August 10, 2015 — SAN DIEGO, Calif. — Research by Rebecca Asch, a recent graduate of Scripps Institution of Oceanography at UC San Diego, shows a strong correlation between warmer ocean temperatures and changes in the timing of fish reproduction.

The study, “Climate Change and Decadal Shifts in the Phenology of Larval Fishes in the California Current Ecosystem ,” was published in the July 9 early edition of the Proceedings of the National Academy of Science. This is the first study to examine the effects of temperature, upwelling, and abundance of zooplankton on fish phenology in the Southern California Current ecosystem.

Climate variability has changed the seasonal cycle of larvae production by fishes in the California Current. Such shifts in seasonal, biological processes are known as phenology. Changes in phenology are studied by scientists as a key way to assess the effects of climate change on a species.

There have been extensive studies on the phenology of terrestrial (land) species, but comparatively few studies on how climate variability affects seasonal behavior of marine species. Existing studies indicate that changes in seasonal cycles are occurring earlier in most terrestrial ecosystems. Climate change may cause the phenology of marine animals to change more rapidly than terrestrial species.

Unseasonably warm ocean temperatures may also affect migration patterns, bringing several marine species usually found in regions closer to the Equator closer to Southern California. In February, a pod of false killer whales were seen from the Scripps Pier; this was the first time these whales have been seen north of central Baja California.

Read the full story at Phys.org