Sunday, February 5, 2012


Over the past couple of seasons I've ran into another phenomenon that I haven't seen before. Steelhead missing pectoral fins.  Sometimes these fish are missing one pectoral fin.  Others have both missing.  All are hatchery fish.  Years ago, I would see this occasionally because hatchery fish were once marked this way.
This hatchery fish was harvested in my boat on Friday while working in the 20th annual Umpqua Steelhead Enhancement Derby (my partner and I ended up taking 2nd place with 35 steelhead in two days of fishing the Umpqua system) This fish was caught on the south Umpqua and was not only missing the adipose, but also both pectoral fins.
Not long after we caught the fish missing all the fins, we hooked this fish.  This is what the fin's look like on a native south Umpqua winter steelhead.
Back in December, Justin Crump harvested this hatchery fish while fishing the Umpqua with K8 and I. The port-side pectoral fin is missing from this fish.  Also note the crooked, mis-shapen dorsal fin and missing adipose.

Later that day, K8 caught this gorgeous, perfect native.  Fin's intact, straight and translucent. PERFECT!

When I first started seeing hatchery fish with the adipose missing and a pectoral fin or two missing, I erroneously believed that the fish were strays from some other state, possibly California.  I knew that Oregon hasn't done any pectoral clips for years.

Recently, I've learned that over-crowding of steelhead smolts in concrete hatchery raceways are the culprit.  ODFW is aware of the problem and have made efforts at reducing this problem.  It seems that when too many steelhead smolts are packed into hatcheries, the little fella's get to nippin' at each others fins causing them to be bitten off.  I'm not sure why they target the pectoral fins only and not other fins, perhaps its because of the pectoral fins proximity to their eyes?  Might explain why it seems flies with "eyes" seem to outfish flies without? Just another thing to ponder during the middle of the night when I can't sleep, thinking about steelhead!  

I've spent a fair amount of time thinking about these missing fins.  This has brought to the forefront more questions and points to ponder.  I haven't come up with any answers to these thoughts, but I wanted to share them.  Why don't we see this phenomenon with hatchery Salmon?  I've seen bent, crooked and mis-shapen fins, but not missing fins - other than the adipose fin intentionally clipped by hatchery personnel on coho and chinook.  Could it be that steelhead are just more aggressive than salmon?  Could it be that Steelhead just don't do as well as Salmon in crowded raceways?  Why don't we find hatchery steelhead on other rivers missing fins? Its only on the Umpqua and its only the past couple of years?  I don't recall EVER seeing this on hatchery fish we've caught on the Siuslaw, Alsea, Siletz, Wilson, Willamette and McKenzie.  
As I said, ODFW is aware of the problem and they have addressed the issue by taking some Umpqua hatchery smolts to the Cole Rivers hatchery to be raised prior to release in the Umpqua to help spread the little guys out a bit.  They're hoping this will alleviate the problem.  Time will tell.

1 comment:

  1. The case of the missing fins, by Sherlock Dean!!! Awesome work Dean, I'll be curious to see the end results. We miss you!