Sunday, January 17, 2010

Case of the missing pike tails is solved

Around the first week of July last summer anglers at camp caught a number of big pike that had part of their tail fins missing.

If I remember right we caught six pike, all of them slot size or larger, with either the top half or the bottom half of their fins absent as if they had been surgically removed. In some cases the wounds were so fresh that the fish bled profusely from the tail. In one case the wound had occurred some other year and that part of the tail was healed over entirely although the actual fin was gone. One fish had parts of both the top and bottom halves of its tail gone.

Pike frequently have gashes and cuts on their bodies from fighting with other pike or from spawning activities and they also often have split fins.

But in the fish caught in 2009 the fin was removed neatly right where the fin would join the body. It just didn't look accidental.

We could think of no other explanation but that someone was catching big pike, cutting off part of their tails and releasing them.

Incensed that anybody would do such a thing, we reported the catches to the Ministry of Natural Resources. Neither MNR conservation officers nor biologists there could think of another explanation either.

Except for that one week, however, we never saw the phenomenon again.

It wasn't until the MNR was at camp this fall gathering lake trout eggs to be raised in a hatchery that we got the answer.

Jason (sorry, I have forgotten his last name) from the MNR Dorion Fish Hatchery knew all about it. It is called tail/fin rot and it's caused by a fungus that is only present when the water is unusually cold.

Sure enough, the lake last summer was at flood stage and was much colder than normal from all the rain. Also, all the fish came from the same general area, a spot where the water tends to be colder anyway.

So there isn't a maniac out there after all. Thank goodness!

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