Re: NANFA-- hatchery shad vs. hatchery salmon answer

Christopher Scharpf (
Thu, 24 Feb 2000 17:46:45 -0400

>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.

Yes, they are putting a spin on it. But 100,000 fish crossing a dam's fishway
when few did before is somewhat significant, I think. And a large percentage of
the coming home to spawn are hatchery raised.

>> 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?

No, the Susquehanna itself. The Conowingo Dam is the closest dam to Chesapeake
Bay, about 14 miles upstream.

>If so, are you saying the shad
>numbers are now higher than before the dam nearly wiped them out?

Actually, the dam didn't wipe them out. 200 years of overfishing and small canal
feeder dams and mill dams did. The hydro dams just blocked spawning runs for
good. (Fact: Pennsylvania had shad protection laws on the books as far back as
1700! In 1830, the fishery was starting to decline.)

> Also, we
>can consider that particular stock to be gone now, can't we, since they used
>different stocks to "restore" the run.

Yes, I've wondered about this, too. The realization that shads (American) live
in distinct stocks is fairly recent.

>Where is the Conowingo Dam in relation to the one with the new fish passage
>you said will open all 444 miles of river?

There are 4 or 5 dams on the Susquehanna. Conowingo's was the first to get a
fish lift. The others have followed suit. Before the others got fish lifts, shad
were trucked from Conowingo upstream for 60 miles. (Fun fact: American shad
historically migrated as far inland as Cooperstown, the headwaters of the
Susquehanna. Does that make them the Official Fish of Major League Baseball?)

>Is anyone aware of any published shad tagging study results that might
>answer these and other questions?

I don't know of any off-hand, but I did come across this one fun anecdote. A
biologist was tracking a radio-tagged shad that suddenly seemed to leave the
water and disappear into the air. When he looked up from his notebook, he saw
the fish being carried off in the claws of an osprey!

Chris Scharpf

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