Regulation of wild pigs in Japan

• Wild pigs have attracted much public attention in Hong Kong since late 2021, not only because of their rapid growth to a stock of up to 3 300 in recent years, but also their increased encroachment into urban areas.^{1Environment Bureau (2021) and Environmental Protection Department (2021).} While wild pigs are usually "secretive and wary of human contact", they could intrude into human settlement when searching for food and could become aggressive when threatened. Over the past decade, the number of nuisance complaints caused by wild pigs (e.g. noise, environmental hygiene, disease transmission and safety threats) had thus sextupled to a peak of 1 417 in 2021. There is advocacy in society to reduce the population of wild pigs through more killings, but this is countered by conservationists arguing for the adoption of more humane and non-lethal measures.
• The Agriculture, Fisheries and Conservation Department ("AFCD") used to hunt and kill nuisance-causing wild pigs, but such operations were halted in 2017 amidst increased public awareness of animal welfare. Instead, AFCD launched the Capture and Contraception/Relocation Programme ("CCRP"), applying fertility control to such wild pigs and moving them to countryside.^{2Panel on Environmental Affairs (2021).} Yet CCRP was seemingly unable to moderate the damage caused by wild pigs after being regularized in 2019, as the number of injured persons doubled from nine to 22 over the period. To address the public safety concerns, AFCD announced in November 2021 to reinstate culling wild pigs spotted in urban areas through capture and humane dispatch, but this was met with opposition from environmental groups.^{3GovHK (2021a, 2021b) and South China Morning Post (2021c).} Over the past five years, the subject of wild pig nuisances and management has been discussed at the Legislative Council ("LegCo") on at least 17 occasions.^{4Legislative Council Secretariat (2021) and GovHK (2022).}
• In many advanced places (e.g. the United States, Germany, Singapore and Japan), lethal killing is the most common measure taken to abate wild pig nuisances. More specifically, the wild pig management strategy in Japan comprises both lethal and non-lethal elements and should thus have certain reference value.^{5Melletti and Meijaard ed. (2018), The Guardian (2019) and林務局 (2019).} This issue of Essentials reviews the policy measures on wild pigs in Hong Kong first, followed by those in Japan.

• Recent global developments: Wild pigs (Sus scrofa) are now one of the largest mammals (up to 2 meters in body length and 200 kg in weight) widely distributed on earth. They have experienced exponential growth across the world in recent decades, on the back of their ultra-high reproduction rate (breeding throughout the year, a pair of adult pigs could give birth to eight offspring in just 15 months), strong survival skills (omnivorous and can move around extensively both on land and in waters), reforestation amidst shrinking human population in rural areas, fewer wildlife predators and reduced human hunting activities.^{6Massei et al. (2011), Melletti and Meijaard ed. (2018) and Environment Bureau (2019).}
  Proliferation of wild pigs becomes a global issue, not just because of human safety risks, crop damage and property loss. From the perspective of public health, it could be easier for wild pigs to transmit their diseases to both humans (e.g. hepatitis E and influenza A) and livestock (e.g. classic swine fever ("CSF")) due to genetic reasons.^{7Amidst the outbreak of COVID-19, there are rising concerns on the potential threat to public health posed by wild pigs because they are genetically more similar to humans, as compared with that of bats which is the origin of SARS and MERS. See Chan and Wang (2021).} For this reason, most governments take lethal methods (e.g. hunting and poison baiting) to halt the growth of wild pigs, with a usual target to remove at least 75% of their existing population annually. Yet some cities (e.g. Barcelona and Singapore) have also taken more preventive and non-lethal methods (e.g. fencing and contraception) since the 2000s to address animal welfare concerns.^{8Melletti and Meijaard ed. (2018) The Guardian (2019) and Loo (2021).}
• Rising number of wild pigs in Hong Kong: Based on a statistic model and time-lapse data collected from infrared cameras, AFCD crudely estimated that there were 1 800-3 300 wild pigs in local countryside in 2019. It is believed that their number has picked up noticeably over the past decade due to (a) their ultra-high reproductive rate; (b) improved wildlife environment amidst more forestation and vegetation cover in countryside; (c) a lack of predators especially after cessation of hunting operation; (d) increased food availability from urban garbage; and (e) human feeding.
• Upsurge in complaints and injuries: Partly due to (d) and (e) above, more wild pigs have been spotted in urban areas in recent years, with at least 60 urban black spots identified by AFCD. As a result, local complaints over wild pig nuisances had tripled to 738 cases during 2011-2017, before leaping further by 92% in just four years to 1 417 in 2021 (i.e. about 120 cases per month on average) (Figure 1). The number of injury reports jumped from none in 2011 to 20 cases in 2021, triggering widespread public alarm.
  
