keepers?

[Covelo]

The number of naturally spawning fish, or rather unclipped fish since this does not include hatchery fish spawning in the river, may not be dependent on how many unclipped fish are taken by anglers or for that matter how many fish naturally spawn. The limiting factor may be either accessible and suitable spawning habitat and/or the carrying capacity of the lower river. Since most steelhead fry spend at least one year in the river, the carrying capacity of the AR may be what is limiting the return of unclipped fish especially since the lower river experiences temperature problems every summer/fall and the carrying capacity of a stream goes down exponentially with an increase in temperature. It may well be that unless we can get higher releases to keep the water temps down, the number of natural spawners (up to a point) is possibly an irrelevant factor in determining how many unclipped fish return each year.

[Jgoding]

Hi Darian,

I wrote a big ol rant about politics and how our current political situation basically sux but I felt it best to leave it be...

I'm all for conservation and agree with you. I guess the best advice is to enjoy it while you can....

Cloning, I bet there are some companies institutions out there who would do it just for all the PR they would get but yes it would be expensive, but just think about the knowledge gained... it's priceless. Too bad people don't understand this about a lot of the "technologies" we fail to acknowledge and pursue better.

[Darian]

Hi Jeff,..... I have a friend who has a scientific background and is, also, an entrepreneur. He does start-ups, sets 'em on the path and then goes on to another business. What made me bring this up follows:

The business of one of his companies was genetic engineering. Of course, that company had little to do with aqua-culture, but, I'm wondering if you or anyone else could see any potential applications for fish progation that might enhance a natural fishery over time

[Jgoding]

Technology and fishkeeping....I can see a lot of possibilities. Some hatcheries work with triploid strains and even tetraploids I believe. I do believe they come up with them naturally, but they have 3 (triploids) or 4-(tetraploids) copies of chromosomes instead of two. Benefits....fish are sterile.....they grow faster...... Drawbacks.....fish are sterile so they cannot sustain a population themselves, but they are more for a "market" fishery so to say. Tetraploids are not sterile though, as even numbers of chomosomes do segegrate properly during cell division. As I believe if you cross a tetraploid with a diploid (2 copies of each chromosome, normal) you get the resulting triploid-sterile-hybrids...

As far as engineering fish....as it has been with plants, disease resistance would probably be the most important and even some environmental survivability issues (probably heat tolerance). Some species of fish carry resistance to certain pathogens/parasites etc... If they could be identified, it would be a simple matter to import them into other species. Or even certain individuals within a species are resistant to certain diseases/pathogens and you could clone them so they could pass on their genes much faster to help the entire population become resistant as well....Or certain genes that allow for survivability for higher temperatures would also help as well. Growth rates etc... could be enhanced or supressed as well.

But on a more basic level, if hatcheries could somehow monitor the fertilizations and keep track of offspring to limit inbreeding, they would be much better off as well... but this is simply not feasible as it would be hard to track each offspring with the numbers they work with...


But as Covelo says, it all comes down to habitat..... if we managed the habitat correctly we wouldn't have to have these discussions... but the technology could be used to help restore depleted fisheries with a competitive fish in the more competitive environments....

Jeff

[Darian]

HMmmm,..... Disease resistance..... Probably not realistic but how about elimination of whirling disease in Trout.

I do agree that Habitat enhancement/protection is the key. Pressures for development of property and competetition for water being what they are in this state, it's highly unlikely that these things will occur.

[Jgoding]

Whirling disease would be a tough one I think. It's caused by a parasitic nematode (small worm basically) I believe. But if biologists can figure how out other fish avoid infection then it is a possibility. Or if you can figure out something to kill the parasite once it enters the host, that would be the best bet to engineer that into the fish. I think snail eradication in thost infected waters is what's needed though....if I remember the biology of whirling disease correctly...... been awhile, probably 5-6 years at least since I read anything on it.....

