ALCES VOL. 46, 2010 CHILD ET AL. - VULNERABILITY AND ANTLER REGULATIONS 113 POTENTIAL VULNERABILITY OF BULL MOOSE IN CENTRAL BRITISH COLUMBIA TO THREE ANTLER-BASED HUNTING REGULATIONS Kenneth N. Child1, Daniel A. Aitken2, Roy V. Rea3, and Raymond A. Demarchi4 16372 Cornell Place, Prince George, British Columbia V2N 2N7, Canada; 2College of New Caledonia, 3330 22nd Avenue, Prince George, British Columbia V2N 1P8, Canada; 3Natural Resources and Environmental Studies Institute, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada; 4934 Khenipsen Road, Duncan, British Columbia V9L 5L3, Canada. ABSTRACT: Antlers from bull moose (Alces alces andersoni) harvested in the Omineca sub- region of central British Columbia were submitted by hunters for inspection, measurement, and comparison by age in 1982-1989. After correcting for non-reporting bias, we examined the potential vulnerability of these moose (n = 1,886) to 3 antler-based hunting regulations currently advertised in British Columbia: spike/fork (S/F), tripalm (TP), and 10 point (10PT). The S/F regulation put 15.9% of all bulls at risk, and the TP and 10PT regulations put 11.1% and 12.0% at risk, respectively. Bulls with cervicorn antlers were at higher risk (41.3%) to the S/F regulation than the TP (1.4%) or 10PT (<1%) regulations. By contrast, bulls with palmicorn antlers were at low risk (5.4%) to the S/F regulation, but were at high risk to the TP (19.0%) and 10PT (17.1%) regulations. The S/F regulation focused harvest on yearlings, potentially exposing 46% of yearlings to harvest. The TP regulation exposed 20-40% of bulls older than 4.5 years of age; whereas, the 10PT regulation exposed 40-60% of bulls >7.5 years of age to harvest. Maximum spread and shaft circumferences of antlers were significantly smaller for yearlings at risk to the S/F regulation than for their same aged counterparts not at risk. Distance between the innermost points on the brow palm was significantly larger for yearlings at risk to the S/F regulation than for yearlings not at risk. Maximum spread, shaft circumference, palm height, and width were all significantly greater for bulls at risk to the TP and 10PT regulations than for those not at risk. Distance between the innermost points on the brow palms was significantly smaller for bulls at risk to TP and 10PT regulations than for those not at risk. These findings suggest that yearling bulls with smallest antlers are most at risk to harvest by the S/F regulation, whereas the largest antlered bulls are most at risk to harvest by the TP and 10 PT regulations. The consequences of this directed selection of bull moose by antler-based hunting regulations on the breeding biology, population genetics, and fitness of moose requires further study. ALCES VOL. 46: 113-121 (2010) Key words: Alces alces, harvest risk, hunting, social class, spike/fork, tripalm, yearling bull, 10 point. Moose (Alces alces andersoni) hunting in British Columbia has traditionally been oriented toward the male segment of the population. In the long term, bull-only sea- sons may lead to age and sex imbalances that affect the growth, productivity, and ability of moose populations to sustain management and recreational objectives (Baker 1975, Demarchi and Hartwig 2008). Consequently, restrictive hunting seasons with increasing complexity of regulations and hunter dissatisfaction result (Hatter 1994, Child 1996, Hatter 1999). Traditional practices of harvesting may act as an evolutionary force that can chal- VULNERABILITY AND ANTLER REGULATIONS - CHILD ET AL. ALCES VOL. 46, 2010 114 lenge conservation goals for wildlife and may impair both the health and genetic diversity of a species (Boer 1991, Darimont et al. 2009). Selective harvesting of large antlered males over the long term can alter genetics (Laurian et al. 2000) by negatively impacting those alleles that underpin fitness (Hundertmark and Bowyer 2004). Such changes can be ir- reversible if harvesting systems continue to target the larger individuals in a population (Van Ballenberghe 2004, Paquet 2009). In this study