Applied California Current Ecosystem Studies (ACCESS)
Research and Monitoring

ACCESS partners have been investigating the spatial and temporal relationships between oceanographic processes, zooplankton, and marine birds and mammals in the region surrounding Cordell Bank and Gulf of the Farallones.

Ongoing surveys started in May 2004. Three to four cruises are conducted annually between April and October. Forty-six (46) cruises have been completed to date and 3 more cruises have been planned for 2017.

Research updates to 2016

You can download our Ocean Climate Indicators Status Report or read our synopsis below.

El Niño / Warm ocean year in 2016

Alongshore winds (strong = blue, weak = red) are responsible for driving upwelling. Winds were moderate to weak for most of 2016, with short periods of strong northerly winds. Other average to warm water years also showed weak alongshore winds (e.g. 2004-06, 2010, 2014-15), while most other years of our study period experienced strong winds in the early months.

The spring transition that marks the beginning of the upwelling season in each year occurred about 10 days later than the average transition date in 2016. Spring transition dates have varied, with earlier dates observed in most years (2006-09, 2012-13), while some of the warmer years had later transition dates (e.g. 2005 and 2010).

Sea surface temperature (cold = blue, warm = red) measured by the NOAA buoy near Bodega Bay showed warm temperatures through mid-2016, then showed signs of cooling in the latter half of the year. In 2004, sea surface temperatures were relatively warm but close to the long-term averages. Warm temperatures were observed in 2005-06, followed by cold surface temperatures in 2007-09. Sea surface temperatures in 2010 were warm early in the year and cold for all other months, and temperatures have remained relatively cold until mid-2014. The anomalous warm water mass known as “the blob” manifested along the central California coast in mid-2014; only in the latter half of 2016 have these warm waters started to cool.

Pacific-scale climate indices have shown great variability in ocean conditions since the start of our research in 2004. Overall, results from 2016 showed a warm ocean state. However, positive NPGO values in early and late months of 2016 indicate a more productive ocean state during these periods. From 2005 to 2009, PDO and NPGO were following opposite trends; a positive PDO and negative NPGO values indicated poor ocean conditions in 2005-06, while a negative PDO and positive NPGO indicated productive ocean conditions in 2007-08. Beginning in mid-2009, both PDO and NPGO have been following relatively parallel trends; a positive PDO and NPGO indicated productive ocean conditions during 2010, despite the year being deemed an El Niño year. These indices showed signs of diverging in mid-2012, but by late 2013, the indices had converged and were indicating warm conditions.

Strong upwelling = more zooplankton

Zooplankton community composition results are not yet available for 2014-16, but results to date illustrate the effects of improved ocean conditions on overall zooplankton abundance, with low abundances in periods of warmer ocean conditions (2004-06; late 2009; early 2010 and 2012) and increased zooplankton abundance (particularly for copepods and euphausiids [also known as krill]) in colder ocean periods (2007-08; late 2010, 2011-13).

Strong upwelling = more adult krill and fatty copepods

Zooplankton communities were different between poor and productive years. Gelatinous zooplankton dominated under poor ocean conditions (2004-06; late-2009 to mid-2010). Northern copepod species (i.e., large, fatty copepods) reappeared in the study region starting in 2007 and tend to be found in higher abundances during colder, productive ocean conditions.

We caught mostly adult krill in Tucker trawl samples during May and July cruises in 2016. These adults were larger than adult krill sampled in the recent warm water years of 2014-15, and they more resembled the size classes observed in other cold water years (e.g. 2007-13) in our time series.

Copepod community composition results are not yet available for 2014-16. Results to date indicate a large increase in the abundance of boreal (northern) copepods during times of cold, productive ocean conditions in our region (e.g. 2007-08; spring/summer of 2009, 2011, and 2013; and summer/fall of 2010). Species common to mid-latitudes (transition zone copepods) also became more abundant in 2007, although not as dramatically; more noticeable increases were seen in 2011. Equatorial copepods (i.e., copepods from southern latitudes) increased in abundance in the September cruises of most years, likely when the equatorward California Current flow relaxed.

Average times for the Cassin’s auklet (the krill-eater)

The Cassin’s auklet, a zooplanktivorous seabird, mainly ate euphausiids (krill) in most years, including 2016. Mysids were the dominant prey in 2005-06 (poor ocean condition years), and the Cassin’s auklet experienced unprecedented breeding failure (see figure below). Increasing amounts of krill in the diet since those years has coincided with increasing productivity on the Farallon Islands since 2007. While krill comprised the majority of diet items identified in 2013 samples, most of these krill were juveniles; the prevalence of these smaller krill (which contain fewer calories than the adult krill) is thought to be the cause of a large young-of-the-year Cassin’s auklet die-off event that occurred in 2013.

Bad times for the common murre (the fish-eater)

The common murre, an omnivorous seabird species, fed on anchovy/sardine and juvenile rockfish in 2016. Common murre diet shows predominantly rockfish in the 1970s and 1980s, then mostly pelagic anchovy and sardine in the 1990s and mid-2000s. Rockfish became the dominate prey under improved ocean conditions (2008-13), although murres are now consuming more anchovy/sardine in recent warm water years. In general, poor ocean conditions correspond to a lower percentage of rockfish in the diet and reduced productivity for murres on the Farallones (see figure below), which includes 2016. Results from 2014-15 (“the blob” years) could be considered an exception to this trend.

Low yet increasing trends for krill and Humpback Whales

We do not yet have the acoustic measurements of krill for 2016. However, results to date show krill in the upper 200 m of the water column varied, with higher abundances in 2004-06 and 2008-11, and lower abundances in 2007 and 2012-15 (with a slight increase since 2013). The apparent high abundance in spring 2006 is due to high abundance of highly reflective gelatinous zooplankton in the water at that time. High krill biomass was observed in 2009 and 2010, despite the later year being deemed an El Niño year.

The Humpback Whale, a main predator of krill, follows very similar patterns to the krill abundance. Years of lower krill abundance (2004-08) have corresponded to low abundance of Humpback Whales in the region. Signs of increasing Humpback Whale abundance began in late 2009, and almost five times as many whales were sighted in the summer and fall of 2010 compared to the first four years of the study. This rise in whale abundance coincided with the great krill biomass observed in 2010. Since then, Humpback Whale abundances declined through 2013, but they appear to be increasing in the region since then. Humpback Whales were observed in record high abundances in 2016, so we look forward to analyzing these results with the krill acoustic measurements when they become available.