The following is an exclusive interview with Professor Dave Checkley of the Scripps Institution of Oceanography. He spoke with us regarding the mass of anchovies seen off the coast of San Diego recently. The behavior is considered odd because northern anchovies typically prefer colder waters over that of warm coastal waters. You can also read more about the mass of anchovies here.

How could the increased number of anchovies near shore impact the shallow water ecosystem and people living around the area?

Minimally, if at all. The anchovy visible nearshore off La Jolla Shores last week are elsewhere today, likely further offshore. Thus, their presence nearshore was ephemeral and unlikely to have any lasting effect on the ecosystem or humans within it.

Has there been any incident similar to this in the past?

I have not seen such aggregations in my thirty years here since 1970 (as a PhD student 1970-78, professor since 1992). Others say similarly. However, a long-time expert on anchovy, Paul Smith, now retired from NOAA, said last week that he has seen such aggregations multiple times from his past office overlooking the sea off La Jolla Shores, arguably the best vantage point. Hence, such aggregations are not unprecedented but are rare, at least in recent (last twenty years) time.

What possible connection could there be between the anchovies and the “impending El Nino,” as you called it.

The ocean off southern Baja California has warmed in recent months, likely associated with the developing El Niño. In recent weeks, further warming appears to have occurred off Southern California. Again, I can only speculate that this is associated with the developing El Niño. This warm water offshore may have compressed anchovy nearshore. In fact, last Tuesday’s intense aggregation of anchovy near the surf zone off La Jolla Shores coincided with a brief and slight, but significant, cooling. Anchovy seeking cooler water nearshore may have formed this rare aggregation.

Could there be any other logical explanation as to why the anchovies would venture into near-shore waters?

Not that I am aware of.