When the MNR came out with the selective harvest system back in the 1980’s, they threw out a figure for calf mortality that justified the calf hunt. I don’t remember the percentage that they used but it could have been as high as 40%. Also at that time, they produced an illustration that showed herd growth based on different hunting scenarios e.g. if you shot a cow or if you shot a calf. IIRC, their projections were based on cows having twins at age 4.
Attachment 42053
If we were talking about whitetail deer, we would have more answers as deer have been extensively studied in the USA. Unfortunately moose aren’t studied to the extent that deer are. (part of it is due to their size, population, and the environment where they live). Consequently, the MNR has to rely on studies from other countries (Europe) - where data might not be entirely applicable.
Since 1983, the MNR has learned a few things about moose such as: they are not as productive as once believed, hunter- caused mortality rates shouldn’t exceed 20% if your trying to grow more moose, calf hunting needs to be better managed, bulls aren’t adult-film stars and don’t breed many cows, and aerial surveys aren’t perfect.
EDIT: I found an Ontario study online about calf mortality is central Ontario. The study was carried out by Trent University. Here’s the abstract:
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Although some populations remain stable, moose (Alces alces) density and distribution have been declining in many areas along the southern edge of their North American distribution. During 2006—2009, we deployed 99 vaginal implant transmitters (VITs) in 86 adult female moose in central Ontario, Canada to assist in locating and radiocollaring neonatal moose calves. We monitored radiocollared calves to estimate calf survival and assess the relative importance of specific causes of death. Calves in the western portion of our study area (WMU49) were exposed to a 6-day general hunting season, whereas calves in the eastern portion of our study area (Algonquin Provincial Park [APP]) were not exposed to hunting. Annual survival for 87 collared calves was greater in the protected area than the harvested area (72.4 ± 6.8% and 55.8 ± 8.3%, respectively) and averaged 63.7 ± 7.1% overall. Predation by wolves (Canis sp.) and American black bears (Ursus americanus) was the dominant cause of death but occurred predominately in APP, whereas other natural mortality agents were 4× more common in WMU49. Only 16% of the collared calves in WMU49 were harvested each year despite a high proportion (approx. 50%) of accessible, public land. Most natural mortality occurred prior to the autumn hunting season such that reductions in natural mortality had little potential to compensate for calf harvest. Overall, calf survival in our study area was moderate to high and our findings suggest predator control or further restrictions of calf hunting in this area is not justified.”