Jeff

[RippedLip]

Well guys this has broght me to a summation that what we have is an offspring of our conviction to repair the wrong doing's of man and his water politics (dams). Humm in a nut shell, what naturaly spawning fish that are present is a relative percentage of the overall population, set in stone (sort-of-speak). Never increasing in numbers do to the lack of habitat and most likely of the fish's own self demise. Noting the finite number of reds avialable and in use, and reuse, and over used, shall keep their populous to a set percentage with the lack of successful spawns. Is there a fix?? Not sure... Will introduction or cloned intrevention or stray spawners be the answer?? I think it might be our saving grace... when the hatchery machine depletes the gene pool it's all we have to draw from. So call them natural, wild, etc... angels might be best to describe them. Lets protect them for the children just picking up thier first fly rod today...
Thanks for letting me vent my 2 cents
tight lines...

[Jgoding]

Nice post ripped....here is a question I ask to anyone who may know the answer. Steelhead returning to the hatchery... are they culled as a result of them being stripped of eggs/milt?? Or are they returned to the water?? I am under the impression that steelhead are not one time spawners... am I correct??

Jeff

[Darian]

Hi Jeff,..... Its my understanding that Steelhead may spawn multiple times during their lifetime. I seem to recall a statement, from somewhere, that they may spawn up to five times. Of course, not all Steelhead survive the first return (for whatever reason) So, the average number times is probably much less.

I've been out at the Nimbus Hatchery (15 years ago) when they were taking eggs from Steelhead and spoke to workers there. They said that they placed a mild anesthetic in the water somehow ( ) which calms the fish down after removal from the holding pond. Then they strip eggs/milt and return the spawned out fish back into the holding pens (I've seen that carried out). After the fish recovered in the pens they were returned to the river. I have no idea where/when that occurs.

Since 1974, I don't recall ever catching a spent fish in the AR but that's probably because I rarely fish the AR for Steelhead any longer. Choosing to concentrate on other species, there.

[steeliejim]

I really think that the notion that the "half-pounder" run on the AR is representative of a residual of the native AR steelhead, is a romantic notion that we'd all like to believe is true, but it's highly unlikely. First off, the VA fish typically exhibited a half-pounder component in their respective life histories of about 30% frequency.

The "residual" run of steelhead that many of us are convinced are remnants of the original native steelhead run are not "romantic notions" but based on irrefutable facts.

Now, if you are talking about the half pounders that are caught in the winter, slender immature steelhead from 10 to 14 inches, or the run of football-shaped brightly colored rainbow-looking fish that are caught in August/Sept. I won't argue with you.

But many of us fish for steelhead in the early spring months--middle of Mar. well into April and have been doing so since the 1960's. Those fish are mature adults (very tiny eggs, but would spawn before returning to the ocean), deep-bodied and 3 to 5 pounds.

The proof? DFG's Eric Gerstung wrote a report study of these fish in the early 70's and listed the hatchery return numbers by month starting wiht the first year that the dams were finished. Any returns those first years would be natives. NO steelhead entered the hatchery until March and the run continued through April. It was because the numbers were small and got smaller in subsequent years, that the Eel River straiin was introduced. For many years, DFG ignored this remnant native strain taking all the eggs they could early in the run until they reached capacity, then stopped taking fish, some years as early as Jan. A number of people, me included, were successful in getting DFG to spread the egg take.


Gerstung's report also gives a fascinating history of the AR's steelhead run pre-Folsom/Nimbus dam, pointing out that there was a substantial steelhead run before the power facilility was built in Folsom. There was a fish ladder, but it was washed out in floods and not rebuilt. Still, a remnant of the original run hung on struggling to get past the barrier to the tributaries high in the system.

Further, there was also a spring fishery of what many were convinced were steelhead trapped in Folsom Lake at the inlets (No rubbed fins, silvery) which hasl largely disappeared.

It is unlikely that steelhead came up the AR in the fall, because, as was pointed out, flows pre-dams were very low and warm in the fall until the rains arrived. BTW, I do have a copy of that report somewhere. Perhaps it would be worthwhile to make a copy and get it to Bill for others to be able to look at. It was a great effort and gives great insight to the history of steelhead in the AR and the failings to protect AR fisheries early on.