On September 23, the US Geological Survey (USGS) announced that unfavorable weather conditions prevented their annual California sea otter population survey.
For the first time in more than two decades, inclement weather prevented researchers from collecting aerial observation data used to assess the vulnerability of the threatened California sea otter. The research team was able to conduct their normal shore-based observations. Both measurements are crucial for calculating the total count for sea otters, so without the aerial observation data a reliable is not possible for this year.
This is very unfortunate news and we are disappointed that USGS was unable to complete the 2011 census results as this is a huge setback to sea otter recovery efforts at a particularly distressing time for the species.
The data collected is used by the U.S. Fish and Wildlife Service to calculate the 3–year running population average to gauge the species’ population recovery progress and whether the California sea otter can be removed from the endangered species list.
So what does this mean for sea otters? This is the question yet to be answered.
USGS has stated that the partial data can still be helpful in tallying next year’s population. Next year’s population? What about this year’s population? How will this impact the 3-year running average this year and for years to come?
We just saw the highest number of recorded deaths of otters in 2010, two years of dramatic declines in the 3-year running average, and now a year with no population count. This is like a one, two, three punch to sea otter recovery.
The spring 2010 survey found 2719 otters, slightly up from the 2009 survey count of 2654 but down significantly from the 2007 count of 3026. The number of dead otters found in 2010 was an all time high of 304. We are concerned about this gap in the population status because if the 2011 strandings (dead sea otters found) report results in another high number of dead otters counted, we could be looking at a serious setback for the sea otter population and recovery efforts, especially not having a complete and accurate count of this year’s population.
So, The Otter Project is very concerned about this news. We use this yearly data to assess how the sea otter population is doing and for our annual status report. We will have to wait and see how USGS interprets the data and how this may impact the 3-year running average.
For a summary of or to access our complete 2011 Sea Otter Status Report, visit our website at www.otterproject.org.
 The U.S. Geological Survey coordinates a team of scientists and volunteers to conduct the population survey, which has occurred annually since the 1980s. The survey is conducted in May and June along the entire coast between San Mateo County and Ventura County. Because of limited coastal access, only about half of that stretch can be counted using shore-based techniques.
 The 3–year running average is the metric the U.S. Fish and Wildlife Service’s Southern Sea Otter Recovery Plan recommends using to assess the sea otter population status, thus reducing the influence of anomalously high or low counts from any particular year.