we examined the potential vulnerability of bull moose harvested in the 1980s from the Omineca sub-region of the central interior of British Columbia (Fig. 1) to 3 antler-based hunting regulations (Fig. 2) practiced in the province: spike/fork (S/F), tripalm (TP), and 10 point (10PT). We evalu- ated the potential vulnerability of these bull moose specific to age class, social class, and antler characteristics. METHODS Morphometry of moose antlers in the Omineca sub-region of British Columbia was described by Child et al. (2010). Our data set was comprised of 1,686 sets of antlers from moose harvested in 1982-1989. Of these, 1,586 sets were submitted by successful limited entry hunters (LEH) for mandatory inspection; an- other 100 sets were submitted voluntarily by non-LEH hunters (i.e., hunters not possessing an LEH authorization who hunted in an open season for S/F bulls). We assumed that the LEH harvest was taken randomly from the population (Schwartz et al. 1992), whereas the non-LEH harvest of S/F bulls was taken primarily from the yearling component (Hatter and Child 1992). Concerns regarding harvest bias against S/F bulls by LEH hunters, as well as under reporting by non-LEH hunters (Hatter and Child 1992, Hatter 1993), are reflected in the lack of yearling bulls in the reported age distribution (Child et al. 2010). To correct for non-reporting bias, we increased the number of S/F bulls until their vulnerability to the S/F regulation was 46%. This adjustment matched the vulnerability reported by Hatter (1993) and resulted in a hypothetical sample (hereafter considered to be the population) of 1,886 bull moose for study. From the population (n = 1,886), we reported age of bulls potentially at risk to harvest when subjected to S/F, TP, and 10PT regulations (Fig. 2). We also report the pro- portions of bulls at risk by age class, social class, and antler form. For the analysis, we used the social classes described by Bubenik (1971): yearlings (1.5 years), teens (2.5-3.5 years), primes (4.5-11.5 years), and seniors (>12.5 years). Antler forms were described by Child et al. (2010) as cervicorn (pole type) and palmicorn (split palm or full palm). We separated those with palmicorm antlers as split palm and full palm antlers, and analyzed harvest risk to the regulations for each group. Proportions were calculated only if there were at least 5 bull moose in any age class, social class, or category of antler form. The maximum spread, maximum height, Fig. 1. The Omineca sub-region (Region 7A) of the British Columbia Ministry of Environment in central British Columbia (from British Co- lumbia Hunting and Trapping Regulations and Synopsis, 2008). ALCES VOL. 46, 2010 CHILD ET AL. - VULNERABILITY AND ANTLER REGULATIONS 115 palm width, shaft circumference, and distance between the inner most points on the brow palms (Child et al. 2010) of yearling bulls at risk under the S/F regulation were compared ( t-test, P = 0.05) with the same morphometrics for yearlings not at risk. Similarly, we com- pared the same morphometrics of antlers from bulls >2.5 years old at risk to the TP and 10PT regulations to bulls of similar age not at risk. We treated yearlings separately because this is the only age class subject to high harvest risk when exposed to the S/F regulation. Con- versely, we separated all bulls >2.5 years old because they are at risk when exposed to the TP and 10PT regulations. We used Levene’s test (Milliken and Johnson 1984) for equality of variances and then used the t-test for equal or unequal variances as appropriate. Age-specific mean maximum antler spreads of bulls in the population were com- pared graphically with mean maximum antler spreads of bulls at risk to each of the regula- tions. Age-specific mean maximum spreads were calculated if there were at least 5 bull moose in the age class. RESULTS Harvest risk of bull moose exposed to S/F regulation Bulls in our study (n = 1,886) ranged from 1.5-19.5 years with a mean of 3.9 ± 2.7 years (Fig. 3); nearly 16% were at risk to the S/F regulation. The mean age of bulls at risk was 1.9 ± 1.2 years of age (n = 100); 81% were yearlings and the oldest was 9.5 years. Age- specific vulnerability declined from 46.0% for yearlings to <5.0% for moose >2.5 years (Fig. 4). By social class, 46.2% of yearlings, 6.0% of teens, and 2.4% of primes were at risk. Sample size was insufficient to determine the Fig. 2. Antler-based regulations for bull moose in British Columbia (from British Columbia Ministry of Environment Hunting and Trapping Regulations and Synopsis, 2008). 