Yes, cheers John.

Really enlightening and it would be interesting to see if the water temp trend continues or if it's just part of a general rise and fall that goes on over many years.

It sounds like you've started something that's given you as many questions as it has answers. Keep us informed. 

Very interesting article and certainly a 3 degree increase in average river temperature seems enormous over such a short time. What do the longer term records show? i.e is it possibly a blip or part of a longer term trend?

Interesting article John.  My own view is that we will continue to see a large number of 5lb plus chub in the northern rivers.  My own analysis of Wharfedale Specimen Group records show a step change in the number 5lb plus chub caught in the early 90s and a smaller step change in the early 00s.  The interesting point about the last step change was that it also showed a significant rise in the maximum weight of the fish reported.

I think that we are seeing a significant increase in growth rates in some stretches probably due to warmer temps (as you have shown) and an increase in the amount of feed going in due to the popularity of barbel fishing.

The problem with analysing the records of a small number of anglers is that the sample sizes are very small  This makes the records of organisations such as the Chub Study Group really important.  I wonder if we can persuade Graham to create a database in which we can log catches (just river, date and size).  If we then publicised this we might get some significant and very important data on fish populations.

very interesting read john. thanks.

John,

The problem you face is that there are many variables that could influence the abundanceof 5lb+ chub or otherwise. Studies on the Dorset Stour showed that the long term effect of hot summers followed by benevolent winters was far reaching. This was first found with the 1959 hot summer with the chub being big in the early seventies followed by a comparative dearth of big chub from the cold sixties. The next special year was 1975 whch was hot with a mild dry winter following - giving rise to bigger chub in the early nineties. The next special years were 1990 and 1995. This suggests that what you saw was a benefit from the 1990 year class that has peaked rather than the water temperatures having as much to do with it as you'd think. It also suggests that another peak will be due in about three or four years.

Interestingly the same can occur with roach; it certainly did in the past with the Stour having a fantastic stock of big roach from 1984 - 1990 resulting from the 1975 year class and culminating in the record fish. Since then cormorant predation has had an adverse effect resulting in lots of sub 8oz fish but a very low proportion getting bigger than this.

This is to my mind a classic case in angling of the difficulty of working out which effect or combination of effects is actually the root cause of a phenomena. I suspect Throop has followed a similar pattern in its big chub productivity over the last five years. It might be worth your contacting Cam Cleary who has plotted results there.

Comparisons of the 1993 and 1998 Stour/Avon surveys showed increases in growth rates for chub based on water temperatures. I have been unable to get more up to date data as the EA stopped printing the results.

When I first met John at a Chub Study Group 'do' in Norfolk, I was totally amazed at the thoroughness of his record-keeping and it was obvious he put a LOT of effort into his fishing. This article is typical of the man and he never stops thinking (or fishing!!). As Mark W says, there are many factors dictating how fast fish grow and to what ultimate size, but an enthusiastic enquiring mind like John's may help give us an insight into one or two of them. The Chub Study Group have collected well over 30 years of data and there is much to be learned from it I'm sure. Some people have scoffed at the Group in the past and stated "they'd rather CATCH chub than study them", but a wealth of information has been amassed by members (one of whom has just landed his 1000th 4lb+ chub - well done Mr. G!!), so I'm glad that there are those who may be able to interpret the information in some shape or form.

 Good stuff John.

 Trev

Really interesting stuff. John, you mentioned in one of your replies about looking at the river conditions 15-17 years ago. I used to fish the river quite regularly up to 1993 when I moved up to Scotland. At that time it was rare to get a chub over 4lb but that may be down to poor angling on my behalf rather than the bigger fish not being there. I fished it quite a lot in the summers and the river always seemed to be very low - I do not recall many flood events either. I was also a part-time countryside ranger at the time and often volunteered for the ribble way patrol. Virtually every one of these patrols seemed to be in glorious warm weather - rose tinted memories perhaps!

I also recall a large number of mink in the river in those days too - are they still around?

The barbel really just started to show when I moved away. Myself and a pal had them up to around 6lb in the 92/93 season. I moved away just as they started to get really big. Alas, there's not many barbel up here!!

Mike, I've not seen any mink lately nor have I seen any cormorants, but there again most of my fishing at this time of the year is at night.  Over the last ten years the popularity of barbel fishing has certainly increased the amount of high calorific value feed going into the river.  Just how much this affects the rate of growth in the Chub and Barbel is debatably.

Had several mink sightings last year - may have been the same animal though as always in the same area, almost certainly just the one resident family if nothing else.

Not seen cormorants in great numbers but usually see one or two flying past on each daytime session.

Fishing below Ribchester tuesday afternoon, counted 25 cormorants  in small groups of twos to fives heading to there roost prior to sunset from downriver, this is a large reduction on the numbers there where a few years ago when we would get groups alone of 25plus.