After a brutal spring of toxic algae blooms turning some sea lions into sick, snarling seaside hazards, anxious beachgoers can breathe a sigh of relief as experts say the worst of the poisoning is over. … The California coastline can experience large-scale blooms of algae called Pseudo-nitzschia australis when warm water combines with excess nutrients such as nitrogen and phosphorus. Researchers say that climate change and an increase in agricultural runoff, wastewater discharge and urban stormwater have increased the scale and frequency of these blooms in recent years. Small fish including anchovies and sardines ingest the toxic algae, which then bioaccumulate in larger marine mammals that eat the fish.