Human Crocodile Conflict Research Articles

Faunal Diversity of Bhitarkanika Mangroves, Odisha

Bhitarkanika presents a variety of habitats, microhabitat and climatic conditions. Therefore, the faunal component and diversity is also extremely high in comparison to other mangrove forests of South east Coast of India. A total of 420 species belonging to five Phylums under 14 classes (Nematoda, Annelida, Mollusca, Arthropoda and Vertebrates) were recorded during the study period. Among all, bird species were recorded high (264). Though many checklist of faunal species of Bhitarkanika are available, but still there is lacking on the various aspects of ecological studies. A research programme is recommended, to monitor the effectiveness of policies and human-crocodile relationships in the Bhitarkanika, Odisha, in order to minimize human-crocodile conflict in the future.

An analysis of recent saltwater crocodile (Crocodylus porosus) attacks in Timor-Leste and consequences for management and conservation

Saltwater crocodiles (Crocodylus porosus) are potentially dangerous to humans, yet they have major cultural value to many people in Timor-Leste. Recent increases in attack risk are influencing traditional attitudes, threatening culls of remaining wild crocodile populations. To understand patterns that may assist mitigation, we compiled attack records for the period of April 2007 to April 2014, using the CrocBITE online database. Recorded attacks (n=45) showed a high fatality rate (82.2%), the majority (77.8%) being recorded since 2010. The highest proportion of attacks (46.7%) occurred in southern coastal wetlands suited to crocodiles, areas representing major sources of food, livelihoods and ecosystem services (i.e. fisheries, timber, coastal protection) for locals. Subsistence fishing posed the highest attack risk, particularly from September to February when food security is low. Attacks matched gender roles (most victims were males, the primary fishers) and demographic patterns (teenagers, the fastest growth group, comprised the highest proportion). Predicted increases in food insecurity, fishing activities, coastal impacts and rising human and crocodile populations pose worrying implications for human–crocodile conflict. We recommend essential baseline surveys enabling meaningful management decisions, and suggest that tailored management and educational awareness based on proven existing models could substantially mitigate attack risk while remaining compatible with traditional Timorese attitudes towards crocodiles.

Cohort-Dependent Sex Ratio Biases in the American Crocodiles (Crocodylus acutus)of the Tempisque Basin

A male-biased sex ratio of 3:1 has been reported for a population of American crocodiles (Crocodylus acutus) in the Tempisque River Basin, Guanacaste, Costa Rica. If confirmed, this would constitute one of the largest male-biased sex ratios reported for any population of a member of the genus Crocodylus. Here, we examine the aforementioned population of C. acutus and report on sex ratios of hatchling, juvenile, and adult age classes within a sample of 474 crocodiles captured in the Tempisque Basin between May 2012 and June 2014. Hatchling sex ratio is exceptionally male biased (3.5:1), an imbalance that is maintained in juveniles but is reduced in adults (1.5:1). Mark–recapture data document that juvenile males disperse from the study site, potentially to avoid competition, a process that reduces male bias in the adult age class. An increased role of males in human–crocodile conflict may be a result of juvenile males dispersing to human-inhabited areas.

Human-crocodile conflict and conservation implications of Saltwater Crocodiles Crocodylus porosus (Reptilia: Crocodylia: Crocodylidae) in Sri Lanka

