I had almost began to relax when the phone rang. It was the Todmorden Angling Club legend, Ray Barber, with some bad news. Whilst Shropshire had escaped the worst of the rainfall, the Pennines were not so fortunate. The upper Calder had burst its banks and so, sadly, had a section of the Rochdale canal.
Eyes & ears for the waterways
Angling clubs, as well as paying for the renting of fishing rights, also play an invaluable role as eyes and ears of the waterways. I have lost count over the years of the number of pollutions, vandalism incidents and reports of low water levels that angling clubs have been the first to report. Sometimes their prompt action has averted a major disaster. On this occasion not even King Canute could have done a great deal about the situation.
Fish behaviour and lowering of water levels
What happens to the fish when a canal bursts its banks? I believe that fish have a very acute sense of water depth and instinctively know where slightly deeper areas of water are to be found. I am minded to think that the mechanism for depth detection must be related to an organ called the swim bladder. The swim bladder is filled with gas and gas volumes are very responsive to the changes in pressure that small alterations of water depths bring about. In my experience, fish will swim away from the vicinity of a breach where they are able and head for deeper water if ‘they know' it exists. This is how most fish behave when pounds are drained for engineering works. Inevitably, the majority of fish head for the deeper water to be found at the upper lock chamber area. However, those fish close to the paddles will not be able to resist the physical force of water flow and will be washed downstream.
It's inevitable any fish that happen to be close to the site of a bank collapse will be washed out of the canal. Like the residents of Pompeii and Herculaneum they simply cannot escape their fate. Fish will end up in adjacent water courses fields, back gardens and surrounding fields. Recently, groundsman Dave Mitchell stumbled across three koi carp at Carlisle United's Brunton Park football ground. These fish were happily swimming in pools behind the goal at the aptly named Waterworks End of the ground. Happily, these three wandering fish have since been re-united with their owner. Carp, of all the species, seem especially vulnerable to escape into rivers.
Computer says no
Some years ago, we suffered a breach on the Caldon Canal. Significant quantities of fish ended up in temporary pools that had formed in natural low spots in the fields below the breached embankment. When we came to apply for netting consent to rescue these fish, the EA computer at Brampton was flummoxed for a while. There was no fishery to be seen on GIS at the grid reference co-ordinates where we were wanting to urgently net. The field was clearly not registered with CEFAS as a fishery and so a netting consent could not be issued. After we all had a good giggle, common sense quickly prevailed.
Fish disease and other risks
When fish get washed into new aquatic environments, there is the risk of fish disease transfer. Non-native potentially invasive species may also find themselves in an ecosystem where conditions may be suitable for them to thrive and thus cause damage to native stocks. This is why it's important that unwanted pet fish are not introduced into the wild. Whilst it's true that many tropical species will succumb once water temperatures fall, they could harbour novel parasites that may not be that fussy about their choice of hosts. And some ornamental species do have the potential to establish breeding populations, an example of this being the top mouthed gudgeon and possibly the sterlet.
Repairing the Canal and restoring the fish populations
Where canals suffer infrastructure damage as a result of flooding, priority has to be infrastructure repair to make the canal safe for the public and residents. The Trust has now launched an appeal to help raise the £10 million needed.
Where fish have clearly been lost, the Trusts' fisheries team will try and do what it can, with the limited resources available, to reinstate the fishery in due course. Personally I think it's absolutely imperative for the angling community to be seen to be playing its' part in supporting the appeal. Just sometimes, angling clubs and anglers earn a reputation for excess frugality which does not enhance the reputation of the sport amongst the detractors out there. So now is the perfect time for practitioners of the piscatorial art to show their generous side.