One of my biggest objections to hunting in general and trophy or big-game hunting in specific is the strongly negative effects it has on overall health, population structure and species-specific behavior (especially in lek-breeding species) of almost all large-animal prey. In general, human hunting of large game is biased to healthy adult animals, and trophy hunting in particular is biased to larger (and therefore older and healthier) adult males, particularly those with unusually pronounced secondary sexual characteristics (bigger horns, larger mane, etc); in other words, the prime breeding stock. Furthermore, preferential removal of males leads to distorted sex ratios among the remaining population, which can have seriously deleterious consequences in and of itself.
Even in the case of abundant species where artificial population control is required to prevent overpopulation, discretionary hunting (as opposed to directed culling) produces smaller, less healthy animals with more abnormal traits, as compared to populations still undergoing natural predation or directed culling (i.e., preferential removal of abnormal or sickly animals).
To be clear, I have no objection to hunting animals per se. But in the case of a wild population, the long-term health of that population should be the primary consideration, NOT the preferences or desires of the individual hunters. Trophy hunting in particular should be strictly regulated to ensure that it does not seriously disturb the sex and age structure of the population and that sufficient “trophy” animals are left as breeding stock.
Hunting for subsistence or for population control should be in concordance with management strategies that preserve the genetic and behavioral structure of the population, which may require incentives to harvest animals of a less preferred age/sex/phenotype or penalties for harvesting animals that should be retained. In the extreme case, discretionary hunting may have to be suspended to allow for directed culling for one or more seasons (many whitetail populations in the US could benefit immensely from a few seasons of directed culling).
The primary literature on this topic is, as for most scientific topics, largely not publicly available; here’s the only relevant cite that I could find in a few minute’s searching that was free (warning: not written for a lay audience):
DW Coltman, P O’Donoghue, JT Jorgenson, JT Hogg, C Strobeck and M Festa-Bianchet. “Undesirable evolutionary consequences of trophy hunting.” Nature 426 (2003): 655-658. Available as a PDF from Dr Coltman’s website.
Abstract:
Phenotype-based selective harvests, including trophy hunting, can have important implications for sustainable wildlife management if they target heritable traits. Here we show that in an evolutionary response to sport hunting of bighorn trophy rams (Ovis canadensis) body weight and horn size have declined significantly over time. We used quantitative genetic analyses, based on a partly genetically reconstructed pedigree from a 30-year study of a wild population in which trophy hunting targeted rams with rapidly growing horns, to explore the evolutionary response to hunter selection on ram weight and horn size. Both traits were highly heritable, and trophy-harvested rams were of significantly higher genetic ‘breeding value’ for weight and horn size than rams that were not harvested. Rams of high breeding value were also shot at an early age, and thus did not achieve high reproductive success. Declines in mean breeding values for weight and horn size therefore occurred in response to unrestricted trophy hunting, resulting in the production of smaller-horned, lighter rams, and fewer trophies.
Other cites on request, although no guarantees as to public availability.
JRB, biologist (although admittedly not a wildlife biologist)