03-11-2005, 02:39 PM
From the UDWR website:
"Chub numbers have fluctuated since they were first sampled in our gillnetting in 1992, with their numbers generally increasing from 1998 to 2002. However, chub catches decreased in the fall of 2003 by 25 percent from the previous fall. More specifically, the catch of one and two year old chubs decreased by 61 percent and 37 percent respectively. These fish are within the preferred prey size range for cutthroat. Once a chub grows beyond about six inches they are no longer as susceptible to cutthroat predation. Along with these declines in chub numbers, the predatory behavior of cutthroat on these fish also increased. Diet composition indicated that 28 percent of all cutthroat in Strawberry were feeding primarily on nongame fish (chubs and shiners), while 47 percent of the cutthroat over 18 inches, and 64 percent of the cutthroat over 20 inches were feeding on these fish. The more big cutthroat there are in Strawberry, the more likely it will be that they can help control the expansion of these undesirable nongame fish.
To give an example of how many chubs and shiners these cutthroat predators can eat, if the population of cutthroat in the fall of 2003 preyed on these nongame fish at the rates we saw in the diets from the gillnetting for the entire month of October, 87 tons of chubs and 19 tons of shiners would be eaten. This would equate to nearly 2.5 million chubs and 1.1 million shiners being consumed during October. The cutthroat in Strawberry can have a dramatic impact on the chub populations if given a chance.
Aside from being a good predator, the Bear Lake cutthroat have been shown to be able to survive in spite of high chub abundance. They are able to do this by being good competitors for the same food resources. Rainbows, on the other hand, have time and again demonstrated that they cannot compete with chubs for the same food resources. Therefore, if chub numbers increase to a point where the rainbows that are stocked do not survive, then we will have to modify our program to accommodate this change. However, we are far from that point yet. All of the gamefish species seem to be finding plenty of food to survive, and we are still hopeful that it will remain so for a long time.
The new fishing regulations imposed on Strawberry in 2003 have already begun to show noticeable improvements to the fishery. The population of adult cutthroat has increased beyond our initial expectations, and there are more of the older (larger) cutthroat than we have seen in the past. These improvements in the cutthroat population have resulted in reductions in the undesirable chub populations. Fluctuations in the chub population are expected, and it is not likely that cutthroat predation will ever eliminate or even fully control chub populations in Strawberry. However, cutthroat can have a fairly dramatic impact if given the chance, and it is likely that chubs will not be able to out-compete and overpopulate to the point that they severely limit cutthroat production."
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"Chub numbers have fluctuated since they were first sampled in our gillnetting in 1992, with their numbers generally increasing from 1998 to 2002. However, chub catches decreased in the fall of 2003 by 25 percent from the previous fall. More specifically, the catch of one and two year old chubs decreased by 61 percent and 37 percent respectively. These fish are within the preferred prey size range for cutthroat. Once a chub grows beyond about six inches they are no longer as susceptible to cutthroat predation. Along with these declines in chub numbers, the predatory behavior of cutthroat on these fish also increased. Diet composition indicated that 28 percent of all cutthroat in Strawberry were feeding primarily on nongame fish (chubs and shiners), while 47 percent of the cutthroat over 18 inches, and 64 percent of the cutthroat over 20 inches were feeding on these fish. The more big cutthroat there are in Strawberry, the more likely it will be that they can help control the expansion of these undesirable nongame fish.
To give an example of how many chubs and shiners these cutthroat predators can eat, if the population of cutthroat in the fall of 2003 preyed on these nongame fish at the rates we saw in the diets from the gillnetting for the entire month of October, 87 tons of chubs and 19 tons of shiners would be eaten. This would equate to nearly 2.5 million chubs and 1.1 million shiners being consumed during October. The cutthroat in Strawberry can have a dramatic impact on the chub populations if given a chance.
Aside from being a good predator, the Bear Lake cutthroat have been shown to be able to survive in spite of high chub abundance. They are able to do this by being good competitors for the same food resources. Rainbows, on the other hand, have time and again demonstrated that they cannot compete with chubs for the same food resources. Therefore, if chub numbers increase to a point where the rainbows that are stocked do not survive, then we will have to modify our program to accommodate this change. However, we are far from that point yet. All of the gamefish species seem to be finding plenty of food to survive, and we are still hopeful that it will remain so for a long time.
The new fishing regulations imposed on Strawberry in 2003 have already begun to show noticeable improvements to the fishery. The population of adult cutthroat has increased beyond our initial expectations, and there are more of the older (larger) cutthroat than we have seen in the past. These improvements in the cutthroat population have resulted in reductions in the undesirable chub populations. Fluctuations in the chub population are expected, and it is not likely that cutthroat predation will ever eliminate or even fully control chub populations in Strawberry. However, cutthroat can have a fairly dramatic impact if given the chance, and it is likely that chubs will not be able to out-compete and overpopulate to the point that they severely limit cutthroat production."
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