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| No cause of death was apparent when New Brunswick biologists examined the giant muskie nicknamed the “Nackawic Fatty,” but it’s possible the fish may have asphyxiated. The muskie, which measured 50 7/8 inches long and carried a 29 3/4-inch girth, weighed 60.5 pounds when weighed by a conservation officer shortly after it was found floating in the St. John River near Nackawic , New Brunswick , on December 14.
According to Conservation Officer Steve Eldridge, the necropsy was performed April 8. Cleithra were removed to determine the fish’s age, and it was judged to be 16 years old. Only two pounds of eggs had developed, and a semi-digested white sucker (estimated to have originally been about 16 inches long) was found in its stomach. There was no sign of heart or liver damage. The muskie was found the day after what Eldridge called “one of the worst localized floods in the history of the province,” leading some to speculate that the extremely muddy water that resulted from the flood may have led to the muskie’s demise.
Following the necropsy, Eldridge sent the findings to noted muskellunge researcher John Casselman of Ontario ’s Queen’s University, who agreed the fish might have asphyxiated. Said Casselman: It’s “hard to know what killed this fish, but I’d like to speculate a bit. This fish obviously had substantial oxygen demands because it was feeding heavily, growing actively, and had a very large body mass. And most of its oxygen content would come through the gills — let’s say 90 to 95 percent. So it was probably under some oxygen stress from the outset because these large-bodied fish have a poorer gill surface area to body-weight ratio … this fish would have been under considerable oxygen demand, even stress, from the outset. And on top of that, as you indicate, there was heavy turbidity. This turbidity could affect the gill surface area, adding more stress. So the term asphyxiated may be quite appropriate.”
Casselman was asked about a size discrepancy discovered during the necropsy. Eldridge originally weighed the muskie at 60.5 pounds while using an uncertified Cabela’s stainless steel spring scale and verified the scale’s accuracy at the local Canada Post Office. However, during the necropsy, the muskie was weighed on the same scale at 53.6 pounds and its dimensions had shrunk to 50 1/8 inches long with a 29 1/4-inch girth.
Said Casselman: “If it was in the water for a day or so at low temperature, strange things start to happen. I noticed some years ago that dead pike held in ice water gained some considerable weight. I don’t think this fish deviates much from what I expect happened here. So initially there might have been [an] increase in water content of the carcass.
“So I’m sorry, I can’t really suggest anything definitive. I would suggest that the fish weighed somewhere between 60.5 and 53.6 pounds. If I had a choice, I would probably go with 60.5, because that was a verified weight. But as I mentioned, there may be a few pounds related to increased moisture. From time to time, this question has come up, and I remember checking my files concerning the increase in weight of a dead pike in ice water. I don’t have the data available at the moment, but it was probably around 5 to 7 percent.” Casselman also examined the cleithra and said the muskie was from the 1994 year class.
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| Interesting that the measurements at the time of the necropsy of 29.25" x 50.125" give an 800 formula weight of 53.6 lbs. which is EXACTLY the same as the scale reading.
The original measurements of 29.75" x 50.875" do no such thing. These measurements give the fish an 800 formula weight of only 56.28 lbs.
The same scale was also used for both of the weighings and was verified to be accurate.
The 5 to 7% weight increase Dr. Casselman speaks of would result in a weight of 56.28 to 57.35 lbs. which is confirmed by the measurements of 29.75" x 50.875".
Obviously this fish would never have been 60.5 lbs. alive. | |
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Posts: 3242
Location: Racine, Wi | Even more interesting is that he mentions that a larger fish like that is going to have to work harder to get the necessary amount of O2 for a larger size body based on the gill/body size.
With that being said, could lead to some details on patterning bigger fish as related to higher DO content in the water. If this holds true for all larger muskies, follow the higher DO, and find larger fish. For instance, in Wisconsin, big fish can be found deeper around the thermocline at times during the summer. Is this related to the water temp, higher DO due to the cooler deeper water, or a combination of the two. Then as water cools in the fall and there is more wind (at least that seems to be the case every time I'm on the water this fall), the bigger fish can slide shallower as there's more available DO to ease the burdon of oxegenating their larger body masses.
Okay, that's about as close as I'll come to trying to sound smart on this subject, but hopefully that is enough to get your brains kicking in and discussing...... | |
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| Of even further interest is that the fish was frozen from Dec. 14, 2010 to Apr. 8, 2011 and only shrunk 3/4" in length compared to the canadian record which supposedly shrunk 4" in length after being frozen only 8 days. | |
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Huge New Brunswick Muskie May Have Asphyxiated