[Kuma]

The cbc article can be found here: http://www.cbc.ca/technology/story/2007/10/05/trout.html

It's a study based out of the Northwest (Hood River, Oregon) so it's got to be of concern to us.

The gist:

"Research published in Friday's edition of the journal Science shows that hatchery-raised steelhead trout dramatically and unexpectedly lose their ability to reproduce in the wild.

Oregon State University researchers found the reproductive success of trout, a species critical to many healthy aquatic ecosystems, drops by close to 40 per cent for every generation they spend in a hatchery."

 

[newsman]

I read it and I don't buy it. Sounds like more political spin to me. When ever you read a document like that look very carefully at the wording. If you see things that suggest a possible problem while avoiding pending undeniable problems, it is usualy a diversion tactic.

 

[fishortho]

I'm with Newsman........There was a "stunning lack of CONCRETE evidence" with the study and subsequent published report. In, fact, I am not convinced this report has the backing of any other scientists in the area.
It is easy to work on a project for a number of years, and present your findings to your peers for review and support your claim with all "your evidence" but does the community around you support the findings? Presenting something to the Journal of Science is not necessarily a final chapter....There may be many other causes.

Just look at the local salmon/steelhead debate.

First it was the loggers, then it was the commercial fishers(both herring & salmon fishers) then it was the native nets, then it was the sea lice, then global warming, and now we are looking at a few other possibilities.All of these areas had many studies and published reports.

All of them combined likely have an influence and I suspect the lack of reproduction quality in adult fish may also have a number of factors.

The hatchery programs at present, although not perfect have definitely had a positive spinoff, and unless I am missing something, there is a lot more to raising salmon/steelhead than meets the average person's eye.

Ortho 8)

 

[IronNoggin]

It's a study based out of the Northwest (Hood River, Oregon) so it's got to be of concern to us.

Ummmmm... Not Really. The US (specifically the Hood River scenario) employed methods Radically different than those employed here in BC. Simply put: The Hood had a depressed stock (original population) so this was enhanced by a "domesticated" (hatchery) population originating from a completely different system altogether. Subsequent broodstock captures were directed on the offspring of this domesticated stock, over and over again - in effect using hatchery produced domestics in each and every subsequent year's efforts at enhancing production. Not at all suprising to see the serious impacts that genetic drift caused, nor the overall negative effects on the population as a whole.

Conversely, the BC model is based upon utilizing "wild" origin broodstock captured directly from the system requiring enhancement (in the vast majority of cases). Each year care is paid towards avoiding any hatchery produced fish in the broodstock program, rather continuing the use of the "wild" component for that specific river for brood purposes.

And yes, the BC model has it's quirks, for example:
- there is of course the possibility that one would incidentally incorporate something of a mix as brood (wild parent one side, hatchery produced the other);
- Not all systems clipped their entire hatchery production originally, making it difficult to determine individual fish's origins which lead to the distinct possibility of incorporating hatchery produced fish in the broodstock program (Note: largely dealt with today, as most hatcheries do make a serious attempt at clipping all production prior to release.
Yet even with these "faults" the BC system is far and away advanced over what occured on the Hood as to make the comparision between the two one of "apples and oranges". Were this not so, cases such as the Stamp, the Vedder etc would be far more dismal than their current status.

So, in this Man's opinion, hatchery enhancement of steelhead is very much a viable management option here in BC, and plays a signifigant role in augmenting pressured populations.

Could we do more? Of course. But the political will (read time $ and effort) simply ain't there to address the very real concerns of habitat loss and similiar pressures this valuable resource is suffering under. Shamefull really, that the powers that be are content to simply sit idley by and watch the slow disintegration of a world class resource! :wallbash:

Cheers,
Nog

 

[fishortho]

You know, Nog, you got me thinking on the non-clipped fish that were released. How often is DNA testing done to check a fish' original lineage? Does this also play a role in the hatchery programs? ???Seems to me it could play a vital role......Ortho 8)

 

[dinsdale piranha]

i am no scientist, but i would think a hatchery bred steelhead that returns and spawns in the wild, would be subject to the same selection processes as a true wild fish. in other words, over time, a hatchery fish that subsequently spawns in the wild, perhaps generations later, would revert back to something resembling a wild fish.

also, as for natural selection, i would guess that steelhead were, eons ago, subjected to far less predation than they are today (commercial fishing, sports anglers, habitat loss, disease, non-traditional fishing methods, greed, etc). therefore, weaker strains could well have survived where they might not today. do not today's hatchery raised fish face more obstacles to their survival than wild fish did in the past?

personally, i advocate wild fish. but i also recognize hatcheries - at least, today - still have a part to play in perpetuating the resource.

Dinsdale

 

[Kuma]

Nog makes a fantastic point. Starting from smaller numbers in the Hood most definitely would tip the balance of the population towards hatchery fish and narrow the DNA spectrum.

The only "hole" in dinsdale's point is that nets are non-selective by my estimation and would favour very little DNA-wise other than smaller fish that sneak through the holes in the nets. (Tiny east coast cod anyone?) There is most definitely more diverse pressure on them today and fish more tolerant to pollutants and warmer water might be the genetic wave of the future for our salmon. Just speculating....

 

[professori]

There are a couple of points of interest here. One is the lack of understanding what a publication in a peer reviewed publication means. It actually means that people involved in the field under discussion review the research methods, the statistical analysis, and the resulting conclusions to evaluate the trustworthiness of the project. The reason for this is to ensure that the researcher is not rigging the data to bring about a biased result. The end result is that the research should be much more reliable than the considered opinion of a concerned, but not fully informed layman. Unfortunately, a reporter filing a story for a news service, is not likely to use the whole article, so judging the quality of the research and the conclusion based on the news story is fraught with holes. There is almost always a bias in any story reported in a news service, reflecting the general philosophy and bias of the particular news service involved. However, "I read it and I don't buy it." is the slogan of the Flat Earth Society. Bring some rational argument to the table.
The second point relates to IronNoggins response. Nog is correct, that the methods for enhancement used on the Hood are very different from those used here. The results are also demonstrably different. A recent (within the last 6 months) study found that DNA of hatchery salmonids and wild ones was identical. The conclusion was that the methods of collection used in BC (collecting wild stock as brood stock) ensured that the genetic strains remained strong and unaffected by enhancement programs. This was also a peer reviewed study, and as soon as I can track down the original, I will post it.