Hermaphroditic steelhead in the Trinity River

A colleague sent me a few very interesting pictures today asking if I noticed anything "peculiar." The pictures are of male hatchery-born steelhead from the Trinity River.  At first I thought he was pulling a late April Fools joke on me, but I don't think so.  These "male" steelhead are hermaphroditic, having both eggs and milt within the same fish.  The eggs look underdeveloped, but the milt looks more mature.

Hermaphrodites in nature aren't exactly a "new" thing, but what's interesting here is the sheer abundance of hermaphroditic steelhead seen in the Trinity hatchery run.  According to my colleague, about 1 in every 10 male hatchery steelhead has turned out to be a hermaphrodite.  Anyone ever heard of such rampant hermaphroditism among salmonids?

That's some crazy stuff right there!  I guess I might see a fish spawning by itself in the future at some point...   

I guess I might see a fish spawning by itself in the future at some point...   

You made me LOL with that one Eric!

Never heard of such rampant hermaphroditism but it can't be a bad thing can it?  An adaptative feature maybe to help the species survive?

Nope, I've never see or heard of anything like this before.
I wonder if it can spawn at all?

Nope, I've never see or heard of anything like this before.
I wonder if it can spawn at all?

I'm wondering the same thing.  It looks like the milt is more developed, so maybe it could spawn as a male...but seeing as there's only half the amount of milt than you'd see in a normal male steelhead, I would think the fertilization rate would be greatly reduced.  I dunno, this is a new one on me as well.  I wonder if this phenomenon is affecting the Trinity's wild fish as well...I hope it's only the hatchery fish, but I guess we won't know.

http://www.scientificamerican.com/article.cfm?id=estrogen-in-waterways

Interesting observation on that steelhead Chris. There have been alot of problems with feminization of males in many fish and wildlife species because of estrogen mimic chemicals in the environment in recent years.  It has been recorded in fish, birds, reptiles that I am aware of.  The article above is one example from Google for fish.  I wonder if it is showing in similar rates (10%?) in wild steelhead?   

I'll ask my brother the fish guy about salmon but many fish are hermaphroditic. If the sex ratios are off some individuals will switch. Seems like I recall the switch is usually one direction. Males - females, not sure though? I wouldn't doubt that estrogen mimics could also trigger it.

Whoa that is really strange. Thanks for sharing.

I  am no longer hungry!