Saturday, 16 June 2012

Crucian Carp - The Case for the Defense

Lee Fletcher sent a bundle of pictures over yesterday. They're of a crucian that he once caught on a water well known to local specimen anglers for its tench and bream. The water in question does not contain any carp except for a single 12lb fish that somehow got in there and gets caught once in a blue moon. Lee's crucian is just as rare. It is the only one ever known to be caught from the water, and the water has seen enough maggot feeders and corn rigs flying about to be sure of that fact.

What is remarkable though, is that this fish is the only known survivor of a documented EA stocking of 3,000 crucians along with the lake's bream and tench, roach, rudd, perch and pike, after the lake was drained down, every fish removed, was resculpted as a fishery, and refilled. All the other fish turn up from time to time, tench and bream very regularly, but crucians don't. They seem to have vanished, all excepting this one fish, a fish so old and battered when caught, it might well be long dead now.

Lee has never quite been able to put this fish to bed, refusing to accept it as a true crucian, tortured by a niggling doubt about its parentage. I would hate to be in such a position myself, because the fish weighed an impressive 3lb 7oz, which for the West Midlands, is about as large a crucian I have ever heard of. It's also his best crucian ever, if it is one after all...

Above is a picture of Lee's fish, and below it, one of my own captures from Marsh Farm. As you can see, Lee's fish is really old and battered and mine young and trim, but there are striking similarities, and dissimilarities, between the two. However, my fish is certainly a crucian, not because I say so, or have taken scale counts and the like to prove it to myself, but because I take the word of Marsh Farm's management as the absolute truth when they say that all their stock are true. And I suppose they are, if they say so...

Lee's fish should be a true crucian because it is very unlikely that the EA stocked wrong un's, and even more unlikely that that one carp in the lake mated with a true crucian and produced hybrids, the only one of which that has ever been seen is the fish under question here, especially when this fish is clearly as old as the lake itself, which is fifteen years or less, I believe.

Using the invaluable information about identification of true crucians on The Crucian Website, I had a go at it. From Lee's trophy shots of the fish, it clearly has a carinated back (a gothic arch rather than a roman arch) in front of the dorsal fin and the mouth has no sign of barbules. Though the pictures of both fish here suggest barbules, they are an illusion caused by the open mouths making the upper lips protrude. Lee's other pictures include clear mouth shots. They are not barbules.

The picture above shows scale counts and fin ray counts. My fish has 33 scales along the lateral line, 7 from dorsal fin to lateral line (not including the lateral line scale) 6 (? or 7) scales from lateral line to ventral fin, and 17 rays and spines along the dorsal fin. All of these counts tally for a true crucian, but I cannot count the anal fin rays, because the fin is collapsed.

Lee's fish has an odd lateral line. It starts by the gill plate with what appears to be two half-scales and ends with at least three and probably four missing scales that can only be imagined by counting up diagonally from the scale row below, so the count for the entire lateral line is a matter of conjecture, but counting the half-scales as one, and filling in the gaps at the other end, I come up with 32 scales, which is right for a true crucian.

The count down from the dorsal fin is correct at 7 scales, but the count down to the ventral fin is confused because Lee's picture was taken from well below the fish (I'll explain why later) so the belly scales get counted, but they shouldn't be, the count goes to the root of the fin, not below it, and that makes 7 or 8 scales, which is fine if its 7, true crucians having between 6 and 7, but not if its 8. However, this count is unreliable, because the scales around the root of the fin appear to be, once again, half scales.

However, the count of proper rows between lateral line and ventral fin, is 7, so I think that's OK. My fish clearly has 6 proper rows, but the picture was taken from directly above, and probably just above the vertical if anything, and with a wide angle lens, that always has the effect of flattening the belly and hiding all those confusing half scales and whatnot from view. Which is why its so important to take great care with these mat shots. It don't matter much when it's a small fish (who cares?) but bloody does when trying to prove what a big, and for its environment, possibly unique specimen like this one really is!

Look at those fins though. The anal fin is fine. It's extended and the ray count is clearly that of a crucian. The dorsal fin and caudal fins are so knackered though, that assessing shape and counting rays is hard work and the dorsal fin does appear to be a tad too long. However, on close examination there's a big split in the fin that has made the fin collapse backwards which gives the impression of length. The caudal fin is half a fin really, and that gives the impression of a forked tail, the hallmark of a non crucian...

In this last picture the big red dots show the approximate position of the camera in relation to the fish when taken. Lee's was clearly taken from well below vertical and slightly to the left because the measurements of the meshes and net frame do not match above and below, or side to side. His wide angle lens from this position has bloated the belly and made the fish somewhat pigeon chested. The picture of mine was taken from more or less directly above, evidenced by the same measurements of mesh and frame, and the effect was to shrink the belly and bring the back up a little. Wide angle lenses inflict great distortions on pictures, and much more than you would imagine they would. My fish was somewhat deeper than this picture shows it to be, and I have a trophy shot that proves it.

You may have noticed that I've given the fish a makeover and made it young again. I took the bottom of the caudal fin, copied it, and then pasted it on top of the good portion, and then inverted it to show approximately what the fin would once have looked like when collapsed. I then took the dorsal fin of my fish and pasted it over the ancient relic of a fin of Lee's fish. Hey presto, young crucian!

The dorsal fins had different counts though, so they don't match exactly, dot for dot. But they do show the big gap where the fin was split.

I think this looks about right. It's a trick, of course, smoke and mirrors really, but I reckon if I were to surreptitiously put the picture of Lee's crucian in one of my blogs, post makeover, and claimed as my own, no-one would bat an eyelid, and simply accept it at face value.

So, can Lee finally put a pillow under this fish's head, tuck it under the duvet, and sing it a lullaby?

I don't know, I'm not an expert with crucians, just handy with Photoshop. I do think there's a plausible crucian and a convincing case for the defense here. I'm fishing in hope for a fish just like it from that water. They must still be in there, somewhere, if the resident pike ain't had all 3,000, or they've all died off.

And if so, they 'll be even older, and larger still...

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