Status of two West Greenland caribou populations 2005 1) Akia-Maniitsoq 2) Kangerlussuaq-Sisimiut. Technical Report No. 61

In March 2005 two stocks, Kangerlussuaq-Sisimiut and Akia-Maniitsoq were 
surveyed by helicopter for abundance and herd structure. Methods and analysis 
followed Cuyler et al. (2003). Recommended stocking densities are exceeded by ca 
60,000 caribou in the Kangerlussuaq-Sisimiut population and ca 17,500 in the Akia-Maniitsoq. The 2005 calf percentage and recruitment are low. There is also a 
decrease in the ratio of bulls to cows. The low production and the skewed sex ratio 
may become more pronounced in future. Hunting pressure is not suspected to be a 
major cause for these changes, because the low harvest numbers can have had little 
effect on these large populations. Although quantitative data is lacking, it seems that 
density dependent effects are causing higher mortality rates among calves, and 
perhaps even among bulls, in the Kangerlussuaq-Sisimiut and Akia-Maniitsoq 
populations. Given that densities are three to six-times the recommended target 
value considered sustainable, we expect strong competition between individuals for 
available food resources. If the stocks are allowed to continue at their current size or 
increase further, there is a clear risk of lasting damage to the ranges, e.g. overgrazing 
and trampling. Unsustainable range use may compromise the future health and 
viability of caribou stocks in West Greenland. Regardless of management initiatives 
taken now, population crashes may be inevitable for some West Greenland herds 
within the foreseeable future, but accurate predictions about herd trends are 
impossible. To understand approaching developments the caribou and their range 
must be studied within the wider context of global warming and associated climate 
change. 

Akia-Maniitsoq herd – Central region
The estimate for pre-calving population size of Akia-Maniitsoq herd of the Central 
region in March 2005 is ca 35,807 caribou (27,474 - 44,720; 90% CI). Caribou density 
in 2005 was 3.0 caribou per km2 in the high-density stratum, and 1.1 per km2 in the 
low-density stratum. Mean group size was 4.33 ± 2.91 S.D. in 2005. Late winter calf 
percentage was a low 14%, as was the annual recruitment of 24 calves per 100 cows. 
The bull to cow ratio was only 0.45. If natural mortality is between 8 and 10% then 
on a herd this size between 2,200 and 4,500 animals may be expected to die annually 
of natural causes. 
Kangerlussuaq-Sisimiut herd – North region 
The estimate for pre-calving population size of Kangerlussuaq-Sisimiut herd of the 
North region in March 2005 is ca 90,464 caribou (70,276 – 113,614; 90% CI). Caribou 
density in 2005 was 6.2 caribou per km2 in the high-density stratum, and 2.3 per km2 in the low-density stratum. Mean group size was 4.63 ± 3.38 S.D. in 2005. Late winter 
calf percentage was a low 11%, as was the annual recruitment of 16 calves per 100 
cows. The bull to cow ratio was only 0.33. If natural mortality is between 8 and 10% 
then on a herd this size between 5,600 and 11,400 animals may be expected to die 
annually of natural causes. Since the calf percentage is approaching the natural 
mortality value, this population may be approaching its theoretical carrying capacity 
where births equal deaths, i.e. production equals zero.