If Bruce's note on run cycles applies to American shad, then these numbers
may not be all that significant. Another thing-- something as simple as
ocean conditions could easily have an effect like this. Reliance on annual
fluctuations are like playing the stock market. Long-term success is the
goal. Surely as those agencies are touting the increase as indicative of
their success, if they'd had a decrease they'd have put a positive spin on
it as well. Sorry if I sound skeptical or flippant.
> The number of shad crossing the Conowingo
> Dam on the Susquehanna have been up from about 50 -- that's
> right, 50! -- fish per year in 1979 to a record 103,000 in 1997.
Is this on a tributary of the Susquehanna? If so, are you saying the shad
numbers are now higher than before the dam nearly wiped them out? Also, we
can consider that particular stock to be gone now, can't we, since they used
different stocks to "restore" the run.
Where is the Conowingo Dam in relation to the one with the new fish passage
you said will open all 444 miles of river?
> >Columbia River? Those shad are introduced from Atlantic drainages. Why
> >take Atlantic fish, transfer them to the Pacific, acclimate them
> >there and use them to seed another Atlantic drainage?
> To mix up the genes, I guess.
I hope that if they introduced all these different stocks to the river that
they did not crossbreed them first. That way if one or two stocks were
truly well-suited to the river's conditions, their success would outpace the
others' and the new run would move faster to adaptation rather than hoping
something good would come out of the gene soup.
Is anyone aware of any published shad tagging study results that might
answer these and other questions?
-- Jay DeLong Olympia, WA
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