The decision by the British Record Fish Committee (BRFC) to reject claims for roach and crucian carp records this summer would, in normal circumstances, have raised not an eyebrow. Claims for species records are considered and disallowed pretty well every time this committee meets.

What has made the latest rejections noteworthy and 2009 memorable for angling’s statisticians is that, for the first time, the BRFC used DNA data to inform its decisions. Scales taken from the fish and submitted with the claims showed both to have been hybrids. From now on, DNA scale tests will be applied to all record claims for these two species — and for rudd.

Hybridisation has been a problem for the BRFC for many years. Roach, rudd and crucian carp are shameless bed-hoppers and, after mating, regularly produce offspring showing characteristics of both fish types. These crossbreeds can be difficult to distinguish from pure-bred specimens and it is only pure-bred specimens that qualify for the records.

In the past, along with other supporting evidence, the BRFC has relied on having the body of the claimed fish to inspect or photographs of it. However, anglers have become less and less willing to kill fish, even when pursuing a record claim, and so photographic evidence has become increasingly important.

It has enabled at least some physical features to be checked against known norms for a species. The problem is that these diagnostic criteria — numbers of scales along the flanks, number of rays in particular fins and the like — are not 100 per cent reliable and often photographs submitted show key features obscured.

From now on, while other coarse fish will have but a single list, the bed-hoppers will have two. The existing records, approved without DNA evidence — 4lb 4oz for roach, 4lb 8oz for crucian carp and 4lb 11oz for rudd — will stand in one list, with everyone aware that there may be hybrids among them.

A second list will be compiled to stand alongside it, recording roach, rudd and crucian carp identified on the basis of DNA testing — in other words, fish unarguably from the right side of the blanket. Minimum qualifying weights for the new list will be 4lb 3oz for roach and rudd, and 4lb 8oz for crucian carp. All claims for these species will need to be supported by a scale for analysis.

Although the BRFC had been considering the use of DNA techniques for some time, its hand was forced this year when the captor of a fish taken in Northern Ireland, interested only in a genuine record, voluntarily sent in a scale from his fish along with his application. It was this, when analysed, that showed his catch to be a hybrid — and that generated pressure for change.

Not everyone making a record claim has proved as scrupulous as the Irishman and, over the years, many false claims are known to have been lodged.

The most extraordinary in modern times was one for a record rainbow trout. In April 1999, a claim was made for a fish of 36lb 14oz from a lake in Hampshire. The angler described for the committee how he had hooked and landed the trout and named witnesses who had seen him with it in his net. All other criteria being satisfied, the claim was accepted. In July 2003, apparently conscience-stricken and now “no longer able to live with myself”, the captor wrote to the BRFC saying he had not caught the fish at all. He had seen it lying freshly dead in the margins, had netted it out and in a “moment of madness” when two anglers came along the bank, claimed that he had caught it.

On seeing him standing in front of them with the fish, the two men had no ground to disbelieve him and agreed to stand as witnesses — and the damage was done.

Another famous case is much older. It wasn’t until the 1970s, when F. H. E. Buller, a forensically minded angling historian, got to work on it, that the claim for a pike record made by Alfred Jardine, the great Victorian angler, in 1879 was shown to be false. Jardine had exaggerated by 2lb the weight of a 35-pounder he had caught. At 37lb, the fish moved to the top of the record list and Jardine basked in the glory it brought him for many years.

There have been other dodgy goings-on. Indeed, the very concept of a record for some species — carp and barbel especially — has become devalued of late as chest-beaters have pursued known individual monsters, catching and returning them to the water repeatedly, each time claiming a record because each time the fish proved a few ounces heavier.

But still, records are valuable as milestones, indicating the kinds of conditions in which different species can grow biggest and the ultimate sizes they can achieve. In the process, of course, they identify who caught the fish, when and how. A few records have shone like beacons down the years — among them Georgina Ballantine’s 64lb salmon taken in 1922, Aylmer Tryon’s 14lb 6oz barbel taken in 1934 and Richard Walker’s 44lb carp landed in 1952.

The Ballantine record still stands, Tryon’s record stood for half a century before the present barbel shenanigans began and Walker’s monster, the first record to be caught by design, dragged coarse fishing from a land of myth and potion into a world of logic and technology.

One other point. One thing records cannot do necessarily is to mark angling skills — a fact graphically illustrated by Dean Rawlings in 2002. Fishing a small lake in Fringford, Oxfordshire, this 11-year-old schoolboy landed a record perch, an out-of-sight fish of 5lb 9oz. He caught it by chance, on one of his first fishing outings, on tackle borrowed from his father — and thumbed his nose at anoraks everywhere in the process.