| FISH - INFO -1 |
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| Status Did you know the BULL TROUT isn't really a trout? Instead, it belongs to a branch of the trout family called "chars," along with the lake trout, (eastern) brook trout, and Dolly Varden (which was once considered to be the same species as the bull trout). The bull trout claims distinction among its char relatives and more distant trout cousins, by possessing the most extensive natural range in Alberta. Many people consider the bull trout to be the most "homegrown" of any sport fish in the province and therefore uniquely Albertan. It is perhaps the best candidate we have for Alberta's official fish emblem. Bull trout live in cold mountain headwaters where food is scarce and most species must struggle to survive. Bull trout are slow to mature and, consequently, many of the lakes and streams they inhabit can support only a limited harvest of fish. At one time, bull trout were common to all the major river systems flowing from the Eastern Slopes of the Rocky Mountains. Before the turn of the century, when numbers were probably at their highest, its range extended down the waterways and out into Alberta's prairie and parkland. However, during the last 30 years there has been a significant reduction in both the number and distribution of bull trout, primarily as a result of over fishing. Changes in habitat contributed to the species' decline, and so did the attitudes held by Albertans in the first part of this century. In the early 1900s, fish-stocking programs brought new species to many streams. Some anglers saw bull trout as unwanted predators that fed on the more savoured trout species introduced by people. From the 1930s to the 1950s, the removal of large bull trout from some streams was an accepted practice, because it was believed this removal would improve the survival of the other fish. Although the stocking of trout in these waters provided anglers with a greater variety of fishing opportunities, it also greatly increased the fishing pressure on the bull trout to the extent that its numbers began to decline steadily. At present, most anglers are not aware of the vulnerable state of bull trout populations, and they have difficulty distinguishing this species from other trout and char. In the United States, the American Fisheries Society considers the bull trout to be a "species of special concern" throughout its range. In Alberta, this species is not in immediate danger of extinction but could easily disappear from some of our lakes and streams. Description Can reach ages of more than 20 years and lengths of 30 to 70 cm, depending on the food available and growing conditions in their environment. They can weigh up to 10 kg. The largest bull trout recorded for Alberta was caught in 1947 from the Muskeg River. It weighed 11.7 kg! The bull trout is a long slender fish head and jaws are large in comparison to its body and long ago this shape inspired the term "bull." The tail fin is only slightly forked. A typical bull trout can be quite pale in appearance but if you glance upward from its white belly to its dorsal fin, you will notice a hint of color beginning with olive-green and turning to blue-gray. Along the sides and back, pale round spots in shades of yellow, orange, pink or red can be seen. Occasionally, the spots along the back may be elongated or wormlike in shape. In spawning males, the spots on the sides are brighter and the belly may be red or orange. Lake-dwelling bull trout may have a silver sheen to their sides and young bull trout often have 7 to 10 pale dark bands along their sides, separated by narrow light stripes. Bull trout are often misidentified, especially juveniles. The key to correctly identifying this species, however, is the absence of black spots on its dorsal fin. In fact, the Alberta bull trout Task Force uses the slogan "No black, put it back!" to help anglers identity bull trout so they may be released in support of population recovery plans for this species. Reproduction The reproductive potential for bull trout is naturally low. The fish mature slowly, often spawning for the first time in their fifth or sixth year. Those fish living in more unproductive waters may not spawn until their eighth year . In addition, some female bull trout do not spawn in consecutive years. Bull trout require stable, flowing water to reproduce successfully. They seek out small, spring-fed streams that can provide a continuous supply of oxygen for their developing eggs Therefore, suitable spawning streams will have steady winter flows, free-flowing spring-time flash floods, and clean gravel areas. Mature fish instinctively return to these areas in autumn; often to the very streams where their lives began. Water temperatures below 9�C trigger spawning, which occurs between mid-August and mid-October. Once a suitable site has been chosen, the female bull trout digs a nest or "redd" in an area where there is medium- to large-sized gravel without much sediment. The larger size of some females allows them to choose sites farther from the shore, to move larger stones, and to dig a deeper redd than the females of other fish species. This ability increases the chance of survival of the eggs. Once the female is satisfied that the depression is deep enough, she deposits up to 5000 eggs in the redd. Male fish swim nearby, and release milt to fertilize the newly laid eggs. The female then positions herself directly upstream from the redd. With the help of the current, she covers the fertilized eggs with gravel. When spawning is complete, males and females move downstream to overwinter. For the next six or seven months, bull trout eggs incubate in their gravel nests. Water temperatures of 2� to 4�C are ideal and the eggs begin to hatch during March and April. Young bull trout can remain in their nursery streams for one to five years. Some remain here for their entire lives, and others venture downstream into larger rivers or lakes. Another interesting aspect about this species' reproduction is that it can hybridize with brook trout. There is concern that the sterile hybrids produced could contribute to the decline of some bull trout populations, by reducing the reproductive potential of current and future generations. |