Miramichi River Year End Millerton Trap Numbers Analysis

Miramichi River Year End Millerton Trap Numbers Analysis

This humungous hen salmon was caught and released 20 miles up the Cains in the last few hours of the season. There were a good number of fish quietly pushing up the river that last week, and with the decent returns of large salmon we can hope for a good year of spawning.

The Department of Fisheries and Oceans “DFO” salmon counting trap at Millerton on the Southwest Miramichi River is finished reporting for the year.

I have put together a spread sheet below that has the number of grilse on one tab and salmon on another for each of the bi-weekly reporting dates throughout the season.

I have also charted the counts throughout the season.

Millerton Large Salmon Counts 2015-2018

Millerton Grilse Counts 2015-2018

I’m not a biologist, nor am I someone who has worked closely with these numbers over a long period of years.

I’m sure we’ll hear some analysis from some of these people as time goes along.

What these numbers actually mean can be simple, and yet the information can also be complicated as it may indicate future trends that aren’t at all obvious.

A couple of things that I have definitely learned, and that is that there is a fair amount of disagreement even among the experts as to what some of these numbers mean, and why they are occurring.

Also, I have learned that DFO takes a fairly long term view of the numbers, and no one there is reacting any too quickly to whatever the news may be.

That can be good as the general trend in the United States is for fishery officials to increase harvest on the hint of good news, and drag their feet when it comes reducing harvest levels.

It can also be bad as the wait and see attitude can take you to a point where corrective actions eventually need to be much more draconian than would have been necessary initially.

  • First, the number of large salmon in 2018 was 670 which is the highest in the last three years, and only 15% below the average year from 1995 through 2014 – a period of seemingly good times compared to the last few years. The long term efficiency of the Millerton trap on salmon is roughly 5%, so 670 amounts to about 13,400 fish. All things considered this is not a bad number, and it does not include the NW Branch nor does it include grilse, just salmon larger than 25 inches in the Southwest Miramichi. There were many years in the last 30 when large salmon counts were much lower than they were in 2018.


  • Grilse numbers, however, fell through the floor. At 596 it is the lowest number that I could find in the history of the fishery. In the 90s and early 2000s grilse counts were often 2,500 or more. Clearly salmon are having a worse time in the ocean during their first year at sea than their second. Well-known, DFO biologist Bill Hooper told me that the conservation organizations need to concentrate on finding out what is killing so many grilse during their first months in the ocean.  Certainly in the Miramichi striped bass must play a big part, and no other river seems to have seen the recent decline in grilse runs that the Miramichi has.


  • The grilse numbers also often foretell next year’s salmon numbers since the majority of the salmon run are two year old females that were the sisters of the grilse that returned after one year at sea. If an inordinate number of the males died during that first year at sea it is likely to be similar for the females. Historically the correlation has been there, though it is not always the case. We’ll have to wait and see on that one, but a record low grilse number is not a positive sign.


  • It is also true that the trend of poorer salmon returns based around lower grilse returns didn’t start this year. Mark Hambrook pointed out to me in September that the number of 2 MSW salmon in the Dungarvon barrier count this year is much lower as a percentage of the total than has historically been the case. In other words salmon counts are being buoyed up a bit by larger, older, repeat spawners. Without new recruits, though, that cannot go on forever.


  • The trend to a later fall run is becoming very obvious. In 2015 and 2016 roughly half the salmon in the run had come through Millerton by July 31. In 2017 that number was below 30% and in 2018 it was only 15%. In fact better than 60% of the whole run came in after 9/15! The same thing is more or less true of grilse which historically comprise a much smaller percentage of the fall run than salmon. In 2018 the number of salmon and grilse entering the river after 9/15 was virtually identical.

Later on this fall the data from the CAST cameras at the Blackville Bridge will be available, and at that time I’ll do my best to reconcile what they found with the Millerton data and see if their some new information to share.

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