Ocean Conditions Among The Best For Salmon In Last 50 Years

Ocean conditions for chinook salmon and many other species were vastly improved in 2008, mainly because of a huge influx of cold water across the North Pacific Ocean. Scientists who study changes in ocean patterns note that usually cold water conditions last for a few months in late spring and early summer. Since April 2007, the North Pacific has been in a constant “summer-state”, meaning cold, nutrient-rich water. This is something that has not been observed in more than 20 years of sampling. This is in sharp contrast to 2005, one of the worst years on record. Warm, nutrient-poor water in 2005 caused poor conditions for juvenile salmon from California to Washington.

The Pacific Decadal Oscillation, a pattern of varying shifts between warm and cold water in the Pacific Ocean in 20-30 year cycles may be the cause. During 2008, the Pacific Decadal Oscillation was the most negative (cold) it has been since 1955 according to NOAA Scientists at the Hatfield Marine Science Center in Newport.

Cold water, brought in by strong upwelling fuels plankton growth, which in turn boosts the entire marine food web. The phytoplankton feeds the larger zooplankton species which are crucial to the diet of baitfish such as anchovies and herring. Cold water conditions like those present now help zooplankton retain lipids (fat) as a way to survive through the winter. These lipids are an extra energy boost for baitfish and, in turn, salmon.

Marine surveys off the coasts of Oregon and Washington during the summer of 2008 found the highest numbers of chinook salmon juveniles recorded in the last 11 years and nearly 2 ½ times higher than any survey in the past 13 years. These numbers show good ocean survival. On the downside, scientists did not find as many juvenile coho salmon as they had hoped.

Ocean Patterns Changing?
The Pacific Decadal Oscillation has been changing, and scientists want to know if ocean patterns are shifting due to climate change. Changes between cold water and warm water phases aren’t lasting as long as when the patterns were first observed. A phase of the PDO was lasting 20-30 years, and now they’re much shorter. The last phases were 3 years long. So nobody knows for sure how long our great ocean conditions will last.

Feel free to contact me for more information or contact info for the NOAA scientists involved in these studies.

See you on the water,
Action Jackson

(Please send comments or questions to Action Jackson at 268-6944 or www.actionjacksonfishing.com)