0 100 200 300 400 500 600 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5 Age (years) N u m b e r o f M o o s e Fig. 3. Age distribution of the adjusted population of bull moose corrected for yearling reporting bias. Note: due to sample size (n <5) no data were plotted for bulls >15.5 years old. VULNERABILITY AND ANTLER REGULATIONS - CHILD ET AL. ALCES VOL. 46, 2010 116 proportion of senior bulls at risk. Additionally, when considering antler form, 41.3% of bulls with cervicorn antlers and 5.4% of bulls with palmicorn antlers, including both split palm (5.4%) and full palm antlers (5.3%), were at risk (Table 1). Both yearling and 2.5 year old bulls at risk had mean maximum antler spreads that were smaller than the mean maximum antler spread calculated for all bulls of similar age (Fig. 5). The maximum spread and shaft circumferences of antlers for yearling bulls at risk were smaller (P <0.001) than those of yearlings not at risk. Maximum antler height, palm width, and distance between the inner most points on the brow palms of yearlings were not dif- ferent (P >0.05) between those yearlings at risk and those not at risk (Table 2). Harvest risk of bull moose exposed to TP regulation Of the 1,886 bull moose in the sample population, 12% were at risk to the TP regulation. The mean age of bulls exposed to the TP regulation was 6.3 ± 3.0 years (n = 227); bulls 1.5-19.5 years old were at risk. Vulnerability increased linearly from 5% at 2.5 years to 35% at 7.5 years, then fluctuated between 25-45% to 13.5 years (Fig. 4). Sample size was insufficient to determine the proportion of yearlings at risk, but 7.0% of teens, 25.9% of primes, and 38.2% of se- niors were at risk. By antler form, 1.4% with cervicorn antlers and 19.0% with palmicorn antlers were at risk, including both split palm (18.3%) and full palm antlers (25.4%, Table 1). Mean maximum antler spread for each age class at risk was generally larger than the mean maximum antler spread calculated for the same age class in the population (Fig. 5). Antlers of bulls at risk had larger (P <0.001) maximum spread, height, palm width, and shaft circumference, and smaller (P <0.001) distance between the inner most points on the brow than bulls not at risk (Table 2). 0 10 20 30 40 50 60 70 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 Age (years) P ot en tia l V ul ne ra bi lit y (% ) Fig. 4. Potential vulnerability of bull moose by age to 3 antler-based regulations. Broken line = S/F, gray line = TP, and black line = 10PT. Note: No data points were plotted for S/F regulation ages >5.5 years old, for TP regulation ages 1.5, 12.5, and 14.5 years and older, and for the 10PT regulation ages 1.5, 2.5, and 14.5 years and older due to insufficient sample size (n <5). Regulation Social class % Antler form % S/F Population 15.9 Cervicorn 41.3 Yearling 46.2 Palmicorn 5.4 Teen 6.0 Split palm 5.4 Prime 2.4 Full palm 5.3 Senior NC TP Population 12.0 Cervicorn 1.4 Yearling NC Palmicorn 19.0 Teen 7.0 Split palm 18.3 Prime 25.9 Full palm 25.4 Senior 38.2 10PT Population 11.1 Cervicorn NC Yearling NC Palmicorn 17.1 Teen 1.1 Split palm 17.5 Prime 29.7 Full palm 14.0 Senior 44.1 Table 1. Potential vulnerability (%) of bull moose subjected to 3 antler-based regulations (S/F, TP, and 10PT) by social class and antler form for the population. Note: NC = % not calculated (n <5). ALCES VOL. 46, 2010 CHILD ET AL. - VULNERABILITY AND ANTLER REGULATIONS 117 Harvest risk of bull moose exposed to 10PT regulation Of the 1,886 bull moose in the sample population, 11% were at risk to the 10PT regu- lation. The