Tiger trout — myth or fact?/Biological bits
Since this is being composed in sunny Lakeland, Fla., where moi is scouting our Detroit Tigers for the upcoming season, and in keeping with the spirit of this column, the subject of tigers and trout is appropriate. What is the difference between an avid Tiger fan and a Tiger trout? One is a pseudo-mythological creature, with supernatural powers and knowledge, much like the abominable snowman or yeti, and the other is a fish.
Yes, there is a fish called a Tiger trout, of which most of you have never even seen a photograph. Many biologists have likewise never handled one, as they are very rare in nature. They are naturally occurring in streams where brook and brown trout coexist. They are also produced in hatcheries. They are a sterile hybrid cross between a female brown trout Salmo trutta and a male brook trout Salvelinus fontinalis. They cannot be crossed the other way, female brook trout by male brown trout, because the brookie’s egg is too small to be fertilized by brown trout sperm. The name comes from the “tiger-like” stripes on the sides. The tiger-like markings are called vermiculation, a worm-like pattern, which is found on the backs of all brook trout. They are beautiful and each individual fish is unique. Some look like their brook trout parent, having red fins, with a white front edge. Others look more like their brown trout parent, having a yellowish coloration. Naturally produced tiger trout look more like their brookie parent, while hatchery tigers look more like their brown trout parent. I highly recommend you look on the Internet for photographs.
They are rare in nature, as survival of eggs and fry is very limited, being about five percent. This is due to the parents being very unrelated, recalling brown trout are transplants from Europe, while brook trout are native to the U.P. In other words, the family tree of trout, brooks and browns are widely separated. The brown trout have 80 pairs of chromosomes, while brook trout have 84. This is not good for high survival and usually leads to deformities or death in species not closely related. Another factor leading to this sterile hybrid being rare, is the spawning time of brook and brown trout, with brookies typically spawning later than brown trout. Wild tiger trout are typically found in streams with a higher brook trout population.
In a hatchery, the survival to fry is increased to 85 percent by heat shocking the fertilized eggs, which is done by simply placing them in warm water. This action produces another set of chromosomes, scientifically called diploidy, and dramatically increases survival.
So you want to catch a tiger trout? Well, if the muskie is a fish of 10,000 casts, the tiger trout must be a fish of at least a million casts or more, at least in Michigan or neighboring Wisconsin. Tiger trout are reported to be, pound-for-pound the most aggressive and have the best fighting ability of any trout. This title fits well with its name. They are found in at least 21 different states and Saskatchewan, Canada, New Zealand, Australia and the United Kingdom. If you really want to catch a tiger trout, there are eight states that stock them and provide good opportunity for success. The world-record tiger trout, which weighed in at 20 pounds, 13 ounces, was caught in the Wisconsin waters of Lake Michigan in 1978. Wisconsin stocked them in Lake Michigan from 1974-77. A very large stream tiger would be 5-6 pounds, while they grow to 15 in a lake or pond environment.
In Michigan they have been caught by anglers or captured in DNR surveys in the South Branch Paint River, Iron County, Pine River, Osceola and Wexford Counties, and Upper Manistee River, Kalkaska County. However, you would have a chance, albeit slim, of catching a tiger trout anywhere in Michigan where brooks and browns co-exist. A few places in the U.P. come to mind, the East Branch of the Ontonagon, the Jumbo River, tributary to the East Branch Ontonagon, and the Middle Branch of the Escanaba River. How many casts did you say to catch one?
From Florida, with palm trees, green grass, and the crack of the bat…