Raritan river fish ladder numbers:

[AndyS]

Fish Ladder Feasibility Study 2011-2013
Grant from NY-NJ Harbor Estuary Program
Report August 26th, 2013
The Lawrence Brook, a tributary of the Raritan River in New Jersey, is impounded currently by multiple dams, preventing upstream passage for fish. Following an educational presentation about the serious depletion of herring and other Atlantic fish the Lawrence Brook Watershed Partnership applied to the NY-NJ Harbor Estuary Program (NY-NJ HEP) and was awarded a grant of $47,000 for a partial feasibility study for fish ladders around the lowest two dams on the Lawrence Brook, the Westons Mill Dam and the Westons Arch Dam. A large range of stakeholders in the area were made aware of the project and invited to participate. If successful, the installation of fish ladders at these locations would add three miles of unobstructed stream habitat for migratory fish. Species that have been seen at the base of the dame include blueback herring and alewife. The dams cannot be taken out, as the Brook is a drinking water supply and has been so since the 1860’s. A private company owned it for the first for 10 years; then the City of New Brunswick took it over. The water supply is needed for the future to supply three local communities of approximately 100,000 population, along with the Delaware-RaritanCanal.

[Dave B.]

Originally Posted by shucker

The correct answer here is fisheries science sucks..always has and always will. We continue to make restrictions,accusations,and allot of finger pointing based of flawed data.

It's sad to say but you're absolutely correct, particularly with regards to salt water species!! Freshwater data collection certainly has its drawbacks and shortcomings but compared to what NOAA and the ASMFC use to restrict our fluke, striper, sea bass, tog and so on quotas they make the freshwater biologists look like absolute rocket scientists.

[Billfish715]

Originally Posted by AndyS

Yes American Shad do rely on one thing, WATER !! Dismal spring rains do play a large part on migration on the Raritan river as it is a very wide and for the most part a shallow river..

The depth of the Raritan can definitely be a limiting factor in large, sustainable, anadromous populations. What the studies should conclude is the Raritan is a beautiful river with great potential for recreational use along with having a diverse fish population.

The posts on this site actually give the public more information about the river and the fish that live in it. NJF conducts its own survey with information provided to fishermen directly without any state or federal funding. Does anyone want information about the fish in the Raritan? Just post your question on this site and get an answer immediately without the results of someone's scientific study!

[Jigman13]

Originally Posted by Billfish715

The depth of the Raritan can definitely be a limiting factor in large, sustainable, anadromous populations. What the studies should conclude is the Raritan is a beautiful river with great potential for recreational use along with having a diverse fish population.

The posts on this site actually give the public more information about the river and the fish that live in it. NJF conducts its own survey with information provided to fishermen directly without any state or federal funding. Does anyone want information about the fish in the Raritan? Just post your question on this site and get an answer immediately without the results of someone's scientific study!

Valid point.

[Eskimo]

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Fish and Wildlife should hire Thmyorke1 to cross reference data to make sense of individual points of data.

I guess river systems are an example of "irreducible complexity" where no one piece of data can be comprehended without understanding how it fits into the bigger picture of innumerable environmental conditions and circumstances that make up the South Branch of the Raritan River.




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[Mark B.]

In the Raritan River the American shad favored migrating during relatively low water flow (250 – 1,500 cfs, Figure 4). Studies on the Delaware River, too, have shown that major shad passage events generally occurred at times of relatively low discharge, especially, when flows were waning following periods of elevated water levels. The trigger flow for the major shad passage events on the Delaware River was approximately 30,000 cfs (personal communication Eric Guilfoos BWEC / PACE Environmental Services). On the Raritan River the trigger flow appeared to be approximately 500 cfs. Unfortunately, high turbidity associated with higher flows made it more difficult to see the fish in the video on those days. So, it is not implausible that shad may have passed by the viewing window undetected. Additionally, at higher flow rates shad can swim over the weir, thus avoiding the ladder all together.

Have you ever read this http://raritan.rutgers.edu/wp-conten...itan-river.pdf ?

From which the above is excerpted.

[thmyorke1]

Originally Posted by Mark B.

In the Raritan River the American shad favored migrating during relatively low water flow (250 – 1,500 cfs, Figure 4). Studies on the Delaware River, too, have shown that major shad passage events generally occurred at times of relatively low discharge, especially, when flows were waning following periods of elevated water levels. The trigger flow for the major shad passage events on the Delaware River was approximately 30,000 cfs (personal communication Eric Guilfoos BWEC / PACE Environmental Services). On the Raritan River the trigger flow appeared to be approximately 500 cfs. Unfortunately, high turbidity associated with higher flows made it more difficult to see the fish in the video on those days. So, it is not implausible that shad may have passed by the viewing window undetected. Additionally, at higher flow rates shad can swim over the weir, thus avoiding the ladder all together.

Have you ever read this http://raritan.rutgers.edu/wp-conten...itan-river.pdf ?

From which the above is excerpted.

Thanks for sharing, Mark. That's actually some interesting info that more shad are counted at 500 cfs.

Comparing the discharge graphs to the gauge height graphs 500 is just a few inches above the normal flow for the Raritan.

I've seen spots on the Raritan where it would seem difficult for shad to swim up at normal flow. Yet I can't speak for the shad, it's up to them to determine whether they can swim up these spots or not.

Maybe they prefer the ladder when it's low flow? And at high flow they don't bother swimming up it? Perhaps the ladder's design is to turbulent for them at above average flows?

Or it's just the case you mentioned; can't count anything if you can't see in the murky water.

Perhaps the ladder-cam could use x-ray or something to see through the murky water.