Climate Change, Chub and the River Ribble

Really interesting article John, thanks for the hard work.

Yes, cheers John.

Reallyenlightening 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 manyquestions as it hasanswers. Keep us informed.

You certainly don't believe in doing things by halves do you John? A very thorough and informative article, power to your elbow mate.

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?

Educational and fascinating, thank you John, and what brilliant fish also!!/forum/smilies/big_smile_smiley.gif

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, dateand size). If we then publicised this we might get some significant and very important data on fish populations.

Thanks everyone for your kind comments.Sean your right of course about the size of the data sample, that’s why I had to extrapolate as much as I could from the FM Venue Reports for comparison with my own records.My gut feelings and records, basically put me inline with your views about the general increase in chub numbers and sizes even though there's been a bit of a down turn on the Ribble size wise. However, what we have here are cycles within cycles. In the short term, the lack of 5lb plus chub on the Ribble could just be a missing year class. This may pick up as better years classes start to come through. Or it could be increased competition from the Barbel and now the carp, which ifthis is the case then they will continue to decrease; only time will tell. If my records are right and there are fewer 5lb plus Chub on the Ribble at the moment, then I need to be looking at river condition some 15,16 or 17 years ago for possible reasons and my records don't go that far back yet.I suppose I should now askthe EA for the average river temperatures of rivers in different parts of the country? Because of the recent incident with a discharge of diesel in the Ribble and the phenomenal growth of bio-diesel production plants in the Ribble basin, all of us who fish this beautiful river need to be extremely watchful. The question I would ask all river anglers is: - Is this phenomenal growth of bio diesel production plants a National Problem?

very interesting read john. thanks.

cheers john nice read
a friend of mine posted a thread about the pike/zander ratio ie some year good zander and some year good pike ? i was just wondering if it was the same for chub / barbel ?
i have just looked at youre charts and in 2005 which was a good year for you the ribble record got set for chub

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.

Interesting stuff John. First impressions are that some of the big old fish have died out. I'm not convinced by the inter-specific competition with barbel/carp theory. Intra-specific competition, or suppression of subsequent year classes would be a possibility. It would be interesting to know if the overall biomass of chub has changed much, as changes in size distribution are to be expected over time.

It seems that his little exercise, well perhaps not too little, has thrown up far more questions than answers. I don't have any really strong views on interspecies competition other than flagging it up as a possibility and worth keeping an eye on.Mark, I would like to contact Cam Cleary but I don't have his email address, if he posts on FM then I could drop him a line.Re Global Warming, its not the actual rise in river temperatures that concerns me too much at the moment but warmer weather means more water in the atmosphere and much large flood pulses and these can and do wipe out whole year classes.

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 aLOT 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 ratherCATCH 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

The Ribble also has seals added to the equation. How much effect are they having, if any?

I think you know my thoughts on that Graham....

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 patrolsseemed to bein 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.

Hello John, I have been busy lately and have just logged in for the first time for a while andI just read your article on climate change/river ribblewhich I thought was very interesting; you have done some great work there. I have taken water temperatures since 2000 and have also noted the general increase, I looked at January's figures andI have foundthe same trendas you. I read a few years ago an article that found tench to have increased their weight size in general due to global warming, the idea being that as these fish fed for longer due to a longer summer they would increase weight andI have found this to be the case. I do a bit of part time bird-watching and it is fairly established that some species are becoming rare while other once rare species arenow common through the effect ofglobal warming and I guess this will be the case forcoarse fish and some species will benefit and others will decline. Will chub be one of the species adversely affected? Did you mean the enviorment agency when you mention the E.A?One of the reasons I have written to you is that I am publishing some information next monthon water temperatures on the website surefirefishing.com. I will be mentioning spawning and water temperatures and you may find this interesting. Do you think given the right conditions coarse fish will spawn more than once (multi spawning) and have you knowledge of this. I am just interested as I have never considered this before.