25 March 2015 (Desdemona Despair) – The Pew Charitable Trusts support excellent ongoing research on the state of the oceans, and recently Pew’s Paul Shively wrote a good story on the current mass-starvation event among California sea lions (“Starving pups: It’s more than a sea lion problem”). Mr. Shively observes that in addition to sardines, anchovies are an important forage fish for sea lions, and:
When sardine populations decrease, scientists have generally seen that anchovies increase, but that does not appear to be happening now.
Desdemona has posted the FAO catch data for sardines, showing that the sardine population is depleted (“Graph of the Day: Sardine (sardinops) depletion, 1950-2012”). Now we can compare with the California anchovy population, which shows a similar depletion curve. So, two of the main forage fish species at the base of the Pacific ocean food web have been fished out by humans. It’s no wonder that sea lions are starving en masse; imagine what other species are suffering as this trophic cascade propagates through the ecosystem.
You can get the data and related graphs here: Anchovy (Engraulis) landings FAO.xlsx