Michigan Muskie Alliance

Forgot to give a big AttaBoy for our MC Tim Mottes!!

jasonvkop wrote:

Mayhem wrote:

jasonvkop wrote:. What was the remarkable stat he gave at the end of the presentation? A 2% increase in harvest is equivalent to a 30% decrease in reproduction output? .

2% increase in annual mortality would lead to a 70% decrease in reproduction output.

That's insane! I'm obviously biased, but that seems like a no brainer to have stricter regulations on waters like the Chain and Black/Burt/Mullet.

This is the quote in context from the paper Patrick referenced.

“The high exploitation on muskellunge observed in Elk and Skegemog lakes likely impacts both size
structure and abundance to some degree. While the size structure is still very good, it could probably
be even better. The impact of harvesting large, old muskellunge on a population is such that a 2%
increase in annual mortality (18% to 20%) of trophy muskellunge is comparable to a 70% reduction in
recruitment to the population (Casselman et al. 1996). Although the proportion of released muskies that
were legal size is unknown, without voluntary catch and release, it is likely that angler harvest would
have likely exceeded levels needed to sustain the fishery.”

Will Schultz wrote:
This is the quote in context from the paper Patrick referenced.

“The high exploitation on muskellunge observed in Elk and Skegemog lakes likely impacts both size
structure and abundance to some degree. While the size structure is still very good, it could probably
be even better. The impact of harvesting large, old muskellunge on a population is such that a 2%
increase in annual mortality (18% to 20%) of trophy muskellunge is comparable to a 70% reduction in
recruitment to the population (Casselman et al. 1996). Although the proportion of released muskies that
were legal size is unknown, without voluntary catch and release, it is likely that angler harvest would
have likely exceeded levels needed to sustain the fishery.”

Okay, I want to make sure I have this worked out correctly in my head...
If the annual mortality increases 2% (from 18% to 20%) that would basically mean 30 baby muskies are getting hatched/spawned that given year instead of 100 baby muskies? I obviously made up the 30 and 100 numbers, but wanted to make sure I have the terms 'recruitment to the populations' correct.

Secondly, if the DNR Biologists know the fishery isn't sustainable at the current catch/kill levels, how haven't there been any changes in the restrictions? Are they giving the tag system a couple years to see what effects that has on the system?

jasonvkop wrote:

Will Schultz wrote:
This is the quote in context from the paper Patrick referenced.

“The high exploitation on muskellunge observed in Elk and Skegemog lakes likely impacts both size
structure and abundance to some degree. While the size structure is still very good, it could probably
be even better. The impact of harvesting large, old muskellunge on a population is such that a 2%
increase in annual mortality (18% to 20%) of trophy muskellunge is comparable to a 70% reduction in
recruitment to the population (Casselman et al. 1996). Although the proportion of released muskies that
were legal size is unknown, without voluntary catch and release, it is likely that angler harvest would
have likely exceeded levels needed to sustain the fishery.”

Okay, I want to make sure I have this worked out correctly in my head...
If the annual mortality increases 2% (from 18% to 20%) that would basically mean 30 baby muskies are getting hatched/spawned that given year instead of 100 baby muskies? I obviously made up the 30 and 100 numbers, but wanted to make sure I have the terms 'recruitment to the populations' correct.

Secondly, if the DNR Biologists know the fishery isn't sustainable at the current catch/kill levels, how haven't there been any changes in the restrictions? Are they giving the tag system a couple years to see what effects that has on the system?

Not exactly. The reduction is related to a reduction in the mean age of the population.
"with as little as a 2% increase in annual mortality causing a reduction in mean age of muskellunge from 23 years to 21 years, which is comparable to a 70% decline in recruitment"