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Monday, July 21, 2008

A Point in Time

I decided to look at some test catch data from the Pacific Salmon Commission to get an idea of how our local runs are doing.

As a scientist, it's important to look at data over a long period of time to get an accurate picture of what's going on. The natural world is a flexible place full of fluctuations that a single snapshot won't capture. Still, sometimes looking at a single data point over several consecutive years can be interesting in its own right.

Here are the test catch results for an area near the San Juan Islands, on July 19th of every year from 2000-2008:
YearEffort*#Sockeye#Adult Chinook#Juvenile Chinook

*It's important to note effort when doing something like a test catch because the amount of time you put in is obviously going to influence the number of fish you catch. If you fish for an hour, you'll obviously be likely to catch more than if you fish for ten minutes. Without going into detail of how they calculate effort, it gives you a rough idea for comparison.

Take from this what you will, but I notice a few things. First of all, there are more sockeye this year than there have been since 2000, which is especially surprising since they predicted an extremely low return this year after a low spawning turn out in 2005. Also, they never catch that many chinook - yet the whales are here anyway, year after year, feeding on them almost exclusively (research suggests).


The K said...

The Oregonian ran this article on Sockeye today. Very interesting to see that some of these fish make it over 400 miles upstream into Idaho, even with the dams.

Monika Wieland said...

Thanks for the article, very interesting!!!