What is Selective Harvest
By: Dave Serdar
Catch and release fishing has become very popular these days and for good reason.
Releasing most of the fish we catch is and will always be appropriate. For some
species, such as native trout, catch and release is necessary to maintain the
size and age structure of a population. The Stonefly Society would encourage
trout be released in most fisheries. This ethic has allowed us to enjoy high
catch rates and larger trout. Yet despite the obvious success in some fisheries
catch and release doesn’t work in all bodies of water.
Some species of fish have high reproductive capacities, such as panfish, catfish
and walleye. All fish can have stunted growth as they overrun their food base.
Certain tailwater fisheries can have far too many brown trout. And brook trout
commonly stunt in high mountain lakes. It is also important to realize that it
is necessary to harvest non-native trout to protect the native fisheries. For
example, In Idaho the Federation of Fly Fishers and the Idaho Fish and Game has
requested that all Rainbow trout be harvested from the South Fork of the Snake River.
In many cases, there are too many fish for the available food source or the available
habitat. In most cases where stunting occurs, there is a “bottle neck” in fish growth.
They grow well at first, slow down once they hit the “bottle neck”, and then grow fast
again once they are outside the “bottle neck”. The “bottle neck” is the size range
where there is too much competition for food or territory.
That is where selective harvest comes into play. Very simply, selective harvest is
the removal of fish within a certain size range, 8 to 10 inches for example. Selective
harvest can be used to remove fish that are in the “bottle neck”, thus reducing the
pressure on the food source. With fewer fish eating the same amount of food, they can
grow faster. In effect, selective harvest can remove the “bottle neck” and help
maintain a higher quality fishery. The Division of Wildlife Resources has listed
fisheries in the proclamation that could use some harvest. These include the Provo
River, Ogden River and Blacksmith Fork River for small brown trout.
There is a way for you, the fisherman to determine the size range that should be
caught for selectively harvesting a population. Simply, keep the fish in the size
range that you most commonly catch. For example, if you catch 18 trout on the middle
Provo River and 4 are less than 8 inches, 10 are between 8 and 12 inches and 4 are
over 12 inches then keep the fish in the 8 to 12 inch size range. That is where
the “bottle neck” occurs.
Fish in the lower size range should be released and given the chance to grow larger.
Fish in the upper size range, while tempting to keep should be released. Releasing
the fish in the upper size range allows the genetics that helped them get that large
to remain in the population for future generations. This also gives a few fish the
opportunity to grow to true trophy proportions. Please keep in mind that the fish you
keep are within the legal size and species regulations.
So try selectively harvesting some fish in the future, it is one way anglers can have
a direct impact on the future. It is also a good way to keep some of your catch for
the table, while helping to keep the fish population productive.