mean age of bulls at risk was 7.7 ± 2.7 years (n = 210), ranging from 2.5-15.5 years old. Age-specific vulnerability increased linearly from <5% for bulls 3.5 years old, to about 50% at 8.5 years, then fluctuated between 40-65% to 13.5 years (Fig. 4). Sample size was insufficient to determine the proportion of bulls at risk that were <2.5 years or >13.5 years old. By social class, 1.1% of teens, 29.7% of primes, and 44.1% of seniors were at risk. By antler form, 17.1% with palmi- corn antlers were at risk, including both split palm (17.5%) and full palm (14.0%, Table 1). Sample size was insufficient to determine the proportion of bulls with cervicorn antlers that were vulnerable to the 10PT regulation. The age-specific, mean maximum antler spread for each age class at risk was gener- ally larger than the mean maximum antler spread calculated for the same age class in the population (Fig. 5). Bulls at risk had larger (P <0.001) sized antlers by maximum spread, height, palm width, and shaft circumference, and a smaller (P <0.001) distance between the inner most points on the brow palms than bulls not at risk (Table 2). DISCUSSION Assessment of the harvest risk of bull moose revealed that most bulls at risk to the S/F regulation were yearlings and those yearlings at risk had smaller antlers than yearlings not at risk. On the other hand, when subjected to the TP regulation, a large proportion of prime and senior bulls were at risk; when subjected to the 10PT regulation, risk to prime and senior bulls was higher still. Importantly, bulls at risk to either the TP or 10PT regulations had larger antlers (i.e., greater spread, width, height, number of points) and narrower distance between the innermost points on the brow palms than bulls not at risk to these regula- tions. Generally, bull moose with cervicorn antlers were at greatest risk to harvest under the S/F regulation, and bulls with palmicorn antlers were at high risk to both the TP and 10PT regulations. Bull moose with split palm antlers were similarly vulnerable to the TP and 10PT regulations, whereas bulls with full palm antlers were at higher risk to the TP regulation. Antler size and symmetry reflects social status and fitness in cervids (Markusson and Folstad 1997, Pelabon and van Breukelen 1998, Ditchkof et al. 2001, Malo et al. 2005, Vanpé et al. 2007) including moose (Bube- nik 1983, Solberg and Saether 1993, 1994, Bubenik 1998). Prime bulls carry the largest antlers (Gasaway et al. 1987) and their high numbers on rutting areas are required for opti- mal breeding and productivity (Bubenik 1983, Aitken and Child 1991, 1992, Solberg et al. 2002, Saether et al. 2003). The combination of antler size, form, and symmetry that cows recognize when selecting mates is not fully un- derstood (Solberg and Saether 1993, Bowyer 400 500 600 700 800 900 1000 1100 1200 1300 1400 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 Age (years) M ea n M ax im um S pr ea d (m m ) Fig. 5. Age-specific, mean maximum spread of antlers of bull moose in the population com- pared to those subjected to the 3 antler-based regulations. Thin solid line with open circles = population, broken line = S/F, gray line = TP, and thick black line = 10PT. No data points were plotted for S/F regulation for ages 3.5 years and older, for TP regulation ages 1.5, 12.5, and 14.5 years and older, and for the 10PT regulation for ages 1.5, 2.5, and 14.5 years and older due to insufficient samples (n <5). VULNERABILITY AND ANTLER REGULATIONS - CHILD ET AL. ALCES VOL. 46, 2010 118 et al. 2001). However, prolonged harvests of large antlered bulls and/or those with palmated brow structures may, over time, reduce genetic variability and cause an irreversible loss of al- leles specific to antler features (Hundertmark et al. 1993, Hundertmark and Bowyer 1998, Bowyer et al. 2002, Hundertmark and Bowyer 2004, Van Ballenberghe 2004). Moose hunting focused on bulls often results in age and sex imbalances that can lead to a scarcity of mature breeding bulls. Hunting regimes should ideally produce sex- and