Seeking to bring the city's medical marijuana dispensary boom under tight control, the Los Angeles City Council decided today to cap the total number at 70, but to allow those that originally registered with the city to remain open.

Under the city's 2007 moratorium on new dispensaries, 186 registered with the city. Officials believe at least 137 of those remain open in their original locations. Under the motion adopted this afternoon, those dispensaries could stay open but could be required to move to comply with the ordinance's restrictions on where they may locate.

Councilman Jose Huizar proposed a cap to ensure that dispensaries would not be concentrated in any one neighborhood. Currently, with no ordinance in place to control their location, dispensaries have clustered in some neighborhoods, such as Eagle Rock, Hollywood and Woodland Hills, drawn by empty storefronts or by proximity to night life.

Urging the city to adopt a low number that it could control, Huizar said that "it is always easier to roll up than to ramp down."

Councilman Dennis Zine argued strongly to give preference to the dispensaries that registered with the city. "I think we should hold true to those that followed the rules," he said

After adopting the cap, the council turned to other aspects of the proposed ordinance. It remained unclear when the entire package might come to a final vote.

City officials say between 800 and 1,000 dispensaries are operating. Most opened in violation of a moratorium that the city failed to enforce and that a judge has recently decided was invalid because the City Council illegally extended it.

Mayor Antonio Villaraigosa had also urged the council to send him an ordinance that would put a firm limit on the number of dispensaries in Los Angeles.

With no data on the number of medical marijuana patients in Los Angeles, council members took the same approach as other cities that have adopted caps: picking a number that sounded reasonable to them. Council members acknowledged that they may have to revisit the issue.

The only other city among the state's 10 largest to impose a cap is Oakland, which has less than one-tenth the population of Los Angeles and allows four dispensaries. Those operations have become extremely successful, splitting about $20 million a year in sales. Berkeley, with a population of 107,000, allows three shops; Palm Springs, population 47,600, two; West Hollywood, population 37,000, four; and Sebastopol, population 7,700, two.

Several of these cities, which set their caps arbitrarily, are now considering raising them.