Reimagining Didymo in Salmon Rivers

Didymo growing in the Matapedia River, forming the dense mats that raise concerns about smothering Atlantic salmon habitati. (ASF photo)

Didymo growing in the Matapedia River, forming the dense mats that raise concerns about smothering Atlantic salmon habitat. (ASF photo)

Most Atlantic salmon anglers have come across the name of this alga, Didymosphenia geminata, alias Didymo, alias Rock Snot. It brings vividly to mind great mats of brown furry stuff, the ends of which break off and drift downstream to infect other areas of a salmon river.

The concern, certainly real, has been the potential for smothering areas where Atlantic salmon eggs have been laid, as well as impacting the overall food web within the streams that could affect growing young fry and parr.

Anglers have taken the brunt of accusations when it came to spreading this nasty stuff from river to river. Long and persuasive arguments have been made to change out the felt-solded hip waders for alternate gripping soles. But a major new scientific paper published this spring brings that into question.

The research showed that Didymo has been in these same rivers for centuries. What is different is that apparently earlier springs, changes in nutrient ratios, and warmer summers have modified the growth form. It takes the view that anglers are not a vector for an alien species, but instead climate change is the culprit. Check out the article, that can be downloaded, in the Can. Journal of Fisheries and Aquatic Sciences.

Anglers do need to refresh their live release skills each year, and part of that could be reviewing the ASF-sponsored Live Release video that is available on the website. Click here

Wanted: Live Release Photos with Fish IN the Water, Taken this Year, for Sharing

We would love to see and share on ASF Rivernotes your Live Release images from this year that show the fish in the water, rather than being held above the surface. Just email a copy to: asfweb@nbnet.nb.ca

Rafting Ground - Restigouche. This river of large salmon has a grandeur that is fully evident to anyone standing on its banks. Photo Michelle Charest/ASF

Rafting Ground – Restigouche. This river of large salmon has a grandeur that is fully evident to anyone standing on its banks. Photo Michelle Charest/ASF

Quebec

With most rivers still to open on June 15 and others on July 1, angling to date has been slow due to very high water levels and salmon that are at least 2 weeks behind schedule….but rivers like the Cascapedia are back to 170 cubic 3m/second after dropping down to 140….Rivers in Gaspé and Saguenay dropping at a quick pace…. As far as the fish are concerned, we should know late this coming week around the tides of the full moon.

Matapedia River
To June 7, 20 fish have been reported landed (including 3 releases) To June 7 2013, 20 fish have been landed (including 4 releases).  On opening day June 1 the river was flowing at 165 cubic meters/second.

Causapscal River
The first angling started on May 27 due to high water the previous three days, to June 7, 18 fish have been reported landed (including 4 released).  At the same date in 2013, 22 fish had been landed including 6 releases.

Cascapedia River
ASF (Canada) board member Dan Greenberg is reporting spotty action on the June 8, but signs of fish are becoming more frequent.  The river has flowed between 150 cubic meters per second on opening day June 1 and then down to 120 and back up to 170 by June 7.

Ronnie Condo of Gesgapegiag First Nation at the Cascapedia working with ASF researchers recently to deploy receivers that track Cascapedia smolts beginning their migration. The Cascapedia acheived more than 300 per cent of its base conservation level last year. (Photo Michelle Charest/ASF)

Ronnie Condo of Gesgapegiag First Nation at the Cascapedia working with ASF researchers recently to deploy receivers that track Cascapedia smolts beginning their migration. The Cascapedia acheived more than 300 per cent of its base conservation level last year. (Photo Michelle Charest/ASF)

Moisie River
Firstfish was landed on May 27, river was flowing at 2,400 cubic meters/second!  Down from 3,200 cubic meters/second on May 24. To June 7, a total of 74 salmon were reported landed, 48 killed and 26 released.   This compares with 192 salmon reported landed at the same date in 2013 (129 killed and 63 released).

Nova Scotia

Lewis Hinks was noting late last week that overall in Nova Scotia the rivers could use rain to bring up levels. To some extent his wish was fulfilled over the past few days. As usual, the effects in Cape Breton are short-lived due to the small watersheds of rivers such as the Cheticamp and the Margaree.

René Aucoin, President of NSSA, seen angling yesterday, June, on the Cheticamp River in Cape Breton. (Photo Lewis Hinks/ASF).

René Aucoin, President of NSSA, seen angling yesterday, June, on the Cheticamp River in Cape Breton. (Photo Lewis Hinks/ASF).

On the Cheticamp there are signs of a few fish, but it is still early days, as John Hart points out. Essentially nothing yet on the Margaree he also points out.

A nice downpour on the Margaree over the weekend brought up water levels, but the sunny conditions this week have resulted in reduced water levels.

A nice downpour on the Margaree over the weekend brought up water levels, but the sunny conditions this week have resulted in reduced water levels.

LaHave – The Morgan Falls Fishway is reporting that as of Monday they had eight salmon and one grilse return.

Newfoundland

Reports continue to come in of both high water and very low numbers of returning Atlantic salmon. This has been true of the Humber, as well as the Bay St. George rivers.

Meanwhile, the Strait of Belle Isle appears to be finally clearing out, but on the eastern side of the Northern Peninsula, including south of St. Anthony, the ice is still thick, even in the bays, next to shore.

New Brunswick

Miramichi – The Dungarvon Barrier has counted only a single grilse by June 8, but numbers tend to be very low in early June.  Last year there were 2 grilse and one large salmon.

Restigouche
David Leblanc is reporting conditions remain good for angling, with slightly above normal water levels, but everywhere the actual salmon angling is slow to get g0ing this year.

Maine

Penobscot – Returns continue to be low at the Milford Dam fish lift, with only 31 returns as of this morning, June 11. Last year there were exactly 200 returning by June 13 – and that was a low year. The same date in 2012 saw 488 return, and 2011 was the blockbuster year with 1,464 by June 13.

The Milford Fish Lift is new, but does appear to be working well. Nevertheless because it is new, there are mark and recapture studies underway to make sure it is working well.

This photo is of the main hopper at Milford Dam.  In the photo the hopper is at the top of it's lift to dump fish into the upper flume.  From here, the fish will swim upstream to a collection/counting facility where Atlantic salmon broodstock will be collected.  River herring will also be collected for stocking further upstream.  American shad will be returned directly to the river.  This facility and the Orono trap begin operation today, April 15. 2014. The image was taken about 10 days ago. (photo Don Dow/NOAA)

This photo is of the main hopper at Milford Dam. In the photo the hopper is at the top of its lift to dump fish into the upper flume. From here, the fish will swim upstream to a collection/counting facility where Atlantic salmon broodstock will be collected. River herring will also be collected for stocking further upstream. American shad will be returned directly to the river. This facility and the Orono trap begin operation today, April 15. 2014. The image was taken in early April. (photo Don Dow/NOAA)

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