A drawback with data on operators’ perceptions is that such individuals clearly have a vested interested in the perpetuation of lion hunting and so their reflections on issues such as the trends in lion populations, causes for such trends, and the age of lions hunted must be treated with caution. Operators perceptions on conservation issues associated with trophy hunting were derived before implementation of age restrictions in Tanzania or quota cuts in Zambia.

There is uncertainty regarding some of our quota and off-take data. Data on quotas and off-takes from several countries are somewhat dated. The exclusion of zero values when calculating the percentage of hunting blocks where 0.5 lions per 1,000 km 2 are hunted may over-estimate the intensity of harvest. However, we feel that in most cases (where age restrictions are not in place), failure of operators to secure a lion is more likely to be due to there being few or no lions present than operators abstaining from shooting lions or being unable to sell lions on quota. In Zimbabwe, Namibia and Mozambique estimates of the area per lion shot are under-estimates because we did not have data on the size of a number of hunting blocks in those countries (and thus under-estimated the area used for lion hunting).

African lions are hunted across 27–32% of the lion distribution in countries where trophy hunting of the species is permitted, and at least 16% of the total lion distribution in Africa [6] . Furthermore, these percentages do not include hunting blocks in Chad where the species is also hunted [17] and in some countries (notably Mozambique) we lacked data on some blocks where lions are hunted. Significantly, in Tanzania (which holds ∼15,500 lions of a total population of ∼30,000 individuals [6] ) lions are hunted over 34–49% of their range. Consequently, trophy hunting has potential to impart either significant positive or negative conservation impacts on lions, depending on the way in which it is managed. Lion harvests have declined steeply in recent years, which may be due in part to quota cuts in some countries and the implementation of age restrictions in Tanzania and Mozambique. However, it is not possible to determine the extent to which improved management of lion hunting has contributed to such reductions, versus continued population declines.

Key Problems and Necessary Interventions

Our data highlights several weaknesses associated with the management of lion hunting.

Arbitrary bases for establishing quotas and excessive harvests

Quotas have been reduced significantly in recent years in several countries, including Benin, CAR, Tanzania, and Zambia [24], [25], [26], [28], P. Lindsey unpublished data]. However, quotas are generally not established in a scientific manner and there is an over-reliance on subjective personal opinions during the process, including those of hunting operators. In Namibia, Zimbabwe and Mozambique, the size of quotas is apparently determined partly on the extent and location of problem animal reports, which need not have a close relationship to lion abundance. Such linkages create scope for false reporting of conflict, which further decouples quotas from what populations can necessarily support and are unlikely to help address human-lion conflict effectively. Lion quotas remain higher than the 0.5/1,000 km2 recommended by [8] in all countries except Mozambique. Mean actual harvests are lower than the 0.5/1,000 km2 threshold in most countries (with the exception of Burkina Faso, Zambia, Namibia and Zimbabwe). However, in all countries where data are available, harvests appear too high in a proportion of hunting blocks.

There is a need for decisive efforts to ensure that quotas and harvests are not excessive in any areas that lions are hunted; indeed, given the recent international scrutiny, range states would do well to adopt a conservative approach to managing lion hunting. Steps to improve sustainability could include the interim implementation of quota caps following the suggestions of [8], until age restrictions (as discussed below), trophy monitoring and adaptive quota management have been implemented. In West Africa, where lions are considered regionally endangered [33], efforts to prevent excessive harvests are most urgently required.

Lack of enforced age restrictions

Based on dynamics of the Serengeti lion population, the restriction of trophy harvests to males of six-years or older effectively ensures sustainability of harvest in the absence of reliable population estimates [34], [35]. By six years, male lions have typically had the opportunity to sire at least one litter of cubs, the recruitment of which is sufficient to maintain population stability [34], [35]. There is variability among countries in the presence, extent and type of restrictions imposed on trophy selection and operators admitted that many lions hunted are under six-years of age.

Hunting success rates declined in Niassa National Reserve following implementation of age limits ( [31]). The number of lions shot as trophies in Tanzania also dropped after implementation of age restrictions (which commenced in 2011) from: 243 during 1996–2006 [8], 132 in 2009/2010; 101 in 2010/2011 and 85 in 2011/2012 [28]. Hunting operators suggested that declining off-takes in Tanzania were the result of greater selectivity among operators to avoid penalties for shooting young lions. However, quota cuts and continuing declines in lion populations also likely played a role [8]. Nonetheless, properly-enforced age restrictions are likely to reduce off-takes due to the need for greater selectivity and the scarcity of such individuals in lion populations [11]. In addition to increasing the sustainability of harvests, age restrictions could result in greater financial returns, as lions on quota could potentially be re-sold in the same year in the event of an unsuccessful hunt. For such age restrictions and trophy monitoring to be most effective and least likely to be undermined by corruption, they should be as transparent as possible and ideally involve input from multiple independent organisations.