  
  Figure 1 – Complaints and injury reports over wild pig nuisances in Hong Kong
  
  Source: Agriculture, Fisheries and Conservation Department.
• Turnarounds in application of lethal measures: Before 2017, AFCD used to authorize two civilian hunting teams to remove aggressive wild pigs if other management options were ineffective. However, in response to rising concerns of animal welfare, AFCD suspended the hunting operations in early 2017 and launched CCRP on a pilot basis (to be discussed below). After a policy review, hunting was terminated in 2019, along with regularization of CCRP which was deemed to be safer with "higher capture efficiency".^{9Environment Bureau (2019) and Legislative Council Secretariat (2021).}
  However, after several bloody human-boar clashes, AFCD reinstated the killing of wild pigs in November 2021 by using dart guns with anaesthetics for eventual humane dispatch. Priority is given to those wild pigs in urban sites (a) in larger numbers; (b) with past injury cases caused; or (c) posing greater risks to members of the public. After three months of implementation, a total of 66 wild pigs had been culled by late February 2022.^{10Latest figure was provided by AFCD on request on 1 March 2022. See GovHK (2021a, 2022) and South China Morning Post (2021a).}
• Fertility control and relocation measures under CCRP: CCRP targets fertility control of local nuisance-causing wild pigs through application of contraceptive vaccines or sterilization, or else relocating them to remote areas when conditions permit. As of March 2021, 803 wild pigs had been captured and over three-quarters of them were relocated to the countryside far away from residential areas. One-quarter of the captured pigs were vaccinated/sterilized and nine-tenths of them did not get pregnant again. For those wild pigs attacking or chasing after people without provocation, thus considered aggressive cases, AFCD might kill them through humane dispatch after risk assessment.^{11Environment Bureau (2021).}
• Penalty of illegal feeding: Under the Wild Animals Protection Ordinance (Cap. 170), it is prohibited to feed wild animals (including wild pigs) in the designated ban areas spanning 3 150 hectares (e.g. Kam Shan, Lion Rock, Shing Mun Country Parks). Offenders are liable to a maximum fine of HK$10,000. During 2017-2021, there was a total of 281 successful prosecutions against illegal feeding, yet the highest fine imposed was just HK$2,000.^{12Latest figures were provided by AFCD on request on 19 January 2022. See Environment Bureau (2021) and Panel on Environmental Affairs (2021).} For wildlife feeding outside the ban areas, it could be liable to littering offence under the Fixed Penalty (Public Cleanliness and Obstruction) Ordinance (Cap. 570), but the maximum fine is even lower at HK$1,500. This apart, the Government for now relies on public education to discourage wildlife feeding due to the difficulty of enforcement.
• Key issues of local concerns: First on the population of wild pigs, there are concerns that the estimation method is too crude and unscientific because it was just based on infrared cameras set up in Ma On Shan Country Park only. While AFCD undertook to install more cameras in other sites in 2020, it has not released the progress yet.^{13Legislative Council Secretariat (2021), Environmental Protection Department (2021) and Wong (2021).} Secondly on CCRP, AFCD indicates that it takes 4-6 years to assess the effect of contraception. This is apparently too long as highly reproductive pigs can give birth to many generations of offspring during this period and thus potentially more than offset any population reduction effect arising from the use of contraception. While a motion passed in the Panel on Environmental Affairs of LegCo in January 2019 expressed support to resuming hunting operations, authorized civilian hunting was eventually terminated by the Government later that year.^{14Legislative Council Secretariat (2021), Panel on Environmental Affairs (2021) and Environment Bureau (2019, 2021).} Thirdly on illegal feeding, the feeding ban areas represent just 7% of the total areas of country parks, thus failing to cover most of the urban black spots. Also, both the number of prosecutions and penalty of up to HK$2,000 seem to have a limited deterrent effect.^{15The feeding ban areas designated in 1999 were originally aimed to tackle monkey nuisances. This apart, the success rate of prosecution against illegal feeding was just 61% in 2021, down from 90% in 2017. See Legislative Council Secretariat (2021), Panel on Environmental Affairs (2021), GovHK (2022) and Wong (2021).} Fourthly on buffers between natural habitats and urban areas, there are suggestions to use more non-lethal means (e.g. electric fencing, repellents, or rubbish bins with improved design) to prevent wild pigs from getting into urban black spots, instead of just culling.^{16Environmental Protection Department (2021) and South China Morning Post (2021b).}

