Were the Spanish alert when Dewey arrived?

Were the Spanish alert when the American fleet arrived at Manila Bay?

Yes, as alert as they could be, but damaged ships, missing guns, and ineffective shore batteries severely limited their response.

The Spanish were alert to the American arrival as far as their condition allowed. Several ships lacked the machinery or armament needed to fight effectively. Guns transferred ashore did not ensure effective support, since many batteries failed to fire. Recognizing the threat left Montojo with very limited means of resisting it.