooked, only if ingested raw in ceviche or Aguachile.
(This post was edited by Marlene on Mar 20, 2005, 1:05 PM)