Recovery after relaxation, or even reversal, of selectiveharvest is likely to be slower than the initial accumulation ofharmful genetic changes (98).
Would this require more extreme or intense measures to ensure a consistent improvement in genetic diversity? If so, what kind of scale would be appropriate to begin these changes on, considering it hasn't really been considered in North America, and we haven't seen the effects?
How effective can managementbe in detecting and countering these effects?
Another question would be: even with this data available, would the potential risks of reducing genetic quality outweigh the demands of other stakeholders (e.g. managing stands for a private landowner to achieve their specific objectives).
Such selection is likely to beeffective when populations are rare, phenotypes are dramatic, andopportunity for harvest by humans is substantial. Highly selectivecollection practices could affect the sustainability of these tradesand the conservation of rare species (77, 78).
I think this puts an interesting spin on the exotic animal trade argument and the boundaries that should be drawn in terms of captive breeding for pets and keepers. I.e. Does captive breeding for unnatural morphs actually help with harvest of wild populations, or does it stimulate the market more?
The actions of collectors, which mostcommonly target vertebrates, such as tropical fishes, and inverte-brates, such as arthropods and gastropods, could impose selectionon wild populations through the removal of specimens conspicuousby their large size and appearance.
Is this such a disadvantage for inverts? Wouldn't inconspicuity be beneficial for avoiding natural predation? Actually, thinking about it, this could be bad on a grander scale, for predators that primarily feed on whatever species are being harvested, and invert populations could increase dramatically instead.
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
I'm not overly familiar with many species of North American game species, but this seems like a potentially misleading generalization. White-tailed deer, for example, seem like a pretty large exemption. They're the most hunted mammal in the US, and their populations are not hurting in (arguably) most areas. In addition, there are over 30 acknowledged subspecies in the Americas (many of which occur due to geography). Is this potentially evidence of extreme speciation based on hundreds of years of harvest?
The temporal dynamics of life history appear toreflect the combined influences of a half century of natural andfishing selection; growth rate and reproductive investment atyounger ages tended to decline during periods of higher exploita-tion, a pattern that diminished when fishing rates eased.
I'm trying to imagine management plans that take this in mind. Rotating fishery bodies (via accessibility or creel limit), shifting acceptable length limits (which would still affect size distribution, since anglers are more likely to keep the larger species regardless), improving identification knowledge to distinguish sexes and level of maturity...
Handfordet al. (25) stated that management was ‘‘seriously deficient in [itsfailure] to take into account the possibility of adaptive geneticchange in exploited stocks of fish.’’
While this is a fair concern based on previous claims in this article, fish are some of very few taxa bred for stock via hatcheries. If areas are already receiving artificial population increases from these stocks, would it not be possible to work on selectively breeding or genetically engineering these fish to improve their genetics?
Edit: I just remembered that released fish are generally sterile, however, the framework is still there.
Fish can be killed through fishing either as immature ormature individuals, depending on the characteristics of theindividual fishery; the point in the life history at which fishingmortality is exacted has important ramifications for fisheries-induced evolution (17). The relatively high fecundities and highnatural mortality rates, especially early in life, for many fishes,mean that although fishing mortality can be high in some years,it is not often as high as natural mortality. By contrast, huntingmortality is often substantially higher than natural mortality for
With fish being more naturally vulnerable, and game species seeing higher mortality from hunting, would that mean it's more important to evaluate the genetic impact from hunting than fishing? Fishing can be highly selective and impactful in addition to natural mortality (depending on the area).
Fisheries and wildlife managers have yet to adopt manage-ment strategies that guard against rapid evolutionary response toexploitation
I guess this answers my other question. Is it just deemed unimportant by managers? Is it due to a lack of data? Would a more holistic management plan with genetic data be able to mitigate this?
Nevertheless, Coltman (12) argued thatrapid contemporary evolution has now been shown to occur inresponse to invasive species, habitat degradation, and climatechange, and exploitation, and he went on to say that exploitation-induced evolution may well have the most dramatic impact of anyof these anthropogenic sources of selection to date
With all of these other anthropocentric changes, does unnatural selection really have that big of an impact in comparison?
‘‘Natural’’ is sometimes defined as not being affected byhuman influence (10)
I don't believe anything on this planet's land mass is still 100% "natural" under this definition.
Therefore, harvest of wild populations has tended to increase thefrequency of less desirable phenotypes in wild populations.
Is this ever a consideration when deciding wildlife management practices?
Suchselective removal will bring about genetic change in harvestedpopulations if the selected phenotype has at least a partial geneticbasis (Table 1)
I'd be interested to see if this was the case for commonly hunted North American megafauna, such as white-tailed deer, since those are primarily selected based on sex and body condition.