Researchers from UC Davis, UC Santa Barbara, and Farallon Institute have published a paper that explains northward shifts in the occurrence of marine species normally found in more southern latitudes that took place during the 2014-2016 marine heat wave. Coastal California experienced much higher than normal sea surface temperatures in 2014-2016 first due to onset of warmer-than-normal water produced offshore by “The Blob”, and then from the incursion of warmer water from the south during the El Nino event. Under normal conditions, the coastal current offshore of California primarily flows south. This new paper in Scientific Reports shows that during those years, there was unusual northward flow along the coast. This northward flow contributed to the warm water conditions measured in Northern California and then also to the ability of southern species to be found outside of the northern bounds of their range. The authors explain that this flow brought planktonic larvae of southern species from the south and with the persistent warm water during those years, those species were able to settle and grow much farther north than normal. In the Bodega Bay area, they documented range expansions for 37 species and occurrences of 21 other species that are considered rare in Northern California.
Photo bottom left by Roger Harshaw, bottom second left and far right by Eric Sanford, and all others by Jacqueline Sones.