Fishing News: World Record Muskellunge

World Record Muskie - Thank You Letter
By: Dr. John Casselman
Publication: Muskies Canada.
Issue: February 2 2001

Martin:

Special thanks for sending me the picture, beautifully framed, of your muskellunge. It's nice to see such a beautiful, authentic fish, confirming much of the science that I know about muskellunge growth potential. I never have hung pictures of caught fish. This is the first one. So it will reside on my office wall and I emphasize the reason why I want to do this because I think it will contain a very interesting and fascinating story. Thanks again.

The reason why the fish is special interest to me is because the measurements describe the fish exactly. In 1964, when working on the St. Lawrence River, we tagged a female muskellunge that was 54 inches long, weighing 54 pounds. It was taken a spawning time. I don't know whether I mentioned to you, but males that were caught at the same time by electrofishing and tagged were subsequently recaptured a considerable distance away adn at a larger size, one after eight years. The proportions of these two fish - yours and that one - are very similar.

I very much look forward to obtaining the cleithral bone from your fish. I leave it to you, Larry Jones, and Arunas to organize. As I mentioned, I'm particularly interested in year-class. In other words, in what year the fish hatched. Large trophy muskellunge have a very interesting synchrony in these year-classes. They almost invariably come from the strong El Niño years produce strong year-classes of these largest muskellunge. Particularly important years were, in order of summer temperature, 1955, 1959, 1973, 1975, 1995, 1998. I very much look forward to an independent age assessment of your fish to see where it falls - whether on one of these. Just as an aside, I'll enclose a copy of a recent e-mail on a muskellunge that was found dead in the Ottawa River. You'll see there how important it is to have accurate age assessments and how we are still trying to get more resolution on these age assessments, because with these older fish, we are really only accurate, at the best, plus or minus one year. We are working on developing some mathematical methods of improving this. Incidentally, the 1980s was a decade of frequently El Niño years just below the extremes, and as you may know, 1983 was specially warm. Muskellunge fishing in the past couple of years has improved tremendously. Since our age assessments on younger fish are more reliable, we know the 1980s produced exceptional reproduction. This also goes hand in hand with the value of catch and release and increased size limits. Fortuitously, in the mid-1980s, Ontario size limits were increased, and about that time, organized muskellunge anglers were promoting catch and release - Muskies Inc. and Muskies Canada, for example. So not only did we have increased egg production (in fisheries we call it reproductive capactiy, or potential), but climatic conditions were favourable for the production of strong year-classes. We have some ideas how this works, but I won't elaborate on it right now.

A couple of other points of interest: Mathematically, we can estimate from growth of trajectory of ultimate size. I will include a copy of a paper we published recently for Ontario. It's a little heavy on the science, buy you may find it of interest. The female muskellunge that I tagged years ago on the St. Lawrence River and your fish fall almost exactly on the the average ultimate size. The can get larger than this, but not very much. When recent size limits were discussed, mathematically we recommended that waters that produce large-bodied muskellunge go to a minimum ultimated size equal to the lower 99% confidence limits. What that means is that if females live indefinetely, 99% of them will reach this length limit. It is, without looking up exact numbers, for large-bodied populations usually in the 48-to-50-inch range, not exceeding the latter. By deciding to go to 54 inches, this means that probably half of the females will eventually never be harvested. This, of course, naturally falls into an ethical question. For many reasons, I prefer the minimum ultimate size. It has a biological basis and is quite precise. This length, or within an inch of it, was chosen for the St. Lawrence River. I think the new size limit for the St. Lawrence River is going to be 48 inches.

For someone who works in fisheries research, it is especially rewarding to see our water bodies producing these gigantic fish, and as I mentioned, your fish is one of the best examples. But if we are going to use weight as our criterion of fishing prowess, then I believe the only way we are going to reach excessive weight in this species is to catch females when they are fully gravid. I wouldn't be surprised if up to 30% of the weight of you fish was made up of eggs. We know something about egg development in the pikes and have some specific information from muskellunge. By late November and December, they have built probably 60% to 90% of their egg mass. Then ovary size doesn't increase much until about a month after spawning, when the moisture content increases as the eggs are "finished". This increase is not large, probably a 10% increase in ovary mass.

During the winter period, these large females are not feeding actively. In fact, they are burning up muscle and, to some extent, abdominal fat. So there's a loss of weight from this component. This means that to reach a very large size, the fish needs to be caught late in the fishing season. I don't support increasign teh length of the season to accomplish this.

All of this is simply some of the science behind fish growth and age. None of it in any detracts from the beautiful fish you caught, its egg mass, or time of year. Indeed, it confirms the science that we've been deligently developing over a long period of time. There is another interesting aspect to this. Fish activity, hence catchability, is affected by climate. Once we get this together and get it out, I think observant anglers will see a very interesting relationship between catch and release and climate.

And as I try to emphasize, it is important that we have a scientific basis for setting size limits and that they be sett in reality and positively supported. Muskellunge can be a beautiful example of anglers working together with the science by supplying data - cleithral bones, etc. - to manage positively what is truly a verable, noble beast, as exemplified by your fish.

Sorry to be so long-winded. I had intended just to write a special thanks. But I wanted to empasize why I appreciate your gift of the picture. This fish says a lot. I look forward to seeing the cleithral bone and any other information that might be obtained.

Sincerly,
John Casselman


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