age-specific mortality patterns similar to those occurring naturally, and should maintain demographic structures conducive to natural breeding patterns (Harris et al. 2002) in order to ensure social well-being (Bubenik 1971, 1983), genetic variability (Ryman et al. 1981, Hartl et al. 1991, Hundertmark et al. 1993, Coltman et al. 2003), and high productivity Regulation Morphometric Mean value P At risk Not at risk S/F MS 569 ± 122, 241 667 ± 95, 65 <0.001 MHL 289 ± 140, 116 324 ± 97, 27 0.122 MHR 287 ± 143, 98 302 ± 102, 24 0.567 PWL 111 ± 63, 199 104 ± 39, 22 0.610 PWR 114 ± 67, 203 102 ± 37, 22 0.442 SCL 110 ± 16, 270 124 ± 17, 75 <0.001 SCR 110 ± 18, 266 125 ± 18, 75 <0.001 DIPB 431 ± 60, 189 414 ± 82, 28 0.295 TP MS 1030 ± 181, 244 831 ± 194, 1536 <0.001 MHL 676 ± 161, 154 489 ± 187, 769 <0.001 MHR 658 ± 160, 146 474 ± 183, 670 <0.001 PWL 227 ± 63, 241 149 ± 61, 1118 <0.001 PWR 222 ± 57, 242 149 ± 61, 1113 <0.001 SCL 168 ± 21, 251 144 ± 26, 1634 <0.001 SCR 167 ± 21, 250 144 ± 26, 1566 <0.001 DIPB 323 ± 86, 216 383 ± 85, 1303 <0.001 10PT MS 1142 ± 154, 235 815 ± 174, 1545 <0.001 MHL 771 ± 123, 124 481 ± 175, 799 <0.001 MHR 756 ± 109, 107 469 ± 173, 709 <0.001 PWL 259 ± 52, 196 147 ± 56, 1163 <0.001 PWR 254 ± 46, 197 146 ± 56, 1158 <0.001 SCL 180 ± 18, 241 142 ± 24, 1644 <0.001 SCR 179 ± 18, 238 142 ± 24, 1578 <0.001 DIPB 319 ± 92, 213 384 ± 84, 1306 <0.001 Table 2. Summary of morphometric measurements (mean ± SD, n) and statistical significance of differ- ences between bull moose at risk and those not at risk to the 3 antler-based regulations. Comparisons (t-tests) for the S/F regulation were only made for 1.5 year-old bulls, whereas comparisons for both the TP and 10PT regulation were made for bulls 2.5 years and older (see Methods). MS = maximum spread, MHL = maximum height left side, MHR = maximum height ride side, PWL = palm width left side, PWR = palm width right side, SCL = shaft circumference left side, SCR = shaft circumference right side, and DIPB = distance between the innermost points on brow. ALCES VOL. 46, 2010 CHILD ET AL. - VULNERABILITY AND ANTLER REGULATIONS 119 (Aitken and Child 1991, Timmerman 1991, Aitken and Child 1992, Schwartz 1998). Moreover, since a high proportion of mature breeders in the population prevents declines in population fitness (Ferer et al. 2003), a harvest strategy that reduces pressure on older, larger antlered males may be the most prudent. Open seasons or limited entry hunting (LEH) systems without antler restrictions are generally thought to randomize bull harvests (Child and Aitken 1989, Schwartz et al. 1992) and thereby ensure a normal age distribution. Antler-based regulations, on the other hand, direct hunters to selectively harvest bulls by antler characteristics that may have either beneficial or harmful consequences depend- ing on the particular antler restriction (Harris et al. 2002). The results of this study suggest that the S/F regulation targets mainly young bulls with the smallest antlers whereas the TP and 10PT antler regulations target bulls with the largest antlers across all age classes. It is important to understand the harvest risk of bull moose to antler-based regulations because genetic effects are suspected, if not likely (Hartl et al. 1991, Hundertmark et al. 1993, Coltman et al. 2003), and normal behavior (Bubenik 1987, 1998) and reproductive patterns (Schwartz 1998, Timmermann 1991) may be disrupted. Because of these negative consequences asso- ciated with over harvest of the largest bulls in a population, we advocate further monitoring and study of harvest impacts associated with antler-based hunting regulations. ACKNOWLEDGEMENTS We thank Sean Barry for his meticulous attention to detail in measuring and recording the forms of all inspected antlers, and to Ken Fujino and Sean Barry of the Wildlife Branch who prepared and aged the tooth samples. A special thanks to Gerry Kuzyk for release of the antler data records and to the many hunt- ers who willingly submitted their antlers for inspection. We also thank Nic Larter and an anonymous reviewer for their comments on an earlier draft of the manuscript. REFERENCES Aitken, D. A., and k. n. ChilD. 