Human-wildlife conflict occurs when human requirements encroach on those of wildlife populations, with potential costs to both humans and wild animals. As top predators in most inland waters, crocodilians are involved in human-wildlife conflicts in many countries. Here we present findings of a 5-year survey on human-crocodile conflict on the island of Sri Lanka and relate the results to improving management practices. We aimed to quantify and understand the causes of human-crocodile conflict in Sri Lanka, and propose solutions to mitigate it. Visual encounter surveys were carried out to estimate the population size of Saltwater Crocodiles. We recorded 778 sightings of Saltwater Crocodiles at 262 of 400 locations surveyed, and estimate the total population to comprise more than 2000 non-hatchlings and to have increased at an average rate of 5% p.a. since 1978. We propose four crocodile vigilance zones within the wet zone and one crocodile vigilance zone within the dry zone of the country. Specific threats to Saltwater Crocodiles identified in crocodile vigilance zones were: habitat destruction and loss; illegal killing and harvesting (17 killings out of fear, ~200 incidents of killing for meat and skins, ~800 eggs annually for consumption); unplanned translocations; and, interaction with urbanization (10 incidents of crocodiles being run over by trains/vehicles and electrocution). Additionally, 33 cases of crocodile attacks on humans were recorded [8 fatal, 25 non-fatal (minor to grievous injuries)] and more than 50 incidents of attacks on farm and pet animals.

Featured article: Management of human-crocodile conflict in the Northern Territory, Australia: Review of crocodile attacks and removal of problem crocodiles

We reviewed the historical records of attacks by saltwater crocodiles (Crocodylus porosus) and the removal of problem saltwater crocodiles in the Northern Territory of Australia. Between 1977 and 2013, 5,792 problem crocodiles were removed, of which 69.04% were males and 83.01% were caught within the Darwin Crocodile Management Zone where suitable breeding habitats were hardly available. The most common size class was 150–200 cm and their mean size did not change significantly over years. This reflected the greater mobility of juvenile males as the majority of problem crocodiles, dispersing from core habitats that were occupied by dominant individuals. Eighteen fatal attacks and 45 non-fatal attacks occurred between 1971 and 2013. The rate of crocodile attacks, particularly non-fatal cases, increased over time. This increase was strongly related to the increasing populations of both humans and crocodiles, and the increasing proportion of larger (>180 cm) crocodiles. The management of human-crocodile conflict (HCC) should incorporate both human (e.g., public education and safety awareness) and crocodile (e.g., population monitoring, removal of problem crocodiles) components. Crocodiles in the 300–350-cm class were most responsible for attacks, and they should be strategically targeted as the most likely perpetrator. Approximately 60% of attacks occurred around population centers including remote communities. Problem crocodile capture and attacks both peak in the beginning (Sep–Dec) and end (Mar–Apr) of the wet season. However, fatal attacks occurred almost all year around. Attacks by crocodiles >400 cm often resulted in death of the victim (73.33%). Local and male victims were much more common than visitors and females, respectively. The most common activity of victims was swimming and wading. Despite the increasing rate of attacks over time, the Northern Territory's management program, and in particular the removal of problem crocodiles from urban areas, is considered to have reduced potential HCC. Public education about crocodile awareness and risks must be maintained. © 2014 The Wildlife Society.

Recovery of saltwater crocodiles following unregulated hunting in tidal rivers of the Northern Territory, Australia

AbstractSaltwater crocodiles (Crocodylus porosus) in the Northern Territory of Australia were protected in 1971, after a severe population decline resulting from 26 yr of intense commercial hunting. By that time wild saltwater crocodiles were rarely sighted anywhere and they were commercially extinct in areas where they had once been abundant. Standardized monitoring by spotlight surveys started in 1975 and provided relative density indices over time (1975–2009) as a unique record of the post‐protection recovery of a wild crocodilian population. We examined the survey data for populations at 12 major tidal rivers, individually and as a single subpopulation. The pattern of recovery in the subpopulation in both abundance and biomass was approximated by logistic curves, predicting 5.26 non‐hatchling crocodiles weighing 387.64 kg sighted per kilometer of river in 2010. We predicted potential carrying capacity as 5.58 non‐hatchling crocodiles (5.73% higher than 2010) weighing 519.0 kg (25.31% higher than 2010). Individual rivers showed largely different abundance and biomass among rivers. The statistical model that best described the recovery in individual rivers was not always logistic. However, where it was logistic, expected carrying capacity of different rivers showed considerable variation in abundance and biomass. The variation indicates different habitat quality among the rivers. Recovery occurred despite various consumptive uses, particularly a widespread egg‐harvest program, which has been an integral part of the incentive‐driven conservation program for saltwater crocodiles in the Northern Territory since 1983. We suggest that the saltwater crocodile population of the Northern Territory is achieving full recovery from uncontrolled hunting in 1945–1971. Although saltwater crocodiles are considered an important natural resource, their increase in number, size, and distribution is posing management issues for public safety. Continuation of human–crocodile conflict management through public education and strategic removal of problem crocodiles will be essential. © 2011 The Wildlife Society.

