" F1 Splake: An Annotated Bibliography and Literature Review"

By: S. J. Kerr

The following is a precise of the above mentioned article. 

The splake is a man-created hybrid between our two native trout resulting from the fertilization of lake trout eggs with brook trout sperm. The hybrid combines many of the qualities of its parents – including the brook trout’s fast growth and the lake trout’s large size.

• Hybrids are intermediate in the characters of both their parents.

• Preferred temperatures can be influenced by the thermal history of the fish but generally F1 hybrids prefer waters near 12º C while F3 and F4 hybrids favor temperatures in the 15 – 16º C range.

• Growth is generally rapid. Relative growth rates change with age.

• Maturation is intermediate from both parents (i.e., 1 – 2 years later than brook trout and 3 – 4 years earlier than lake trout).

• Splake have a much broader range in seasonal spawning time than either parent.

• Hybrids frequent relatively shallow waters during the spring and fall. In summer they aggregated near the thermocline concentrating within the 8 – 20º C isotherm.

• Splake prefer barren, clear water of medium-sized lakes ranging from 50 – 200 acres in size with maximum depths of 40 – 80 feet.

• The hybrid has a more rapid growth rate than either parent and a longer life span than the brook trout.

• Splake feed heavily on crustaceans and insects during early life and gradually become more piscivorous as size increases.

• Splake have a strong tendency to school which often gives rise to short periods of intensive angling success.

• Splake are excellent fighters with flesh which is pink through orange in color and is highly regarded for its eating qualities.

• Unlike many hybrids, the splake is able to reproduce and while it prefers the gravel seepage shoals usually used by brook trout for lake spawning, in the absence of these it will use the boulder shoals favoured by lake trout.

• Splake are usually mature in their third year of life and their spawning period falls closer to thatof the brook trout in late October or early November.

.The largest splake, currently on record with the National Fishing Hall of Fame, is a fish weighing 20 pounds 11 ounces (9.38 kg) .

Because of their intermediate nature, many anglers many not realize they have caught a hybrid trout unless they know what to look for. The spots are usually pinkish, although many fish have little or no colour, and the tail is generally intermediate between the deeply forked tail of the lake trout and the square tail of the brook trout. The only positive way to tell is to open up the fish and examine the worm-like projections on the front part of the stomach. These are called pyloric caeca and function in digestion. Lake trout have 100 – 190 of them and brook trout have 20 – 50, and splake usually have 70 – 80. A character such as this is much more reliable than external appearance. It is important to identify your catch correctly in lakes  known to contain splake because the catch limit for splake is less than it is for brook trout and you are responsible for knowing which you have.

       Experiments with developing Splake have been around since the late 1800's. Between 1915 – 1917 reference was made to crossing brook trout and lake trout at the Port Arthur federal fish hatchery in Ontario (Scott 1956). As far back as 1946, this cross was undertaken in western Canada and third generation fish have been produced there. It may be interesting to note that the cross can only be made successfully byusing lake trout females and speckled trout males. In the reverse cross, the speckled trout eggs is too small for the developing embryo.

    After the collapse of the lake trout population in the upper Great Lakes, the Department of Lands and Forests embarked on a trout rehabilitation program during the late 1950s. The species chosen for the job was the splake, a cross between the lake trout and the brook trout. What was desired was a fish with the early maturing characteristics of the brook trout and the deep swimming ability of the lake trout.

    Geneticists refer to the progeny of the first cross as the F1 generation. The hybrids are fertile so an F1 male may be crossed to an F1 female to produce the second generation known as F2 splake. This process may be repeated indefinitely giving rise to F3, F4, F5 splake and all possible combinations of crosses such as F2 x F5. It is also possible to breed splake back to either parent species. Progeny of these crosses are called "backcrosses". Geneticists now know that the splake is a stable hybrid which will not revert to the parental species. Selective breeding of splake has been successful in two important respects. First, they mature at age 3 or younger like the speckled trout; this is four to five years earlier than lake trout. Second, they occupy deep water; the latter characteristic is similar to that of lake trout which differ from brook trout in their ability to retain swimbladder gas.

    An intensive study of their life history and habits has been made. Water temperature is an important factor which determines distribution of splake.  Their depth distribution in lakes in the summer months is similar to that of the speckled trout, that is, they live in the layer of water between the warm surface layer and the deep cold layer. In the smaller lakes this is generally in depths of 20 to 35 feet. Their food habits are similar to those of the speckled trout as they feed extensively on invertebrate forms of crayfish and insects, switching to a fish diet after several years of growth. The predatory habits of splake more closely resemble lake trout  than brook trout. Young splake (e.g., yearlings) feed primarily on invertebrates while older splake feed predominantly on fish

    In Ontario, there was interest in splake for two reasons: (i) to provide recreational fishing opportunities in inland waters where plantings of brook trout and lake trout had been relatively unsuccessful, and (ii) to create a deepwater salmonid predator which could be utilized to rehabilitate degraded lake trout stocks in Lake Huron. Although the F1 splake is a fertile hybrid, it is used primarily to provide put-grow-and-take angling opportunities.

The hybrid trout is an excellent game fish, although here too, it reveals its split personality. Some fight much more like speckled trout while others fight deep and doggedly like lake trout. The hybrid has a very marked schooling behavior and this profoundly affects your fishing luck. The splake is an excellent game fish, most frequently fighting like the brook trout, but occasionally diving deep like the lake trout. It appears more vulnerable to fly fishing and other means of angling than either the brook trout or lake trout.

this is a brook trout, not a splake.

The result from the fertilization of lake trout eggs with brook trout sperm

Splake