Another Fish Question

[flocktothewall]

So a few weeks ago I asked about the orange bellies of small rainbows in a particular drainage.

I returned again to this body of water, and this time I noticed on several occasions, #1 a shocking amount of dead fish, that seemed to be healthy (girth/size wise) as well as a few larger fish, with these conditions:

White fins, white spots, or white growths over their body

Now, I will say, the dead fish I saw did not have these indicators, but a few live fish did.

I snapped a pic, but forgive its quality, it was hard to sneak up on this fish and take a picture of him under water.



If you notice the head and abouts there are white spots, like growths. More than one fish had this.

[WanderingBlues]

Post spawn. The large fish are done, or soon to be done. We saw a massive dead spawner a few weeks back. What I would have given to have C&R'd him in his prime. It would have been a PR for locals.

[NorcalBob]

Ditto what Curtis said. Some studies have shown 50% mortality rates in spawners. The fungal infections (white patches) are typical spawning effects.

[flocktothewall]

That would also likely be an indicator of why we so so many "healthy" dead fish?

[BobK]

All of the big (over20") fish in my pond die once they get the fungus. The water-born spore invades wounds and raw spots caused by making redds and fighting during the spring. Very few of my Browns ever get it and a few of the bigger ones have survived, but most of the time the Rainbows are history. You also find hatchery brooders develop it after being planted up here. I do have Rainbows 5lbs and bigger that have never showed any signs of the fungus. BobK

[8NoFish]

Could the fungus and mortality also be a result of over-handling or poor catch-and-release methods?

[darrin terry]

Could the fungus and mortality also be a result of over-handling or poor catch-and-release methods?

Yes. Just as digging out redds and over crowding in hatchery raceways causes patches of skin where the natural slime has been rubbed away, so too can poor fish handling. Wetting the hands and net before letting them touch a fish reduces this, not laying them on rocks/grass/twigs and such reduces it even more. Using a net made from knotless material or a rubber material is good too. See fish with the white fungal sores on my local every winter. It is always more evident in larger planted fish (I believe because they weigh more/have more strength, they therefor are more likely to hit the sides of the raceways with enough force to cause damage to themselves or the other fish there).

[lucfish]

Interesting observations. I've seen this many times locally and I never put 2 and 2 together. I should have, I've seen it in steelhead and knew the spots were attributed to spawning but never made the connection to the locals. Thanks for asking the question and everybody for their responses.