Neither the Health Ministry nor Peru's oceanographic institute has determined the cause of the deaths, and there is no indication the deaths of the birds and the mammals are related.
And Saturday's warning did not indicate why it might be dangerous to visit beaches. Peru's agricultural safety service ruled out Friday that the pelicans could have died of avian flu, which could be contagious to humans.
Since February, some 877 dolphins and, more recently, at least 1,200 pelicans have been found dead on Peruvian beaches for unexplained reasons.
Local fishermen and restaurant owners said Saturday's warning hasn't had much effect on their businesses.
It's the low season for Peruvian beach-goers, in any case.
A check of Lima's beaches found no dead animals on the shore but sanitation crews were cleaning up an unusually large amount of garbage and debris including plastic bags and bottles and pieces of wood.