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Re: Summer Doldrums

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Re: Summer Doldrums In reply to
Carl wrote:
Great story Jeff!

Is there any insight on why the fishway is not working as designed??


Lots of theories. It's not just shad it does not work for, but also alewife and blueback herring.

It seems to be better for Atlantic salmon (57 passed as of June 20 this year), but there are still some big inefficiencies.

One clear problem is the shape of the dam, which results in an attraction flow to the river left side of the dam during periods of high flow (like May and early June when alewife, bluebacks, shad, and salmon are all on the move). The fishway is on river right, and the dam is L-shaped such that fish attracted to spill on river left are ~1500' upstream of the fishway attraction flow on the other side of the river. So they beat themselves up on the ledges below the dam trying to find a passage that does not exist.

But shad have poor passage at dams everywhere on the east coast. Every historic shad river that has had a dam removed has seen rapid increase in shad numbers as soon as the dam was gone and fish could access upstream habitat. The same has not been true when fishways were constructed, and that includes fishways of many different types. Some pass more shad than others, but none of them come close to passing enough shad for meaningful restoration of upstream habitat, especially on rivers where they need to pass more than one dam.

There is a reason the undammed Hudson, Delaware, and Potomac--and now the lower Kennebec, up to the first dam--are the best shad fisheries in the Mid Atlantic and Northeast. All the other large rivers that formerly supported big shad runs--especially the Connecticut and the Susquehenna--have multiple dams. A few fish pass the first dam; fewer pass the second; and when you get to upstream habitat the numbers are very small.

"At first blush I am tempted to conclude that a satisfactory hobby must be in large degree useless, inefficient, laborious, or irrelevant."
— Aldo Leopold
Subject Author Views Date
Thread Summer Doldrums Carl 2114 May 27, 2022, 7:13 AM
Thread Re: Summer Doldrums
Rod VanZile 2042 May 27, 2022, 7:43 AM
Post Re: Summer Doldrums
Carl 1985 May 27, 2022, 3:17 PM
Thread Re: Summer Doldrums
Dani 1996 May 27, 2022, 2:07 PM
Post Re: Summer Doldrums
Nick Zito 1933 May 28, 2022, 10:35 AM
Thread Re: Summer Doldrums
Dale Wilcox 1747 Jun 27, 2022, 8:00 AM
Thread Re: Summer Doldrums
Jeff Reardon 1734 Jun 27, 2022, 9:50 AM
Thread Re: Summer Doldrums
Carl 1730 Jun 27, 2022, 10:48 AM
Thread Re: Summer Doldrums
Jeff Reardon 1728 Jun 27, 2022, 11:07 AM
Post Re: Summer Doldrums
Rossja 1712 Jun 27, 2022, 12:23 PM
Thread Re: Summer Doldrums
Carl 1670 Jun 27, 2022, 7:02 PM
Thread Re: Summer Doldrums
Jeff Reardon 1667 Jun 27, 2022, 7:14 PM
Thread Re: Summer Doldrums
greg setter 1658 Jun 27, 2022, 8:07 PM
Post Re: Summer Doldrums
Jeff Reardon 1650 Jun 27, 2022, 8:50 PM
Thread Re: Summer Doldrums
Carl 1616 Jun 28, 2022, 7:01 AM
Thread Re: Summer Doldrums
Vince Pagliaroli 1603 Jun 28, 2022, 9:22 AM
Thread Re: Summer Doldrums
greg setter 1562 Jun 28, 2022, 8:32 PM
Thread Re: Summer Doldrums
greg setter 1561 Jun 28, 2022, 8:46 PM
Thread Re: Summer Doldrums
Jeff Reardon 1526 Jun 29, 2022, 7:41 AM
Thread Re: Summer Doldrums
Vince Pagliaroli 1517 Jun 29, 2022, 8:34 AM
Thread Re: Summer Doldrums
James Woods 1498 Jun 29, 2022, 10:20 AM
Thread Re: Summer Doldrums
Jeff Reardon 1495 Jun 29, 2022, 10:30 AM
Thread Re: Summer Doldrums
Dani 954 Jun 29, 2022, 11:46 AM
Thread Re: Summer Doldrums
tod osier 941 Jun 29, 2022, 4:18 PM
Thread Re: Summer Doldrums
Jeff Reardon 935 Jun 29, 2022, 5:38 PM
Thread Re: Summer Doldrums
tod osier 931 Jun 29, 2022, 5:56 PM
Thread Re: Summer Doldrums
Jeff Reardon 930 Jun 29, 2022, 6:04 PM
Thread Re: Summer Doldrums
greg setter 913 Jun 29, 2022, 9:34 PM
Post Re: Summer Doldrums
Jeff Reardon 892 Jun 30, 2022, 8:50 AM
Post Re: Summer Doldrums
Carl 891 Jun 30, 2022, 9:14 AM
Post Re: Summer Doldrums
rfberan 944 Jun 29, 2022, 2:57 PM
Post Re: Summer Doldrums
Carl 1531 Jun 29, 2022, 6:55 AM
Thread Re: Summer Doldrums
Troy Fields 879 Jun 30, 2022, 11:26 AM
Post Re: Summer Doldrums
Jeff Reardon 866 Jun 30, 2022, 2:13 PM
Post Re: Summer Doldrums
Carl 1726 Jun 27, 2022, 10:51 AM
Post Re: Summer Doldrums
Huntindave McCann 1699 Jun 27, 2022, 1:19 PM
Thread Re: Summer Doldrums: Finally got out fishing.
Carl 797 Jul 2, 2022, 1:34 PM
Post Re: Summer Doldrums: Finally got out fishing.
greg setter 677 Jul 9, 2022, 8:16 AM