• In Japan, the number of wild pigs rebounded visibly after the 1980s, partly attributable to (a) declining farming and hunting activities amidst rural depopulation; and (b) reforestation in rural areas upon a continued shift in fuel mix from charcoal to fossil fuel. Indicative of this, the number of Japanese wild pigs soared five-fold from 280 000 in 1989 to 1.32 million in 2010. While crop damage (amounting to ¥6.8 billion (HK$461 million) in 2010) is the most visible threat posed by wild pigs in Japan, nuisances and injuries arising from their encroachments into cities are other key issues of concerns.^{17The Washington Post (2018), Kodera (2020) and 林務局(2019).}
• National plan on wild pig control in 2013: Before the 2010s, hunting was the most important policy instrument in managing wild pigs in Japan, but it was not effective in checking their rapid growth. In December 2013, the Japanese government launched the National Policy on Enhanced Control of Birds and Beasts ("the Policy"), with a key objective to halve the wild pig population within a decade to only 520 000 by 2023 and with local governments as the key execution agencies. A few pieces of legislation were amended during 2014-2021 to empower local authorities and facilitate coordination amongst them.^{18參議院事務局(2014), 環境省(2021b) and 農林水產省(2022a).}
• Key measures under a holistic management approach: Under the Policy, hunting is just one of the policy components under an integrated approach on wild pig management. Other components are scientific estimation of population and annual culling number, habitat management and prevention and buffer, as detailed below.^{19Kodera (2020) and 吳立越、吳幸如(2019).}
  • (a)
    Solid estimation of wild pig numbers for policy formulation: Local governments are required to (i) establish regular surveillance systems; and (ii) conduct scientific surveys on wild pig populations and project their number in the future annually. On this solid basis, they can set annual culling numbers accordingly.

    In April 2015, the Ministry of the Environment ("MoE") improved the survey methodology, taking into account more variables like sighting frequency, harvest rate, faecal density, natural increase rate and hunter population obtained from over 40 prefectures. Based on these empirical findings, the annual culling target of wild pigs across Japan was raised by 17% to 700 000 in 2020 so as to achieve the aforesaid population control target by 2023;^{20環境省、農林水產省(2013), 環境省(2015) and 農村振興局(2020).}
  • (b)
    Preventive habitat management: Habitat management is one of the key pillars to prevent damage caused by wild pigs in Japan. Local governments receive annual subsidies to adopt a number of preventive measures, including (i) strengthening control of those habitats attracting wild pigs near populated areas (e.g. abandoned farmland, spots with garbage accumulation or fruit trees); (ii) blocking entry corridors with newly-designed repellents (e.g. floating resin net and Texas gate) and high-performance fences; and (iii) instituting buffer areas (e.g. cutting off bush cover) to divide forest and urban areas.^{21Both Texas gate and floating resin net are designed with gaps or holes that are wide enough for the feet of wild pigs to be trapped or entangled in, causing them reluctant to pass through the repellents. See 環境省、農林水產省(2013), 農林水產省(2021b) and 日經BP(2021).}