1991. Gross productivity of moose in the central in- terior of British Columbia. Proceedings of the 1991 Moose Harvest Management Workshop, Kamloops, British Columbia Wildlife Branch, British Columbia Min- istry of Environment, Victoria, British Columbia, Canada. _____, and _____. 1992. Relationship be- tween in-utero productivity of moose and population sex ratios: an exploratory analysis. Alces 28: 175-187. BAker, r. A. 1975. Biological implications of a bull moose-only hunting regulation in Ontario. Proceedings of the North American Moose Conference and Work- shop 11: 464-476. Boer, A. h. 1991. Hunting: a product or tool for wildlife managers? Alces 27: 74-78. Bowyer, r. t, k. M. StewArt, J. G. kie, and w. C. GASAwAy. 2001. Fluctuating asymmetry in antlers of Alaskan moose: size matters. Journal of Mammalogy 82: 814-824. _____, _____, B. M. PierCe, k. J. hunDert- MArk, and w. C. GASSAwAy. 2002. Geo- graphical variation in antler morphology of Alaskan moose: Putative effects of habi- tat and genetics. Alces 38: 155-165. BuBenik, A. B. 1971. Social well-being as a special agent of animal sociology. Inter- national Conference on the Behavior of Ungulates and its Relation to Manage- ment. Calgary, Alberta, Canada. _____. 1983. The behavioral aspects of antlerogenesis. Pages 389-449 in R. D. Brown, editor. Antler Development in Cervidae. Caesar Kleberg Wildlife Re- search Institute. Texas A&I University, Kingsville, Texas, USA. _____. 1987. Behaviour of moose (Alces alces) of North America. Swedish Wildlife VULNERABILITY AND ANTLER REGULATIONS - CHILD ET AL. ALCES VOL. 46, 2010 120 Research Supplement 1: 333-366. _____. 1998. Behavior. Pages 173-221 in A. W. Franzmann and C. C. Schwartz, edi- tors. Ecology and Management of North American Moose. Smithsonian Institution Press, Washington, D.C., USA. ChilD, k. n. 1996. Moose harvest manage- ment in British Columbia: Regulation simplification and strategy harmonization. Wildlife Branch, Ministry of Environ- ment, Lands and Parks, Victoria, British Columbia, Canada. _____, and D. A. Aitken. 1989. Selective harvests, hunters and moose in central British Columbia. Alces 25:81-97. _____, D. A. Aitken, and r. V. reA. 2010. Morphometry of moose antlers (Alces alces andersoni) in central British Co- lumbia. Alces 46: 123-134. ColtMAn, D. w., P. o’DonouGue, J. t. Jor- GenSen, J. t. hoGG, C. StroBeCk, and M. FeStA-BlAnChe. 2003. Undesirable evo- lutionary consequences of trophy hunting. Nature 426: 655-658. DAriMont,C. t., S. M. CArlSon, M. t. kin- niSon, P. C. PAquet, t. e. reiMChen, and C. C. wilMerS. 2009. Human predators outpace other agents of trait change. Pro- ceedings National Academy of Sciences, USA. 106: 952-954. DeMArChi, r. A., and C. l.hArtwiG. 2008. Towards an improved moose management strategy for British Columbia. Habitat Conservation Trust Fund Report CAT07- 0-0325. Victoria, British Columbia, Canada. DitChkoF, r. l., r. l. loChMiller, r. e. MASterS, w. r. StArry, and D. M. leSlie Jr. 2001. Does fluctuating asymmetry of antlers in white-tailed deer (Odocoileus virginianus) follow patterns predicted for sexually selected traits? Proceedings Biological Sciences 268: 891-898. Ferrer, M., V. PenteriAni, J. BAlBontín, and M. PAnDolFi. 2003. The proportion of immature breeders as a reliable early warning signal of population decline: evidence from the Spanish imperial eagle in Doñana. Biological Conservation 114: 463-466. GASAwAy, w. C., D. J. PreSton, D. J. reeD, and D. D. roBy. 1987. Comparative antler morphology and size of North American Moose. Swedish Wildlife Research Supplement 1: 311-325. hArriS, r. B., w. A. wAll, and F. w. Al- lenDorF. 2002. Genetic consequences of hunting: what do we know and what should we do? Wildlife Society Bulletin 30: 634-643. hArtl, G. B., G. lAnG, F. klein, and r. willinG. 