Monday March 16, 2009

A 5-foot rotary screw trap. Last seen upriver sampling outmigrating young-of-the-year salmonids at 1,300 cfs.


The high river flows occurring throughout most of California right now may be good for fish, but they’re not always so good for fisheries monitoring equipment. This rotary screw trap had a difficult time the other night when flows increased from less than 2,000 cfs to over 15,000 cfs, in only a couple of hours. Generally, high flows created by wet winters benefit fish by providing cool well oxygenated water. This particular river system is known to be “flashy”, with spikes in high flows. So, we knew from the outset that this river might pose challenges.

Although we’ve lost traps in the past for a variety of reasons, including high flows and vandalism, this is not the worst condition we have ever found a trap in. Lucky, the trap was recovered approximately 1,000 yds. down river and sustained relatively little damage. Disassembling the pontoons and other small components was relatively easy, but we then spent the rest of the day digging the cone out of the sand and debris. By the end of the day the trap components were loaded on a trailer and transported back to our FABLAB where repairs are underway. We anticipate the trap will be back in action catching young-of-the-year salmon and trout in a few days.

Photo source: FISHBIO

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