Friday, May 26, 2017

RE: Spokesman Article on Harvesting Columbia Smallmouth


I fully understand both sides of this issue and have had this debate with both sides regarding the best possible scenario for an ideal plan to manage the bass population on the Columbia. There is scientific evidence that supports my arguments regarding the matter, which are as follows:

1. You will never rid the Columbia of bass species. They are here to stay, regardless of angler retention limits, or any other form of removal endorsed or funded by the state(s).

2. Reasonable slot limits are the most scientifically feasible way to positively impact the population in a manner that will likely reduce the consumption of smolts.

If the matter truly interests you in finding a solution, I would suggest studying some of the research that has been done in areas where the strategic eradication of smallmouth has been attempted through more extreme means. Over the course of five years, 48,000 smallmouth were removed from an Adirondack lake via electrofishing, an average of 300 per trip, which would be difficult for any angler to match that CPUE. If you want to read the entire study, I'll leave a link at the bottom, but here's a summary of what the researchers discovered during the course of the study, which can be found on the bottom of page 10, and continued on page 11:

"The optimal harvest strategy is highly dependent on the control objective. If the goal of the harvest is to reduce the
overall population abundance (regardless of demographic structure), then in situations in which the population’s reproduction rate at low spawner abundance is large, harvest will not be effective until very high levels are achieved. In such cases, it may not be beneficial to remove any individuals unless it is possible to remove nearly all of the population.
In other situations, the structure of the population may be of greater importance. For example, increased abundance of
large smallmouth bass (>200 mm) in Little Moose Lake has altered food web linkages and has had a measured impact on the abundance of other littoral fish species (Lepak et al. 2006; Weidel et al. 2007). Therefore a key management
goal is to minimize the impact of large bass (and reduce the total biomass of the bass) rather than simply reduce the
overall population abundance. In such cases, a management tradeoff exists between a reduction in abundance of one life stage and a potential overcompensatory response in another. In this scenario, continued regular harvesting may be necessary to maintain a reduction in adults. If it remains impossible to eliminate all bass from the lake, the best Little Moose Lake smallmouth bass management strategy may be to reduce the proportion of adult fish (>200 mm) that are harvested. The sensitivity analyses showed that removal of adults caused the largest increase in yearling and juvenile abundances. Because we do not have annual population abundance estimates, it is difficult to determine exactly how many adults should be harvested to both achieve the management objectives described above and not produce an overcompensation of yearlings or juveniles. However, some reduction in the harvest of adults would likely mitigate the observed overcompensatory response without producing large increases in adult abundance, as well as reduce the effort necessary to maintain the positive affects of the removal."

If you made it this far, thanks for taking an interest in being informed on the best possible management strategy, which also just so happens to be an ideal compromise for anglers of both fisheries. The most effective plan to significantly reduce the population of bass is one that specifically reduces the retention of adult-sized "trophy" bass. Compare this scientific data with the statements made by the biologists in the spokesman article:

"walleye and bass –notably the younger ones – take a lot of young chinook in the two-inch range as they hold in shoreline rocky areas, said Anthony Fritts, a department biologist who’s conducted research on smallmouth predation in the lower Yakima River."

^ This statement further supports evidence that an ideal strategy is to specifically target smaller bass (and walleye) for retention in order to reduce predation of smolts.

A reasonable approach to preserving a trophy bass fishery while maintaining retention of the abundant population of smaller fish in the system is a win-win for everybody, and all the fish species that inhabit the Columbia River.

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