1991. Relationship between al- lozyme heterogeneity and morphological characters in red deer (Cervus elaphus), and the influence of selective hunting on allele frequency distribution. Heredity 66: 343-350. hAtter, i. w. 1993. Yearling moose vulner- ability to spike-fork regulation. Memo dated Jan. 26, 1993. Wildlife Branch, British Columbia Environment, Victoria, British Columbia, Canada. _____. 1994. Moose harvest regulations review-Peace/Liard Subregion. Wildlife Conservation and Management Section, Wildlife Branch, British Columbia En- vironment, Victoria, British Columbia, Canada. _____. 1999. An evaluation of moose harvest management in Central and Northern Brit- ish Columbia. Alces 35: 91-103. _____, and k. n. ChilD. 1992. An evalu- ation of a spike-fork bull moose antler regulation in central British Columbia. Proceedings of the 1991 Moose Harvest Workshop, Kamloops, BC. Wildlife Branch, British Columbia Environment, Victoria, British Columbia, Canada. hunDertMArk, k. J., and r. t. Bowyer. 1998. Effects of population density and selective harvest on antler phenotype in simulated moose populations. Alces 34: 375-383. ALCES VOL. 46, 2010 CHILD ET AL. - VULNERABILITY AND ANTLER REGULATIONS 121 _____, and _____. 2004. Genetics, evolution, and phylogeography of moose. Alces 40: 103-122. _____, t. h. thelen, and C. C.SChwArtz. 1993. Population and genetic effects of selective harvest strategies in moose: A modeling approach. Alces 29: 225-234. lAuriAn, C., J-P. ouellet, r. CourtoiS, l. Breton, and S. St-onGe. 2000. Effects of intensive harvesting on moose repro- duction. Journal of Applied Ecology 37: 515-531. MAlo, A. F., E. R. S. RolDAn, J. GArDe, A. J. Soler, and M. GoMenDio. 2005. Antlers honestly advertise sperm production and quality. Proceedings: Biological Sciences 272: 149-157. MArkuSSon, e., and i. FolStAD. 1997. Rein- deer antlers: visual indicators of individual quality? Oceologia 110: 501-507. Milliken, C. A., and D. e. JohnSon. 1984. Analysis of Messy Data. Volume I. Wadswoah Inc., Belmont, California, USA. PAquet, P. 2009. Humans as ‘super-predators’ driving evolution. UTODAY, Univer- sity of Calgary News, Calgary, Alberta, Canada. PélABon, C., and l. VAn Breukelen. 1998. Asymmetry in antler size in roe deer (Capreolus capreolus): an index of indi- vidual and population conditions. Oeco- logica 116: 1-8. ryMAn, n., r. BACCuS, C. reuterwAll, and M. h. SMith. 1981. Effective population size, generation interval, and potential loss of variability in game species under different hunting regimes. Oikos 36: 257-266. SAether, B. e., e. J. SolBerG, and M. heiM. 2003. Effects of altering sex ratio structure on the demography of an isolated moose population. Journal of Wildlife Manage- ment 67: 455-466. SChwArtz, C. C. 1998. Reproduction, natal- ity, and growth. Pages 141-171 in A. W. Franzmann and C. C. Schwartz, editors. Ecology and Management of North American Moose. Smithsonian Institution Press, Washington, D.C., USA. _____, k. J. hunDertMArk, and t. h. SPrAker. 1992. An evaluation of selective bull- moose harvest on the Kenai Peninsula, Alaska. Alces 28: 1-13. SolBerG, e. J., loiSon, A., rinGSBy, t. h., Sæther, B-e., and M. heiM. 2002. Biased adult sex ratio can affect fecundity in primiparous moose Alces alces. Wildlife Biology. 8: 117-128. _____, and B-e. SAether. 1993. Male traits as life-history variables: annual variation in body mass and antler size in moose (Alces alces). Journal of Mammalogy 75: 1069-1079. _____, and _____. 1994. Fluctuating asym- metry in antlers of moose (Alces alces): does it signal male quality? Proceedings: Biological Sciences 354: 251-252. tiMMerMAnn, h. r. 1991. Moose sociobiology and implications for harvest. Proceedings of the 1991 Moose Harvest Management Workshop, Kamloops, British Columbia, Wildlife Branch, British Columbia En- vironment, Victoria, British Columbia, Canada. VAn BAllenBerGhe, V. 2004. In the Company of Moose. Stackpole Books, Mechanics- burg, Pennsylvania, USA. VAnPé, C., J-M.GAillArD, P. kJellAnDer, A. MySteruD, P. MAGnien, D. DelorMe, G. VAn lAFere, F. klein, o. liBerG, and A. J. M. hewiSon. 2007. Antler size provides an honest signal of male phenotypic qual- ity in red deer. The American Naturalist 4: 481-493.