Speaking very technically, taking (2) to be true (A massive algae bloom starved the dolphins) does not necessarily end our search. While the dolphins may have been starved, could something else not have killed them while they were starving? An analogous situation would be one dying of a gunshot wound while they had the flu. You may very well think that the flu was the cause of their death (or caused the thing which causes their death), but we should be careful about assuming that one thing (however likely for death) guarantees their death, especially when an intervening phenomenon may break the chain of causation. This may be a pedantic point, but one I found worth mentioning.