Forexample, trophy hunting might reduce or eliminate alleles for largehorn size, but gene flow from areas with no hunting might quicklyrestore alleles associated with large horn size (12).
This reminds me of the rescue effect in metapopulation dynamics. However, instead of organisms within populations being rescued, genes are being returned from the population to prevent the loss of that genotype from a population.
Theory predictsthat the more abundant sex will become less choosy in matechoice and more aggressive in competition for mates (86)
It is interesting to see that there is not only a morphological/physiological consequence to selection but also a behavioral change, such as increased aggression for mates.
In addition, collection of especially attractive morphs was compet-itive so that some attractive morphs were purposefully overcollectedbecause they were more valuable when they became rare.
The subspecies of butterfly that I studied this past summer has a history very similar to this. The man that was credited with first discovering the subspecies also purposely killed the butterflies (which were already endangered) in order to increase the price of the butterflies when sold to collectors. It is absolutely abominable.
With regard to the loss of genetic diversity thatcan result from hunting mortality, Harris et al. (52) and Allendorfet al. (6) focused on the relationship between harvest and declinein heterozygosity or allelic diversit
Is this loss of genetic diversity causing these populations to become more susceptible to other issues, including disease and an increased likelihood of genetic disorders? Has this been documented in widely-hunted species, such as deer in North America? How would this influence other trophic levels and aspects of the ecosystem?
European wildlife managers have paid more attention than theirNorth American counterparts to the selective effects of hunting,and hunting in Europe has often targeted specific phenotypiccharacteristics of game; as a result, European hunting regulationsare typically more specific than American regulations (18, 52).
It is interesting to see how significantly the human dimension of hunting, ultimately, influences the genetics of the population being hunted. This really underscores how important awareness and perspective are in conservation.
Kendall et al. (44) estimated standard-ized selection differentials for a 60-year dataset of Bristol Baysockeye salmon (Oncorhynchus nerka) and found that selectionintensity often differed substantially between sexes of returningfish and among years, although selection was generally higher onlarger fish (especially females)
I would expect this unnatural selection to also alter the wild sex ratios, especially if males and females vary in the traits that humans are selecting.
Unfortunately, fisher-ies tend to impose selection that alters distributions of charac-teristics that affect fitness and population viability, principallythrough removal of larger and older fish that differ in growth,development, and reproductive characteristics
It surprises me that fisheries would not take these selection effects into consideration, considering the traits will impact the "fitness and population viability." This is a strong example of the fact that the economically sustainable option is often at the intersection of the ecologically sustainable option.
Fisheries and wildlife managers have yet to adopt manage-ment strategies that guard against rapid evolutionary response toexploitation
If the concern with current exploitation is the proliferation of damaging genes in a population, could a captive breeding and reintroduction program reintroduce the beneficial genes? Even if this were to be a viable option, the captive breeding of endangered individuals is already not as widespread as it ought to be, so the captive breeding of commercial, nonendangered species would not likely receive funding.
exploitative selection
How are we defining "exploitive selection" in this article? Is it merely harvesting at a rate faster than the individuals are replaced in the population? In the context of this article, a better definition may also include the component that exploitive selection causes deleterious genes to proliferate in a population. Just a thought!
Unnatural selection generally acts at cross purposes to thelong-term goal of sustainable harvest of wild populations and canreduce the frequency of phenotypes valued by humans.
If unnatural selection functions at odds with the goals of sustainable harvesting, how would we mimic natural selection? Could a modeling system be made for a population to determine the "likelihood of natural selection" in order to have the beneficial genes persist within a population? How would we balance this "natural selection mimicry" while still delivering the desired "product" to people? So many questions!
The most desirableindividuals have been harvested, leaving behind the less desir-able to reproduce and contribute genes to future generations.
If these less desirable genes are increasing in the population, I would expect these traits to be eventually selected against by natural selection. This becomes concerning because if the beneficial genes that would allow the population to persist are being removed (and the less desirable genes will eventually be selected against), the population could suffer from extinction (or at least extirpation in areas with high harvesting).