    Taking Kobe as an illustration, the length of guard fences mostly for prevention of encroachment of wild pigs had doubled from 151 km in 2014 to 320 km in 2020, with 23 hectares of buffer zones deployed by 2020. In February 2022, the Kobe government planned to install more preventive equipment in the next five years in view of their effectiveness in minimizing contact between wild pigs and residents over the past few years;^{22Kobe is the 7th largest city in Japan with the highest human injuries caused by wild pigs amongst Japanese municipalities (representing three-tenths of the national caseload) during 2016-2017. Reportedly, the surging wild pig population there was mainly due to frequent human feeding in Mount Rokko National Park near the city. See 兵庫縣 (2016, 2022a, 2022b).}
  • (c)
    Promoting "smart capture" technology: Each municipality is offered an annual subsidy subject to a maximum of ¥3 million (HK$203,400) for purchase of new and innovative technologies on pest management (including wild pigs). Up to now, over 37 kinds of smart devices (e.g. remote/automatic capture equipment, animal sensors, drones and monitoring systems) have been utilized or scheduled for introduction.^{23農林水產省(2019, 2020a, 2021c, 2022b).}

    According to a study on the usage of technology over pest management conducted by the Ministry of Internal Affairs and Communications in May 2018, over two-thirds of the surveyed municipalities had increased the number of captures significantly after using such smart devices. 86% of respondents also claimed that the smart devices helped reduce the patrol burden;^{24總務省 (2018).}
  • (d)
    Raising penalty on wildlife feeding: At present, at least 19 prefectures/municipalities in Japan have enacted by-laws to ban wildlife feeding. Taking Kobe as an example, it legislated the first law against feeding wild pigs in Japan for regulating those behaviours in residential areas near Mount Rokko National Park in 2002. To enhance the deterrent effect, the Kobe government imposed a "name and shame" penalty in December 2014. Personal information of repeated offenders on wildlife feeding would be disclosed to the public. As of 2020, no cases had been punished in this way, though verbal warnings were issued in some cases.^{25神戶新聞(2021) and 地方自治研究機構(2022).}

    More recently in September 2021, the Japanese government amended the Natural Parks Act, imposing a new prohibition on wildlife feeding in over four-fifths of areas in national parks. Offenders will be liable to a maximum fine of ¥300,000 (HK$20,340) scheduled for implementation in April 2022;^{26環境省(2021a).} and
  • (e)
    Targeted culling operations: Despite the emphasis on non-lethal components, culling is still a key pillar to contain the growth of wild pigs in Japan. Yet culling targets primarily sows and piglets. To this end, MoE released identification criteria of sows in 2017, with reference to their body hair pattern, teeth and hind paw length.^{27環境省(2021b).}

    The Japanese government also enhanced financial incentives to farmers and residents to form their local hunting teams as from 2016 on the one hand, and streamlined hunting licensing process on the other. More recently in 2020, cross-prefectural hunting campaigns were launched in designated "capture priority areas" (mainly in central Japan and Shikoku) to curb the spread of CSF amongst wild pigs. As of 2021, over seven-tenths of Japanese municipalities (1 229) had set up hunting teams, up by 82% in just eight years. Between 2013 and 2020, the annual number of wild pigs culled also increased steeply by 50% to 679 000.^{28環境省(2021b), 農林水產省(2021a, 2021b, 2022a).}
• Policy effectiveness: The aforesaid integrated approach seemed to have contained the growth of wild pigs in Japan, which actually dropped by one-third to 800 000 between 2014 and 2019. There was also abatement in nuisances caused by wild pigs, as manifested in a 17% decline in annual crop damage caused by wild pigs to ¥4.6 billion (HK$312 million) during 2014-2020. While cases of human injuries caused by wild pigs decreased from 49 in 2016 to 38 in 2021, there were three human fatalities over the past five years. More specifically for Kobe, where more active measures had been launched, the caseload of injuries even plummeted by 86% in four years to just 2 cases in 2020.^{29農林水產省(2020b, 2021b), 環境省(2022) and 神戶新聞(2021).} However, it is difficult to quantify the respective contributions of lethal and non-lethal methods to these successes.