Science Advisory Report 2013/028
State of the Pacific Ocean 2012
- The global temperature in 2012 was warmer than the 20th century average almost everywhere, but not in the northeast Pacific Ocean where cool waters have been present in almost every year since 2007; this is part of a Pacific-wide weather pattern associated with La Niña conditions of these years.
- An intense bloom of phytoplankton was observed by MODIS satellite in the Gulf of Alaska more than 200 nautical miles west of Haida Gwaii in August 2012.
- Off the west coast of Vancouver Island, the zooplankton community contained more cool-water zooplankton than average, which is associated with good local survival and growth of young salmon and other fish, as well as plankton-eating sea birds.
- Non-Fraser southern Sockeye Salmon stocks continued to exhibit re-building, while those from the central and north coast continued a decadal-scale, sub-average return trend through 2012.
- The number of Pink Salmon returning in even-numbered years, including 2012, tend to be stable, while populations returning in odd years, are generally increasing.
- In 2012, research cruise catch rates of juvenile Chum, Sockeye, Coho and Chinook Salmon were generally higher off the west coast of Vancouver Island and in the central coast than in 2011, while they were at or above the 1998-2012 long-term average for all species.
- A detailed study of Puget Sound waters revealed significant changes in oxygen concentration in waters below 20 metres depth over the past decade, with highest concentration in 2002 and 2012, and significantly lower concentration in 2005 to 2009. These changes correlate well with variations in the strength of upwelling winds off the west coast, suggesting that intrusions of deep coastal water into Puget Sound are a main cause. A longer time series is available for the Strait of Georgia, where oxygen concentration in deep waters over the past half century declined, attributed to similar declines in deep waters on the continental shelf that advect into the strait.
- Phytoplankton in the Strait of Georgia bloom in the late winter and early spring, reaching a peak when they have consumed all nutrients in the surface layer. The timing and duration of this peak of the spring bloom is believed to affect the survival of juvenile salmon and herring. The spring bloom of phytoplankton in the Strait of Georgia in 2012 was later than normal and similar in timing to the previous 6 years.
- Juvenile salmon from the Fraser River generally enter the Strait of Georgia from April to June, many remaining there until the fall. A multi-year study of tagged sockeye salmon smolts exiting Chilko Lake in the Fraser River watershed found consistent early survival patterns among years. Tagged fish moved rapidly through the Strait of Georgia and Queen Charlotte Strait. Large catches of two-year-old juvenile Sockeye Salmon in research trawl surveys in the Strait of Georgia in 2012 resulted from record high returns to the Fraser River in 2010.
This Science Advisory Report is from the February 20-21, 2013 State of the Ocean: 2013 Workshop. Additional publications from this workshop will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.
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