Living with predators: a focus on the issues of human - crocodile conflict within the lower Zambezi valley

Context Human–wildlife conflict is a global problem and increasing worldwide as people and wildlife compete for limited resources. Conflict between people and crocodiles, especially in Africa, is recognised as a serious problem. The people of the Chiawa Game Management Area are heavily dependent on the Zambezi River for several resources from potable water and irrigating fields to a source of food (subsistence and small-scale commercial fishing). Aims To assess the spatial and temporal scale of human–crocodile conflict (HCC) and identify associated factors, with a view to recommending mitigation measures. Methods A questionnaire survey and Zambia Wildlife Authority data were utilised to estimate the scale of HCC. Key results Between 2000 and 2009, there were 98 crocodile attacks on people, 62.2% were fatal. Most of the attacks occurred while canoe fishing (57.1%) and collecting water (29.6%). Crocodiles were disliked and seen as a ‘problem’ by the majority of the populace. Even though crocodiles are a charismatic mega-fauna species, being employed within the tourism industry had only a minor positive effect on people’s attitudes. The area is an important location for crocodile egg and adult harvesting, although the local population gains no financial benefit. An increase in the number of boreholes in the villages was suggested by the local people as the primary mitigation measure, as well as the removal of crocodiles by various means. Conclusions Although people displayed an understanding of the risks of crocodile attack, very few actually employed mitigation techniques or utilised protective barriers when at the river. Increased water-access points (and their maintenance) in the villages would reduce people’s dependency on the river. The negative attitude towards crocodiles is an issue that has to be addressed to allow successful implementation of long-term conservation strategies. Implications Understanding local people’s attitudes towards wildlife is an important aspect within any conservation management plan.Competition for limited resources by people and wildlife is guaranteed to cause confrontations. The existing mitigation for human crocodile conflict in Zambia is ineffective. The negative attitude towards wildlife needs to be addressed and a suitable response formulated. The most favoured type of mitigation suggested by local people was more boreholes and the removal of crocodiles. Photograph by Kevin Wallace.

The Impact of Nile Crocodiles on Rural Livelihoods in Northeastern Namibia

Nile crocodiles (Crocodylus niloticus) are one of the few dangerous predators regularly found outside protected wildlife areas. This is particularly so in northeastern Namibia where an extensive network of rivers and wetlands coupled with successful conservation measures has allowed crocodile populations to flourish since uncontrolled exploitation ended over three decades ago. This area is predominantly communal land characterized by numerous subsistence communities dependent on river and wetland resources. In recent years, the combination of a growing human population and resurgent crocodile populations has resulted in considerable conflict between humans and crocodiles. The principle objective of this study was to quantify the impact of crocodiles on rural livelihoods. Data were obtained from existing records and through community surveys on the lower Kavango, Chobe and Kwando rivers and upper Zambezi River. Existing estimates suggest an annual loss of ∼255 domestic cattle per year for northeastern Namibia whilst community survey estimates suggest a substantially greater annual loss of ∼6864 cattle per year. Community surveys also revealed conflict between crocodiles and artisinal fishermen, with an estimated 71 500 fishing nets damaged by crocodiles per year. Human-crocodile conflict in Namibia may have greater impacts than previously assumed, and may undermine conservation and development objectives.