Fisheries conservation has been a big interest of mine
for a long time, and I follow a number of the organizations dedicated to
protecting freshwater species and their habitats. One of those organizations,
Trout Unlimited, posted an article last fall celebrating the 40th
anniversary of Montana’s ground breaking decision to stop stocking its famous
rivers. Initially anglers and businesses across the state were furious with the
decision, which they believed would ruin one of the country’s best fisheries. Instead,
the absence of stocked fish has actually taken an already great fishery and
made it one of the premier fly fishing destinations in North America.
It seems counter intuitive to think that removing the
stocked fish could actually increase the quality of the fishery, but there is
sound science behind it. Dick Vincent, a Montana biologist, conducted a study
on state rivers where the stocking was suspended on one river, and introduced
to a previously wild one. On the previously stocked river wild populations of
rainbow and brown trout exploded in the first year and tripled the total
population from stocking days. The wild river which had stocked trout
introduced rapidly collapsed, with numbers of fish cut in half in the first
year and continual reductions in the following years.
There are a few simple reasons that Vincent found for
why the stocked fish have such a negative impact on the fishery. The first is
that within three months of stocking 95% of the fish have already died. About
15% is by anglers keeping their catch, while 80% is due to predation and being
unable to adapt to the new environment. The cost of producing the stocked fish
combined with the high fatality numbers made the tough decision to stop
stocking slightly easier, but it took a
couple years before the general population realized how brilliant this plan
was.
Reading this post you may be wondering what this has
to do with the Adirondacks, but this represents an
interesting opportunity for the New York State conservation authorities. By
looking at the 2014 stocking records for the legendary Ausable River near Lake
Placid, you will find that almost 43,000 trout were stocked in its waters last
year alone. Taking a page out of Montana’s books it may be possible to improve
this fishery greatly in a short period of time. The only real step we have to take
is to step back and watch the natural reproductive powers of these amazing
creatures reclaim their place in the rivers, occupied for so long by stocked
fish.
Montana Stocking- http://fwp.mt.gov/mtoutdoors/HTML/articles/2004/DickVincent.htm
NY Fish Stocking Numbers- http://www.dec.ny.gov/outdoor/23324.html
It seems like this case study is a prime example of nature's ability to bounce back and return to equilibrium given the right conditions. I would have never guessed that stocking a river creates a population that is less likely to survive but your explanation makes perfect sense. Although the initial population of a species may take a little longer to grow, the offspring of a wild fish are more likely to thrive in this environment than those that were raised in a fishery. I'm curious as to why the rivers began stocking in the first place. Was it simply to increase populations for fly fishing? I also wonder how the end of stocking had a noticeable effect on the rest of the ecosystem in these areas.
ReplyDeleteStocking began to help bolster fish populations which were crashing due to over harvesting and inadequate regulations. Once the fisheries recovered the stocking kept going because people believed they were necessary to keep fish numbers high. This article was a real eye opener.
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