In Bone Lake....
It's a Question of Balance
Craig Sandell ©
There have recently been movements to increase the minimum
size limit for Musky to 48, 50 and even 55 inches, thereby assuring an almost 100% catch
& release. For those of us who suffered through the "Bad
Old Days" when almost every Musky caught was kept, the concept of a 100% catch
and release regulation seems to make sense. There is, however, sound reasoning that
indicates that intelligent harvesting of Musky in a fishery will actually make that
fishery a better fishery.
This reasoning is based upon the concept known as "Carrying Capacity." We all deal with the concept of
"Carrying Capacity" every day. If you overload your truck or car you may break a
spring, if you overload the electrical outlet you may blow a fuse and if you overload a
fishery you may end up doing more harm than good.
Preliminary findings from the Wisconsin
DNR's study of Bone Lake brings the concept of carrying capacity into a clearer
focus. Bone Lake has enjoyed the benefit of Musky stocking for many years. The larger size
of the fingerlings released has increased the survival rate of stocked fish. Consequently,
the Musky population is robust. However, the rate at which Musky are growing is less than
what was expected. Indeed, the average size of mature musky has actually
Lake is right on the cusp of having too may fish chasing too little forage.
As another example, lets take one of the Wisconsin lakes where a 50 inch limit has been
imposed for no other reason than to attempt to create a "Trophy Fishery". Lac
Courte Oreilles is identified by the DNR as a Class "B" lake. That means that
the lake is not capable of sustaining a completely viable Musky population without some
stocking intervention. The pyramid chart shown here demonstrates a normal profile for a
fishery and, for the purposes of this discussion, we will assume that Lac Courte Oreilles
was balanced in this manner prior to the 50 inch size limit. The Musky at the top of the
pyramid represent a population of top line predator that is small enough so as not to put
undue stress upon the other resources of the fishery. The population of the mid-level
predators is larger than the Musky population but not so big as to overtax the forage base
that occupies the lowest level of the fishery pyramid. As long as this fishery maintains a
relative balance between these pyramid levels, the fishery will be healthy and productive
within its capacity.
that Lac Courte Oreilles has a 50 inch Musky limit, the harvest of Musky will be
significantly reduced. The Musky that are the "eating machines" will not be
culled and will therefore place pressure upon the mid-level predators as they seek to
satisfy their appetite. (This has been seen in Bone Lake.)
The hour glass chart shown here is a projection of how the
balance of the fishery may be distorted over time. As more and more Musky eat more of the
mid-level predators, they make it more difficult for the mid-level predators to establish
a mature spawning population. The numbers of the mid-level predator will decline making it
harder for Musky to catch the fish they must in order to have normal growth patterns. As
mid level predator numbers decline, the forage base will undergo a population expansion.
These increased numbers will eventually place a greater burden upon the ecological system
of the fishery. Unless the mid-level forage base is replenished, the fishery will move
toward an imbalance that will eventually cause the collapse of the fishery.
True, mid-level predators can have their populations
increased by stocking. Of course, stocking is an expensive activity and with the imbalance
at the top of the food chain, the only thing that stocking will accomplish will be to
provide more food for the Musky. The other solution is to harvest some of the Musky and
relieve the stress upon the mid-level predator population thereby placing us right back
where we started before the 50 inch limit was imposed.
Although most Musky anglers consider themselves
'extremists' when it comes to conservation of the Musky resource through a devotion to
catch & release; it appears as though, in some instances, conservation and care of the
fishery is better served through the application of intelligent harvesting.