Annual California Sea Otter Census: 2016 Spring Census Summary

The spring 2016 mainland sea otter count began on 1 May and was completed on 11 May. Overall viewing conditions this year were very good, being more favorable than those during the 2015 spring census (3.1 vs. 2.6, where 0=poor, 1=fair, 2=good, 3=very good, and 4=excellent) and contributed to the relatively short duration of the count. The surface canopies of kelp (Macrocystis sp.) were considered by most participants to be below normal for this time of year in the northern half of the range and about normal in the southern half. Sea otters along the mainland were surveyed (using a combination of ground-based and aerial-based surveys) from Pillar Point in San Mateo County in the north, to Rincon Point in the south at the Santa Barbara/Ventura County line (Figure 1). A separate ground-based survey of the sea otter population at San Nicolas Island was completed earlier (April 15-April 18). Surface kelp canopies at the time of survey at San Nicolas Island were estimated to be below normal near shore off the western end of the island and about normal elsewhere. Survey viewing conditions were very good (View Score = 3.0).