There is general support among hunting operators for age-based restrictions, and specifically for the system implemented in Niassa National Reserve where quotas are managed adaptively based on the age of lions hunted in the previous year. Age restrictions are likely to be more effective than attempts to reduce the impacts of hunting by operators attempting to avoid shooting pride males or females with cubs as in both cases the ability of operators to identify such animals is questionable. Some operators expressed uncertainty regarding their ability to age lions and hunters performed poorly when attempting to age leopards [36]. However, experiences from Niassa indicate that hunters can learn to age lions effectively [31]. A key source of contention (among operators and some scientists) is whether the cues used to age lions vary regionally. Consequently, there is a need to further develop national or regional aging guidelines for lions (to complement those already produced for Tanzania and Zambia ( [37]; White unpublished). These guidelines require the development of a suite of cues that can be used to age live animals [38], including characteristics such as nose colour, facial scarring, mane development and teeth wear. The use of a suite of cues reduces the likelihood of lions being aged incorrectly as a result of variation in individual characteristics [37] and addresses the contention associated with the validity of individual cues such as nose colour. Furthermore, employing a suite of cues reduces the difficulty of assessing individual characteristics under the low light conditions when lions are typically hunted.

Operators will have to be educated on lion aging techniques if age-based hunting restrictions are to be successfully implemented. More than a quarter of operators feel unable to distinguish six-year-old males and some use unreliable cues such as the absence of spots, body colour and body size [37]. Lion aging techniques should be included in the curricula of appropriate hunting courses with the successful completion of an examination a prerequisite for licensing (as is the case for mountain lions Puma concolor in the United States; http://wildlife.state.co.us/Hunting/HunterEducation/MtnLionEduc/Pages/MountainLionExam.aspx, accessed November 2011). Similarly, hunting clients must be educated such that they understand the importance of, and reasons behind age restrictions. Clients should be encouraged to appreciate the experience of lion hunting more than the actual product and to understand that going on a lion hunting safari is no guarantee that a lion will be shot. Safari hunting clubs such as Safari Club International and Dallas Safari Club could play a key role in educational efforts involving clients. Furthermore, organisations that hold trophy record books (such as Safari Club International and Rowland Ward) could play an important role by ensuring that lion trophies must be from lions of a minimum age to qualify. Such measures motivate clients as well as professional hunters to avoid shooting young lions.

The hunting of females is permitted in Namibia

The hunting of females creates a risk that dependent cubs will die, removes the most reproductively productive individuals, can increase the vulnerability of prides to loss of territory to neighbouring prides and can render cubs more vulnerable to infanticidal males [39]. Consequently, the hunting of lionesses should be prohibited, except where the express management objective is to control the size of a lion population [40].

The prevalence of fixed quotas

Several countries have large ‘fixed’ quota, meaning that operators are charged for a proportion (40–100%) of lions on quota, irrespective of whether animals are actually hunted. Such a system is likely to encourage utilization of the entire fixed portion of the quota regardless of sustainability and potentially result in the harvest of underage individuals.

The lack of minimum hunt lengths in some countries

Several countries either have no limit on the length of lion hunting safaris, or have short minimum lengths (most notably in West and Central Africa). Minimum hunt lengths of least 21 days would allow hunters time to be selective and maximize the revenue earning potential from lion hunts.

General problems associated with management of trophy hunting

Several other problems associated with the management of trophy hunting are likely to exacerbate negative impacts associated with the hunting of lions (where such impacts occur) and/or undermine conservation incentives created by trophy hunting. Corruption is a challenge that affects multiple aspects of the trophy hunting industry [41] and could undermine steps to reform the hunting of lions. Such possibilities stress the importance of transparency within the hunting industry and independent verification of processes such as quota setting, concession allocation and trophy monitoring. There are other problems associated with the process of allocating hunting concessions, such as the use of closed tender systems which do not account for the conservation track record of operators [42]. Concessions are leased for periods that are too short, particularly in Tanzania, which encourages over-use of and underinvestment in hunting blocks [43]. Under-investment in anti-poaching for example, can result in rapid loss of wildlife resources in hunting concessions due to pressure from illegal hunting and the bushmeat trade [44]. The threat posed by poaching is elevated in many cases due to the fact that communities are often marginalized from the benefits generated by trophy hunting (and ecotourism) due to inappropriate legislation which does not recognize community ownership of land and wildlife resources [14], [17]. Furthermore, due to the high costs associated with effective law enforcement and severe threat from the bushmeat trade [44] there may be need for additional funding support for protection of wildlife regardless of whether trophy hunting and the hunting of lions occurs. That said, some revenue is better than none and in the absence of realistic alternatives, governments should be careful not to foreclose an important means of generating income from and for wildlife.