There was some discussion/criticism about high bou bag limits here in Alaska on another thread. Since the WACH is the largest herd, with very generous bag limits, I thought I would copy/paste a few blurbs from a recent article by a F&G bio:
By JIM DAU
Alaska's largest caribou herd, the Western Arctic herd numbered about 401,000 animals as of July 2009 according to the Alaska Department
of Fish and Game.
The Western Arctic herd last peaked around 2003 at 490,000 caribou.
Biologists classify factors that limit the size of caribou herds into two categories: density dependent and density independent factors. Density
dependent factors exert a greater negative force on the caribou population as it grows. Examples of density dependent factors are range
condition, predation and disease. Density independent factors possess effects not related to caribou herd size, such as weather or resource
development. Both types of factors can affect caribou herds simultaneously, and predators can shift from a prey species that becomes scarce
to one that is more abundant. This web of interactions makes it difficult to understand what causes caribou numbers to change.
Although the Western Arctic herd has numbered over or around 400,000 caribou since 1990, the body condition of caribou from this herd has
consistently remained. Additionally, the department has found no evidence that disease has become a problem for this herd. So far, it
appears that the herd is not being limited by density dependent factors. Instead, the decline of this herd from 2003 to 2007 may have been
largely attributable to severe icing during one or two winters.
In 1970, the herd numbered 242,000 caribou but then declined to roughly 75,000 individuals by 1976 - an 18 percent annual rate of decline
The department recently intensified its monitoring program so that when this herd next declines it won't catch anyone by surprise.
The next census is scheduled for 2011.
The above lines are from The Arctic Sounder, if you want to read the whole thing.
This herd has been very healthy for over 20 years. High bag limits have not contributed to any overharvest. Plenty of hunting opportunity. Likely if this herd ever suffers a substantial decrease in size, it will NOT be from human harvests.