Okay, I didn't realize that. However, from what I've read, these hatcheries
are indeed enhancement facilities. Enhancement is a term meaning to produce
fish for harvest. I'm curious why he said they are restoration projects.
I'd take anything these folks say with a grain of salt. This gets back to
Chris' phrase of "reliance on hatcheries" from his initial post on this
subject. The first question I'd ask is "What is the status of the habitat
at this time?" Hatcheries which are designed to restore species
populations, but without also working towards restoring natural
(non-hatchery) spawning, aren't "restoring" anything but fishing
opportunity. Pennsylvania taxpayers are footing the bill for these efforts,
right? What do you folks think the real goals here is?
> 3. Numbers of spawners used for shad is large. Several thousand
> adults are
> used annually for the Susquehanna restoration project. This reduces the
> potential for founder effects and increases genetic diversity.
Not necessarily. How those adults are selected, then subsequently used, is
important.
> Our
> assumption is that natural selection will occur on the hatchery
> fish and the
> population will evolve from one which is a genetic combination of
> the rivers
> from which we take our eggs to a new "Susquehanna stock", adapted
> to survive the unique environmental conditions of the Susquehanna.
This is a potentially false assumption. Where are selective pressures the
greatest anyway? I don't know. In the ocean? In freshwater? And these
"environmental conditions"? How many miles of the Susquahanna do the fish
have access to anyway, and therefore actually how significant are the
river's "conditions" when it comes to environmental selection?
> 4. Eggs are taken from wild broodstock. There is no attempt to
> domesticate shad to provide a source of eggs for the hatchery.
>
> 5. Eggs are taken from rivers with abundant populations of wild shad so
> there is little potential for back-crossing with hatchery-reared fish.
>
> 6. We have maximized genetic diversity by taking eggs from a large number
> of source populations including: James River, VA; Pamunkey River, VA;
> Delaware River, PA; Hudson River, NY; Connecticut River, MA; and Columbia
> River, OR.
This may not maximize genetic diversity, and may have the opposite effect.
Also, this doesn't really explain things. What about the sperm they used?
Did they cross breed fish from different river basins?
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?
-- Jay DeLong Olympia, WA
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