2014 Ocean Indicators Summary
A summary of ocean indicators of the northern California Current for 2014.
Many of the ecosystem indicators for 2014 point towards this being a relatively poor year for salmon survival. The summer PDO values were strongly positive (warm), coinciding with a 'warm blob' of water-centered in the Gulf of Alaska. El Niño conditions were 'neutral,' sea surface temperatures were warmer than usual, and the upwelling season started very late and ended early. The biological indicators featured a high abundance of large, lipid-rich zooplankton but a low abundance of winter fish larvae that develop into salmon prey in the spring, and moderate catches of juvenile spring Chinook salmon during the June survey off Washington and Oregon. Overall, juvenile salmon entering the ocean in 2014 encountered below-average ocean conditions off Oregon and Washington.
PDO and ONI
The PDO switched to positive (warm) in January and stayed strongly positive throughout 2014, following several years of being consistently negative. The ONI transitioned to ENSO neutral conditions with forecasts from the NOAA Climate Prediction Center estimating a >70% chance of an El Niño event this year. In December, the equatorial temperature anomalies crossed the threshold into El Niño-like conditions.
Upwelling Index at 45°N
This year was average in terms of the total amount of upwelling, but the 'season' was significantly shorter than usual, as indexed by the Cumulative Upwelling Index (CUI). The day of spring transition (start of the upwelling season) was on 10 May, which is 26 days later than average (40-year climatology). The upwelling season ended on 20 September (Day 263), nearly three weeks earlier than usual. Despite the late start and early ending, strong upwelling winds in early June and throughout July and August compensated, and overall the total amount of upwelling was nearly the same as the 19-year average.
Sea Surface Temperatures (SST) at NOAA Buoy 46050
The first few months of the year were relatively cool, nearly 1.5°C cooler than normal. A late start to upwelling resulted in warmer than average temperatures through the end of May. Similarly, an early end to upwelling and the presence of a 'warm blob' of water in the northeast Pacific coincided with very warm surface temperatures (2 – 4°C above average) being recorded throughout the fall.
Temperature and Salinity
Water that upwells onto the shelf originates from deep waters just offshore of the shelf from a depth of ~ 150 m. Temperature and salinity characteristics of the deep waters on the shelf are good indicators of the upwelling of deep waters up onto the shelf because usually, these waters are relatively cold and salty. However, bottom waters on the shelf at our baseline station (NH 5) throughout the year of 2014 were quite fresh and relatively warm compared to the previous 17 years. During the summer upwelling months (May through September), the T-S measurements showed that the deep water on the shelf was fresh and warm, in fact, as fresh and almost as warm as 1997 and 1998 when we experienced a strong El Niño and ranked the third warmest and second freshest over the past 17 years. Warm and fresh could be indicators of decreased upwelling in that water upwelled from a shallower depth than usual, and therefore have lower nutrient content. Alternatively, the source waters that upwelled had a different origin point (which is unknown to us at this time). Given that the total cumulative upwelling during 2014 was average compared to the last 17 years, we suggest that upwelled waters did not originate from a shallower depth. Instead, the source waters which fed the upwelling were different.
Low oxygen concentrations were detected earlier than usual again this year. Values below the hypoxia threshold (<1.4 ml L-1) were detected in June but stayed at average levels (~1.5 ml L-1) throughout the rest of the summer. Low oxygen concentrations are often detected through September, but the strong southerly winds that brought an early end to upwelling helped to mix high oxygen surface waters down into the water column. A June survey of coastal waters off the Washington and northern Oregon coast detected hypoxic water over 26% of the shelf north of Newport, Oregon. This is about average for that time of year. There is not likely a direct impact of these low oxygen waters on salmon, as the hypoxia is primarily in the lower portion of the water column and the salmon (especially juveniles) tend to be in the upper portion.
During spring and summer of 2014, the biomass of northern ("cold water") copepods (Figure NSC-01) were moderately high, and the biomass of southern ("warm water") copepods and the copepod species richness were relatively low. However, during the fall, the biomass of northern copepods decreased while the biomass of southern copepods and species richness increased. This likely corresponded to the sign change of the PDO from persistently negative values since the summer of 2010 to positive values throughout 2014. There is generally a lag in the PDO phase and the biological response to different copepod communities. This shift in the copepod community from high biomass of lipid-rich northern species to increased species richness and high biomass of lipid poor southern species indicates warm ocean conditions and a bio energetically depleted ecosystem in the northern California Current.
The winter-time (Jan-March) abundance of larval stages of fish species common in salmon diets was well below average this year, ranking 16th lowest over the 17 years of data. The abundance of all larval fish species combined ranked 15th of 17.
Adult Salmon Returns
The spring Chinook salmon counts at Bonneville Dam (188,078) in 2014 were average compared to returns over the past 17 years. These returns matched our forecast (190,000) based on ocean conditions when these fish entered the sea in 2012. On the other hand, the returns of fall Chinook salmon to Bonneville dam in 2014 were very high (854,478), similar to the record returns in 2013. These high returns far exceed what we expected given the mixed ocean conditions in 2012. However, we note that the correlation of fall Chinook salmon returns with a single index, the northern "cold water" copepods, has improved over the past two years such that nearly 80% of the variation in fall Chinook salmon counts at Bonneville Dam are explained by northern copepods alone.
The Marine Heat Wave
Anomalously warm water dominated much of the North Pacific Ocean for the past year or more, first observed in October 2013 as a mass of warm water that was 30 degrees of longitude wide and 8 degrees of latitude high, centered on the dateline at ~ 40°N. This warm water mass shifted west in November to 45°N and 155°W and 45°N 140W° by December where it was more or less centered through summer 2014. In January 2014, SST anomalies were +3°C above the long-term (1982-2014) average and centered at 42°N°148W (Freeland and Crawford, PICES Press Vol 22 No 2). This warm water mass expanded during the summer months of 2014 such that anomalously warm waters were seen in the Bering Sea and west into the Sea of Okhotsk. This was not a shallow puddle of warm water. Rather the layer was thick – along Line P, warm water was found to depths of 100 m on hydrographic survey cruises in February and June 2014 (PICES Press, 22 No. 2 and 3). This mass of warm water has been named "the blob" by the Climatologist of the State of Washington (Dr. Nick Bond), which is now in common usage.
For waters off Washington and Oregon, the anomalously warm conditions in offshore waters may have influenced the local winds because, as noted above, the start of the upwelling season was delayed, being the second latest start to the upwelling season in 30 years; the length of the upwelling season was among the shortest in recent times. Once upwelling was established (in mid-June), relatively cool ocean conditions were observed all along the coast from Vancouver Island south to northern California but off central and southern California, the coastal ocean was anomalously warm during summer 2014. In late September, northerly winds ceased, and the "blob" came ashore, and the copepod community immediately changed from a 'cold water-upwelling assemblage' to a 'warm water assemblage. Notable unusual copepod species included Rhincalanus nasutus, Clausocalanus furcatus, and Centropages bradyi, species that, apart from one or two other occurrences, have not been seen in coastal waters of Oregon since the 1998 El Niño event.
Major impacts on commercially important salmonid fisheries will not be known for a year or two, but early signs suggest that the warm water was not harmful to some stocks. For example, record returns of pink salmon have been forecasted for 2015 for fish returning to southeast Alaska (Joe Orsi, NOAA Fisheries, Auke Bay, Juneau, AK). Forecasts for the northern California current are for below-average returns for Chinook and coho salmon returning to the Columbia River in 2016 based on analysis of our 16 physical and ecological indicators. However, this forecast is based only on WA and OR conditions and does not consider any potential influence of conditions in the Gulf of Alaska.