First year of N.H. moose study shows high mortality rates up north
Ticks are sucking the life out of New Hampshire’s moose population.
This winter, 64 percent of the calves collared for a state Fish and Game Department study died from winter ticks. Five percent of the collared adult cows were killed by the parasite.
“The mortality rate this year was pretty bad,” said Fish and Game moose biologist Kristine Rines.
The department, in partnership with the University of New Hampshire, launched the three-year moose mortality study in January. Researchers collared 43 animals in northern New Hampshire to track how long they live, when they die and why.
The research will follow up on a similar five-year study completed in 2006 to see whether the moose mortality rate has increased since then and what role the winter tick may play.
Officials began seeing the parasite affect the state’s moose about 15 years ago, Rines said. The ticks can’t survive the winter without a host, and moose make prime targets because they don’t groom the parasites off, like deer do.
A single moose can pick up between 120,000 and 160,000 ticks. That many parasites feeding on one animal takes a toll. Calves can loose the equivalent of their entire blood supply once or even twice in one year, Rines said. That can lead to severe anemia.
“They have to consume their own muscle mass to survive,” she said.
The moose carrying high tick loads can look thin and show a patchy coat, rubbed off trying to remove the parasites.
The shorter winters the state has seen over the past few years feed the problem, Rines said. A brief winter means the tick has more time during the fall to search for a host and a better chance in the spring of laying eggs on snow-free ground.
“If we continue to have shorter winters, those ticks will continue to be problematic, at high enough levels to kill lots of moose,” Rines said.
Short winters will also have an effect in the southern part of the state, where moose face a different plight: brainworm. Carried by deer, which are immune to the parasite because they are its natural host, brainworm affects the central nervous system in moose and has a nearly 100 percent mortality rate, Rines said.
“Deer density is what really drives brainworm,” she said. “And as our winters grow shorter, that is good for deer.”
Overall the state’s moose population has dropped from about 7,000 in 1998, to roughly 4,000, Rines said. And while half of the decrease was purposeful and planned, the other part is due to parasitism.
As a result, moose hunting permits are also on the decline. This year’s hunt will run from Oct. 18 to 26. To participate, hunters have until the end of May to register for a chance to get one of 124 permits the Fish and Game Department will issue this year. Registration for the lottery costs $15 for residents and $25 for nonresidents.
In years past, the department handed out 275 permits. Last year, more than 13,000 hunters applied.
If the moose population continues to decline, there may not be a moose hunt anymore, Rines said.
Larry Hartle, owner of Pemi Valley Moose Tours in Lincoln, hopes the department will stop the hunt for a few years to revive the population.
Moose tours now take an hour longer to find the animals, said Hartle, who has been in the business since 1999.
“It’s a big thing for tourists; they come up here and want to see moose,” he said. “It brings in millions of dollars.”
According to a 2011 U.S. Fish and Wildlife Service survey, anglers, hunters and wildlife watchers spend more than $112 million in the state.
Next January, the Fish and Game Department will collar roughly 45 more moose for the second year of the mortality study. “We really don’t know what the future holds, if things will settle down or if we will continue to get shorter and shorter winters, moose probably will not be able to survive,” Rines said.
(Allie Morris can be reached at 369-3307 or at amorris@ cmonitor.com.)