Wednesday 25 April 2012

2011 Severn salmon catch statistics

I've received the final data from the Environment Agency on the 2011 season.

The total declared salmon catch for 2011 stands at 361 of which 331 were reported from the Severn, 10 from the Teme and 20 from the Vyrnwy. This is the second highest catch from the system in the last 15 years.

The 2011 catch is a very significant improvement on 2009 and 2010 seasons which like last year also suffered from low flows in the spring . So what was different? Evidence from a wide range of sources suggest that 2011 was a good year for multi-sea-winter (MSW) salmon throughout the North Atlantic and the Severn clearly benefited from this.

The long term rod catch figures over the last 15 years are relatively stable showing a small upward trend.


However, these catch figures should not be taken at face value as an accurate measure of the long term trend in the salmon population. This is because they do not account for the impact the1999 spring byelaws had in reducing rod effort and the number of salmon caught.

The ban on bait fishing before June 16th effectively closed a substantial part of the Spring Salmon fishery on the Severn, while compulsory catch and release deterred many anglers who were unhappy with treating spring salmon as 'play things'. It is very difficult to quantify the impact of the byelaws, but in 2007 the EA noted that there had been a 58% fall in the median annual pre-June catch on the Severn in comparison to pre-byelaw days, but said that this was 'not significant' as it did not represent any fall in stocks: EA assessment of impact of spring bye laws on salmon catches

Put in layman's terms that means the Severn rod catch has been reduced by around 160 fish per year since 1999 as a result of the spring byelaws. More in good fishing years and less in poor ones.

The real state of stocks is seen more clearly if we look at the underlying trend in catch per unit effort which has improved significantly over the last 15 years.


The catch and release rate has risen to 61% which is above the long term England and Wales average of 56%. This was no doubt helped by awareness raising activities such as the Shakespeare Severn Salmon Competition in which a prize of a Shakespeare Oracle XT fly rod was offered for the largest salmon caught and released from the river.

Nearly two thirds 65% of the fish were caught after June 16th. Spinning was the most productive method (58%) with bait accounting for 34% and the fly 8%.

96 anglers caught Severn, Teme or Vyrnwy salmon last year. Of that just 15 anglers (less than 5% of the total number fishing) caught over 50% of the fish. Sixty anglers (15% of the total) caught 90% of the fish.

The catch breaks down in terms of weight category like this:

Under 8lb: 85

8lb - 14lb: 214

14lb - 22lb: 59

22lb and over: 6

The average and largest weights by river were:

Severn: average 10.55lb largest 30lb

Vyrnwy: average 10.6lb largest 15.6lb

Teme: average 9.48lb largest 13lb

Significantly no large salmon were declared from the Teme last year. This no doubt reflected the very low flows throughout virtually the whole season.

The proportion of large salmon over 14lbs in the rod catch had risen to 18% which represents a significant improvement on the previous 5 year average of 12%.

The monthly capture rate of large salmon is shown below. This could be evidence that large salmon are running later, but we would need the pattern to be repeated over several years and varied flows to establish that. It may well just be a reflection of the very dry April which delayed the arrival of the larger fish at the rod fishery.

Monday 9 April 2012

2011 provisional catch figures

The provisional rod catch for 2011 stands at 332. This figure is based on returns up to mid February. It represents a significant improvement on catches in 2009 and 2010 which like last year suffered from low water. It would be a mistake to try and isolate a single cause for this upturn, but good catches of 2SW fish across much of England and Wales in 2011 suggests that the 2009 smolts may well have found favourable currents after the leaving the rivers. This could keep down marine mortality and boost rod catches.  


This catch is another indicator of improving stocks after the collapse in catches in the late '90s.



The 2011 catch was 180% of the 1998 figure. Yet since the late 90's the number of anglers has declined by more than two thirds. This suggests strongly that the stock is increasing. If we look at catch-per-unit-effort we can see the trend over the last decade or so more clearly.

Flows impact very strongly on the distribution of the rod catch with the navigation weirs on the lower river accounting for the majority of fish in low water years. This pattern was again evident in the 2011 catches. The lower river is a very long stretch of river, but the effective fishing area is made up mainly from a handful of weir pools. Over 65% of the fish reported from below Stourport actually came from just one such hotspot: Diglis weir at Worcester. 


Prior to 2009 the catch from below Bridgnorth would've been considerably higher in a drought year. However, changes of ownership at one particularly productive low water fishery has led   to a big reduction in catches. This is due to less rod effort and highly productive water remaining un-fished. 


The graph below represents fish reported to me for the T&S monthly report. It isn't exhaustive, but I believe it does give a broadly accurate picture.