12-15-2005, 06:55 PM
[cool][#0000ff]I don't think anybody knows for certain what causes any of the dieoffs. It can be several different factors at work. In smaller size perch, they will sometimes die off because of a lack of food. When the water is not fertile enough to produce their food chain...algae, zooplankton, etc...they simply run out of food. [/#0000ff]
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[#0000ff]That can happen with larger perch too. If there are no larger aquatic insects or small minnows, prior to a spawn hatching out, they can expire before reinforcements arrive. And, only the largest perch can eat smaller perch once the young have grown beyond edible size. [/#0000ff]
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[#0000ff]There are also temperature and stress factors, created by drastic rises or drops in temperature. Perch are pretty hardy and can tolerate cold water, but they cannot live in poorly oxygenated water...such as that beneath a shallow reservoir that has an ice cap for too long.[/#0000ff]
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[#0000ff]I'm sure there are also different bacteria and viruses that perch are uniquely sensitive to. Never heard of "perch flu", but it is entirely possible that there is something like that. It might explain the multiple declines in the perch populations of the reservoirs in the Wasatch range.[/#0000ff]
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[#0000ff]We haven't seen a dieoff in Fish Lake. Too bad. Those perch helped wipe out the chubs which were the main fodder for the macks. The macks do not eat the perch nearly as aggressively as they did the chubs. Now the perch have overpopulated their environment and are all stunted. You can catch a lot of them in Fish Lake, but they are good for little except frying whole or cutting up for bait.[/#0000ff]
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[#0000ff]Agricultural runoff can be a problem in some waters, but apparently it is not a major one in Fish Lake. I'm sure there are ongoing water quality studies to monitor that. Maybe we could have our next perch derby on fish lake and award special prizes for sheer poundage, rather than numbers of fish. If DWR would relax all limits on perch for awhile, and encourage greater harvest of the little buggers, they would thin out and grow bigger.[/#0000ff]
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[#0000ff]That can happen with larger perch too. If there are no larger aquatic insects or small minnows, prior to a spawn hatching out, they can expire before reinforcements arrive. And, only the largest perch can eat smaller perch once the young have grown beyond edible size. [/#0000ff]
[#0000ff][/#0000ff]
[#0000ff]There are also temperature and stress factors, created by drastic rises or drops in temperature. Perch are pretty hardy and can tolerate cold water, but they cannot live in poorly oxygenated water...such as that beneath a shallow reservoir that has an ice cap for too long.[/#0000ff]
[#0000ff][/#0000ff]
[#0000ff]I'm sure there are also different bacteria and viruses that perch are uniquely sensitive to. Never heard of "perch flu", but it is entirely possible that there is something like that. It might explain the multiple declines in the perch populations of the reservoirs in the Wasatch range.[/#0000ff]
[#0000ff][/#0000ff]
[#0000ff]We haven't seen a dieoff in Fish Lake. Too bad. Those perch helped wipe out the chubs which were the main fodder for the macks. The macks do not eat the perch nearly as aggressively as they did the chubs. Now the perch have overpopulated their environment and are all stunted. You can catch a lot of them in Fish Lake, but they are good for little except frying whole or cutting up for bait.[/#0000ff]
[#0000ff][/#0000ff]
[#0000ff]Agricultural runoff can be a problem in some waters, but apparently it is not a major one in Fish Lake. I'm sure there are ongoing water quality studies to monitor that. Maybe we could have our next perch derby on fish lake and award special prizes for sheer poundage, rather than numbers of fish. If DWR would relax all limits on perch for awhile, and encourage greater harvest of the little buggers, they would thin out and grow bigger.[/#0000ff]
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