Afishinado - your Pohopoco answer

[Mike]

RT most likely do not occupy the same niche as BT, although there is probably some overlap. As such, competition is reduced. For instance, and this is a simplified example, you have probably noticed that a general observation is that RT will occupy faster flowing water than most BT, yet there is overlap of their populations in certain slower velocities as well.

In Pohopoco, my observation was that the fingerling stocked RT were in better condition and they clearly appeared to be growing much faster than the naturally occurring BT, at least during the first stocking year's evaluation. That may be more of a general characteristic of RT than a reflection of their ability to compete with BT, however. They grow faster in hatcheries as well where there is not shortage of food.

The stocking of RT fingerling as I recall fell into two possible PFBC programs at once. First, there was a desire to implement fingerling stockings instead of adult stockings in some waters and AFMs were to experiment with this. Second, there was the charge to the staff to further look into tail-race management. This could include fingerling stockings. I do not know whether the tail-race mgmt interest came into play at Pohopoco as I am not the AFM there, but the fingerling RT stockings were a trial and were being evaluated during the past two years' surveys.

Finally, I have been assured on many occasions that Pohopoco is popular with stocked trout anglers. That is presently a consideration in its management.

 

[salvelinusfontinalis]

Mike,

First let me apologize to you. Iam sorry. Sometimes during discussions that I am passionate about I can be a bit over bearing.
Hope you accept that, as I do mean it. In the future, I will try to be more respectful.

As far as your post I have a few questions after reading this link:
Link

RT most likely do not occupy the same niche as BT, although there is probably some overlap. As such, competition is reduced. For instance, and this is a simplified example, you have probably noticed that a general observation is that RT will occupy faster flowing water than most BT, yet there is overlap of their populations in certain slower velocities as well.

Are you guys sure about this? From the link:

The rainbow trout has been observed living at both deep depths in stream and river columns, while also feeding close to the surface. This shows that the trout is adaptable to varied conditions in its habitat, but it also demonstrates a deviation from the behavior of natural populations, whose individuals primarily occupy the base of the water column. It has been suggested that this strange behavior is a result of 100 years of domestication of the rainbow trout in fisheries.

It would seem to me that after all the cross breeding the PFBC has done ,this very well may apply to PFBC hatchery fish.
Furthermore:

Reason(s) Why it has Become Established: Rainbow trout is a highly adaptable predator species that, in foreign habitats, has the ability to out compete native fish for food resources (prey) and habitat space. Rainbow trout is prized among fishermen because it puts up a fight when hooked, sometimes leaping into the air from the water's surface while on the line. This behavior may be indicative of an aggressive nature that perhaps lets it dominate the underwater community. While some other exotic trout species, such as the brown trout, have an advantage because they spawn at opposite times from the native fish, the rainbow trout must have an inherent advantage at exploiting resources given a broadly competitive niche.

Not only are they able to out compete most other trout species, haven't PFBC rainbows been bred to breed in the fall? Also didn't you mention the Po as having poor mid column habitat? This would put the high population of fish in a more condensed manner. Rainbow trout are highly adaptive, this would not bode well for the wild brown population.

I dunno mike but I think the PFBC should take a serious hard look at what they are doing to the Po.

Finally, I have been assured on many occasions that Pohopoco is popular with stocked trout anglers. That is presently a consideration in its management.

Resource first please.

 

[Mike]

I think that the points the author(s) make are worth consideration. At the same time, I did indicate that there is probably some overlap in their niches. Perhaps I should have said "at least" some overlap. I will add, however, that we have very few places in Pa where good wild rainbow trout populations have become established, so their long term competitive advantage, if it exists over BT, has not materialized to any great degree. I don't know whether Pa strains are more or less competitive than the western USA strains.

I will reiterate that I am not the AFM for that stream. I will be curious to see what the outcome of the studies will be relative to the direction that the stream's fish population management heads.